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Juniper Networks, Inc.1194 North Mathilda AvenueSunnyvale, CA 94089USA408-745-2000www.juniper.net
E-Series RoutersRouting Protocols
Configuration Guide, Vol. 1
Release 5.1.x
Part No. 162-00734-00 Rev. A00
Juniper Networks is registered in the U.S. Patent and Trademark Office and in other countries as a trademark of Juniper Networks, Inc. Broadband Cable Processor, ERX, ESP, E-series, G1, G10, G-series, Internet Processor, J-Protect, Juniper Your Net, JUNOS, JUNOScript, JUNOSe, M5, M10, M20, M40, M40e, M160, M-series, NMC-RX, SDX, ServiceGuard, T320, T640, T-series, UMC, and Unison are trademarks of Juniper Networks, Inc. All other trademarks, service marks, registered trademarks, or registered service marks are the property of their respective owners. All specifications are subject to change without notice.
Products made or sold by Juniper Networks (including the G1 and G10 CMTSs, ERX-310, ERX-705, ERX-710, ERX-1410, ERX-1440, M5, M10, M20, M40, M40e, M160, and T320 routers, T640 routing node, and the JUNOS, SDX-300, and ServiceGuard software) or components thereof might be covered by one or more of the following patents that are owned by or licensed to Juniper Networks: U.S. Patent Nos. 5,473,599, 5,905,725, 5,909,440, 6,333,650, 6,359,479, and 6,406,312.
E-Series Routers Routing Protocols Configuration Guide, Vol. 1, Release 5.1.xCopyright © 2003, Juniper Networks, Inc.All rights reserved. Printed in USA.
Writers: Mark Barnard, Bruce Gillham, Justine Kangas, Helen Shaw, Brian Wesley Simmons, Michael Taillon, Nathaniel WoodwardEditor: Fran Mues
Revision HistoryAugust 2003
The information in this document is current as of the date listed in the revision history above.
Juniper Networks assumes no responsibility for any inaccuracies in this document. Juniper Networks reserves the right to change, modify, transfer, or otherwise revise this publication without notice.
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Contents
About This Guide
E-Series Routers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xixAudience . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xxConventions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xxDocumentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xxi
MIBS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xxiiiRelease Notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xxiiiAbbreviations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xxiiiWeb Access . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xxiii
Comments About the Documentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xxiiiContacting Customer Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xxiv
Part 1. Routing Policy
Chapter 1 Configuring Routing Policy
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2Route Maps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
Sample Route Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4Multiple Values in a Match Entry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5Negating Match Clauses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5Matching a Community List Exactly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6Removing Community Lists from a Route Map . . . . . . . . . . . . . . . . . . . . . . . 1-7Redistributing Access Routes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-7
Access Lists . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-16Filtering Prefixes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-17Filtering AS Paths . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-19Using Access Lists in a Route Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-22Creating Table Maps for Access Routes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-26
Using the Null Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-26Prefix Lists . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-27
Using a Prefix List . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-27
Contentsviii
Prefix Trees . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-30Using a Prefix Tree . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-30
Community Lists . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-31Extended Community Lists . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-35
Using Regular Expressions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-37AS-path Lists . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-37Community Lists . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-38Community Numbers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-38Metacharacters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-38Using Metacharacters as Literal Tokens . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-39Regular Expression Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-40
Managing the Routing Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-43Troubleshooting Routing Policy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-43Monitoring Routing Policy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-43
Part 2. Internet Protocol
Chapter 2 Configuring IP
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2IP Packets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2IP Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2
Moving Data Between Layers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-2Routing Datagrams to Remote Hosts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3Fragmenting and Reassembling Datagrams . . . . . . . . . . . . . . . . . . . . . . . . 2-3
IP Layering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3Network Interface Layer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-3Internet Layer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4Transport Layer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4Application Layer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-4IP Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-5IP Addressing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6
Physical and Logical Addresses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6Internet Addresses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-6Subnet Addressing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-7Classless Addressing with CIDR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-8Adding and Deleting Addresses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-9
Adding a Primary Address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-10Deleting a Primary Address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-10Adding a Secondary (Multinet) Address . . . . . . . . . . . . . . . . . . . . . . . . . 2-10Deleting a Secondary Address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-10ip address Command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-10
Before You Configure IP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-11Creating a Profile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-11
Assigning a Profile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-14Address Resolution Protocol (ARP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-14
How ARP Works . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-15MAC Address Validation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-18
E-Series Routersix
Broadcast Addressing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-19Broadcast Tasks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-20
Fragmentation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-20IP Routing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-21
Routing Information Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-21Setting the Administrative Distance for a Route . . . . . . . . . . . . . . . . . . . . . . . 2-23Setting the Metric for a Route . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-25Routing Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-25Identifying a Router Within an Autonomous System . . . . . . . . . . . . . . . . . . . 2-25Establishing a Static Route . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-25Setting Up Default Routes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-26Setting Up an Unnumbered Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-26Adding a Host Route to a Peer on a PPP Interface . . . . . . . . . . . . . . . . . . . . 2-26Enabling Source Address Validation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-27Shutting Down an IP Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-27Removing the IP Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-27Clearing IP Routes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-27Clearing IP Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-28Setting a Baseline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-28Disabling Forwarding of Packets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-29Enabling Forwarding of Source-Routed Packets . . . . . . . . . . . . . . . . . . . . . . 2-29Forcing an Interface to Appear Up . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-30Specifying a Debounce Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-30Adding a Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-30Enabling Link Status Traps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-31Configuring the Speed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-31Configuring Equal-Cost Multipath Load Sharing . . . . . . . . . . . . . . . . . . . . . 2-31Setting a TTL Value . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-33
Shared IP Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-33Configuring Prefixes for Dynamic Shared IP Interfaces . . . . . . . . . . . . . . . . 2-34Configuring Shared IP Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-34Moving IP Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-37IP Shared Interface Statistics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-37Subscriber Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-37
Internet Control Message Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-38ICMP Tasks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-38Specifying a Source Address for ICMP Messages . . . . . . . . . . . . . . . . . . . . . . 2-39
Reachability Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-40Response Time Reporter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-42
Configuration Tasks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-43Configuring the Probe Type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-43Configuring Optional Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-44
Capturing Statistics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-46Collecting History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-46
Setting Reaction Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-47Scheduling the Probe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-48Shutting Down the Probe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-49Monitoring RTR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-50
Contentsx
Monitoring IP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-55Establishing a Baseline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-55IP show Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2-56
Chapter 3 Configuring IPv6 and Neighbor Discovery
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-2References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3IPv6 Packet Headers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3
IPv4 and IPv6 Header Differences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-3Standard IPv6 Headers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4Extension Headers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5
IPv6 Addressing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5Address Representation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-5
IPv6 Address Compression . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-6IPv6 Address Prefix . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-6
Address Types . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-6Address Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-7Address Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-8ICMP Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-8
Understanding Neighbor Discovery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-9Before You Configure IPv6 or Neighbor Discovery . . . . . . . . . . . . . . . . . . . . . . . 3-10IPv6 Configuration Tasks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-11
Configuring an IPv6 License . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-11Creating an IPv6 Profile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-11Assigning a Profile . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-13Establishing a Static Route . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-13Specifying an IPv6 Hop Count Limit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-13Managing IPv6 Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-14Adding a Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-16Removing an IPv6 Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-16Clearing IPv6 Routes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-17
Creating Static IPv6 Neighbors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-17Neighbor Discovery Configuration Tasks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-17
Configuring Neighbor Discovery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-17Configuring Proxy Neighbor Advertisements . . . . . . . . . . . . . . . . . . . . . . . . . 3-19Configuring Duplicate Address Detection Attempts . . . . . . . . . . . . . . . . . . . . 3-19
Clearing IPv6 Neighbors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-20Monitoring IPv6 and Neighbor Discovery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-20
Establishing a Baseline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-20IPv6 show Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-21
Chapter 4 Configuring NAT
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2NAT Configurations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2
Traditional NAT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-2Basic NAT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3NAPT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3
E-Series Routersxi
Bidirectional NAT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-3Twice NAT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-4
Network and Address Terms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-4Inside Local Addresses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-5Inside Global Addresses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-5Outside Local Addresses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-5Outside Global Addresses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-5
Understanding Address Translation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-5Inside Source Translation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-5Outside Source Translation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-6
Address Assignment Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-6Static Translations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-6Dynamic Translations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-6
Order of Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-7References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-7Before You Begin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-8Limiting Translation Entries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-8Specifying Inside and Outside Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-8Defining Static Address Translations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-9
Creating Inside Source Translations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-9Creating Outside Source Translations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-10
Defining Dynamic Translations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-10Creating Access List Rules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-10Defining Address Pools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-11Defining Translation Rules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-12
Creating Dynamic Inside Source Translations . . . . . . . . . . . . . . . . . . . . . 4-13Creating Dynamic Outside Source Translations . . . . . . . . . . . . . . . . . . . 4-14
Defining Translation Time-Outs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-14Clearing Dynamic Translations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-15Configuration Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-15
NAPT Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-15Bidirectional NAT Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-17Twice NAT Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-19Cross-VRF Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-21
Monitoring NAT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-23Displaying Translation Statistics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-23Displaying Translation Entries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-24
Part 3. Internet Protocol Routing
Chapter 5 Configuring IP Multicasting
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-2References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-3Before You Begin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-4Enabling IP Multicasting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-4Deleting Multicast Forwarding Entries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-4Reverse-Path Forwarding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-5
Contentsxii
Multicast Packet Forwarding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-6Disabling RPF Checks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-7Using Unicast Routes for RPF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-8
Monitoring IP Multicast Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-8Support for Multicast Router Information . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-14
IGMP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-15IGMP Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-15
Group Membership Queries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-15Group Membership Reports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-16Leave Group Membership Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-16
Configuring Static and Dynamic IGMP Interfaces . . . . . . . . . . . . . . . . . . . . 5-17Enabling IGMP on an Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-18Configuring IGMP Settings for an Interface . . . . . . . . . . . . . . . . . . . . . . . . . 5-19Assigning a Multicast Group to an Interface . . . . . . . . . . . . . . . . . . . . . . . . . 5-21Specifying Multicast Groups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-22Limiting the Number of Accepted IGMP Groups . . . . . . . . . . . . . . . . . . . . . 5-22Including and Excluding Traffic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-23Accepting IGMP Reports from Remote Subnets . . . . . . . . . . . . . . . . . . . . . . 5-24Disabling and Removing IGMP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-25Monitoring IGMP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-25
IGMP Proxy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-29Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-29Configuring IGMP Proxy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-30Setting the IGMP Proxy Baseline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-32Monitoring IGMP Proxy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-32
PIM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-34PIM DM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-35
Overriding Prunes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-36Preventing Duplication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-37
PIM SM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-37Joining Groups . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-39Remote Neighbors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-39Timers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-41
PIM S-DM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-42PIM SSM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-42Enabling and Disabling PIM on a VR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-42Enabling PIM on an Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-43Configuring an RP Router for PIM SM and PIM S-DM . . . . . . . . . . . . . . . 5-44
Configuring a Static RP Router . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-44Configuring an Auto-RP Router for PIM SM . . . . . . . . . . . . . . . . . . . . . 5-44Configuring an Auto-RP Router for PIM S-DM . . . . . . . . . . . . . . . . . . . 5-45
Switching to an SPT for PIM SM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-46Configuring PIM SM Remote Neighbors . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-47
Configuration Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-48Configuring PIM SSM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-49Removing PIM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-49Resetting PIM Counters and Mappings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-50Monitoring PIM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-51
Monitoring PIM Events . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-51Monitoring PIM Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-51
E-Series Routersxiii
DVMRP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-59Identifying Neighbors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-59Advertising Routes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-60Enabling DVMRP on a VR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-61Activating DVMRP on an Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-61Configuring DVMRP Limits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-62Filtering DVMRP Reports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-62Configuring DVMRP Summary Addresses . . . . . . . . . . . . . . . . . . . . . . . . . . 5-63Changing the Metric for a Route . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-64Importing Routes from Other Protocols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-65Specifying Routes to Be Advertised . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-66Preventing Dynamic Route Distribution . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-66Exchanging DVMRP Unicast Routes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-66Disabling and Removing DVMRP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-67Deleting DVMRP Routes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-68Configuring DVMRP Tunnels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-68Monitoring DVMRP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-69
BGP Multicasting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-74Investigating Multicast Routes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-74
Chapter 6 Configuring IP Tunnels
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-2GRE Tunnels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-2DVMRP Tunnels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-2
Line Module Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-2Managing TSMs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-3References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-3Configuration Tasks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-3
Configuration Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-5Configuring IP Tunnels to Forward IP Frames . . . . . . . . . . . . . . . . . . . . . . . . 6-6Preventing Recursive Tunnels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-7
Monitoring IP Tunnels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-8
Chapter 7 IP Reassembly for Tunnels
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-1Reassembly Processing Within the System . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-2
Configuring IP Reassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-2Monitoring IP Reassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-3
Chapter 8 Configuring RIP
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-1RIP Metric . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-2RIP Messages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-2
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-2Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-3
Route Tags . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-3Authentication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-3
Contentsxiv
Subnet Masks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-4Next Hop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-4Multicasting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-5Route Summaries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-5Split Horizon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-6Equal-Cost Multipath . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-6Applying Route Maps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-6
Before You Run RIP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-6Configuration Tasks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-7
Relationship Between address and network Commands . . . . . . . . . . . . . . . . . 8-9Using RIP Routes for Multicast RPF Checks . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-18Remote Neighbors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-19Monitoring RIP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-22
debug Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-22show Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8-23
Chapter 9 Configuring OSPF
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-2Terms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-2
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-4Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-5
Intra-area, Interarea, and External Routes . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-5Routing Priority . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-5
Virtual Links . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-6Authentication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-6Opaque LSAs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-6Route Leakage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-6Equal-Cost Multipath . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-7OSPF MIB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-7Interacting with Other Routing Protocols . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-7
With IS-IS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-7With RIP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-7With BGP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-7
Configuration Tasks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-8Configuring OSPF Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-8
Enabling OSPF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-9Creating a Range of OSPF Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-9Creating a Single OSPF Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-11
Aggregating OSPF Networks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-12Configuring OSPF Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-13
address Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-13ip ospf Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-16Comparison Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-18Precedence of Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-18
Configuring OSPF Areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-19Configuring Authentication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-22
Authentication Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-23Configuring Additional Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-27
Default Metrics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-33
E-Series Routersxv
Configuring OSPF for NBMA Networks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-34Traffic Engineering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-35
Configuring OSPF for TE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-35Using OSPF Routes for Multicast RPF Checks . . . . . . . . . . . . . . . . . . . . . . . . . . 9-37OSPF and BGP/MPLS VPNs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-37Remote Neighbors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-37Disabling and Reenabling Incremental SPF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-40Configuring OSPF Traps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-41Monitoring OSPF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-42
debug Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-42show Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-43
Chapter 10 Configuring IS-IS
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-1Terms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-2ISO Network Layer Addresses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-4
Level 1 Routing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-4Level 2 Routing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-5
Dynamic Hostname Resolution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-5Authentication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-5
Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-6Specifying Start and Stop Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-7Halting MD5 Authentication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-8Managing and Replacing Keys . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-8
Extensions for Traffic Engineering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-8Integrated IS-IS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-9Equal-Cost Multipath . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-9
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-10Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-11Before You Run IS-IS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-11Configuration Tasks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-11Enabling IS-IS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-12
Summary Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-14Configuring IS-IS Interface-Specific Parameters . . . . . . . . . . . . . . . . . . . . . . . . 10-14
Summary Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-19Configuring Global IS-IS Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-20
Setting Authentication Passwords . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-20Configuring Redistribution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-21Redistributing Routes Between Levels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-23Controlling Granularity of Routing Information . . . . . . . . . . . . . . . . . . . . . 10-24Configuring Metric Type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-25Setting the Administrative Distance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-26Configuring Default Routes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-26Setting Router Type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-27Summarizing Routes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-27Configuring the Router to Be Ignored . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-28Ignoring LSP Errors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-29Logging Adjacency State Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-29Configuring LSP Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-30
Contentsxvi
Specifying the SPF Interval . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-31Defining the SPF Route Calculation Level . . . . . . . . . . . . . . . . . . . . . . . . . . 10-32Setting CLNS Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-33Setting the Maximum Parallel Routes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-34Configuring a Virtual Multiaccess Network . . . . . . . . . . . . . . . . . . . . . . . . . 10-34Summary Example . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-34
Configuring IS-IS for MPLS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-35Using IS-IS Routes for Multicast RPF Checks . . . . . . . . . . . . . . . . . . . . . . . . . . 10-36Monitoring IS-IS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-37
Monitoring IS-IS Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-37Displaying CLNS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-47
Chapter 11 Configuring VRRP
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-1Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-2
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-2How VRRP Works . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-3
Configuration Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-3Basic VRRP Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-3Commonly Used VRRP Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . 11-4VRRP Configuration Without the Real Address Owner . . . . . . . . . . . . . 11-6
How VRRP Is Implemented in the E-Series Router . . . . . . . . . . . . . . . . . . . . . . . 11-7Router Election Rules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-7
Configuring VRRP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-8Configuring the IP Interface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-8Creating VRIDs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-9Configuration Steps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-9
Monitoring VRRP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-12
Part 4. Internet Protocol Security
Chapter 12 Configuring IPSec
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-1Terms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-2
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-3IPSec Concepts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-4
Secure IP Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-4RFC 2401 Compliance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-4IPSec Protocol Stack . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-5
Security Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-6Manual Versus Signalled Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-8Operational Virtual Router . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-8Transport Virtual Router . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-9Perfect Forward Secrecy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-10Lifetime . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-10Inbound and Outbound SAs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-11Transform Sets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-12
E-Series Routersxvii
Other Security Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-14IP Security Policies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-14ESP Processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-15AH Processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-15IPSec Maximums Supported . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-15
IKE Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-15Main Mode and Aggressive Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-16
Aggressive Mode Negotiations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-17IKE Policies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-17
Priority . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-18Encryption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-18Hash Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-18Authentication Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-19Diffie-Hellman Group . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-19Lifetime . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-19
IKE SA Negotiation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-20Configuration Tasks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-20
Configuring an IPSec License . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-20Configuring IPSec Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-21Creating an IPSec Tunnel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-24Defining an ISAKMP/IKE Policy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-28Refreshing SAs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-31
Configuration Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-31Configuration Notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-31Example 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-31Example 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-36
Monitoring IPSec . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-42System Event Logs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-42show Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-42
Chapter 13 Configuring Digital Certificates
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-1Terms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-2
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-2IKE Authentication Using Digital Certificates . . . . . . . . . . . . . . . . . . . . . . . . . . 13-3
Signature Authentication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-3Generating Private/Public Key Pairs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-4Obtaining a Public Key Certificate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-5Obtaining a Root CA Certificate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-5Authenticating the Peer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-5Checking CRLs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-6File Extensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-7
Configuration Tasks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-7Monitoring Digital Certificates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13-12
Chapter 14 Configuring L2TP with IPSec
Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-1References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-2
Contentsxviii
How Secure Remote Access Works . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-2Setting Up the Secure Connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-3L2TP with IPSec Control and Data Frames . . . . . . . . . . . . . . . . . . . . . . . . . 14-4Compatibility and Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-4
End-to-End Security . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-4Client Software Supported . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-5Interactions with NAT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-5Tunnel Creation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-5Interaction Between IPSec and PPP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-5Number of L2TP/IPSec Connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-6LNS Change of Address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-6LNS Change of Port . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-6Group Preshared Key . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-6
Configuration Tasks for Client PC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-7Configuration Tasks for E-Series Routers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-7
Configuring L2TP Destination Profiles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-7Configuring IPSec Transport Profiles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-8
Monitoring L2TP over IPSec . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-13System Event Logs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-13show Commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14-13
Index
About This Guide
This E-Series Routing Protocols Configuration Guide, Vol. 1 provides the information you need to configure certain routing protocols (primarily IP and IPv6 protocols) on your E-series router.
Note: If the information in the latest E-Series Release Notes differs from the information in this guide, follow the E-Series Release Notes.
The E-series router is shipped with the latest system software installed. If you need to install a future release or reinstall the system software, refer to the procedures in the E-Series Installation and User Guide, Appendix B, Installing JUNOSe Software.
E-Series RoutersFive models of E-series routers are available:
• ERX-1440 router
• ERX-1410 router
• ERX-710 router
• ERX-705 router
• ERX-310 router
All models use the same software. For information about the differences between the models, see E-Series Installation and User Guide, Chapter 1, E-Series Overview.
In the E-series documentation, the term ERX-14xx models refers to both the ERX-1440 router and the ERX-1410 router. Similarly, the term ERX-7xx models refers to both the ERX-710 router and the ERX-705
About This Guidexx
router. The terms ERX-1440 router, ERX-1410 router, ERX-710 router, ERX-705 router, and ERX-310 router refer to the specific models.
AudienceThis guide is intended for experienced system and network specialists working with E-series routers in an Internet access environment.
ConventionsTable 1 defines notice icons used in this guide, and Table 2 defines text conventions used throughout the book, except for command syntax. Table 3 provides command syntax conventions used primarily in the E-Series Command Reference Guide. For more information about command syntax, see E-Series System Basics Configuration Guide, Chapter 2, Command Line Interface.
Table 1 Notice icons
Icon Meaning Description
Informational note Indicates important features or instructions.
Caution Indicates that you may risk losing data or damaging your hardware.
Warning Alerts you to the risk of personal injury.
Table 2 Text conventions (except for command syntax)
Convention Description Examples
Bold typeface Represents commands and keywords in text.
� Command example: Issue the clock source command.
� Keyword example:Specify the keyword exp-msg.
Bold Courier typeface Represents text that the user must type.
user input
Key name in angle brackets Indicates the name of a key on the keyboard.
Press <Enter>.
Key names linked with a plus sign (+) in angle brackets.
Indicates that you must press two or more keys simultaneously.
Press <Ctrl+B>.
DocumentationE-Series Routers
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DocumentationThe E-Series Installation Quick Start poster is shipped in the box with all new routers. This poster provides the basic procedures to help you get the router up and running quickly.
With each software release, we provide the E-Series Routers Documentation CD (formerly ERX Edge Routers Documentation CD). The documentation CD contains the document set in PDF format and HTML format (with and without frames). From the HTML files, you can also access PDF files of individual chapters and appendixes.
The documentation is also available on the Web. You can order a set of printed documents from your Juniper Networks sales representative.
Plain Courier typeface Represents information as displayed on your terminal�s screen.
host1#show ip ospf 2
Routing Process OSPF 2 with Router ID 5.5.0.250
Router is an Area Border Router (ABR)
Italics � Emphasize words. � Identify variables. � Identify chapter, appendix, and
book names.
� There are two levels of access, user and privileged.
� clusterId, ipAddress.� Appendix A, System Specifications.
Table 2 Text conventions (except for command syntax) (continued)
Convention Description Examples
Table 3 Syntax conventions in Command Reference Guide
Convention Description Examples
Words in plain text Represent keywords. terminal length
Words in italics Represent variables. mask, accessListName
Words separated by the | symbol Represent a choice to select one keyword or variable to the left or right of this symbol. (The keyword or variable may be either optional or required.)
diagnostic | line
Words enclosed in [ brackets ] Represent optional keywords or variables.
[ internal | external ]
Words enclosed in [ brackets ]* Represent optional keywords or variables that can be entered more than once.
[ level1 | level2 | l1 ]*
Words enclosed in { braces } Represent required keywords or variables.
{ permit | deny } { in | out }{ clusterId | ipAddress }
About This Guidexxii
The document set comprises the following books:
• E-Series Installation and User Guide – Provides the necessary procedures for getting the router operational, including information on installing, cabling, powering up, configuring the router for management access, and general troubleshooting. Describes SRP modules, line modules, and I/O modules available for the E-series routers, and provides information about the compatibility of line modules and I/O modules with software releases. Lists the layer 2 protocols, layer 3 protocols, and applications that line modules and their corresponding I/O modules support.
• E-Series System Basics Configuration Guide – Describes planning and configuring your network, managing the router, configuring passwords and security, configuring the router clock, and configuring virtual routers. Includes a list of references that provide information on the protocols and features supported by the router.
• E-Series Physical Layer Configuration Guide – Describes configuring physical layer interfaces.
• E-Series Link Layer Configuration Guide – Describes configuring link layer interfaces.
• E-Series Routing Protocols Configuration Guide, Vol. 1 – Provides information about configuring routing policy and configuring IP, IP routing, and IP security.
• E-Series Routing Protocols Configuration Guide, Vol. 2 – Describes BGP routing, MPLS, BGP-MPLS VPNs, and encapsulation of layer 2 services.
• E-Series Policy and QoS Configuration Guide – Provides information about configuring policy management and quality of service (QoS).
• E-Series Broadband Access Configuration Guide – Provides information about configuring remote access.
• E-Series Command Reference Guide A to M; E-Series Command Reference Guide N to Z – Together comprise the E-Series Command Reference Guide. Contain important information about commands implemented in the system software. Use to look up command descriptions, command syntax, a command’s related mode, or a description of a command’s parameters. Use with the E-series configuration guides.
• E-Series Product Overview Guide – Gives a thorough overview of the router from a software and hardware perspective. It provides illustrations and configuration examples that present the “big picture.”
Comments About the DocumentationE-Series Routers
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MIBSCopies of the MIBs available in a software release are included on the JUNOSe Software CD (formerly ERX Edge Routers Software CD) and on the Web.
Release NotesRelease notes are included on the corresponding software CD and are available on the Web.
In the Release Notes, you will find the latest information about features, changes, known problems, resolved problems, and system maximum values. If the information in the Release Notes differs from the information found in the documentation set, follow the Release Notes.
AbbreviationsA complete list of abbreviations used in this document set, along with their spelled-out terms, is provided in the E-Series System Basics Configuration Guide, Appendix A, Abbreviations and Acronyms.
Web AccessTo view the documentation on the Web, go to:
http://www.juniper.net/techpubs/
Comments About the DocumentationWe encourage you to provide feedback, comments, and suggestions so that we can improve the documentation to better meet your needs. Please e-mail your comments to:
Along with your comments, be sure to indicate:
• Document name
• Document part number
• Page number
• Software release version
About This Guidexxiv
Contacting Customer SupportFor technical support, contact Juniper Networks at [email protected], or at 1-888-314-JTAC (within the United States) or 408-745-9500 (from outside the United States).
Part 1Routing Policy
1
Configuring Routing PolicyThis chapter provides information on configuring routing policy for your E-series router. It describes routing policy configuration in general as it might be used with various routing protocols, such as BGP, IS-IS, OSPF, and RIP.
OverviewRouting policy determines how the system handles the routes it receives from and sends to neighboring routers. In many cases, routing policy consists of filtering routes, accepting certain routes, accepting and modifying other routes, rejecting some routes, and determining the
Topic Page
Overview 1-1
References 1-2
Route Maps 1-2
Access Lists 1-16
Using the Null Interface 1-26
Prefix Lists 1-27
Prefix Trees 1-30
Community Lists 1-31
Using Regular Expressions 1-37
Managing the Routing Table 1-43
Troubleshooting Routing Policy 1-43
Monitoring Routing Policy 1-43
CHAPTER 1Configuring Routing Policy
1-2
routing protocol used to distribute the routes. You can think of routing policy as a way to control the flow of routes into and out of the router.
The decision about which routes to accept from and advertise to various neighbors has an important impact on the traffic that crosses a network. Routing policy is used to enforce business agreements between two or more ISPs concerning the amount and type of traffic that is allowed to pass between them.
You can use one or more of the following mechanisms to configure routing policy:
• Route maps
• Access lists
• Prefix lists
• Prefix trees
• Community lists
ReferencesFor more information about the protocols discussed in this chapter, refer to their respective chapters in this guide and in E-Series Routing Protocols Configuration Guide, Vol. 2, and to the References sections within those chapters.
Route MapsYou can use route maps to control and modify routing information and to define conditions for redistributing routes between routing domains. You can apply route maps to inbound, outbound, or redistribution routes. A route map consists of match clauses and set clauses.
Match clauses specify the attribute values that determine whether a route matches the route map. A route that has the same attribute values passes the match condition. Routes that pass all the match conditions match the route map. You issue match commands to define the match conditions for a route map. You can specify the match conditions in any order. If you do not specify any match conditions in a route map, that route map then matches all routes.
Set clauses define how the attributes are modified for matching routes. The set conditions apply only to routes that pass all the match conditions (or a route map with no match conditions). When a route passes all the
Route MapsE-Series Routers
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match conditions, all set conditions are applied. You issue set commands to define the set conditions for a route map.
You assign a unique string called the map tag to identify each route map. You can have multiple instances of a route map, where each instance consists of a different group of clauses. Each instance is identified by a sequence number. When you apply a route map, the routing protocol evaluates routes against the instance of the route map with the lowest sequence number. If the routes pass all the match conditions specified in the lowest-numbered instance, and if all set commands are successfully applied, then no other instance of the route map is considered. However, any routes that do not pass all the match conditions are evaluated against the next instance of the route map. For example, suppose you create two instances of route map boston5, one with sequence number 10 and one with sequence number 25. When you apply boston5, routes are evaluated first against instance 10; any that do not match are evaluated against instance 25.
When you apply a route map, you specify the permit or deny keyword.
• If you specify permit, routes that match the route map are accepted, forwarded, or redistributed. Routes that do not match the route map are rejected or blocked.
• If you specify deny, routes that match the route map are rejected or blocked. Routes that do not match the route map are accepted, forwarded, or redistributed.
A route map must have at least one match clause or one set clause. If you have no match clauses, all routes match the route map, and the set conditions apply to all routes. If you have no set clauses, no action is taken other than that specified by the permit or deny keyword.
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Sample Route MapConsider the network structure shown in Figure 1-1. Suppose you do not want router Boston to receive any routes that originate in or pass through router Chicago.
Figure 1-1 Applying route maps to routes
You can use a route map to filter routes based on the AS path to accomplish this goal. Use the following commands to configure router NY:
host1(config)#router bgp 293
host1(config-router)#network 192.168.5.0 mask 255.255.255.0
host1(config-router)#neighbor 10.5.5.2 remote-as 32
host1(config-router)#neighbor 10.2.2.2 remote-as 873
host1(config-router)#neighbor 10.2.2.4 remote-as 17
host1(config-router)#neighbor 10.2.2.4 route-map block1 out
host1(config-router)#exit
host1(config)#ip as-path access-list boston deny _32_
host1(config)#route-map block1 deny 1
host1(config-route-map)#match as-path boston
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Route MapsE-Series Routers
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Multiple Values in a Match EntryYou can specify more than one value in each match entry of a route map using any of the match commands shown in Table 1-1. A clause with multiple values matches a route having any of the values; that is, the multiple values are logical ORed.
host1(config-route-map)#match ip address lisbon madrid
host1(config-route-map)#match as-path 10 20 30
You can also issue successive match commands to add new values to a route map entry for any of the commands in Table 1-1.
host1(config-route-map)#match ip address boston
host1(config-route-map)#match ip address newyork
This is equivalent to issuing the following single command:
host1(config-route-map)#match ip address boston newyork
You cannot specify multiple values for the match metric-type command, because it has only two acceptable values, which are mutually exclusive. Specifying both values would have the same effect as not specifying a metric type at all; specifying the same value more than once has no meaning.
Negating Match ClausesIf you specify a value when you negate a match command configured in a route map, only that value for the match entry is deleted. The entire match entry is deleted only if no other values are specified by the entry. In earlier releases, any value specified with a no match command was ignored, and the entire match entry was deleted. This change applies to all match commands configured in a route map.
For example, consider the following match entry to route map miami:
host1(config)#ip community-list corporate5 permit 32 463 21
host1(config)#ip community-list dade2 permit 41 53 22
Table 1-1 Match commands enabling multiple values
match as-path match ipv6 next-hop
match community match ipv6 route-source
match distance match level
match extcommunity-list match metric
match ip address match route-type
match ip next-hop match tag
match ipv6 address
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host1(config)#route-map miami permit 1
host1(config-route-map)#match community corporate5 dade2
host1(config-route-map)#exit
host1(config)#exit
host1#show route-map
route-map miami, permit, sequence 10
Match clauses:
match community corporate5 dade2
In earlier releases, issuing a command to remove a community not specified in the entry deleted the whole entry, but now nothing happens:
host1(config-route-map)#no match community southbeach
host1(config-route-map)#exit
host1(config)#exit
host1#show route-map
route-map miami, permit, sequence 10
Match clauses:
match community corporate5 dade2
If you instead issue the following commands, the specified value is deleted:
host1(config-route-map)#no match community dade2
host1(config-route-map)#exit
host1(config)#exit
host1#show route-map
route-map miami, permit, sequence 10
Match clauses:
match community corporate5
You could delete the entire match community entry by issuing either of the following commands:
host1(config-route-map)#no match community
host1(config-route-map)#no match community corporate5 dade2
Matching a Community List ExactlyYou can use the exact-match keyword for the match community command to specify that a match exists only for the exact community numbers specified in the community list. The exact-match keyword applies only to a standard community list—that is, one not specified by a regular expression. You cannot use the exact-match keyword with a community list that is specified by a regular expression.
Consider the following example:
host1(config)#ip community-list 1 permit 100 200 300
host1(config)#exit
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host1#show ip community-list
Community standard list 1
permit 0:100 0:200 0:300
host1(config)#route-map example1 permit 10
host1(config-route-map)#match community 1 exact-match
host1(config)#exit
host1#show route-map example1
route-map example, permit, sequence 10
Match clauses:
community (community-list filter): 1 exact-match
The route map example1 permits a route only if the route contains community 100 and community 200 and community 300 and no additional communities.
If you do not specify the exact-match option, the route map also permits a match on a route containing additional communities. For example, a route containing communities 100, 200, 300, 400, and 450 would match.
Removing Community Lists from a Route MapYou can use the set comm-list delete command to remove the specified community list from routes matching the route map, provided that you created the community list with a single community number per list entry. For example, you cannot remove the community lists 231:10 and 231:20 with the set comm-list delete command if you created them with the following command:
host1(config)#ip community list 1 permit 231:10 231:20
You can, however, remove the lists with the set comm-list delete command if you created them separately:
host1(config)#ip community list 1 permit 231:10
host1(config)#ip community list 1 permit 231:20
Redistributing Access RoutesTo redistribute access and access-internal routes by matching on a tag:
1 Configure route map 2 to match tag 30.
host1(config)#route-map 2
host1(config-route-map)#match tag 30
2 Configure redistribution into BGP of the access routes with route map 1.
host1(config)#router bgp testnet
host1(config-router)#redistribute access
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match as-path� Use to match an AS-path access list. � The implemented weight is based on the first matched AS path.� Example
host1(config-route-map)#match as-path pathlist5
� Use the no version to delete the match clause from a route map or a specified value from the match clause.
match community� Use to match a community list.� Supported for inbound and outbound route maps.� Example
host1(config-route-map)#match community comm5
� Use the no version to delete the match clause from a route map or a specified value from the match clause.
match distance� Use to match any routes being redistributed out of the routing table that have
the specified administrative distance.� Distance is used to determine the relative preference between routes to the
same prefix in order to pick the best route to that prefix in the routing table. Distance has no meaning in any other circumstance, and any attempt to match distance will fail.
� Examplehost1(config-route-map)#match distance 25
� Use the no version to delete the match clause from a route map or a specified value from the match clause.
match extcommunity� Use to match an extended community list in a route map. � You can specify one or more extended community list names in a match
clause. If you specify more than one extended community list, the lists are logically ORed.
� Examplehost1(config-route-map)#match extcommunity topeka10
� Use the no version to remove the match clause from a route map or a specified value from the match clause.
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match ip address� Use to match any route that has a destination network number that is permitted
by an access list, a prefix list, or a prefix tree, or that performs policy routing on packets.
� Examplehost1(config-route-map)#match ip address prefix-tree boston
� Use the no version to delete the match clause from a route map or a specified value from the match clause.
match ip next-hop� Use to match any routes that have a next-hop router address passed by the
specified access list, prefix list, or prefix tree. � Example
host1(config-route-map)#match ip next-hop 5 192.54.24.1
� Use the no version to delete the match clause from a route map or a specified value from the match clause.
match ipv6 address� Use to match any routes that have a destination network number address that
is permitted by the specified prefix list. The no version removes all address match clauses from a route map unless you specify a prefix list, in which case only that prefix list match is removed from the route map.
� Examplehost1(config-route-map)#match ipv6 address prefix-list boston
� Use the no version to delete all address match clauses from a route map unless you specify a prefix list, in which case only that prefix list match is removed from the route map.
match ipv6 next-hop� Use to match any routes that have a next-hop router address passed by the
specified prefix list. � Example
host1(config-route-map)#match ipv6 next-hop prefix-list next1
� Use the no version to delete all next-hop match clauses from a route map unless you specify a prefix list, in which case only that prefix list match is removed from the route map.
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match ipv6 route-source� Use to match any routes that are advertised from addresses contained in the
specified prefix list. � Example
host1(config-route-map)#match ipv6 route-source prefix-list source
� Use the no version to delete all route-source match clauses from a route map unless you specify a prefix list, in which case only that prefix list match is removed from the route map.
match level� Use to match routes for the specified type.� Example
host1(config-route-map)#match level-1
� Use the no version to delete the match clause from a route map or a specified value from the match clause.
match metric� Use to match a route for the specified metric value.� Example
host1(config-route-map)#match metric 10
� Use the no version to delete the match clause from a route map or a specified value from the match clause.
match metric-type� Use to match a route for the specified metric type.� Example
host1(config-route-map)#match metric-type external
� Use the no version to delete the match clause from a route map.
match route-type� Use to match a route for the specified route type. � Example
host1(config-route-map)#match route-type level-1
� Use the no version to delete the match clause from a route map or a specified value from the match clause.
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match-set summary prefix-tree� Use to specify the prefix tree that summarizes routes for a particular route map.� Use the ip prefix-tree command to set the conditions of the prefix tree,
including which routes to summarize and how many bits of the network address to preserve.
� Examplehost1(config-route-map)#match-set summary prefix-tree boston
� Use the no version to disable the use of the prefix tree by the route map.
match tag� Use to match the tag value of the destination routing protocol. � Example
host1(config)#route-map 1
host1(config-route-map)#match tag 25
� Use the no version to delete the match clause from a route map or a specified value from the match clause.
route-map� Use to define the conditions for redistributing routes from one routing protocol
into another, and for filtering or modifying updates sent to or received from peers.
� Each route-map command has a list of match and set commands associated with it. That is, the route map itself consists of a set of clauses; each clause (also called an entry) consists of a match or set command.
� match commands specify the match criteria, the conditions under which redistribution is allowed for the current route map.
� set commands specify the set actions, the redistribution actions to perform if the criteria enforced by the match commands are set.
� You can specify match and set clauses to modify attributes of redistributed routes.
� Use route maps when you wish to have detailed control over how routes are redistributed between routing processes. � You specify the destination routing protocol with the router command. � You specify the source routing protocol with the redistribute command.
� Examplehost1(config)#route-map nyc1 permit 10
host1(config-route-map)#match ip address list1
host1(config-route-map)#set metric-type internal
� Use the no version to delete the route map.
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set as-path prepend� Use to modify an AS path for BGP routes by prepending one or more AS
numbers or a list of AS numbers to the path list. � The only global BGP metric available to influence the best path selection is the
AS path length. By varying the length of the AS path, a BGP speaker can influence the best path selection by a peer farther away.
� Examplehost1(config-route-map)#set as-path prepend list list10
� Use the no version to delete the set clause from a route map.
set automatic-tag� Use to automatically compute the tag value of the destination routing protocol. � Example
host1(config-route-map)#set automatic-tag
� Use the no version to delete the set clause from a route map.
set comm-list delete� Use to remove communities specified by the community list from the
community attribute of routes matching the route map. � You can use this command to delete communities only if the community list was
created with a single community per list entry, as shown in the following sample configuration for router Test:host1(config)#ip community-list 1 permit 231:10
host1(config)#ip community-list 1 permit 231:20
host1(config)#router bgp 45
host1(config-router)#neighbor 10.6.2.5 remote-as 5
host1(config-router)#neighbor 10.6.2.5 route-map indelete in
host1(config-router)#route-map indelete permit 10
host1(config-route-map)#set comm-list 1 delete
Router Test receives the same route from 10.6.2.5 and applies the indelete route map. BGP compares each list entry with the community attribute. A match is found for the list entry 231:10, and this community is deleted from the community attribute. Similarly, a match is found for the list entry of 231:20, and this community is deleted from the community attribute.
� Use the no version to delete the set clause from a route map.
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set community� Use to set the community attribute in BGP updates.� You can specify a community list number in the range 1�4294967295, or in the
new community format of AA:NN, or one of the following well-known communities: � local-as � prevents advertisement outside the local AS� no-advertise � prevents advertisement to any peer� no-export � prevents advertisement beyond the BGP confederation
boundary� Alternatively, you can use the list keyword to specify the name of a community
list that you previously created with the ip community-list command. � Example
host1(config-route-map)#set community no-advertise
� Use the none keyword to remove the community attribute from a route.� Use the no version to delete the set clause from a route map.
set dampening� Use to enable BGP route flap dampening only on routes that pass the match
clauses of, and are redistributed by, a particular route map. � BGP creates a dampening parameter block for each unique set of dampening
parameters�such as suppress threshold, reuse threshold, and so on�used by BGP. For example, if you have a route map that sets the dampening parameters to one set of values for some routes and to another set of values for the remaining routes, BGP uses and stores two dampening parameter blocks, one for each set.
� Examplehost1(config-route-map)#set dampening 5 1000 1500 45 15
� Use the no version to delete the set clause from a route map.
set distance� Use to set the administrative distance on routes being installed into the routing
table that match the route map. � Distance establishes preference between routes to the same prefix to identify
the best route to that prefix. Setting distance in any other circumstance has no effect.
� Examplehost1(config-route-map)#set distance 5
� Use the no version to delete the set clause from a route map.
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set extcommunity � Use to set the extended community attributes in a route map for BGP updates. � You can specify a site-of-origin (soo) extended community and a route target
(rt) extended community at the same time in a set clause without overwriting the other.
� Examplehost1(config-route-map)#set extcommunity rt 10.10.10.2:325
� Use the no version to delete the set clause from a route map.
set ip next-hop� Use to set the next hop attribute of a route that matches a route map. � You can specify an IP address or an interface as the next hop.� Use the peer-address keyword to have the following effect:
� On outbound route maps, disables the next-hop calculation by setting the next hop to the IP address of the BGP speaker
� On inbound route maps, overrides any third-party next-hop configuration by setting the next hop to the IP address of the peer
� Examplehost1(config-route-map)#set ip next-hop 192.56.32.1
� Use the no version to delete the set clause from a route map.
set ipv6 next-hop� Use to set the next-hop attribute of a route that matches a route map. � You can specify an IPv6 address or an interface as the next hop.� Example
host1(config-route-map)#set ip next-hop 192.56.32.1
� Use the no version to delete the set clause from a route map.
set level� Use to specify where to import routes when all of a route map�s match criteria
are met.� Example
host1(config-route-map)#set level level-2
� Use the no version to delete the set clause from a route map.
set local-preference� Use to specify a preference value for the AS path. � Example
host1(config-route-map)#set local-preference 200
� Use the no version to delete the set clause from a route map.
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set metric� Use to set the metric value�for BGP, the MED�for a route. � To establish an absolute metric, do not enter a plus or minus sign before the
metric value.� Example
host1(config-route-map)#set metric 10
� To establish a relative metric, specify a plus or minus sign immediately preceding the metric value. The value is added to or subtracted from the metric of any routes matching the route map. The relative metric value range is 0�4294967295.
� Examplehost1(config-route-map)#set metric -25
� You cannot use both an absolute metric and a relative metric within the same route map sequence. Setting either metric overrides any previously configured value.
� Use the no version to delete the set clause from a route map.
set metric-type� Use to set the metric type for a route. � For BGP, this command affects BGP behavior only in outbound route maps and
has no effect on other types of route maps. If the route map contains both a set metric-type and a set metric clause, the set metric clause takes precedence. If you specify the internal metric type in a BGP outbound route map, BGP sets the MED of the advertised routes to the IGP cost of the next hop of the advertised route. If the cost of the next hop changes, BGP is not forced to readvertise the route.
� For BGP, you can specify:� external � reverts to the normal BGP rules for propagating the MED; this is
the BGP default� internal � sets the MED of a received route that is being propagated to an
external peer equal to the IGP cost of the indirect next hop� For IS-IS, you can specify:
� external � only the metric of the route itself is considered for comparison� internal � both the metric of the route and the cost to the router that
advertised the route are considered for comparison; this is the IS-IS default� For OSPF, you can specify:
� 1 � cost of the external routes is equal to the sum of all internal costs and the external cost
� 2 � cost of the external routes is equal to the external cost alone; this is the OSPF default
� Examplehost1(config-route-map)#set metric-type internal
� Use the no version to delete the set clause from a route map.
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set origin� Use to set the BGP origin of the advertised route.� Example
host1(config-route-map)#set origin egp
� Use the no version to delete the set clause from a route map.
set route-type� Use to set the routes of the specified type.� Example
host1(config-route-map)#set route-type internal
� Use the no version to delete the set clause from a route map.
set tag� Use to set the tag value of the destination routing protocol.� Example
host1(config-route-map)#set tag 23
� Use the no version to delete the set clause from a route map.
set weight� Use to specify the BGP weight for the routing table. � The weights assigned with the set weight command in a route map override
the weights assigned using the neighbor weight and neighbor filter-list weight commands.
� Examplehost1(config-route-map)#set weight 200
� Use the no version to delete the set clause from a route map.
Access ListsAn access list is a sequential collection of permit and deny conditions that you can use to filter inbound or outbound routes. You can use different kinds of access lists to filter routes based on either the prefix or the AS path.
Access ListsE-Series Routers
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Filtering PrefixesTo filter routes based on the prefix, you can do any of the following:
• Define an access list with the access list command, and apply the list to routes received from or passed to a neighbor with the neighbor distribute-list command
• Define a prefix list with the ip prefix-list command, and apply the list to routes received from or passed to a neighbor with the neighbor prefix-list command
• Define a prefix tree with the ip prefix-tree command, and apply the list to routes received from or passed to a neighbor with the neighbor prefix-tree command
The router compares each route’s prefix against the conditions in the list or tree one by one. If the first match is for a permit condition, the route is accepted or passed. If the first match is for a deny condition, the route is rejected or blocked. The order of conditions is critical because testing stops with the first match. If no conditions match, the router rejects or blocks the address; that is, the last action of any list is an implicit deny condition for all routes. The implicit rule is displayed by show access-list and show config commands.
You cannot selectively place conditions in or remove conditions from an access list, prefix list, or prefix tree. You can insert a new condition only at the end of a list or tree.
Example 1 The following example shows the how the implicit deny condition is displayed.
host1(config)#access-list 1 permit 10.10.10.1 0.0.0.255
host1(config)#access-list 2 permit 10.25.25.1 0.0.0.255
host1(config)#access-list 3 permit any any
host1(config)#show access-list
IP Access List 1:
permit ip 10.10.10.1 0.0.0.255 any
deny ip any any
IP Access List 2:
permit ip 10.25.25.1 0.0.0.255 any
deny ip any any
IP Access List 3:
permit ip any any
Note that the implicit deny rule does not appear in the display for access list 3, because any prefix will match access list 3.
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Example 2 The following example demonstrates how to use a route map and an access list to redistribute static routes to IS-IS.
1 Configure three static routes.
host1(config)#ip route 20.20.20.0 255.255.255.0 192.168.1.0
host1(config)#ip route 20.20.21.0 255.255.255.0 192.168.2.0
host1(config)#ip route 20.21.0.0 255.255.255.0 192.168.30.0
2 Configure an access list, f ltra, that filters routes 20.20.20.0/24 and 20.20.21.0/24.
host1(config)#access-list fltra permit 20.20.0.0 0.0.255.255
3 Configure route map 1 to match access list f ltra, and apply an internal metric type.
host1(config)#route-map 1
host1(config-route-map)#match ip address fltra
host1(config-route-map)#set metric-type internal
4 Configure redistribution into IS-IS of the static routes with route map 1.
host1(config)#router isis testnet
host1(config-router)#redistribute static route-map 1
5 Verify the effect of the redistribution (the two static routes matching the route map are redistributed as level 2 internal routes).
host1#show isis database detail l2
IS-IS Level-2 Link State Database
LSPID LSP Seq Num LSP Checksum LSP Holdtime ATT/P/OL
0000.0000.6666.00-00 0x000002B7 0x3E1F 1198 0/0/0
Area Address: 47.0005.80FF.F800.0000.0001.0001
NLPID: 0xcc
IP Address: 192.168.1.105
Metric: 10 IS 0000.0000.6666.01
Metric: 10 IS 0000.0000.3333.00
Metric: 10 IS 0000.0000.7777.00
Metric: 30 IP 20.20.20.0 255.255.255.0
Metric: 30 IP 20.20.21.0 255.255.255.0
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Example 3 The following example demonstrates how to use an access list to filter routes advertised to a BGP speaker. Consider the network structure in Figure 1-2.
Figure 1-2 Filtering with access lists
The following commands configure router Boston to apply access list reject1 to routes inbound from router SanJose. Access list reject1 rejects routes matching 172.24.160.0/19.
host1(config)#router bgp 17
host1(config-router)#neighbor 10.5.5.4 remote-as 873
host1(config-router)#neighbor 10.5.5.4 distribute-list reject1 in
host1(config-router)#exit
host1(config)#access-list reject1 permit 172.24.48.0 0.0.255
host1(config)#access-list reject1 deny 172.24.160.0 0.0.0.255
host1(config)#access-list reject1 permit 172.24.24.0 0.0.0.255
Filtering AS PathsYou can use a filter list to filter incoming and outgoing routes based on the value of the AS-path attribute. Whenever a BGP route passes through an AS, BGP prepends its AS number to the AS-path attribute. The AS-path attribute is the list of ASs that a route has passed through to reach a destination.
To filter routes based on the AS path, define the access list with the ip as-path access-list command, and apply the list to routes received from or passed to a neighbor with the neighbor filter-list command. AS-path access lists use regular expressions to describe the AS path to be matched.
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A regular expression uses special characters—often referred to as metacharacters—to define a pattern that is compared with an input string. For a full discussion of regular expressions, with examples of how to use them, see Using Regular Expressions later in this chapter.
The router compares each route’s AS path against each condition in the access list. If the first match is for a permit condition, the route is accepted or passed. If the first match is for a deny condition, the route is rejected or blocked. The order of conditions is critical because testing stops with the first match. If no conditions match, the router rejects or blocks the route; that is, the last action of any list is an implicit deny condition for all routes.
You cannot selectively place conditions in or remove conditions from an AS-path access list. You can insert a new condition only at the end of an AS-path access list.
Example 1 Consider the network structure in Figure 1-3.
Suppose you want router London to behave in the following way:
• Accept routes originated in AS 621 only if they pass directly to router London.
• Accept routes originated in AS 11 only if they pass directly to router London.
• Forward routes from AS 282 to AS 435 only if they pass through either AS 621 or AS 11, but not both AS 621 and AS 11.
Figure 1-3 Filtering with AS-path access lists
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Access ListsE-Series Routers
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The following commands configure router London to apply filters based on AS path to routes received from router Berlin and router Paris and to routes forwarded to router Madrid.
host1(config)#router bgp 47
host1(config-router)#neighbor 10.2.9.2 remote-as 621
host1(config-router)#neighbor 10.2.9.2 filter-list 1 in
host1(config-router)#neighbor 10.2.8.2 remote-as 11
host1(config-router)#neighbor 10.2.8.2 filter-list 2 in
host1(config-router)#neighbor 10.2.7.2 remote-as 435
host1(config-router)#neighbor 10.2.7.2 filter-list 3 out
host1(config-router)#exit
host1(config)#ip as-path access-list 1 deny ^11
host1(config)#ip as-path access-list 1 permit .*
host1(config)#ip as-path access-list 2 deny ^621
host1(config)#ip as-path access-list 2 permit .*
host1(config)#ip as-path access-list 3 deny [621 11]
host1(config)#ip as-path access-list 3 permit .*
AS-path access list 1 is applied to routes that router London receives from router Paris. Router London rejects routes with the AS path 11 621 or 11 282 621.
AS-path access list 2 is applied to routes that router London receives from router Berlin. Router London rejects routes with the AS path 621 11 or 621 282 11.
Router London accepts routes with the AS path 282 11, 282 621, 282 621 11, or 282 11 621. However, it applies AS-path access-list 3 to routes it forwards to router Madrid, and filters out routes with the AS path 282 621 11 or 282 11 621.
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Using Access Lists in a Route MapYou can use a route map instead of the neighbor filter-list command to apply access lists for filtering routes. In Figure 1-4, a route map is used to determine the weight for routes learned by router Chicago.
Figure 1-4 Route map filtering
Access list 1 permits any route whose AS-path attribute includes 32 or 837. This condition permits routes that originate in (or pass through from elsewhere) AS 32 or AS 837. When these routes are advertised through AS 451 and AS 17 to router Chicago, instance 1 of route map 1 matches such routes and sets their weight to 25, overriding the neighbor weight set for updates received from 10.2.2.4.
Access list 2 permits any route whose AS-path attribute indicates that it originates in AS 74. When these routes are advertised through AS 837 and AS 32 to router Chicago, instance 1 of route map 2 matches such routes and sets their weight to 175, overriding the neighbor weight set for updates received from 10.5.5.2.
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Access ListsE-Series Routers
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To configure router Chicago:
host1(config)#router bgp 293
host1(config-router)#network 192.168.5.0 mask 255.255.255.0
host1(config-router)#neighbor 10.2.2.4 remote-as 17
host1(config-router)#neighbor 10.2.2.4 weight 150
host1(config-router)#neighbor 10.2.2.4 route-map 1 in
host1(config-router)#exit
host1(config-router)#neighbor 10.5.5.2 remote-as 32
host1(config-router)#neighbor 10.5.5.2 weight 50
host1(config-router)#neighbor 10.5.5.2 route-map 2 in
host1(config)#route-map 1 permit 1
host1(config-route-map)#match as-path 1
host1(config-route-map)#set weight 25
host1(config-route-map)#exit
host1(config)#ip as-path access-list 1 permit [ 32 837 ]
host1(config)#route-map 2 permit 1
host1(config-route-map)#match as-path 2
host1(config-route-map)#set weight 175
host1(config-route-map)#exit
host1(config)#ip as-path access-list 2 permit [ 74 ]
The result of this configuration is that router Chicago prefers routes learned via router Boston (weight 150) over routes learned through router NY (weight 50), except that:
• Router Chicago prefers routes learned via router NY that passed through AS 837 or AS 32 (weight 50) over the same routes learned via router Boston (weight 25 according to route map 1).
• Router Chicago prefers routes originating in AS 74 learned via router NY that passed through AS 837 and AS 32 (weight 175 according to route map 2) over the same routes learned via router Boston (weight 150).
access-list� Use to define an IP access list to permit or deny routes based on the prefix.� Each access list is a set of permit or deny conditions for routes based on
matching a route�s prefix.� A zero in the wildcard mask means that the corresponding bit in the address
must be exactly matched by the route. A one in the wildcard mask means that the corresponding bit in the address does not have to be matched by the route.
� Use the neighbor distribute-list command to apply the access list to routes received from or forwarded to a neighbor.
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� Use the log keyword to log an Info event in the ipAccessList log whenever an access-list rule is matched.
� Use the no version to delete an IP access list (no other options specified), the specified entry in the access list, or the log for the specified access list or entry (by specifying the log keyword).
default-information originate� Use to enable RIP, OSPF, or BGP to advertise a default route (0.0.0.0/0) that
exists in the IP routing table.� If you specify the always option for OSPF, OSPF generates a default route if it
does not exist in the IP routing table and advertises it.� Use to generate a default route into an IS-IS domain. � Example
host1(config-router)#default-information originate
� Use the no version to disable advertisement of the default route.
ip as-path access-list� Use to define an AS-path access list to permit or deny routes based on the AS
path. � Each access list is a set of permit or deny conditions for routes based on
matching a route�s AS path to a regular expression. If the regular expression matches the representation of the AS path of the route as an ASCII string, then the permit or deny condition applies. The AS path does not contain the local AS number.
� The AS path allows substring matching. For example, the regular expression 20 matches AS path = 20 and AS path = 100 200 300, because 20 is a substring of each path. To disable substring matching and constrain matching to only the specified attribute string, place the underscore (_) metacharacter on both sides of the string; for example _20_.
� Use the neighbor filter-list command to apply the AS-path access list. You can apply access list filters to inbound and outbound BGP routes. You can assign weights to routes matching the AS-path access list.
� Use the no version to remove the AS-path access list; all entries belonging to this list are removed.
neighbor distribute-list� Use to filter routes to selected prefixes as specified in an access list. Distribute
lists are applied only to external peers.� Use the in keyword to apply the list to inbound routes (inbound policy). Use the
out keyword to apply the list to outbound routes (outbound policy).� Using distribute lists is one of several ways to filter BGP advertisements. Other
methods are to:� Use AS path filters with the ip as-path access-list and the neighbor
filter-list commands
Access ListsE-Series Routers
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� Use route map filters with the route-map and the neighbor route-map commands
� Use the no version to disassociate the access list from a neighbor.
neighbor filter-list� Use to assign an AS-path access list to matching inbound or outbound routes.� Use the in keyword to apply the list to inbound routes (inbound policy). Use the
out keyword to apply the list to outbound routes (outbound policy).� You can specify an optional weight value with the weight keyword to assign a
relative importance to incoming routes matching the AS-path access list. � Access list values can range from 0�65535.� Use the no version to disassociate the access list from a neighbor.
neighbor prefix-list� Use to assign an inbound or outbound prefix list.� If you specify a BGP peer group by using the peer-group-name argument, all
the members of the peer group inherit the characteristic configured with this command unless it is overridden for a specific peer.
� Examplehost1(config-router)#neighbor 192.168.1.158 prefix-list seoul19 in
� Use the no version to remove the prefix list.
neighbor prefix-tree� Use to assign an inbound or outbound prefix tree.� If you specify a BGP peer group by using the peer-group-name argument, all
the members of the peer group inherit the characteristic configured with this command unless it is overridden for a specific peer.
� Examplehost1(config-router)#neighbor 192.168.1.158 prefix-tree newyork out
� Use the no version to remove the prefix tree.
redistribute� Use to redistribute routes from one routing domain into another routing domain.� Example
host1(config)#router bgp 100
host1(config-router)#neighbor 192.56.10.2 remote-as 200
host1(config-router)#redistribute static
host1(config-router)#exit
host1(config)#ip route 155.30.0.0 0.0.255.255
� Use the no version to remove the filter list.
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Creating Table Maps for Access RoutesFor access routes, you can configure and apply a table map that filters routes before an access list adds them to the routing table. You can use the ip access-route table-map command when triggering on the following policy values:
For example, you can configure an access list and route map to filter, based on IP address, any routes that appear in the routing table:
host1(config)#ip access-route table-map just10net
host1(config)#access-list permit10 permit 10.0.0.0 0.255.255.255
host1(config)#access-list permit10 deny any
host1(config)#route-map just10net
host1(config-route-map)#match ip address permit10
Using the same name for both the table map and the route map creates an association specifying (in this case) that only IP addresses matching the access list criterion appear in the routing table.
ip access-route table-map� Use to filter access routes before an access list adds them to the routing table.� Example
host1(config)#ip access-route table-map just10net
� Use the no version to delete the table map.
Using the Null InterfaceYou can use access control lists to filter undesired traffic. Another way to handle undesired traffic is to send it to the null interface. The null interface is always up and acts as a data sink. In other words, the null interface cannot forward or receive traffic.
The E-series router creates the null interface by default; you do not have to create it manually. You can direct traffic to the null interface by specifying the null 0 keywords instead of a next-hop or destination address when configuring routes.
Match Set
ip address metric
metric distance
distance tag
tag
Prefix ListsE-Series Routers
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ip route� Use to configure a static route and redirect traffic from it to the null interface.� Example
host1(config-if)#ip route 10.10.20.5 null 0
� Use the no version to remove the static route.
Prefix ListsA prefix list is a sequential collection of permit and deny conditions that apply to IP or IPv6 addresses. Like an access list, the router tests addresses one by one against the conditions in a prefix list. The first match determines whether the router accepts or rejects the address. Because the router stops testing conditions after the first match, the order of the conditions is critical. If no conditions match, the router rejects the address. An empty prefix list results in an automatic permit of the tested address.
Unlike access lists, the prefix list specifies a base IP or IPv6 address and a length (the number of bits applied to the base to determine the network prefix). The tested address is matched against the prefix.
Use the ip prefix-list command to define an IP prefix list, or the ipv6 prefix-list command to define an IPv6 prefix list. The prefix-list keyword with either the match { ip | ipv6 } address or match { ip | ipv6 } next-hop commands allow you to add a clause to a route map.
Using a Prefix List The following example creates a prefix list that permits routes with a prefix length up to 24 in the 151.0.0.0/8 network:
host1(config)#ip prefix-list abc permit 151.0.0.0/8 le 24
clear ip prefix-list� Use to clear all hit counts in the prefix lists, or the specified entry from the
specified prefix list. (The hit count is incremented +1 each time an entry matches.)
� Examplehost1#clear ip prefix-list abc
� There is no no version.
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clear ipv6 prefix-list� Use to clear all hit counts in the IPv6 prefix lists, or the specified entry from the
specified prefix list. (Each match results in the hit count incrementing by 1.)� Example
host1#clear ipv6 prefix-list abc
� There is no no version.
ip prefix-list� Use to create a prefix list for route filtering and to specify a list entry�a deny or
permit clause for a network address�to the prefix list. Use to add entries to prefix lists.
� The prefix list name can be up to 32 characters long.� Specify the position of each entry in the list with the seq keyword. If a sequence
number is not specified, the value of the last sequence number plus 5 is used.� Use the ge and le keywords to specify a range of network prefixes. These
keywords have the following values:� prefix length < ge <= 32� prefix length < le <= ge
� If you do not specify either ge or le, an exact match is expected. For example, if you issue the following command, only a route with a prefix length of 8 and a network address of 151.0.0.0 is permitted.host1(config)#ip prefix-list abc permit 151.0.0.0/8
� Use the no version to remove the specified prefix list or the specified list entry.
ipv6 prefix-list� Use to create an IPv6 prefix list for route filtering and to specify a list entry�a
deny or permit clause for a network address�to the prefix list. Use to add entries to prefix lists.
� The prefix list name can be up to 32 characters long.� Specify the position of each entry in the list with the seq keyword. If a sequence
number is not specified, the value of the last sequence number plus 5 is used.� Use the ge and le keywords to specify a range of network prefixes. These
keywords have the following values:� prefix length < ge <= 32� prefix length < le <= ge
� If you do not specify either ge or le, an exact match is expected. For example, if you issue the following command, only a route with a prefix length of 8 and a network address of 1:0:0:0:0:0:0:5 is permitted.host1(config)#ipv6 prefix-list abc permit 1::5/8
� Use the no version to remove the specified prefix list or the specified list entry.
Prefix ListsE-Series Routers
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match ip address� Use with the prefix-list keyword to match routes that have a destination
network number address that is permitted by the prefix list. � Example
host1(config-route-map)#match ip address prefix-list abc
� Use the no version to delete the match clause from a route map or a specified value from the match clause.
match ipv6 address� Use to match any routes that have a destination network number address that
is permitted by the specified prefix list. The no version removes all address match clauses from a route map unless you specify a prefix list, in which case only that prefix list match is removed from the route map.
� Examplehost1(config-route-map)#match ipv6 address prefix-list boston
� Use the no version to delete all address match clauses from a route map unless you specify a prefix list, in which case only that prefix list match is removed from the route map.
match ip next-hop� Use with the prefix-list keyword to match routes that have a next-hop router
address passed by the specified prefix list. � Example
host1(config-route-map)#match ip next-hop prefix-list abc
� Use the no version to delete the match clause from a route map or a specified value from the match clause.
match ipv6 next-hop� Use to match any routes that have a next-hop router address passed by the
specified prefix list. � Example
host1(config-route-map)#match ipv6 next-hop prefix-list next1
� Use the no version to delete all next-hop match clauses from a route map unless you specify a prefix list, in which case only that prefix list match is removed from the route map.
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Prefix TreesA prefix tree is a nonsequential collection of permit and deny conditions that apply to IP addresses. Like a prefix list, the prefix tree specifies a base IP address and a length, the number of bits applied to the base to determine the network prefix. The tested address is matched against the prefix. The prefix tree also enables route summarization.
However, the prefix tree does not match addresses one by one in sequence against the listed conditions. The router performs a binary search against the tree structure of the entries. If the tested address is less than a particular entry, it branches one way to another test pair; if it is greater than the entry, it branches the other way to another mutually exclusive test pair. The router stops testing conditions when it finds the best match. If no conditions match, the router rejects the address. An empty prefix tree results in an automatic permit of the tested address.
The prefix tree provides a faster search methodology and matches the test address more closely than either the access list or the prefix list.
Use the ip prefix-tree command to define an IP prefix tree. Use the prefix-tree keyword with the match ip address or match ip next-hop commands to add a clause to a route map. Use the match-set summary prefix-tree command to specify the prefix tree that summarizes routes for a particular route map.
Using a Prefix Tree The following example creates a prefix tree that permits routes with a prefix length of 24 or larger in the 10.10.2.0/24 network:
host1(config)#ip prefix-tree xyz permit 10.10.2.0/24
clear ip prefix-tree� Use to clear all hit counts in the prefix trees, or the specified entry from the
specified prefix tree. (The hit count is incremented +1 each time an entry matches.)
� Examplehost1#clear ip prefix-tree xyz
� There is no no version.
ip prefix-tree� Use to create a prefix tree for best route filtering; specifies a tree entry�a deny
or permit clause for a network address.� The prefix tree name can be up to 32 characters long.
Community ListsE-Series Routers
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� Examplehost1(config)#ip prefix-tree boston42 permit 10.10.2.0/24
� Use the no version to remove the specified prefix tree or the specified tree entry.
match ip address� Use with the prefix-tree keyword to match routes that have a destination
network number address that is permitted by the prefix tree. � Example
host1(config-route-map)#match ip address prefix-tree xyz
� Use the no version to delete the match clause from a route map or a specified value from the match clause.
match ip next-hop� Use with the prefix-tree keyword to match routes that have a next-hop router
address passed by the specified prefix tree. � Example
host1(config-route-map)#match ip next-hop prefix-tree xyz
� Use the no version to delete the match clause from a route map or a specified value from the match clause.
match-set summary prefix-tree� Use to specify the prefix tree that summarizes routes for a particular route map.� Use the ip prefix-tree command to set the conditions of the prefix tree,
including which routes to summarize and how many bits of the network address to preserve.
� Examplehost1(config-route-map)#match-set summary prefix-tree dog3
� Use the no version to disable use of the prefix tree by the route map.
Community ListsA community is a logical group of prefixes that share some common attribute. Community members can be on different networks and in different ASs. BGP allows you to define the community to which a prefix belongs. A prefix can belong to more than one community. The community attribute lists the communities to which a prefix belongs.
You can use communities to simplify routing policies by configuring the routing information that a BGP speaker will accept, prefer, or distribute to other neighbors according to community membership. When a route is learned, advertised, or redistributed, a BGP speaker can set, append, or
CHAPTER 1Configuring Routing Policy
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modify the community of a route. When routes are aggregated, the resulting BGP update contains a community attribute that contains all communities from all of the aggregated routes (if the aggregate is an AS-set aggregate).
Several well-known communities are predefined. Table 1-2 describes how a BGP speaker handles a route based on the setting of its community attribute.
In addition to the well-known communities, you can define local-use communities, also known as private communities or general communities. These communities serve as a convenient way to categorize groups of routes to facilitate the use of routing policies. The community attribute consists of four octets, but it is common practice to designate communities in the AA:NN format. The autonomous system number (AA) comprises the higher two octets, and the community number (NN) comprises the lower two octets. Both are expressed as decimal numbers. For example, if a prefix in AS 23 belongs to community 411, the attribute could be expressed as 23:411. Use the ip bgp-community new-format command to specify that the show commands display communities in this format. You can also use a regular expression to specify the community attribute.
Use the set community command in route maps to configure the community attributes. You can add one or more communities to the attribute, or use the list keyword to add a list of communities to the attribute. By default, the community attribute is not sent to BGP peers. To send the community attribute to a neighbor, use the neighbor send community command.
A community list is a sequential collection of permit and deny conditions. Each condition describes the community number to be matched. If you issued the ip bgp-community new-format command, the community
Table 1-2 Action based on well-known community membership
If the well-known community is... The BGP speaker...
no-export Does not advertise the route beyond the BGP confederation boundary
no-advertise Does not advertise the route to any peers, IBGP, or EBGP
local-as (also known as no-export-subconfed)
Does not advertise the route to any external peers
internet Advertises this route to the Internet community; by default, all prefixes are members of the Internet community
Community ListsE-Series Routers
1-33
number is in AA:NN format; otherwise it is in decimal format (the hexadecimal octets converted to decimal).
The router tests the community attribute of a route against each condition in a community list. The first match determines whether the router accepts (the route is permitted) or rejects (the route is denied) a route having the specified community. Because the router stops testing conditions after the first match, the order of the conditions is critical. If no conditions match, the router rejects the route.
Consider the network structure shown in Figure 1-5.
Figure 1-5 Community lists
Suppose you want router Albany to set metrics for routes that it forwards to router Boston based on the communities to which the routes belong. You can create community lists and filter the routes with a route map that matches on the community list. To configure router Albany:
host1(config)#router bgp 293
host1(config-router)#neighbor 10.5.5.2 remote-as 32
host1(config-router)#neighbor 10.2.2.1 remote-as 451
host1(config-router)#neighbor 10.2.2.4 remote-as 17
host1(config-router)#neighbor 10.2.2.4 route-map commtrc out
host1(config-router)#exit
host1(config)#route-map commtrc permit 1
host1(config-route-map)#match community 1
host1(config-route-map)#set metric 20
host1(config-route-map)#exit
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CHAPTER 1Configuring Routing Policy
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host1(config)#route-map commtrc permit 2
host1(config-route-map)#match community 2
host1(config-route-map)#set metric 75
host1(config-route-map)#exit
host1(config)#route-map commtrc permit 3
host1(config-route-map)#match community 3
host1(config-route-map)#set metric 85
host1(config-route-map)#exit
host1(config)#ip community-list 1 permit 25
host1(config)#ip community-list 2 permit 62
host1(config)#ip community-list 3 permit internet
Community list 1 comprises routes with a community of 25; their metric is set to 20. Community list 2 comprises routes with a community of 62; their metric is set to 75. Community 3 catches all remaining routes by matching the internet community; their metric is set to 85.
ip bgp-community new-format� Use to specify that communities must be displayed in AA:NN format, where AA
is a number that identifies the autonomous system and NN is a number that identifies the community within the autonomous system.
� Examplehost1(config)#ip bgp-community new-format
� Use the no version to restore the default display.
ip community-list� Use to create a community list for BGP and control access to it. The list name
can be up to 32 characters long.� A route can belong to any number of communities, so a community list can
have many entries comprising many communities.� You can specify one or more community values when you create a community
list. A clause in a route map that includes a list having more than one value matches only a route having all of the values; that is, the multiple values are logical ANDed.
� You can specify community values with a number or a regular expression.� Example
host1(config)#ip community-list 1 permit 100:2 100:3 100:4
host1(config)#route-map marengo permit 10
host1(config-route-map)#match community 1
A route matches this community list only if it belongs to at least all three communities in community list 1: communities 100:2, 100:3, and 100:4.
� Use the no version to remove the specified community list, including all list entries.
Community ListsE-Series Routers
1-35
neighbor send-community� Use to specify that a community attribute should be sent to a BGP neighbor.� If you specify a BGP peer group by using the peer-group-name argument, all
the members of the peer group will inherit the characteristic configured with this command.
� Use the no version to specify that common attributes should not be sent to a BGP neighbor.
set community� Use to set the community attribute in BGP updates.� You can specify a community list number in the range 1�4294967295, or in the
new community format of AA:NN, or one of the following well-known communities: � local-as � prevents advertisement outside the local AS� no-advertise � prevents advertisement to any peer� no-export � prevents advertisement beyond the BGP confederation
boundary� Alternatively, you can use the list keyword to specify the name of a community
list that you previously created with the ip community-list command. � Supported for inbound, outbound, and redistribution route maps.� Example
host1(config)#route-map 1
host1(config-route-map)#set community no-advertise
� Use the none keyword to remove the community attribute from a route.� Use the no version to delete the entry.
Extended Community ListsThe router supports the BGP extended community attribute defined in the Internet draft, BGP Extended Communities Attribute – draft-ietf-idr-bgp-ext-communities-05.txt (November 2002 expiration). This attribute enables the definition of a new type of IP extended community and extended community list unrelated to the community list that uses regular expressions.
Note: IETF drafts are valid for only 6 months from the date of issuance. They must be considered as works in progress. Please refer to the IETF Web site at http://www.ietf.org for the latest drafts.
BGP speakers can use the extended community attribute to control routes much like they use the community attribute to determine routes they accept, reject, or redistribute. A BGP speaker can append the extended community attribute to a route that does not have the attribute before advertising the route. For routes that do have the attribute, BGP can modify the attribute.
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ip extcommunity-list� Use to create an extended community list for BGP and control access to it.� A route can belong to any number of communities, so an extended community
list can have many entries comprising many communities.� You can specify one or more community values when you create an extended
community list. A clause in a route map that includes a list having more than one value matches only a route having all of the values; that is, the multiple values are logical ANDed.
� Use the rt keyword to specify a route target community, which consists of one or more routers that can receive a set of routes advertised by BGP that carry the extended community attribute.
� Use the soo keyword to specify a site-of-origin community, which consists of one or more routers that inject into BGP a set of routes that carry the extended community attribute.
� Examplehost1(config)#ip extcommunity-list boston1 permit rt 100:2 rt 100:3 rt 100:4
host1(config)#route-map marengo permit 10
host1(config-route-map)#match extcommunity boston1
A route matches this community list only if it belongs to at least all three communities in extended community list boston1: communities 100:2, 100:3, and 100:4.
� Use the no version to remove a single extended community list entry if permit or deny and a path-expression are specified. Otherwise, the entire community list is removed.
match extcommunity� Use to match an extended community list in a route map. � You can specify one or more extended community list names in a match
clause. If you specify more than one extended community list, the lists are logically ORed.
� Examplehost1(config-route-map)#match extcommunity topeka10
� Use the no version to remove the match clause from a route map or a specified value from the match clause.
set extcommunity � Use to set the extended community attributes in a route map for BGP updates. � Use the rt keyword to specify a route target community, which consists of one
or more routers that can receive a set of routes advertised by BGP that carry the extended community attribute.
� Use the soo keyword to specify a site-of-origin community, which consists of one or more routers that inject into BGP a set of routes that carry the extended community attribute.
Using Regular ExpressionsE-Series Routers
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� You can specify both a route target community and a site-of-origin community at the same time in a set clause without overwriting each other.
� Examplehost1(config)#route-map 1
host1(config-route-map)#set extcommunity rt 10.10.10.2:325
� Use the no version to remove the set clause from the route map.
show ip extcommunity-list � Use to display information about a specific extended community list or all
extended community lists. � Example
host1#show ip extcommunity-list
IP Extended Community List dresden1:
permit soo 10.10.10.10:15
IP Extended Community List bonn:
deny rt 12:12
Using Regular ExpressionsYou can use regular expressions when defining AS-path access lists and community lists to more easily filter routes. A regular expression uses special characters—often referred to as metacharacters—to define a pattern that is compared with an input string.
AS-path ListsFor an AS-path access list, the input string is the AS path of the routes to which the list is applied via the route-map or neighbor filter-list commands. If the AS path matches the regular expression in the access list, then the route matches the access list.
Example The following commands apply access list 1 to routes inbound from BGP peer 10.5.5.2. Access list 1 uses a regular expression to deny routes originating in AS 32.
host1(config-router)#neighbor 10.5.5.2 remote-as 32
host1(config-router)#neighbor 10.5.5.2 filter-list 1 in
host1(config-router)#exit
host1(config)#ip as-path access-list 1 deny 32$
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Community ListsFor a community list, the input string is the community attribute of the routes to which the list is applied via a route-map command. If the community attribute matches the regular expression in the community list, then the route matches the community list.
Example The following commands apply route map 5 to routes forwarded to BGP peer 10.5.5.4. Route map 5 uses a regular expression to match community numbers ending with 305, setting the weight of matching routes to 150.
host1(config-router)#neighbor 10.5.5.4 remote-as 425
host1(config-router)#neighbor 10.5.5.4 route-map 5 out
host1(config-router)#exit
host1(config)#route-map 5 permit 10
host1(config-route-map)#match community 305$
host1(config-route-map)#set weight 150
Community NumbersWhen you use a regular expression to match a community number, use the appropriate format for the community number in the community list. If you issue the ip bgp-community new-format command, the community number has the format AA:NN where AA is a number that identifies the autonomous system, and NN is a number that identifies the community within the autonomous system. Otherwise, the community number is an integer in the range 1–4294967295.
MetacharactersEach regular expression consists of one or more metacharacters and zero or more complete or partial AS or community numbers. Table 1-3 describes the metacharacters supported for regular expression pattern-matching.
Table 1-3 Supported regular expression metacharacters
Metacharacter Description
^ Matches the beginning of the input string.Alternatively, when used as the first character within brackets�[^ ]�matches any number except the ones specified within the brackets.
$ Matches the end of the input string.
. Matches any single character, including white space.
* Matches 0 or more sequences of the immediately previous character or pattern.
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Using Metacharacters as Literal TokensYou can remove the special meaning of a metacharacter by preceding it with a backslash (\). Such a construction denotes that the metacharacter is not treated as a metacharacter for that regular expression. It is simply a character or token with no special meaning, just as a numeral has no special meaning. The backslash applies only to the character immediately following it in the regular expression.
On the E-series router, you are likely to use the backslash only for the parentheses characters, ( or ). BGP indicates a segment of an AS path that is of type AS-confed-set or AS-confed-seq by enclosing that segment within parentheses.
Example The following AS-path access list uses a regular expression to match routes having an AS-path attribute that begins with any AS-confed-set or AS-confed-seq:
host1(config)#ip as-path access-list 1 permit ^\(
The following AS-path access list uses a regular expression to match routes having an AS-path attribute that ends with any AS-confed-set or AS-confed-seq:
host1(config)#ip as-path access-list 1 permit \)$
+ Matches 1 or more sequences of the immediately previous character or pattern.
? Matches 0 or 1 sequence of the immediately previous character or pattern.
() Specifies patterns for multiple use when followed by one of the multiplier metacharacters: asterisk *, plus sign +, or question mark ?
[ ] Matches any enclosed character; specifies a range of single characters.
� (hyphen) Used within brackets to specify a range of AS or community numbers.
_ (underscore) Matches a ^, a $, a comma, a space, a {, or a }. Placed on either side of a string to specify a literal and disallow substring matching. Numerals enclosed by underscores can be preceded or followed by any of the characters listed above.
| Matches characters on either side of the metacharacter; logical OR.
Table 1-3 Supported regular expression metacharacters (continued)
Metacharacter Description
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The following AS-path access list uses a regular expression to match routes having an AS-path attribute that includes the specific AS-confed-set or AS-confed-seq, (100 200):
host1(config)#ip as-path access-list 1 permit \(100 200\)
Regular Expression ExamplesTable 1-4 shows some representative regular expressions that might be used in an AS-path access list or community list, along with sample attribute values that match or do not match the regular expression.
Table 1-4 Sample regular expressions
Regular Expression Matches Any AS-path or Community Attribute That...
^12 Begins with 12, such as the following:12 23 42 12 62912 1245 19but not58 12 7
[^12] Includes any numeral except 1 or 2, such as the following:44 73 46 5 698but not1145 19 122 49
305$ Ends with 305, such as the following:89 611 305 30542 305 19 13056666:305
.5 Includes any one character followed by numeral 5, such as the following:89 611 35 33 252 12 998600:500
1.9 Includes a sequence of three characters where the first character is numeral 1 and the third character is numeral 9, such as the following:179 35 24 33 252 129 482129 14 600:2129321:94
.* Includes any character; matches all AS paths and community lists
42* Includes a number having a numeral 4 followed by zero or more instances of numeral 2, such as the following:67 42 51 31433 252 422 48 31424 339 78 31422
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1(37)* Includes a sequence having a numeral 1 followed by zero or more instances of the pattern 37, such as the following:137 42 21 1373737 29 41but not4 3737 78
42+ Includes a number having a numeral 4 immediately followed by one or more instances of numeral 2, such as the following:67 42 21 33 252 422 48but not4 329 78
1(37)+ Includes a sequence having a numeral 1 immediately followed by one or more instances of the pattern 37, such as the following:1373737 29 4 4 37137 78137 42 21but not4 372 21 21 37 51 456 88 1
42? Includes a number having a numeral 4 followed by zero or only one instance of numeral 2, such as the following:67 42 71 4 359 78but not33 252 422 48
1(37)? Includes a sequence having a numeral 1 followed by zero or only one instance of the pattern 37, such as the following:137 42 21 53 612 491but not4 13737 78
7.. Includes a sequence of three characters where the first character is numeral 7, such as the following:600 700 100 25 7771In the following examples, the three characters are 7, space, 8:307 800 6127 888 999
^7.. Includes a number ranging from 700 to 799, such as the following:6127 723 999 700 100 600but not25 7771 307 800
Table 1-4 Sample regular expressions (continued)
Regular Expression Matches Any AS-path or Community Attribute That...
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For information on using AS-path access lists, see Access Lists on page 1-16. For information on using community lists, see Community Lists on page 1-31.
^7..$ Consists only of a number ranging from 700 to 799, such as the following:723 700but not25 7771 307 800 6127 723 999 700 100 600
[621] Includes any of the numerals 6, 2, or 1, such as the following:60 43 34 545 92200 71086 53The regular expression [162] has the same results.
[0-9] Includes any number in the range 0�9
^\(22 431\) (AS-path attribute only) Begins with the AS-confed-set or AS-confed-seq (22 431), such as the following:(22 431) 102 (22 431) 55 76but not43 (22 431) 5 22 431 59
{41 19} (AS-path attribute only) Includes the AS-set or AS-seq {41 19}, such as the following:{41 19} 53 76 {41 19} 17255 {41 19}but not3 41 19 41 19 532
101 102 | 103 105 Includes either sequence 101 102 or sequence 103 105, such as the following:43 101 102 5 103 105 22but not19 102 101 102 103
_200_ Includes the number 200 (as opposed to the pattern consisting of numeral 2, numeral 0, numeral 0), such as the following:33 200 422 48 ^200$^200 500$but not33 20 422 48 51 2005Our implementation of regular expressions is not literal. Substring matching is enabled by default. Specifying 200 (no underscores) results in a match on 200 and on 2005. The underscore metacharacter disables substring matching.
Table 1-4 Sample regular expressions (continued)
Regular Expression Matches Any AS-path or Community Attribute That...
Managing the Routing TableE-Series Routers
1-43
Managing the Routing TableYou can clear all routes from the IP routing table, then enable the owning protocols—BGP, OSPF, RIP—to reinstall the routes.
clear ip routes� Use to clear all routing entries or a specified entry from the IP routing table.� Example
host1#clear ip routes
� There is no no version.
ip refresh-route� Use to reinstall routes removed from the IP routing table by the clear ip route
command.� Example
host1#ip refresh-route
� There is no no version.
Troubleshooting Routing PolicyYou can turn on debugging for routing policy by issuing the log severity debug ipRoutePolicy command from Global Configuration mode. You can specify different levels of severity for ipRoutePolicy. See E-Series System Basics Configuration Guide, Chapter 4, Managing the System, for more information on using log commands for troubleshooting.
Monitoring Routing PolicyYou can monitor the following aspects of routing policy using show commands:
• Access lists
host1#show access-list
host1#show ip as-path access-list
• Community lists
host1#show ip community-list
• Prefix lists
host1#show ip prefix-list
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• Prefix trees
host1#show ip prefix-tree
• Protocols
host1#show ip protocols
• Redistribution policies
host1#show ip redistribute
• Routes
host1#show ip route
• Interfaces and next hops
host1#show ip route slot 5 192.168.5.4
• Route maps
host1#show route-map
• Static routes
host1#show ip static
• IP traffic
host1#show ip traffic
You can use the output filtering feature of the show command to include or exclude lines of output based on a text string you specify. Refer to E-Series System Basics Configuration Guide, Chapter 2, Command Line Interface, for details.
show access-list� Use to display information about access lists.� The displayed information includes the instances of each access list.� Use the detail keyword to display the automatically assigned element ID for
each access-list entry. Only rules that you explicitly create have element IDs.� Example
host1#show access-list
IP Access List 1:
permit ip host 172.31.192.217 any
permit ip 12.40.0.0 0.0.0.3 any
deny ip any any
IP Access List 2:
permit ip 172.19.0.0 0.0.255.255 any
deny ip 0.0.0.0 255.255.255.255 any
IP Access List 10:
permit ip any any
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IP Access List 11:
deny ip any any
host1#show access-list detail
IP Access List 1:
1: permit ip host 172.31.192.217 any
2: permit ip 12.40.0.0 0.0.0.3 any
deny ip any any
show ip as-path-access-list� Use to display information about AS-path access lists.� Example
host1#show ip as-path-access-list
AS Path Access List 1:
permit .*
AS Path Access List 2:
deny .*
AS Path Access List 3:
permit _109_
deny .*
AS Path Access List 4:
permit _109$
deny .*
AS Path Access List 10:
deny _109$
permit ^108_
deny .*
show ip community-list� Use to display community list information.� Display varies based on whether you issued the ip bgp community
new-format command.� Example 1. If you did not issue the ip bgp community new-format command,
the display appears as follows:host1#show ip community-list
Community List 1:
permit 81200109
permit 81200110
permit 81200108
Community List 2:
deny 81200109
permit 81200110
permit 81200108
Community List 4:
permit local-as
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Community List 5:
permit no-advertise
Community List 6:
permit no-export
Community List 7:
permit internet
� Example 2. If you did issue the ip bgp community new-format command, the display appears as follows:host1#show ip community-list
Community List 1:
permit 1239:1005
permit 1239:1006
permit 1239:1004
Community List 2:
deny 1239:1005
permit 1239:1006
permit 1239:1004
Community List 4:
permit local-as
Community List 5:
permit no-advertise
Community List 6:
permit no-export
Community List 7:
permit internet
show ip prefix-list� Use to display information about the prefix lists currently configured on the
router.� Example
host1#show ip prefix-list
Prefix-list with the last deletion/insertion: def
ip prefix-list name abc: 4 entries
seq 5 permit 192.168.0.0/16 le 24
seq 10 permit 192.178.0.0/16 le 24
seq 15 deny 195.178.0.0/16 le 24
seq 20 deny 195.178.0.0/16 le 32
ip prefix-list name def: 1 entries
seq 5 deny 192.170.0.0/16
� Examplehost1#show ip prefix-list summary
Total memory used for prefix-list: 310 bytes
Prefix-list with the last deletion/insertion: def
ip prefix-list name abc:
count: 4, range entries: 4, sequences: 5-20
Monitoring Routing PolicyE-Series Routers
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ip prefix-list name def:
count: 1, range entries: 0, sequences: 5-5
show ip prefix-tree� Use to display information about the prefix trees currently configured on the
router.� Example
host1#show ip prefix-tree
Prefix-tree with the last deletion/insertion: t_abc5
ip prefix-tree name t_abc1: 1 entries
permit 108.243.0.0/16
ip prefix-tree name t_abc2: 3 entries
permit 101.10.254.0/24
permit 102.10.248.0/21
permit 103.10.192.0/18
permit 108.109.0.0/16
permit 108.109.241.0/24
ip prefix-tree name t_abc3: 1 entries
deny 108.0.0.0/8
� Examplehost1#show ip prefix-tree summary
Total memory used for prefix-tree: 860 bytes
Prefix-tree with the last deletion/insertion: t_abc5
ip prefix-tree name t_abc1:
count: 1
ip prefix-tree name t_abc2:
count: 5
ip prefix-tree name t_abc3:
count: 1
show ip protocols� Use to display detailed information about the protocols currently configured on
the router.� Use the summary keyword to display only a list of the configured protocols.� For field descriptions, see the show commands for the individual routing
protocols in their respective Configuration Guide chapters.� Example
host1#show ip protocols
Routing Protocol is “bgp 1”
Default local preference is 100
IGP synchronization is enabled
Always compare MED is disabled
Router flap damping is disabled
Administrative Distance: external 20 internal 200 local 200
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Neighbor(s):
No neighbors are configured
Routing for Networks:
Routing Protocol is “ospf 255” with Router ID 100.100.100.1
Distance is 110
Address Summarization:
None
Routing for Networks:
Routing Protocol is “rip”
Router Administrative State: enable
System version RIP1: send = 1, receive = 1 or 2
Update interval: 30 seconds
Invalid after: 180 seconds
hold down time: 120 seconds
flushed interval: 300 seconds
Filter applied to outgoing route update is not set
Filter applied to incoming route update is not set
No global route map
Distance is 120
Interface Tx Rx Auth
Routing for Networks:
10.2.1.0/255.255.255.0
show ip redistribute� Use to display configured route redistribution policy.� Field descriptions
� To � protocol into which routes are distributed � From � protocol from which routes are distributed � status � redistribution status� route map number � number of the route map
� Examplehost1#show ip redistribute
To ospf, From static is enabled with route map 4
To ospf, From connected is enabled with route map 3
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show ip route� Use to display the current state of the routing table, including routes not used
for forwarding.� You can display all routes, a specific route, all routes beginning with a specified
address, routes for a particular protocol (BGP, IS-IS, OSPF, or RIP), locally connected routes, internal control routes, static routes, or summary counters for the routing table.
� Field descriptions� Prefix � IP address prefix� Length � prefix length� Type � protocol type� Next Hop � IP address of the next hop� Dist � distance metric for the route� Met � number of hops� Intf � interface type and interface specifier
� Example 1host1#show ip route
Protocol/Route type codes:
I1- ISIS level 1, I2- ISIS level2,
I- route type intra, IA- route type inter, E- route type external,
i- metric type internal, e- metric type external,
O- OSPF, E1- external type 1, E2- external type2,
N1- NSSA external type1, N2- NSSA external type2
Prefix/Length Type Next Hop Dist/Met Intf
------------- ---- -------- -------- ------
172.16.2.0/24 Bgp 192.168.1.102 20/1 fastEthernet0/0
10.10.0.112/32 Static 192.168.1.1 1/1 fastEthernet0/0
10.1.1.0/24 Connect 10.1.1.1 0/1 atm3/0.100
� Example 2host1#show ip route static
Protocol/Route type codes:
I1- ISIS level 1, I2- ISIS level2,
I- route type intra, IA- route type inter, E- route type external,
i- metric type internal, e- metric type external,
O- OSPF, E1- external type 1, E2- external type2,
N1- NSSA external type1, N2- NSSA external type2
Prefix/Length Type Next Hop Dist/Met Intf
------------- ---- -------- -------- ------
10.10.0.112/32 Static 192.168.1.1 1/1 fastEthernet0/0
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� Example 3host1#show ip route summary
5 total routes, 720 bytes in route entries
0 isis routes
0 rip routes
1 static routes
1 connected routes
0 bgp routes
0 ospf routes
3 other internal routes
0 access routes
0 internally created access host routes
Last route added/deleted: 0.0.0.0/0 by StaticLow
At THU MAR 09 2000 05:22:49 UTC
show ip route slot � Use to display the interface and next hop for an IP address in the routing table
of a line module specified by the slot it occupies.� slotNumber � number of slot containing the line module for which the
information is displayed� ipAddress � IP address to look up in the routing table
� Field descriptions� IP address � address reachable via the interface� Interface � interface type and specifier associated with the IP address;
displays �Local Interface� if a special interface index is present in the routing table for special IP addresses, such as broadcast addresses
� Next Hop � next hop to reach the IP address; displays �---� if no next hop is associated with the IP address
� Example 1host1#show ip route slot 6 10.10.0.231
IP address Interface Next Hop
------------ ---------------- ------------
10.10.0.231 fastEthernet 6/0 10.10.0.231
� Example 2host1#show ip route slot 9 90.248.1.2
IP address Interface Next Hop
------------ ---------------- ------------
90.248.1.2 serial9/23:2 ---
� Example 3host1#show ip route slot 9 90.249.255.255
IP address Interface Next Hop
------------ ---------------- ------------
90.249.255.255 Local Interface ---
Monitoring Routing PolicyE-Series Routers
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show ip static� Use to display the status of static routes in the routing table.� You can specify an optional IP mask that filters specific routes.� Field descriptions
� Prefix � IP address prefix� Length � prefix length� Next Hop � IP address of the next hop� Met � number of hops� Dist � administrative distance or weight assigned to the route� Tag � tag value assigned to the route� Intf � interface type and interface specifier
� Examplehost1#show ip static
Prefix/Length Next Hop: Met: Dist: Tag: Intf:
10.2.0.0/24 192.168.1.1 1 1 0 ethernet6/0
10.2.1.0/24 192.168.1.1 1 1 1 ethernet6/0
172.31.1.48/32 172.18.2.2 1 1 0 atm5/1.1
show ip traffic� Use to display statistics about IP traffic.� Field descriptions
� IP Statistics Rcvd:� Router Id � router ID number� total � number of frames received� local destination � frames with this router as their destinations� hdr errors � number of packets containing header errors� addr errors � number of packets containing addressing errors� unkn proto � number of packets received containing unknown protocols� discards � number of discarded packets
� IP Statistics Frags:� reassembled � number of reassembled packets� reasm timed out � number of reassembled packets that timed out� reasm req � number of requests for reassembly� reasm fails � number of reassembly failures� frag ok � number of fragmented packets reassembled successfully� frag fail � number of fragmented packets reassembled unsuccessfully� frag creates � number of packets created by fragmentation
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� IP Statistics Sent:� forwarded � number of packets forwarded� generated � number of packets generated� out disc � number of outbound packets discarded� no routes � number of packets that could not be routed� routing discards � number of packets that could not be routed that were
discarded� IP Statistics Route:
� routes in table � number of routes in the routing table� timestamp req � number of requests for a timestamp� timestamp rpy � number of replies to timestamp requests� addr mask req � number of address mask requests� addr mask rpy � number of address mask replies
� ICMP Statistics Rcvd:� total � total number of ICMP packets received� errors � number of error packets received� dst unreach � number of packets received with destination unreachable� time exceed � number of packets received with time-to-live exceeded� param probs � number of packets received with parameter errors� src quench � number of source quench packets received� redirects � number of receive packet redirects� echo req � number of echo request (ping) packets� echo rpy � number of echo replies received� timestamp req � number of requests for a timestamp� timestamp rpy � number of replies of timestamp requests� addr mask req � number of mask requests sent� addr mask rpy � number of mask replies sent
� ICMP Statistics Sent:� total � total number of ICMP packets sent� errors � number of error packets sent� dest unreach � number of packets sent with destination unreachable� time excd � number of packets sent with time-to-live exceeded� param prob � number of packets sent with parameter errors� src quench � number of source quench packets sent� redirects � number of send packet redirects� echo req � number of echo request (ping) packets� echo rpy � number of echo replies received� timestamp req � number of requests for a timestamp� timestamp rpy � number of replies to timestamp requests� addr mask req � number of address mask requests� addr mask rpy � number of address mask replies
Monitoring Routing PolicyE-Series Routers
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� UDP Statistics Rcvd:� total � total number of UDP packets received� checksum � number of checksum error packets received � no port � number of packets received for which no application listener
was listening on the destination port� UDP Statistics Sent:
� total � total number of UDP packets sent� errors � number of error packets sent
� TCP Global Statistics Connections:� attempted � number of outgoing TCP connections attempted� accepted � number of incoming TCP connections accepted� established � number of TCP connections established� dropped � number of TCP connections dropped� closed � number of TCP connections closed
� TCP Global Statistics Rcvd:� total pkts � total number of TCP packets received� in-sequence pkts � number of packets received in sequence� bytes � number of bytes received� chksum err pkts � number of checksum error packets received� authentication err pkts � number of authentication error packets received� bad offset pkts � number of packets received with bad offsets� short pkts � number of short packets received� duplicate pkts � number of duplicate packets received� out of order pkts � number of packets received out of order
� TCP Global Statistics Sent:� total pkts � total number of TCP packets sent� data pkts � number of data packets sent� bytes � number of bytes sent� retransmitted pkts � number of packets retransmitted� retransmitted bytes � number of retransmitted bytes
� OSPF Statistics � not supported for this version of the router� IGMP Statistics � not supported for this version of the router� ARP Statistics � not supported for this version of the router
� Examplehost1#show ip traffic
IP statistics: Router Id: 172.31.192.217
Rcvd: 97833 total, 171059 local destination
0 hdr errors, 0 addr errors
167 unkn proto, 0 discards
Frags: 4 reassembled, 30 reasm timed out, 8 reasm req
0 reasm fails, 145 frag ok, 0 frag fail
290 frag creates
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Sent: 15 forwarded, 25144 generated, 0 out disc
0 no routes,0 routing discards
Route: 57680 routes in table
0 timestamp req, 0 timestamp rpy
0 addr mask req, 0 addr mask rpy
ICMP statistics:
Rcvd: 561 total, 0 errors, 15 dst unreach
0 time exceed, 0 param probs, 0 src quench
0 redirects, 0 echo req, 0 echo rpy
0 timestamp req, 0 timestamp rpy
0 addr mask req, 0 addr mask rpy
Sent: 0 total, 0 errors, 0 dest unreach
0 time excd, 0 param prob, 0 src quench
0 redirects, 0 echo req, 0 echo rpy
UDP Statistics:
Rcvd: 93326 total, 0 checksum errors, 90610 no port
Sent: 0 total, 0 errors
TCP Global Statistics:
Connections: 7358 attempted, 4 accepted, 7362 established
0 dropped, 14718 closed
Rcvd: 75889 total pkts, 53591 in-sequence pkts, 3120283 bytes
0 chksum err pkts, 0 authentication err pkts, 0 bad offset
0 short pkts, 0 duplicate pkts, 0 out of order pkts
Sent: 82318 total pkts, 44381 data pkts, 656321 bytes
34 retransmitted pkts, 487 retransmitted bytes
OSPF Statistics:
IGMP Statistics:
ARP Statistics:
show route-map� Use to display the configured route maps.� The displayed information includes the instances of each access list such as
match and set commands.� Example
host1(config)#route-map 1 permit 10
host1(config-route-map)#match community 44
host1(config-route-map)#set local-pref 400
host1(config-route-map)#exit
host1(config)#exit
host1#show route-map 1
Monitoring Routing PolicyE-Series Routers
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route-map 1, permit, sequence 10
Match clauses:
match community 44
Set clauses:
set local-pref 400
CHAPTER 1Configuring Routing Policy
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Part 2Internet Protocol
2
Configuring IPThis chapter describes how to configure Internet Protocol (IP) routing on your E-series router.
Topic Page
Overview 2-2
References 2-4
IP Features 2-5
IP Addressing 2-6
Before You Configure IP 2-11
Creating a Profile 2-11
Address Resolution Protocol (ARP) 2-14
Broadcast Addressing 2-19
Fragmentation 2-20
IP Routing 2-21
Shared IP Interfaces 2-33
Internet Control Message Protocol 2-38
Reachability Commands 2-40
Response Time Reporter 2-42
Monitoring IP 2-55
CHAPTER 2Configuring IP
2-2
OverviewTCP/IP is a suite of data communications protocols. Two of the more important protocols in the suite are the Transmission Control Protocol (TCP) and the Internet Protocol (IP).
IP provides the basic packet delivery service for all TCP/IP networks. IP is a connectionless protocol, which means that it does not exchange control information to establish an end-to-end connection before transmitting data. A connection-oriented protocol exchanges control information with the remote computer to verify that it is ready to receive data before sending it.
IP relies on protocols in other layers to establish the connection if connection-oriented services are required and to provide error detection and error recovery. IP is sometimes called an unreliable protocol, because it contains no error detection or recovery code.
IP PacketsA packet is a block of data that carries with it the information necessary to deliver it to a destination address. A packet-switching network uses the addressing information in the packets to switch packets from one physical network to another, moving them toward their final destination. Each packet travels the network independently of any other packet. The datagram is the packet format defined by IP.
IP FunctionsSome of the functions IP performs include:
• Moving data between the network access layer and the host-to-host transport layer
• Routing datagrams to remote hosts
• Fragmenting and reassembling datagrams
Moving Data Between LayersWhen IP receives a datagram that is addressed to the local host, it must pass the data portion of the datagram to the correct host-to-host transport layer protocol. IP uses the protocol number in the datagram header to select the transport layer protocol. Each host-to-host transport layer protocol has a unique protocol number that identifies it to IP.
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Routing Datagrams to Remote HostsInternet gateways are commonly referred to as IP routers because they use IP to route packets between networks. In traditional TCP/IP terms, there are only two types of network devices: gateways and hosts. Gateways forward packets between networks, and hosts do not. However, if a host is connected to more than one network (called a multihomed host), it can forward packets between the networks. When a multihomed host forwards packets, it acts like any other gateway and is considered to be a gateway.
Fragmenting and Reassembling DatagramsAs a datagram is routed through different networks, it may be necessary for the IP module in a gateway to divide the datagram into smaller pieces. A datagram received from one network may be too large to be transmitted in a single packet on a different network. This condition occurs only when a gateway interconnects dissimilar physical networks.
Each type of network has a maximum transmission unit (MTU) that determines the largest packet it can transfer. If the datagram received from one network is longer than the other network’s MTU, it is necessary to divide the datagram into smaller fragments for transmission in a process called fragmentation. See Fragmentation later in this chapter.
IP LayeringTCP/IP is organized into four conceptual layers (as shown in Figure 2-1).
Figure 2-1 TCP/IP conceptual layers
Network Interface LayerThe network interface layer is the lowest level of the TCP/IP protocol stack. It is responsible for transmitting datagrams over the physical medium to their final destinations.
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Internet LayerThe Internet layer is the second level of the TCP/IP protocol stack. It provides host-to-host communication. In this layer, packets are encapsulated into datagrams, routing algorithms are run, and the datagram is passed to the network interface layer for transmission on the attached network.
Transport LayerThe transport layer is the third level of the TCP/IP protocol stack. It is responsible for providing communication between applications residing in different hosts. By placing identifying information in the datagram (such as socket information), the transport layer enables process-to-process communication.
The transport layer provides either a reliable transport service (TCP) or an unreliable service (User Data Protocol). In a reliable delivery service, the destination station acknowledges the receipt of a datagram.
Application LayerThe application layer is the fourth and highest level of the TCP/IP protocol stack. Some applications that run in this layer are:
• Telnet
• File Transfer Protocol (FTP)
• Simple Mail Transfer Protocol (SMTP)
• Simple Network Management Protocol (SNMP)
• Domain Name System (DNS)
ReferencesFor more information about IP, consult the following resources:
• RFC 768 – User Datagram Protocol (August 1980)
• RFC 791 – Internet Protocol DARPA Internet Program Protocol Specification (September 1981)
• RFC 792 – Internet Control Message Protocol (September 1981)
• RFC 793 – Transmission Control Protocol (September 1981)
• RFC 854 – Telnet Protocol Specification (May 1983)
• RFC 919 – Broadcasting Internet Datagrams (October 1984)
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• RFC 922 – Broadcasting Internet Datagrams in the Presence of Subnets (October 1984)
• RFC 950 – Internet Standard Subnetting Procedure (August 1985)
• RFC 1112 – Host Extensions for IP Multicasting (August 1989)
• RFC 1122 – Requirements for Internet Hosts—Communication Layers (October 1989)
• RFC 1812 – Requirements for IP Version 4 Routers (June 1995)
• E-Series Release Notes, Appendix A, System Maximums – Refer to the Release Notes corresponding to your software release for information on maximum values.
IP FeaturesThe E-series router supports the following IP features:
• Internet Control Message Protocol (ICMP)
• Traceroute
• User Datagram Protocol (UDP)
• Transmission Control Protocol (TCP)
• Classless interdomain routing (CIDR)
• Maximum transmission unit (MTU)
• Support for simultaneous multiple logical IP stacks on the same router
• Flexible IP address assignment to support any portion of a physical interface (for example, a channel or circuit), exactly one physical interface, or multilink PPP interfaces
• Packet segmentation and reassembly
• Loose source routing to specify the IP route
• Strict source routing to specify the IP route for each hop
• Record route to track the route taken
• Internet timestamp
• Broadcast addressing, both limited broadcast and directed broadcast
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• Support for 32,000 discrete, simultaneous IP interfaces per router to support thousands of logical connections
• Capability of detecting and reporting changes in the up or down state of any IP interface
• IP policy support. See Chapter 1, Configuring Routing Policy, for more information on policy configuration.
IP AddressingThis section provides an overview of IP addressing in general and includes a discussion of CIDR, which your router fully supports.
Physical and Logical AddressesPhysical node addresses are used at the network access layer to identify physical devices in a network. For example, each Ethernet controller comes from the manufacturer with a physical address, called a MAC address.
IP implements a system of logical host addresses called IP addresses. The IP addresses are used by the internetwork and higher layers to identify devices and to perform internetwork routing. The Address Resolution Protocol (ARP) enables IP to identify the physical (MAC) address that matches a given IP address. You can use ARP only on Ethernet and bridged IP 1483 interfaces.
IP is used by all protocols in the layers above and below it to deliver data. This means that all TCP/IP data flows through IP when it is sent and received, regardless of its final destination.
Internet AddressesInternet addressing uses a 32-bit address field. The bits in this address field are numbered 0 to 31. The 32-bit address field consists of two parts: a network number and a host number whose boundaries are defined based on the class of IP address. Hosts attached to the same network must share a common prefix designating their network number.
Four types of IP classes lend themselves to different network configurations, depending on the desired ratio of networks to hosts. Figure 2-2 shows the format of IP address classes.
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Figure 2-2 IP address classes
• Class A – The leading bit is set to 0, a 7-bit number, and a 24-bit local host address. Up to 125 class A networks can be defined, with up to 16,777,214 hosts per network.
• Class B – The two highest-order bits are set to 1 and 0, a 14-bit network number, and a 16-bit local host address. Up to 16,382 class B networks can be defined, with up to 65,534 hosts per network.
• Class C – The three leading bits are set to 1, 1, and 0, a 21-bit network number, and an 8-bit local host address. Up to 2,097,152 class C networks can be defined, with up to 254 hosts per network.
• Class D – The four highest-order bits are set to 1, 1, 1, and 0. Class D is used as a multicast address.
Subnet AddressingA subnet is a subset of a class A, B, or C network. Subnets cannot be used with class D (multicast) addresses.
A network mask is used to separate the network information from the host information on an IP address. Figure 2-3 shows the network mask 255.0.0.0 applied to network 10.0.0.0. The mask in binary notation is a series of 1s followed by a series of contiguous 0s. The 1s represent the network number; the 0s represent the host number. The sample address splits the IP address 10.0.0.1 into a network portion of 10 and a host portion of 0.0.1.
Note: The router supports a 31-bit mask on point-to-point links. This means that the IP address 1.2.3.4 255.255.255.254 is valid. A point-to-point link in which only one end supports the use of 31-bit prefixes may not operate correctly.
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Figure 2-3 Basic network masking
Classes A, B, and C have the following natural masks, which define the network and host portions of each class:
• Class A natural mask 255.0.0.
• Class B natural mask 255.255.0.0
• Class C natural mask 255.255.255.0
The use of masks can divide networks into subnetworks by extending the network portion of the address into the host portion. Subnetting increases the number of subnetworks and reduces the number of hosts.
For example, a network of the form 10.0.0.0 accommodates one physical segment with about 16 million hosts on it. Figure 2-4 shows how the mask 255.255.0.0. is applied to network 10.0.0.0. The mask divides the IP address 10.0.0.1 into a network portion of 10, a subnet portion of 0, and a host portion of 0.1. The mask has borrowed a portion of the host space and has applied it to the network space. The network space of the class 10 has increased from a single network 10.0.0.0 to 256 subnetworks, ranging from 10.0.0.0 to 10.255.0.0. This process decreases the number of hosts per subnet from 16,777,216 to 65,536.
Figure 2-4 Subnetting
Classless Addressing with CIDRClassless interdomain routing (CIDR) is a system of addressing that improves the scaling factor of routing in the Internet. CIDR does not use an implicit mask based on the class of network. In CIDR, an IP network is represented by a prefix, which is an IP address and an indication of the leftmost contiguous significant bits within this address.
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For example, without CIDR, the class C network address 192.56.0.0 would be an illegal address. With CIDR, the address becomes valid with the notation: 192.56.0.0/16. The /16 indicates that 16 bits of mask are being used (counting from the far left). This would be similar to an address 198.32.0.0. with a mask of 255.255.0.0.
A network is called a supernet when the prefix boundary contains fewer bits than the network’s natural mask. For example, a class C network 192.56.10.0 has a natural mask of 255.255.255.0. The representation 192.56.0.0/16 has a shorter mask than the natural mask (16 is less than 24), so it is a supernet.
Figure 2-5 shows how CIDR can reduce the number of entries globally in Internet routing tables. A service provider has a group of customers with class C addresses that begin with 192.56. Despite this relationship, the service provider announces each of the networks individually into the global Internet routing mesh.
Figure 2-5 Routing with and without CIDR
Adding and Deleting AddressesThis section provides information on adding or deleting IP addresses.
Multinetting is adding more than one IP address to an IP interface—that is, a primary address and one or more secondary addresses.
To make an interface unnumbered, see Setting Up an Unnumbered Interface later in this chapter.
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Adding a Primary Address • The primary address must be the first address added to the interface.
• Adding a new primary address overwrites the existing primary address.
• You can change a secondary address to be the primary address on an interface only via SNMP.
• An unnumbered address is always the primary address; adding an unnumbered address, therefore, overwrites any other numbered address.
Deleting a Primary Address • You must always remove the primary address from an interface last.
• You cannot delete the primary address if the interface still has assigned secondary addresses.
Adding a Secondary (Multinet) Address • You cannot add a secondary address until you add the primary
address.
• You cannot add a secondary address to bridged Ethernet interfaces.
• You cannot change a primary address to a secondary address.
• An interface can have multiple secondary addresses.
Deleting a Secondary Address • You must delete secondary addresses before deleting the primary
address.
ip address CommandUse the following command to add addresses to or delete addresses from an interface:
ip address� Use to add a primary address or to add secondary addresses to an interface.� To add multiple addresses to a single IP interface, use the secondary keyword.
(Remember, if you add an address using the ip address command and do not include the secondary keyword, the new address becomes the primary address.)
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� Example � this example adds a primary address (192.168.2.77) and two secondary addresses (172.31.7.22 and 10.8.7.22); the Fast Ethernet interface now has addresses in three networks.host1(config)#interface fastEthernet 0/0
host1(config-if)#ip address 192.168.2.77 255.255.255.0
host1(config-if)#ip address 172.31.7.22 255.255.255.0 secondary
host1(config-if)#ip address 10.8.7.22 255.255.255.0 secondary
Note: You can use this command in Interface Configuration, Subinterface Configuration, or Profile Configuration mode.
� Use the no version to remove an IP address. If you remove a primary IP address, IP processing is disabled on the interface.
Before You Configure IPBefore you configure IP, you should have created lower-layer interfaces over which IP traffic f lows.
For example, to configure an ATM interface:
host1(config)#interface atm 1/0
host1(config-if)#atm sonet stm-1
host1(config-if)#no loopback
host1(config-if)#atm clock internal chassis
host1(config-if)#interface atm 1/0.10
host1(config-if)#atm pvc 10 0 20 aal5snap
Refer to the appropriate chapters for information on configuring a specific type of interface.
Note: If you choose to configure VRRP, we recommend that you complete all IP address configurations before you configure VRRP. See Chapter 11, Configuring VRRP, for additional information.
Creating a Profile You can configure an IP interface dynamically by creating a profile. A profile is a set of characteristics that acts as a pattern that can be dynamically assigned to an IP interface. You can manage a large number of IP interfaces efficiently by creating a profile with a specific set of characteristics. In addition, you can create a profile to assign an IP interface to a virtual router.
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A profile can contain one or more of the following characteristics:
• access-route – Enables the creation of host access routes on an interface
• address – Configures an IP address on an interface
• directed-broadcast – Enables directed broadcast forwarding
• mtu – Configures the maximum transmission unit for a network
• nat – Configures the interface as inside or outside for Network Address Translation (NAT)
• redirects – Enables transmission of ICMP redirect messages
• unnumbered – Configures IP on this interface without a specific address
• virtual-router – Specifies a virtual router to which interfaces created by this profile will be attached
Use the profile command from Global Configuration mode to create or edit a profile. See E-Series Link Layer Configuration Guide, Chapter 13, Configuring Dynamic Interfaces for information on creating profiles and on other characteristics that can be applied to the profile.
host1(config)#profile acton
host1(config-profile)#ip virtual-router warf
host1(config-profile)#ip unnumbered atm 3/0
ip access-routes� Use to enable an access route in a profile.� Example
host1(config)#profile foo
host1(config-profile)#ip access-routes
� Use the no version to remove the access route.
ip address� Use to assign an IP address to a profile.� You must first specify the layer 2 encapsulation before you can set the IP
address for serial interfaces.� Use the no version to remove the IP address assigned to the profile.
ip directed-broadcast� Use to enable a directed broadcast address in a profile.� Use the no version to remove the directed broadcast address from the profile.
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ip mtu� Use to assign the MTU size sent on an IP interface.� Use the no version to remove the assignment from the profile.
ip redirects� Use to enable the sending of redirect messages if the software is forced to
resend a packet through the same interface on which it was received.� Use the no version to remove the assignment from the profile.
ip unnumbered� Use to specify the numbered interface with which dynamic unnumbered
interfaces created with the profile are associated.� You can specify an unnumbered interface using RADIUS instead of using the ip
unnumbered command in a profile.� Example
host1(config-profile)#ip unnumbered fastEthernet 0/0
� Use the no version to remove the assignment from the profile.
ip virtual-router� Use to assign a virtual router to a profile.� You can configure a virtual router using RADIUS instead of adding one to the
profile by using the ip virtual-router command.� Use the no version to remove the virtual router assignment.
profile� Use to create a profile. � You specify a profile name with up to 80 characters.� Example
host1(config)#profile foo
� Use the no version to remove a profile.
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Assigning a Profile To assign a profile to an interface, use the profile command from Interface mode.
profile� Use to assign a profile to a PPP interface. The profile configuration is used to
dynamically create an upper IP interface. � Example
host1(config-if)#interface serial 2/1
host1(config-if)#encapsulation ppp
host1(config-if)#profile acton
� Use the no version to remove the assignment from the interface.
Address Resolution Protocol (ARP) Sending IP packets on a multiaccess network requires mapping from an IP address to a MAC address (the physical or hardware address).
In an Ethernet environment, ARP is used to map a MAC address to an IP address. ARP dynamically binds the IP address (the logical address) to the correct MAC address. Before IP unicast packets can be sent, ARP discovers the MAC address used by the Ethernet interface where the IP address is configured.
Hosts that use ARP maintain a cache of discovered Internet-to-Ethernet address mappings to minimize the number of ARP broadcast messages. To keep the cache from growing too large, an entry is removed if it is not used within a certain period of time. Before sending a packet, the host looks in its cache for Internet-to-Ethernet address mapping. If the mapping is not found, the host sends an ARP request.
Note: For information on MAC address validation, see the section MAC Address Validation.
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How ARP WorksThe way ARP works can best be explained in a simple example. As shown in Figure 2-6, host 1 wants to send an IP packet to host 2 on a different subnet. To complete this transmission, host 1 needs the MAC address of router 1, to be used as the forwarding gateway.
A typical scenario is:
1 Host 1 broadcasts an ARP request to all devices on subnet 1, composed by a query with the IP address of router 1. The IP address of router 1 is needed because host 2 is on a different subnet.
2 All devices on subnet 1 compare their IP address with the enclosed IP address sent by host 1.
3 Having the matching IP address, router 1 sends an ARP response, which includes its MAC address, to host 1.
Figure 2-6 How ARP works, steps 1, 2, and 3
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4 Host 1 proceeds with its intended transmission of IP packet to layer 3 DA (host 2) using router 1’s MAC address.
5 Router 1 forwards IP packet to host 2. Router 1 may send an ARP request to identify the MAC of host 2.
Figure 2-7 How ARP works, steps 4 and 5
ARP forces all receiving hosts to compare their IP addresses with the IP address of the ARP request. Keeping the above example in mind, if host 1 sent another IP packet to host 2, host 1 would first check its ARP table for router 1’s MAC address.
If the default router/gateway becomes unavailable, then all the routing/packet forwarding to remote destinations ceases. Usually, it requires manual intervention to restore connectivity, even though alternative paths may be available. Alternatively, Virtual Router Redundancy Protocol (VRRP) may be used to prevent loss of connectivity. See Chapter 11, Configuring VRRP.
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Address Resolution Protocol (ARP)E-Series Routers
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arp� Use to add a static (permanent) entry in the ARP cache. � You specify one of the following:
� ipAddress and macAddress of the interface� ipAddress, interfaceType and interfaceSpecifier, and an optional MAC
address� You can issue this command only for an Ethernet or bridged IP 1483 interface.� Example
host1(config)#arp 192.56.20.1 0090.1a00.0170
� Use the no version to remove an entry from the ARP cache.
arp timeout� Use to specify how long an entry remains in the ARP cache. � On the FE-2 module, you can set the ARP timeout only on bridged IP 1483 and
Fast Ethernet interfaces. You cannot set the timeout on the SRP module.� The default value is 21,600 seconds (6 hours). Use the show config command
to display the current value.� If you specify a timeout of 0 seconds, entries are never cleared from the ARP
cache.� Example
host1(config-if)#arp timeout 8000
� Use the no version to restore the default value.
clear arp� Use to clear dynamic entries from the ARP cache. � To clear a particular entry, specify all of the following:
� ipAddress � IP address in four-part dotted-decimal format corresponding to the local data link address
� interfaceType � interface type; see Interface Types and Specifiers in About This Guide
� interfaceSpecifier � particular interface; format varies according to interface type; see Interface Types and Specifiers in About This Guide
� To clear all dynamic ARP entries, specify an asterisk (*).� Example
host1#clear arp
� There is no no version.
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ip proxy-arp� Use the ip proxy-arp command to enable proxy ARP on an Ethernet or
bridge1483 interface.� Proxy ARP is enabled by default.� Example
host1(config-if)#ip proxy-arp unrestricted
� Use the no version to disable proxy ARP on the interface.
MAC Address ValidationMAC address validation is a verification process performed on each incoming packet to prevent spoofing on IP Ethernet-based interfaces, including bridged Ethernet interfaces. When an incoming packet arrives on a layer 2 interface, the validation table is used to compare the packet’s source IP address with its MAC address. If the MAC address and IP address match, the packet is forwarded; if it does not match, the packet is dropped.
Note: MAC address validation for bridged Ethernet interfaces is supported only on OC12a line modules.
MAC address validation on the E-series router can be accomplished in two ways:
• You can statically configure it on a physical interface via the arp validate command
• You can allow DHCP to perform the function independently and dynamically. See DHCP in E-Series Link Layer Configuration Guide, Chapter 8, Configuring Bridged IP.
The arp validate command adds the IP-MAC address pair to the validation table maintained on the physical interface.
If the validation is added statically via the CLI, the IP address–MAC address pairs are stored in NVS. The entries are used for MAC validation only if MAC validation is enabled on the interface via the ip mac-validate command.
Caution: When you configure an interface using the arp validate command, you cannot overwrite the ARP values that were added by DHCP.
You can enable or disable MAC address validation on a per interface basis by issuing the ip mac-validate command. See E-Series Physical Layer Configuration Guide, Chapter 6, Configuring Ethernet Interfaces or E-Series Link Layer Configuration Guide, Chapter 9, Configuring Bridged Ethernet for information.
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arp validate� Use to add IP address�MAC address validation pairs. When validation is
enabled, all packets with the source IP address received on this IP interface are validated against the IP-MAC entries.
� You specify one of the following:� ipAddress and macAddress of the interface� ipAddress, interfaceType and interfaceSpecifier, and an optional MAC
address� You can issue this command only for an IP Ethernet-based interface.� For subscriber interface configurations, the IP address�MAC address pair must
have a matching source prefix that already exists on the subscriber interface. If the matching source prefix does not exist, the IP�MAC address pair is rejected. See E-Series Broadband Access Configuration Guide, Chapter 8, Configuring Subscriber Interfaces for information about using subscriber interfaces.
� The following example shows packets originating from host 192.56.20.1 and validated at Gigabit Ethernet interface with the MAC address 0090.1a00.0170.host1(config)#arp 192.56.20.1 gig 2/0 0090.1a00.0170 validate
� The following example shows the subscriber interface MAC address validation enabled.host1(config)#arp 192.168.32.0 ip subsc 1 000.0001.8100
� Use the no version to remove an entry from the ARP cache.
Broadcast AddressingA broadcast is a data packet destined for all hosts on a particular physical network. Network hosts recognize broadcasts by special addresses.
The router supports the following kinds of broadcast types:
• Limited broadcast – A packet is sent to a specific network or series of networks. A limited broadcast address includes the network or subnet fields. In a limited broadcast packet destined for a local network, the network identifier portion and host identifier portion of the destination address is either all ones (255.255.255.255) or all zeros (0.0.0.0).
• Flooded broadcast � A packet is sent to every network.
• Directed broadcast � A packet is sent to a specific destination address where only the host portion of the IP address is either all ones or all zeros (such as 192.20.255.255 or 190.20.0.0).
Several early IP implementations do not use the current broadcast address standard. Instead, they use the old standard, which calls for all zeros instead of all ones to indicate broadcast addresses. Many of these implementations do not recognize a broadcast address of all ones and fail
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to respond to the broadcast correctly. Others forward broadcasts of all ones, which causes a serious network overload known as a broadcast storm. Implementations that exhibit these problems include systems based on versions of BSD UNIX before version 4.3.
Routers provide some protection from broadcast storms by limiting their extent to the local cable. Bridges (including intelligent bridges), because they are layer 2 devices, forward broadcasts to all network segments, thus propagating all broadcast storms.
The best solution to the broadcast storm is to use a single broadcast address scheme on a network. Most IP implementations allow the network manager to set the address to be used as the broadcast address. Many implementations of IP, including the one on your router, can accept and interpret all possible forms of broadcast addresses.
Broadcast TasksThere are two broadcast-related IP commands you can use to perform broadcast-related tasks.
ip broadcast-address� Use to broadcast to all addresses in the host portion of an IP address.� You specify an IP address to set the broadcast address.� Example
host1(config-if)#ip broadcast-address 255.255.255.255
� Use the no version to restore the default IP broadcast address.
ip directed-broadcast� Use to enable translation of directed broadcasts to physical broadcasts. � Example
host1(config-if)#ip directed-broadcast
� Use the no version to disable the function.
FragmentationFragmentation is the process of segmenting a large IP datagram into several smaller pieces. Fragmentation is required when IP must transmit a large packet through a network that transmits smaller packets, or when the MTU size of the other network is smaller.
By default, the router does not fragment the packet if the don’t-fragment bit (DF bit) is set in the IP header. You can specify that the router not consider the DF bit before determining whether to fragment a packet.
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Note: It is possible that lower-layer protocols may also set the MTU value. If MTU values set in lower layers differ from the one set at the IP layer, the router always uses the MTU lower-layer�s value.
ip ignore-df-bit� Use to force the router to ignore the DF bit if it is set in the IP packet header for
packets on an interface. � Example
host1(config-if)#ip ignore-df-bit
� Use the no version to restore the default behavior, which is to consider the DF bit before fragmentation.
ip mtu� Use to set the MTU size of IP packets sent on an interface. � The range is 128�10240.� Example
host1(config-if)#ip mtu 1000
� Use the no version to restore the default MTU size.
IP RoutingThe Internet is a large collection of hosts that communicate with each other and use routers as intermediate packet switches.
Routers forward a packet through the interconnected system of networks and routers until the packet reaches a router that is attached to the same network as the destination host. The router delivers the packet to the specified host on its local network.
Routing Information TablesA router makes forwarding decisions based on the information that is contained in its routing table. Routers announce and receive route information to and from other routers. They build tables of routes based on the collected information on all the best paths to all the destinations they know how to reach.
Each configured protocol has one or more local routing tables, sometimes referred to as a routing information base (RIB). This table is a database local to the protocol that contains all the routes known by that protocol to the prefixes in the table. For example, OSPF might have four different routes to 10.23.40.5.32. Only one of these routes is the best route to that prefix known to OSPF, but all four routes are in the OSPF local routing table.
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The global routing table is a database maintained by IP on the SRP module. It contains at most one route per protocol to each prefix in the table. Each of these routes is the best route known by a given protocol to get to that prefix. The IP routing table does not, for example, have two OSPF routes to 10.5.11.0/24; it will have only one (if any) OSPF route to that prefix. It might also have a BGP route to the prefix, and a RIP route to the prefix, but no more than one route to a prefix per protocol.
IP compares the administrative distances for the routes to each prefix and selects the overall best route regardless of protocol. The best route to 10.5.11.0/24 might be via IS-IS. The best route to 192.168.0.0/16 might be via EBGP, and so on. These selected overall best routes to each prefix are used to create the forwarding table. The forwarding table is pushed to each line module. The line modules use their local instance of the forwarding table to forward the packets that they receive. When the global IP routing table is updated, so are the forwarding tables on the line modules.
Figure 2-8 illustrates a very simple network composed of three networks and two routers. The hosts that are attached to each network are not shown, because each router makes its forwarding decisions based on the network number and not on the address of each individual host. The router uses ARP to find the physical address that corresponds to the Internet address for any host or router on networks directly connected to it.
Figure 2-8 Routers in a small network
Table 2-1 and Table 2-2 represent information from the routing tables for routers NY and LA. Each routing table contains one entry for each route for each protocol or route type. Each routing table entry includes the following information:
• The destination IP network address.
• The IP address of the next-hop router.
• The type of network, such as static, directly connected, or the particular protocol.
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• An administrative distance that is used to select the least-cost route among multiple routes to the same destination network. The least-cost (best) route is placed in the forwarding table. The administrative distance is not included in the forwarding table.
• A metric that is used by protocols to which the route is redistributed to select the least-cost route among multiple routes to the same destination network. The metric is not used to determine the best route to be placed in the forwarding table. The metric is also not listed in the forwarding table.
Setting the Administrative Distance for a RouteThe administrative distance is an integer that is associated with each route known to a router. The distance represents how reliable the source of the route is considered to be. A lower value is preferred over a higher value. An administrative distance of 255 indicates no confidence in the source; routes with this distance are not installed in the routing table.
Table 2-3 shows the default distance for each type of source from which a route can be learned.
Table 2-1 Routing table for router NY
Destination Network Next-Hop Router Route type Administrative Distance Metric
10.1.0.0/16 10.1.0.1 connected 0 0
10.2.0.0/16 10.5.0.3 OSPF 110 10
10.2.0.0/16 10.5.0.3 IS-IS 115 10
10.2.0.0/16 10.5.0.3 EBGP 20 15
10.2.0.0/16 10.5.0.3 RIP 120 5
10.5.0.0/30 10.5.0.2 connected 0 0
Table 2-2 Routing table for router LA
Destination Network Next-Hop Router Route type Administrative Distance Metric
10.1.0.0/16 10.5.0.2 static 1 0
10.1.0.0/16 10.5.0.2 OSPF 110 10
10.1.0.0/16 10.5.0.2 RIP 120 4
10.2.0.0/16 10.2.0.1 connected 0 0
10.5.0.0/30 10.5.0.3 connected 0 0
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If the IP routing table contains several routes to the same prefix—for example, an OSPF route and a RIP route—the route with the lowest administrative distance is used for forwarding.
To set the administrative distance for BGP routes, see Setting the Administrative Distance for a Route in E-Series Routing Protocols Configuration Guide, Vol. 2, Chapter 1, Configuring BGP Routing.
To set the administrative distance for RIP, IS-IS, and OSPF, use the following distance commands in Router Configuration mode.
distance� Use to set an administrative distance for RIP or OSPF routes in the range
0�255. � For RIP routes, the default value is 120.� For OSPF routes, the default value is 110. � Example
host1(config)#router rip
host1(config-router)#distance 100
� Use the no version to restore the default value.
distance ip� Use to set the administrative distance for IS-IS routes in the range 1�255. � Example
host1(config)#router isis
host1(config-router)#distance 80 ip
� Use the no version to restore the default value of 115.
Table 2-3 Default administrative distances for route sources
Route Source Default Distance
Connected interface 0
Static route 1
Internal access route 2
Access route 3
External BGP 20
OSPF 110
IS-IS 115
RIP 120
Internal BGP 200
Unknown 255
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Setting the Metric for a RouteFor information on how to set a metric for a route, see E-Series Routing Protocols Configuration Guide, Vol. 1, Chapter 1, Configuring Routing Policy as well as the individual routing protocol chapters in E-Series Routing Protocols Configuration Guide, Vol. 1 and E-Series Routing Protocols Configuration Guide, Vol. 2.
Routing Operations Routers keep track of next-hop information that enables a data packet to reach its destination through the network. A router that does not have a direct physical connection to the destination checks its routing table and forwards packets to another next-hop router that is closer to that destination. This process continues until the packet reaches its final destination.
Identifying a Router Within an Autonomous SystemThe router ID is commonly one of the router’s defined IP addresses. Although the router ID is, by convention, formatted as an IP address, it is not required to be a configured address of the router. If you do not use the ip router-id command to assign a router ID, the router uses one of its configured IP addresses as the router ID.
ip router-id� Use to assign a router ID�a unique identifier that IP routing protocols use to
identify the router within an autonomous system. � Example
host1(config)#ip router-id 192.32.15.23
� Use the no version to remove the router ID assignment.
Establishing a Static RouteYou can set a destination to receive and send traffic by a specific route through the network.
ip route� Use to establish a static route.� Example
host1(config)#ip route 192.56.15.23 255.255.255.0 192.66.0.1
� Use the no version to remove a static route from the routing table.
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Setting Up Default RoutesA router examines its routing table to find a path for each packet. If the router cannot locate a route, it must discard the packet. You can set up a default route using the special address: 0.0.0.0. If the router cannot locate a path to a destination network and a default route is defined, the router forwards the packet to the default router. For example:
host1(config)#ip route 0.0.0.0 0.0.0.0 192.56.21.3
Default routes are typically used to reduce the size of the routing table. Routing is simplified because the router can test for a few local networks or use the default route. However, a disadvantage of default routes is the possible creation of multiple paths and routing loops.
Setting Up an Unnumbered Interface An unnumbered interface does not have an IP address assigned to it. Unnumbered interfaces are often used in point-to-point connections where an IP address is not required.
ip unnumbered� Use to set up an unnumbered interface.� This command enables IP processing on an interface without assigning an
explicit IP address to the interface. � You supply an interface location, which is the type and number of another
interface on which the router has an assigned IP address. This interface cannot be another unnumbered interface.
� Examplehost1(config-if)#ip unnumbered fastEthernet 0/0
� Use the no version to disable IP processing on an interface.
Adding a Host Route to a Peer on a PPP InterfaceYou can enable the ability to create host access routes on a PPP interface. This feature is useful in B-RAS applications.
ip access-routes� Use to enable the ability to create host access routes on a PPP interface. � Example
host1(config-if)#ip access-routes
� Use the no version to disable this feature.
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Enabling Source Address Validation Source address validation verifies that a packet has been sent from a valid source address. When a packet arrives on an interface, the router performs a routing table lookup using the source address. The result from the routing table lookup is an interface to which packets destined for that address are routed. This interface must match the interface on which the packet arrived. If it does not match, the router drops the packet.
ip sa-validate� Use to enable source address validation. � Example
host1(config-if)#ip sa-validate
� Use the no version to disable source address validation.
Shutting Down an IP Interface The router lets you disable an interface at the IP level without removing it.
ip shutdown� Use to shut down an IP interface.� Example
host1(config-if)#ip shutdown
� Use the no version to restart the interface.
Removing the IP Configuration You can remove the IP configuration from an interface or subinterface.
no ip interface� Use to remove the IP configuration from an interface or subinterface and
disable IP processing on the interface. � Example
host1(config-if)#no ip interface
Clearing IP RoutesThe router enables you to clear the specified routing entries from the routing table. You must specify the IP address prefix and the mask of the IP address prefix to clear specific routes. You can later reinstall the routes you have cleared.
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clear ip routes� Use to clear specified IP routes according to an IP prefix or a VPN routing and
forwarding (VRF) table.� Use an asterisk (*) to clear all dynamic routes from the routing table.� Example
host1#clear ip routes *
� There is no no version.
ip refresh-route� Use to enable the owning protocols (BGP, IS-IS, OSPF) to reinstall routes
removed from the IP routing table by the clear ip routes command.� Example
host1#ip refresh-route
� There is no no version.
Clearing IP Interfaces The router enables you to clear the counters on the specified IP interface(s).
clear ip interface� Use to clear a specified IP interface. � Example
host1#clear ip interface pos 2/0
� There is no no version.
Setting a Baseline The router enables you to set a baseline for statistics on an IP interface.
baseline ip interface� Use to set a baseline for a specified IP interface.� Example
host1#baseline ip interface pos 2/0
� There is no no version.
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Disabling Forwarding of Packets The router allows you to disable forwarding of packets on an SRP Ethernet interface.
ip disable-forwarding� Use to disable forwarding of packets on the SRP Ethernet interface. � The purpose of this command is to maintain router performance by maximizing
the CPU time available for routing protocols. Although you can allow data forwarding on the SRP Ethernet interface, router performance will be affected.
� You see an error message if you try to set this command for interfaces other than the SRP Ethernet interface.
� Examplehost1(config-if)#ip disable-forwarding
� Use the no version to enable forwarding of packets on the interface.
Enabling Forwarding of Source-Routed PacketsIP packets are normally routed according to the destination address they contain based on the routing table at each hop through a path. The originator or source of the source-routed packets specifies the path (the series of hops) that the packets must traverse; the source makes the routing decisions. The source can specify either of the following types of source routing:
• Strict-source routing specifies every hop that the packet must traverse. The specified path consists of adjacent hops. The source generates an ICMP error if the exact path cannot be followed. For example, for a path going from source router A to router B to router C to router D, router A would specify a strict-source route as B, C, D.
• Loose-source routing specifies a set of hops that the packet must traverse, but not necessarily every hop in the path. That is, the specified hops do not have to be adjacent. For example, for a path going from source router A to router B to router C to router D, router A would specify a loose-source route as B, D or C, D, or B, C, D.
ip source-route� Use to enable forwarding of source-routed packets. � Forwarding is enabled by default.� Example
host1#ip source-route
� Use the no version to disable forwarding of source-routed packets on the interface.
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Forcing an Interface to Appear UpThe router enables you to force an IP interface to appear as if it is up, regardless of the state of the lower layers.
ip alwaysup� Use to force an IP interface to appear as up regardless of the state of lower
layers.� This command reduces route topology changes when the network attached to
this link is single-homed.� Example
host1(config-if)#ip alwaysup
� Use the no version to make the interface appear in the current state.
Specifying a Debounce TimeYou can set a debounce time that requires an IP interface to be in a given state—for example, up or down—for the specified time before the state is reported. This feature prevents a link that briefly goes up or down from causing an unnecessary topology change, for example by causing an interface down condition.
ip debounce-time� Use to set the interval for which an interface must maintain a given state before
the state change is reported. � Example
host1(config)#ip debounce-time 5000
� Use the no version to remove the debounce time requirement.
Adding a DescriptionThe router enables you to add a text description or an alias to an IP interface or subinterface. Adding a description helps you identify the interface and keep track of interface connections.
Note: The ip description command is replacing the description command to assign a description to an IP interface.
ip description� Use to assign a text description or an alias to an IP interface or subinterface.� The description or alias can be a maximum of 256 characters.� Use the show ip interface command to display the text description.
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� Exampleshost1(config-if)#ip description canada01 ip interface
host1(config-subif)#ip description montreal011 ip subinterface
� Use the no version to remove the text description or alias.
Enabling Link Status TrapsThe router allows you to enable link status traps on an interface.
snmp trap ip link-status� Use to enable link status traps on an interface.� Example
host1(config-if)#snmp trap ip link-status
� Use the no version to disable link status traps on an interface.
Configuring the SpeedThe router enables you to set the speed of an IP interface.
ip speed� Use to set the speed of the interface in bits per second.� By default, the speed is determined from a lower-layer interface.� Example
host1(config-if)#ip speed 1000
� Use the no version to set the speed to the default, 0.
Configuring Equal-Cost Multipath Load SharingEqual-cost multipath (ECMP) sets are formed when the router finds routing table entries for the same destination with equal cost. You can add routing table entries manually (as static routes), or they are formed as routers discover their neighbors and exchange routing tables (via OSPF, BGP, and other routing protocols). The router then balances traffic across these sets of equal-cost paths by using one of the following ECMP modes:
• Hashed � uses hashing of source and destination addresses to determine which of the available paths in the ECMP set to use
• Round-robin � distributes packets equally among the available paths in the ECMP set
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ip multipath round-robin� Use to specify round-robin as the mode for ECMP load sharing on an interface.� ECMP uses the round-robin mode when you have configured all interfaces in
the set to round-robin. Otherwise, ECMP defaults to hashed mode because round-robin mode could cause reordering of packets. You must explicitly ensure that the possible reordering is acceptable on all the member interfaces by setting them to round-robin mode.
� Use the no version to set the ECMP mode to the default, hashed.� Example
host1(config)#virtual-router router_0
host1:router_0(config)#interface serial 4/0:1/22.22
host1:router_0(config-subif)#ip multipath round-robin
host1:router_0(config-subif)#exit
host1:router_0(config)#exit
host1:router_0#show ip interface serial 4/0:1/22.22
serial4/0:1/22.22 is up, line protocol is up
Network Protocols: IP
Internet address is 190.121.1.1/255.255.0.0
Broadcast address is 255.255.255.255
Operational MTU = 1600 Administrative MTU = 0
Operational speed = 64000 Administrative speed = 0
Router advertisement = disabled
Administrative debounce-time = disabled
Operational debounce-time = disabled
Access routing = disabled
Multipath mode = round-robin
In Received Packets 0, Bytes 0
In Policed Packets 0, Bytes 0
In Error Packets 0
In Invalid Source Address Packets 0
Out Forwarded Packets 0, Bytes 0
Out Scheduler Drops Packets 0, Bytes 0
maximum-paths� Use to control the maximum number of parallel routes that the routing protocol
(BGP, IS-IS, OSPF, or RIP) can support.� The maximum number of routes can range from 1�6 for BGP and from 1�16 for
IS-IS, OSPF, or RIP. � Example
host1(config-router)#maximum-paths 2
� Use the no version to restore the default value, 1 for BGP or 4 for IS-IS, OSPF, or RIP.
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Setting a TTL ValueYou can use the ip ttl command to set the TTL (time-to-live) field in the IP header for all IP operations. The TTL specifies a hop count. This configured TTL value can be overridden by other commands that specify a TTL.
ip ttl� Use to set a default value for the IP header TTL field for all IP operations.� Example
host1(config)#ip ttl 255
� Use the no version to restore the default value, 127.
Shared IP InterfacesYou can create multiple shared IP interfaces over the same layer 2 logical interface—for example, atm 5/3.101—enabling more than one IP interface to share the same logical resources. This capability is useful, for example, when data received in one VPN routing and forwarding (VRF) needs to be forwarded out an interface in another VRF, such as for BGP/MPLS VPNs (see E-Series Routing Protocols Configuration Guide, Vol. 2, Chapter 3, Configuring BGP/MPLS VPNs, for more information). You can configure one or more shared IP interfaces. Data sent over shared interfaces uses the same layer 2 interface. You can configure shared interfaces as you would unshared IP interfaces. Each shared interface has its own statistics.
Some layer 2 interfaces require a primary IP interface to negotiate certain IP parameters—for example, IPCP for PPP, ARP for Ethernet, and Inverse ARP for Frame Relay. If you do not configure a primary IP interface in such cases, the layer 2 interface cannot become operationally up.
A primary IP interface is the default interface for receiving data that arrives on the layer 2 interface. If you configure shared IP interfaces for the same layer 2 interface as your primary IP interface, by default data received on the layer 2 interface is received on the virtual router corresponding to the primary IP interface. A primary IP interface and all of its shared IP interfaces have the same interface location. You cannot configure a shared IP interface to receive data on the same layer 2 interface as a primary IP interface. You can delete primary and shared IP interfaces independently of each other.
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You can create a primary IP interface as you do any other IP interface, as shown in the following example:
host1(config)#virtual-router vr-a:vrf-2
host1:vr-a:vrf-2:(config)#interface atm 5/3.101
host1:vr-a:vrf-2:(config-if)#ip address 10.1.1.1 255.255.255.255
host1:vr-a:vrf-2:(config-if)#exit
You do not have to configure a primary IP interface if you do not need one as described above. In the absence of a primary interface, you can still configure shared IP interfaces; however, in this scenario, data received on the layer 2 interface is discarded.
You cannot create shared IP interfaces for the following kinds of interface:
• IP floating interfaces (IP interfaces that stack over MPLS stacked tunnels)
• Loopback interfaces
• Null interfaces
For information about configuring shared IP interfaces to receive data on the same layer 2 interface as a primary IP interface, see E-Series Broadband Access Configuration Guide, Chapter 8, Configuring Subscriber Interfaces.
Configuring Prefixes for Dynamic Shared IP InterfacesFor the typical BGP/MPLS VPN scenario, shared interfaces are created dynamically based on VPN membership in support of overlapping VPNs. In screen output, dynamic interfaces are distinguished from those you configure statically by a prefix (default prefix is dyn). You can define the prefix with the ip dynamic-interface-prefix command.
See E-Series Routing Protocols Configuration Guide, Vol. 2, Chapter 3, Configuring BGP/MPLS VPNs, for more information on VPNs and shared IP interfaces.
Configuring Shared IP InterfacesTo share IP interfaces:
1 Create a layer 2 interface.
host1(config)#interface atm 5/3
host1(config-if)#interface atm 5/3.101
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2 (Optional) Create a primary IP interface.
host1(config-if)#ip address 10.1.1.1 255.255.255.255
host1(config-if)#exit
3 Create the shared IP interface.
host1(config)#interface ip si0
4 Associate the shared IP interface with the layer 2 interface by one of the following methods:
• Statically
host1(config-if)#ip share-interface atm5/3.101
• Dynamically
host1:vr-a:vrf-1(config-if)#ip share-nexthop 10.0.0.1
5 To fully configure the shared interface, assign an address (or make the interface unnumbered).
host1(config-if)#ip address 2.2.2.2 255.0.0.0
6 (Optional) For BGP/MPLS VPNs, configure a prefix for the shared IP interfaces.
host1(config-if)#ip dynamic-interface-prefix vrf2 rt66
interface ip � Use to create an IP interface for interface sharing.� Use the specified name to refer to the shared IP interface; you cannot use the
layer 2 interface to refer to them, because the shared interface can be moved.� Example
host1(config)#interface ip si0
� Use the no version to delete the IP interface.
ip dynamic-interface-prefix� Use to specify the prefix that distinguishes dynamic shared IP interfaces
(created for overlapping BGP/MPLS VPNs) from static shared IP interfaces.� You can specify the VRF in which the shared IP interface is created.� Dynamic shared IP interfaces are represented in screen output as
ipprefixvrfName-number
where prefix is the prefix you specified, vrfName is the VRF where the primary interface is located, and number is incremented as these interfaces are created.
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� Examplehost1:pe1(config)#ip dynamic-interface-prefix vrf pe12 vpnsh
host1:pe1(config)#exit
host1:pe1#show ip vrf
VRF Name Default RD Interfaces
pe11 1:1 null0
atm4/0.2
ipdynpe12-6
pe12 1:2 null0
ipvpnshpe11-5
atm4/0.3
� The no version restores the default prefix value, dyn.
ip share-interface� Use to specify the layer 2 interface used by a shared IP interface. The
command fails if the layer 2 interface does not yet exist.� If you issue this command on a shared IP interface, you cannot issue the ip
share-nexthop command for the interface. � After creating the shared IP interface, you can configure it as you would any
other IP interface.� The shared interface is operationally up when the layer 2 interface is
operationally up.� You can create operational shared IP interfaces in the absence of a primary IP
interface.� Example
host1(config-if)#ip share-interface atm5/3.101
� Use the no version to remove the association between the layer 2 interface and the shared IP interface. You can delete shared and primary IP interfaces independently.
ip share-nexthop� Use to specify that the shared IP interface dynamically tracks a next hop. If the
next hop changes, the shared IP interface moves to the new layer 2 interface associated with the IP interface toward the new next hop.
� If you issue this command on a shared IP interface, you cannot issue the ip share-interface command for the interface.
� If you specify a virtual router, the command fails if the VR does not already exist. If you do not specify a VR, the current VR is assumed.
� After creating the shared IP interface, you can configure it as you would any other IP interface.
� The shared interface is operationally up when the layer 2 interface associated with the specified next hop is operationally up.
� Use the no version to halt tracking of the next hop.
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Moving IP InterfacesYou cannot directly move a primary IP interface. However, primary IP interfaces created dynamically by MPLS move when the underlying MPLS minor interface moves or changes.
You can move an IP shared interface from one layer 2 interface to another by issuing the ip share-interface command to specify a different layer 2 interface. Moving an IP interface does not affect interface statistics, packets forwarded through the interface, or policies attached to the IP interface.
Example The following commands create shared interface si0 on the layer 2 interface atm5/3.101:
host1(config)#virtual-router vr-a:vrf-1
host1:vr-a:vrf-1(config)#interface ip si0
host1:vr-a:vrf-1(config-if)#ip share-interface atm5/3.101
host1:vr-a:vrf-1(config-if)#exit
The following commands move shared interface si0 to the layer 2 interface atm5/3.201:
host1:vr-a:vrf-1(config)#interface ip si0
host1:vr-a:vrf-1(config-if)#ip share-interface atm5/3.201
IP Shared Interface StatisticsEach shared interface has its own statistics. Packets transmitted on a shared IP interface are always counted only in the shared IP interface.
Subscriber InterfacesA subscriber interface is an extension of a shared IP interface. Shared IP interfaces are unidirectional–they can transmit but not receive traffic. In contrast, subscriber interfaces are bidirectional–they can both receive and transmit traffic.
For details about configuring and using subscriber interfaces, see E-Series Broadband Access Configuration Guide, Chapter 8, Configuring Subscriber Interfaces.
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Internet Control Message ProtocolIP was not designed to provide reliable delivery service. The higher-layer protocols that operate as clients of IP implement their own reliability procedures if reliable communications are required.
Internet Control Message Protocol (ICMP) provides a mechanism that enables a router or destination host to report an error in data traffic processing to the original source of the packet. ICMP messages provide feedback about problems that occur in the communication environment.
ICMP messages are sent only when errors occur in either the processing of an unfragmented data packet or the first fragment of a fragmented data packet.
ICMP messages are encapsulated as part of the data portion of an IP data packet and are routed like any other IP data packets. Thus, there is no guarantee to the sender of an ICMP message that it will be delivered to its destination.
The router supports ICMP redirects. When a packet enters an IP interface and exits the same interface, the router may send an ICMP message to the originator of the packet. This message notifies the originator that there is a better gateway for the assigned destination address.
The ip redirects command (used in Interface Configuration mode) lets you enable or disable ICMP redirects. This attribute is enabled by default. If it is enabled on the IP interface and if the internal ICMP redirect queue is not full, the router sends an ICMP redirect packet to the originator. When the originator receives the ICMP redirect notification, it is up to the originator to start using the better gateway.
ICMP TasksYou can enable the following ICMP features:
• ICMP Router Discovery Protocol (IRDP)
• ICMP netmask reply
• Sending of IP redirects
• Generation of ICMP unreachable messages
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ip irdp� Use to enable IRDP processing on an interface.� Example
host1(config-if)#ip irdp
� Use the no version to disable the function.
ip mask-reply� Use to enable ICMP netmask reply.� Example
host1(config-if)#ip mask-reply
� Use the no version to disable the function.
ip redirects� Use to enable the sending of redirect messages if software is forced to resend
a packet through the same interface on which it was received. � Example
host1(config-if)#ip redirects
� Use the no version to disable the sending of redirect messages.
ip unreachables� Use to enable the generation of an ICMP unreachable message when a packet
is received that the router cannot deliver. � Example
host1(config-if)#ip unreachables
� Use the no version to disable the function.
Specifying a Source Address for ICMP MessagesBy default, ICMP uses the IP address of the outgoing interface as the source IP address for the ICMP message. However, you can use the ip icmp update-source command to instruct ICMP to use an already configured interface or a specified IP address, as the source address of the ICMP message.
For example, you can specify that ICMP use Fast Ethernet interface 1 in slot 0 as the source for any messages that it sends:
host1(config)#ip icmp update-source fastEthernet 0/1
You must use an already configured interface or an existing IP address when using the ip icmp update-source command. Also, you cannot specify a multicast address when using this command.
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ip icmp update-source� Use to define an update source address for all ICMP messages that the
E-series router generates from the specified interface.� Example
host1#ip icmp update-source 192.35.42.1
� Use the no version to disable the function.
Reachability CommandsUse the ping and traceroute commands to determine reachability of destinations in the network.
• Use the ping command to send an ICMP or ICMPv6 echo request packet. In the following example, the request packet is sent to IP address 192.35.42.1, with a packet count of 10 and a timeout value of 10 seconds:
host1#ping 192.35.42.1 10 timeout 10
• Use the traceroute command to discover routes that router packets follow when traveling to their destination. In the following example, the trace destination IP address is 192.56.20.1, the maximum number of hops of the trace is 20, and the timeout value is 10 seconds:
host1#traceroute 192.56.20.1 20 timeout 10
ping� Use to send an ICMP or ICMPv6 echo request packet to the IP address that
you specify.� You can specify a VRF context.� Use the source interface keywords to specify a source interface other than the
one from which the probe originates. � Use the source address keywords to specify a source IP address other than
the one from which the probe originates. � You can specify the following options:
� packetCount � number of packets to send to the destination IP address. If you specify a zero, echo requests packets are sent indefinitely.
� data-pattern � sets the type of bits contained in the packet to all ones, all zeros, a random mixture of ones and zeros, or a specific hexadecimal data pattern that can range from 0x0�0xFFFFFFFF. The default is all zeros.
� data-size � sets the number of bytes comprising the IP packet and reflected in the IP header in the range 0�64000; the default is 100 bytes
� extended header attributes � set the following:� A value to be set in the type of service (ToS) byte, in the range 0�255, to
support quality of service (QoS) offerings
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� Don�t-fragment bit to prevent IP from fragmenting the packet if it is too long for the MTU of a given link; if the nonfragmented packet cannot be delivered, it is discarded.
� Strict-source or loose-source routing, including the IP address of the hops the packets must traverse. For loose-source-route, you specify some or all of the hops, but they do not have to be adjacent. For strict-source-route, you must specify every adjacent hop through which the packet must traverse.
� The IP addresses to be recorded for a specified number of routers that the packets traverse
� The time that a packet traverses a router to be recorded for a specified number of routers
� An interface type and specifier of a destination address on the router that is configured for external loopback; the command succeeds only if the specified interface is configured for external loopback
� sweep-interval � specifies the change in the size of subsequent ping packets while sweeping across a range of sizes. For example, you can configure the sweep interval to sweep across the range of packets from 100 bytes to 1000 bytes in increments equal to the sweep interval. By default the router increments packets by one byte; for example, it sends 100, 101, 102, 103, ... 1000. If the sweep interval is 5, the router sends 100, 105, 110, 115, ... 1000.
� sweep-sizes � enables you to vary the sizes of the echo packets being sent. This capability is useful for determining the minimum sizes of the MTUs configured on the nodes along the path to the destination address. Determining the minimum size reduces packet fragmentation, which contributes to performance problems. The default is not to sweep (all packets are the same size).
� timeout � sets the number of seconds to wait for an ICMP echo reply packet before the connection attempt times out
� ttl � sets the time-to-live hop count in the range 1�255; the default is 32 � The following characters can appear in the display after issuing the ping
command:� ! � reply received� . � timed out while waiting for a reply� ? � unknown packet type� A � address mask request message� a � address mask reply message� D � router discovery advertisement message� d � router discovery request message� H � host unreachable� I � information request message� i � information reply message� L � TTL expired message� M � could not fragment, DF bit set� m � parameter problem message
CHAPTER 2Configuring IP
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� N � network unreachable� P � protocol unreachable� Q � source quench� r � redirect message� T � timestamp request message� t � timestamp reply message� U � destination unreachable
� Examplehost1(config)#interface serial 5/2:1/1
host1(config-if)#ip address 172.16.1.1 255.255.255.0
host1(config-if)#exit
host1#ping 172.16.1.1 extended interface serial 5/2:1/1
� There is no no version.
traceroute� Use to discover the routes that router packets follow when traveling to their
destination.� You can specify:
� A VRF context� Destination IP or IPv6 address� Source interface for each of the transmitted packets� Source address for each of the transmitted packets� Maximum number of hops of the trace and a timeout value� Size of the IP packets (not the ICMP payload) in the range 0�64000 bytes
sent with the traceroute command. Including a size might help locate any MTU problems that exist between your router and a particular device.
� Extended IP header attributes, including the ToS byte and whether to set the DF bit for the transmitted packets
� You can also force transmission of the packets on a specified interface regardless of what the IP address lookup indicates.
� Examplehost1#traceroute 172.20.13.1 20 timeout 10
� There is no no version.
Response Time ReporterThe Response Time Reporter (RTR) feature enables you to monitor your network’s performance and its resources. It does this by measuring response times and the availability of your network devices.
Response Time ReporterE-Series Routers
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Configuration TasksTo configure RTR:
1 Configure the probe type—an echo probe or a path echo probe.
2 (Optional) Configure probe characteristics:
• frequency
• hops-of-statistics-kept (path echo)
• max-response-failure (path echo)
• operations-per-hop (path echo)
• owner
• request-data-size
• samples-of-history-kept
• tag
• timeout (echo)
• tos
Note: You cannot set any of these characteristics until you have set the probe type. The default values of these characteristics depend on the type of the entry.
3 (Optional) Set reaction conditions.
4 Schedule the probe.
5 (Optional) Capture statistics and collect error information.
6 (Optional) Collect history.
Note: RTR configuration is associated with a specific virtual router, distinct from any other virtual router.
Configuring the Probe TypeTo begin configuring RTR, enter RTR Configuration mode and configure the probe type—either an echo probe or a path echo probe.
rtr� Use to configure an RTR probe and to enter RTR Configuration mode.� Example
host1(config)#rtr 1
� Use the no version to delete all configuration information for an RTR probe.
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type� Use to set an echo or path echo probe:
� echo � limited to end-to-end RTR operations; corresponds to SNMP ping� pathEcho � finds a path to the destination and echoes each device in the
path; corresponds to SNMP traceroute� You must specify this value before any other.� If you change the type for an existing RTR entry, all values are reset, including
the administrative status. There is no default value. � More than one RTR entry can become active, provided each entry�s target
address is unique.� If you use a target address already configured for another RTR entry that is
active, the test will not run if both entries are in the same virtual router. If they are in distinct virtual routers, however, there is no restriction.
� Examplehost1(config-rtr)#type echo protocol ipIcmpEcho 10.10.0.9
� Use the no version to remove the type configured for the probe.
Configuring Optional CharacteristicsIn addition to configuring the probe’s type, you can configure the probe characteristics presented in Table 2-4.
frequency� Use to set the rate (in seconds) the RTR probe uses to start a response time
operation.� Example
host1(config-rtr)#frequency 90
� Use the no version to return to the default value, 60 seconds.
Table 2-4 Probe characteristics
Characteristic Description
frequency Time between tests (in seconds)
hops-of-statistics-kept Hops per path for which statistics are gathered
max-response-failure Maximum number of consecutive failures
operations-per-hop Number of probes per hop
owner Owner of the probe
request-data-size Request�s payload size
samples-of-history-kept Maximum number of history samples
tag User-defined tag
timeout Probe timeout (in milliseconds)
tos A value for the TOS byte
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operations-per-hop� Use to set the number of RTR probe operations sent to a given hop. � You can apply this option only to a pathEcho type.� Example
host1(config-rtr)#operations-per-hop 5
� Use the no version to return to the default, 3.
owner� Use to identify the owner of the probe.� If the SNMP agent is the owner of the probe, the owner�s name may begin with
agent.� Example
host1(config-rtr)#owner 192.10.27.6 rtc.boston.com 555.1212
� Use the no version to return to the default, no owner.
request-data-size� Use to set the protocol data size in the request packet.� Example
host1(config-rtr)#request-data-size 20
� Use the no version to return to the default value, 1 byte.
tag� Use to set an identifier for the probe.� Example
host1(config-rtr)#tag westford
� Use the no version to return to the default, no tag.
timeout� Use to set the time (in milliseconds) that the probe waits for a response.� You can apply this option only to an echo type.� Do not set the value for timeout to more than the value set for frequency. If you
do, it will be ignored.� Example
host1(config-rtr)#timeout 3000
� If you set the timeout to 0, no timeout is set.� Use the no version to return to the default value, 5000 milliseconds.
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tos� Use to set the type of service (ToS) byte in the probe�s IP header.� Example
host1(config-rtr)#tos 16
� Use the no version to return to the default value, 0. The default applies to both the echo and pathEcho types.
Capturing StatisticsThe primary objective of RTR is to collect statistics and information on network performance. You can control the number and type of statistics collected.
hops-of-statistics-kept� Use to set the number of hops per path for which statistics are collected.� When the number of hops reaches the specified number (that is, size), no
additional statistical information on the path is stored.� This option applies only to pathEcho entries.� Example
host1(config-rtr)#hops-of-statistics-kept 5
� To turn off this feature, set the value to 0. � Use the no version to set the default, 16 hops.
max-response-failure� Use to set the maximum number of consecutive failures to respond to a probe�s
request.� When the maximum number is reached, the test stops.� This option applies only to pathEcho entries.� Example
host1(config-rtr)#max-response-failure 2
� To turn off this feature, set the value to 0.� Use the no version to set the default, 5 consecutive failures.
Collecting HistoryRTR can collect data samples for a given probe. These samples are referred to as history data. When RTR collects history, it refers to tests. A test is the lifetime of a probe operation.
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samples-of-history-kept� Use to set the maximum number of entries in the history table for each RTR
probe.� This command enables you to control the number of samples saved in the
history table.� Because collecting history increases memory usage, you should do so only
when there is a problem in your network.� Example
host1(config-rtr)#samples-of-history-kept 5
� If you set the number of samples to 0, no samples will be kept.� Use the no version to set the default, 16 hops for pathEcho type; 1 hop for echo
type.
Setting Reaction ConditionsYou can set the RTR probe to react to events that take place and to send notifications about these events.
Note: The only no version for all the rtr reaction-configuration commands is no rtr reaction-configuration rtrIndex. Use the no version to clear all traps. This works for all the options.
rtr reaction-configuration action-type� Use to specify the type of actions to occur depending on the events controlled
by RTR.� The default is to take the traps of enabled events.� Example
host1(config)#rtr reaction-configuration 1 action-type trapOnly
� There is no no version.
rtr reaction-configuration operation-failure� Use to enable the operation-failure reaction.� The operation-failure event is triggered when a number of consecutive probe
operations are not received or when they are received after a timeout.� Example
host1(config)#rtr reaction-configuration 1 operation-failure 3
� There is no no version.
rtr reaction-configuration path-change� Use to enable the path-change reaction.� The path-change event is triggered when a change is detected in the hop table.
At most, there can be one such event per test.
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� Examplehost1(config)#rtr reaction-configuration 1 path-change
� There is no no version.
rtr reaction-configuration test-completion� Use to enable test-completion reaction.� The test-completion event is triggered when a test is completed successfully.
� For echo, a successful test means that all probes were sent.� For pathEcho, a successful test means that the destination was reached at
least once.� At most, there can be one such event per test.� Example
host1(config)#rtr reaction-configuration 1 test-completion
� There is no no version.
rtr reaction-configuration test-failure� Use to enable test-failure reaction.� The test-failure event is triggered when a test fails. Failure is determined in the
following ways:� If Echo, this event is triggered after testFailureValue probes are either not
received or are received after a timeout.� If PathEcho, this event is triggered when the test ends and no responses are
received from the destination.� At most, there can be one such event per test.� Example
host1(config)#rtr reaction-configuration 1 test-failure
� There is no no version.
Scheduling the ProbeWhen you have configured the RTR probe, you must schedule the operation to begin collecting statistics and other information on problems that may arise.
rtr schedule� Use to create an RTR schedule.� Example
host1(config)#rtr schedule 5
� Use the no version to stop the test. The no version stops the probe operation by putting it in the pending state. The no version also resets the restart-time attribute and the life attribute.
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rtr schedule life� Use to schedule the test�s length.� Life is a value that depends on the type of the RTR entry; it is not a length of
time.� If the type is echo, life relates to the number of probes sent until a test
finishes. � If the type is pathEcho, life relates to the maximum number of hops used by
the traceRoute trap.� Example
host1(config)#rtr schedule 5 life 1800
� Use the no version to stop the test. The no version stops the probe operation by putting it in the pending state. The no version also resets the life attribute.
rtr schedule restart-time� Use to restart a test.� Example
host1(config)#rtr schedule 5 restart-time 15
� Use the no version to stop the test. The no version stops the probe operation by putting it in the pending state. The no version also resets the restart-time attribute.
rtr schedule start-time� Use to schedule a test�s starting time.� Example
host1(config)#rtr schedule 5 start-time now
� Use the no version to stop the test. The no version stops the probe operation by putting it in the pending state.
Shutting Down the ProbeYou can shut down the RTR probe operation.
rtr reset� Use to shut down the RTR, stop all probe operations, and clear the RTR
configuration for the given virtual router.� We recommend that you use this command only in extremely serious
situations, such as problems with the configurations of a number of probe operations.
� Examplehost1(config)#rtr reset
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Monitoring RTRYou can monitor RTR by displaying status and configuration information.
show rtr application� Use to display global information about RTR.� Field descriptions
� numberOfEntries � number of RTR entries according to type� entriesEnabled � RTR entries with administrative status enabled� entriesActive � RTR entries with operational status enabled
� Examplehost1#show rtr application
numberOfEntries entriesEnabled entriesActive
------------------ ----------------- ---------------
echo 1 1 1
pathEcho 1 1 1
total 2 2 2
show rtr collection-statistics� Use to display statistical information for a particular probe operation or for all
operations.� Field descriptions
� rtrIndex � index number of the RTR probe� operationsSent � number of probe operations sent� operationsRecvd � number of probe operations received� lastGoodResponse � time when last valid probe operation was received� operStatus � operational status of the probe: enabled, disabled� minRtt � minimum round-trip time in milliseconds� maxRtt � maximum round-trip time in milliseconds� avgRtt � average round-trip time in milliseconds� rttSumSqr � sum of the square of all round-trip times in milliseconds � testAttempts � number of times the test ran� testSuccesses � number of times the test ran successfully� currentHop � current hop (TTL) used in the test� currentOperation � current probe operation index sent to the hop
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� Examplehost1#show rtr collection-statistics
Echo Entries:
rtrIndex operationsSent operationsRcvd lastGoodResponse
---------- -------------- -------------- ----------------
1 5208 5187 08/30/2000 05:09
rtrIndex operStatus minRtt maxRtt avgRtt rttSumSqr
---------- ---------- ------ ------ ------ ---------
1 enabled 0 1785 3 7109208
PathEcho Entries:
rtrIndex testAttempts testSuccesses lastGoodResponse
---------- ------------ ------------- ----------------
2 156 156 08/30/2000 05:09
rtrIndex operStatus currentHop currentOperation
---------- ---------- ---------- ----------------
2 enabled 2 4
show rtr configuration� Use to display the configuration for a particular probe or for all probes.� Field descriptions
� rtrIndex � index number of the RTR probe� type � probe type: echo, pathEcho� targetAddress � address of the probe�s target� reqSize � protocol data size in the request packet� freq � rate in seconds that the RTR probe uses to start a response time
operation� life � length of the test� source � interface from which the probe is sent� restartTime � restart time of the test in seconds� owner � owner of the probe� samples � maximum number of entries saved in the history table for this
RTR probe� admin � administrative status of the probe: enabled, disabled� tos � setting of the type of service (ToS) byte in the probe�s IP header� reactionConfiguration � RTR reactions that are configured for the probe� operFail � operation failure event is triggered when this number of
consecutive probe operations is not received or when the operations are received after a time-out
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� testFail � test failure event is triggered when this number of probe operations is not received or when the operations are received after a timeout
� timeout � time in milliseconds that the probe waits for a response� tag � identifier configured for the probe� operPerHop � number of RTR probe operations sent to a given hop� maxFail � maximum number of consecutive failures to respond to a probe�s
request. When the maximum number is reached, the test stops. Applies only to pathEcho entries.
� hopKpt � number of hops per path for which statistics are collected. When this number is reached, no additional statistical information on the path is stored. Applies only to pathEcho entries.
� Examplehost1#show rtr configuration
rtrIndex type targetAddress reqSize freq life
------- -------- ------------ ------ ------ -----
1 echo 10.5.0.200 1 1 20
2 pathEcho 10.5.0.11 1 1 30
rtrIndex source restartTime owner
---------- ------------------ ----------- ----------
1 fastEthernet0/0 10
2 60
rtrIndex samples admin tos reactionConfiguration
---------- ------- -------- --- ------------------------
1 5 enabled 0
2 5 enabled 0
rtrIndex operFail testFail timeout tag
---------- -------- -------- ------- ------
1 1 1 10000
rtrIndex operPerHop maxFail hopKpt tag
---------- ---------- ------- ------ ------
2 5 3 16
show rtr history� Use to display history (data samples) for a particular probe or for all probes.� Field descriptions
� rtrIndex � index number of the RTR probe� operation � index number of the probe operation� rtt � round-trip time in milliseconds� statusDescription
� concurrentLimitFail � target already being used by another rtrIndex� ifInactiveToTarget � interface used to reach target is not operational
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� invalidHostAddress � target address is not supported� noRouteToTarget � target address is not reachable� responseReceived � probe operation replied by target� requestTimedOut � probe operation not replied to by target or reply
received after timeout� unknownDestAddress � target address is invalid� unableToResolveName � target address could not be looked up
� timeStamp � date and time when the RTR entry was created� test � index number of the pathEcho test� hop � index number of the hop count� operation � index number of the probe operation� address � address of router at the hop
� Examplehost1#show rtr history
Echo Entries:
rtrIndex operation rtt statusDescription timeStamp
-------- --------- --- ----------------- ---------
1 5476 0 responseReceived 08/30/2000 05:17
1 5477 0 responseReceived 08/30/2000 05:17
1 5478 0 responseReceived 08/30/2000 05:17
1 5479 0 responseReceived 08/30/2000 05:17
1 5480 0 responseReceived 08/30/2000 05:17
PathEcho Entries:
rtrIndex test hop operation rtt statusDescription
---------- ------ ---- --------- ------ -----------------
2 165 3 5 0 responseReceived
2 165 3 1 0 responseReceived
2 165 3 2 0 responseReceived
2 165 3 3 0 responseReceived
2 165 3 4 0 responseReceived
rtrIndex test hop operation timeStamp address
---------- ------ ---- --------- ---------------- --------
2 165 3 5 08/30/2000 20:39 10.5.0.11
2 165 3 1 08/30/2000 20:40 10.5.0.11
2 165 3 2 08/30/2000 20:40 10.5.0.11
2 165 3 3 08/30/2000 20:40 10.5.0.11
2 165 3 4 08/30/2000 20:40 10.5.0.11
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show rtr hops� Use to display RTR hops information.� Field descriptions
� rtrIndex � index number of the RTR probe� hop � index number of the hop count� address � address of the router at the hop� minRtt � minimum round-trip time in milliseconds� maxRtt � maximum round-trip time in milliseconds� avgRtt � average round-trip time in milliseconds� rttSumSqr � sum of the square of all round-trip times in milliseconds� operationsSent � number of probe operations sent� operationsRcvd � number of probe operations received� lastGoodResponse � time when last valid probe operation was received
� Examplehost1#show rtr hops
rtrIndex hop address minRtt maxRtt avgRtt rttSumSqr
---------- ---- ----------- ------ ------ ------ --------
2 1 192.168.1.1 1 276 1 955363
2 2 10.2.0.3 0 1109 2 10094451
rtrIndex hop operationsSent operationsRcvd lastGoodResponse
-------- --- -------------- -------------- ------------
2 1 36985 36838 09/18/2000 20:20
2 2 30717 21494 09/18/2000 20:20
show rtr operational-state� Use to display RTR operational information.� Field descriptions
� rtrIndex � index number of the RTR probe� type � type of RTR probe: echo, pathEcho� entryStatus � if the entry was created via the SNMP DISMAN MIB, the row
may be partially constructed; if that is the case, the CLI displays notReady as the entry�s status
� adminStatus � derived from the rtr schedule start-time command; if the option is now, the status is enabled; if the option is pending, the status is disabled
� operStatus � enabled only if entryStatus and adminStatus are enabled and the test is running; operStatus remains enabled if the test finishes and restart time is not 0
Monitoring IPE-Series Routers
2-55
� Examplehost1#show rtr operational-state
rtrIndex type entryStatus adminStatus operStatus
---------- -------- ----------- ----------- ----------
1 echo active enabled enabled
2 pathEcho active enabled enabled
Monitoring IPThis section shows how to set a statistics baseline and use the show commands to view your IP configuration and monitor IP interfaces and statistics.
Establishing a BaselineIP statistics are stored in system counters. The only way to reset the system counters is to reboot the router. You can, however, establish a baseline for IP statistics by setting a group of reference counters to zero.
baseline ip� Sets a statistics baseline for IP statistics. � The router implements the baseline by reading and storing the statistics at the
time the baseline is set and then subtracting this baseline whenever baseline-relative statistics are retrieved.
� Use the delta keyword with IP show commands to specify that baselined statistics are to be shown.
� Examplehost1#baseline ip
� There is no no version.
baseline ip tcp� Sets a statistics baseline for TCP statistics. � The router implements the baseline by reading and storing the statistics at the
time the baseline is set and then subtracting this baseline whenever baseline-relative statistics are retrieved.
� Use the delta keyword with IP show commands to specify that baselined statistics are to be shown.
� Examplehost1#baseline ip tcp
� There is no no version.
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baseline ip udp� Sets a statistics baseline for UDP statistics. � The router implements the baseline by reading and storing the statistics at the
time the baseline is set and then subtracting this baseline whenever baseline-relative statistics are retrieved.
� Use the delta keyword with IP show commands to specify that baselined statistics are to be shown.
� Examplehost1#baseline ip udp
� There is no no version.
IP show CommandsYou can monitor the following aspects of IP using show ip commands:
To Display Command
Access lists show access-listshow ip as-path-access-list
ARP show arp
General IP information show ip
IP addresses show ip address
Community lists show ip community-list
Prefix for the names of dynamic IP shared interfaces
show ip dynamic-interface-prefix
Routing table show ip forwarding-table slot
Interfaces show ip interface
Shared IP interfaces show ip interface shares
Protocols show ip protocols
Redistribution policies show ip redistribute
Routes show ip route
Interfaces and next hops show ip route slot
Static routes show ip static
TCP statistics show ip tcp statistics
Traffic show ip traffic
UDP statistics show ip udp statistics
Profiles show ip profile
Route maps show route-map
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To set a statistics baseline for IP interfaces, use the baseline ip tcp and baseline ip udp commands. Use the delta keyword with IP show commands to specify that baselined statistics are to be shown.
You can use the output filtering feature of the show command to include or exclude lines of output based on a text string that you specify. See E-Series System Basics Configuration Guide, Chapter 2, Command Line Interface, for details.
show access-list� Use to display information about access lists, including the instances of each
access list. � Example
host1#show access-list
IP Access List 1:
permit ip 172.31.192.217 0.0.0.0 0.0.0.0 255.255.255.255
permit ip 12.40.0.0 0.0.0.3 0.0.0.0 255.255.255.255
deny ip 0.0.0.0 255.255.255.255 0.0.0.0 255.255.255.255
IP Access List 2:
permit ip 172.19.0.0 0.0.255.255 0.0.0.0 255.255.255.255
deny ip 0.0.0.0 255.255.255.255 0.0.0.0 255.255.255.255
IP Access List 10:
permit ip 0.0.0.0 255.255.255.255 0.0.0.0 255.255.255.255
IP Access List 11:
deny ip 0.0.0.0 255.255.255.255 0.0.0.0 255.255.255.255
show arp� Use to display information about ARP.� Field descriptions
� Address � IP address of the entry� Age � time to live for this entry in seconds� Hardware Addr � physical (MAC) address of the entry� Interface � interface-specifier of the entry (for example, fastEthernet6/0 is an
Ethernet interface on slot 6, port 0)� * � indicates that an ARP entry was added because of an arp-validate
command, rather than just an arp command.� Example
host1#show arp
Address Age Hardware Addr Interface
172.31.192.217 21340 00d0.58f2.67e0 loopback1
192.168.1.0 20730 00e0.09ed.5312 fastEthernet6/0 *
192.168.1.1 12550 00e0.b06a.4c75 fastEthernet6/0 *
192.168.1.217 21600 0090.1a00.0230 fastEthernet6/0 *
192.168.1.255 21600 00f0.c2d1.1200 fastEthernet6/0 *
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12.40.0.2 24320 0020.6393.4233 atm5/0.1
172.18.2.1 21600 0020.bed2.8738 atm5/1.1
172.18.2.2 21600 0020.5b91.60f2 atm5/1.1
172.31.192.206 21600 00d0.43b5.1032 atm5/1.1
show ip� Use to display general information on IP. � Example
host1#show ip
IP Router Id: 192.168.1.155
Router Name: default
Default TTL: 60
Reassemble Timeout: 30
show ip address� Use to display detailed or summary information on a particular IP interface. � Field descriptions
� Network Protocols � network protocols configured on this interface� Internet address � IP address and subnet mask of this interface� Broadcast address � broadcast address of this interface� Operational MTU � MTU of this interface� Administrative MTU � value of the MTU if it has been administratively
overridden using the configuration� Operational speed � speed of the interface� Administrative speed � value of the speed if it has been administratively
overridden using the configuration� Discontinuity Time � value of the SysUpTime when the interface statistics
last started being valid � Router advertisement � status of router discovery advertisement: enabled,
disabled� Proxy Arp � status of the feature: enabled, disabled� Administrative debounce-time � configured time in milliseconds that an
interface event has to be in the same state before being reported � Operational debounce-time � time in milliseconds that an interface event has
to be in the same state before being reported � Access routing � access route addition: enabled, disabled� Multipath mode � equal cost multipath mode method: hashed, round-robin� In Received Packets, Bytes � total number of packets and bytes received on
this interface� Unicast Packets, Bytes � unicast packets and bytes received on the IP
interface; link-local received multicast packets (non-multicast-routed frames) are counted as unicast packets
� Multicast Packets, Bytes � multicast packets and bytes received on the IP interface which are then multicast-routed are counted as multicast packets
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� In Policed Packets, Bytes � packets and bytes that were received and dropped because of rate limits
� In Error Packets � number of packets received with errors� In Invalid Source Address Packets � packets received with invalid source
address (for example, spoofed packets)� In Discarded Packets � packets received that were discarded for reasons
other than rate limits, errors, and invalid source address� Out Forwarded Packets, Bytes � total number of packets and bytes that
were sent from this interface� Unicast Packets, Bytes � unicast packets and bytes that were sent from
this interface� Multicast Routed Packets, Bytes � multicast packets and bytes that were
sent from this interface� Out Scheduler Drops Committed Packets, Bytes � outgoing packets and
bytes dropped by the scheduler even though they had a committed traffic contract
� Out Scheduler Drops Conformed Packets, Bytes � outgoing packets and bytes dropped by the scheduler even though they conformed to the traffic contract
� Out Scheduler Drops Exceeded Packets, Bytes � outgoing packets and bytes that were dropped by the scheduler because they exceeded the contract
� Out Policed Packets, Bytes � outgoing packets and bytes dropped because of rate limiters
� Out Discarded Packets � outgoing packets that were discarded for reasons other than those dropped by the scheduler and those dropped because of rate limits
� Example host1#show ip address 10.6.136.73
fastEthernet0/0 is up, line protocol is up
Network Protocols: IP
Internet address is 10.6.136.73/255.255.128.0
Broadcast address is 255.255.255.255
Operational MTU = 0 Administrative MTU = 0
Operational speed = 1 Administrative speed = 0
Discontinuity Time = 5766
Router advertisement = disabled
Proxy Arp = disabled
Administrative debounce-time = 10 mSecs
Operational debounce-time = disabled
Access routing = disabled
Multipath mode = hashed
In Received Packets 2849, Bytes 759428
Unicast Packets 2849, Bytes 759428
Multicast Packets 0, Bytes 0
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In Policed Packets 0, Bytes 0
In Error Packets 0
In Invalid Source Address Packets 0
In Discarded Packets 0
Out Forwarded Packets 1866, Bytes 84650
Unicast Packets 1866, Bytes 84650
Multicast Routed Packets 0, Bytes 0
Out Scheduler Drops Committed Packets 0, Bytes 0
Out Scheduler Drops Conformed Packets 0, Bytes 0
Out Scheduler Drops Exceeded Packets 0, Bytes 0
Out Policed Packets 0, Bytes 0
Out Discarded Packets 0
show ip as-path-access-list� Use to display information about AS-path access lists.� Example
host1#show ip as-path-access-list
AS Path Access List 1:
permit .*
AS Path Access List 2:
deny .*
AS Path Access List 3:
permit _109_
deny .*
AS Path Access List 4:
permit _109$
deny .*
AS Path Access List 10:
deny _109$
permit ^108_
deny .*
show ip community-list� Use to display routes that are permitted by a BGP community list.� Example
host1#show ip community-list
Community List 1:
permit 752877569 (11488:1)
permit 752877570 (11488:2)
permit 752877571 (11488:3)
permit 752877572 (11488:4)
Community List 2:
permit 4294967043 (local-as)
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show ip dynamic-interface-prefix� Use to display the prefix for the names of dynamic IP shared interfaces. � Example
host1#show ip dynamic-interface-prefix
Dynamic Interface Prefix: dyn
show ip forwarding-table slot� Use to display details on the forwarding table for a specific line module,
including the memory used by each virtual router configured on the line module and free memory available on the module.
� The Load Errors field records any failed routing table distribution attempt as an error. Attempts can fail for many reasons during normal operation; a failed attempt does not necessarily indicate a problem. It is normal to see many Load Errors per day.
� If the Status field does not indicate Valid, then the routing table distribution has failed constantly for that VR. It is normal and appropriate behavior for the Status field to indicate Valid while the Load Error field increases daily.
� Field descriptions� Free Memory � amount of routing table memory free on the line module, in
kilobytes� Virtual Router � name of the virtual router(s) configured on the line module� Memory (KB) � amount of routing table memory consumed by the virtual
router, in kilobytes� Load Errors � count of errors made while loading the routing table on the line
module� Status � indicates whether the routing table for the virtual router is valid
� Examplehost1#show ip forwarding-table slot 9
Free Memory = 3,166KB
Virtual Router Memory Load Errors Status
(KB)
---------------- --------- ------------- --------
vr1 4128 0 Valid
vr2 3136 0 Valid
vr3 2256 0 Valid
vr4 1512 0 Valid
default 1024 0 Valid
-----------------------------------------------------------
show ip interface� Use to display the current state of all IP interfaces or the IP interfaces you
specify.� The default is all interface types and all interfaces.� Field descriptions
� interface � interface type and interface specifier
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� interface status � status of the interface� line protocol � status of the line protocol� Description � text description or alias if configured for the interface� Link up/down trap � status of SNMP link up/down traps on the interface� Internet address � IP address of the interface� IP Statistics Rcvd:
� local destination � frames with this router as their destinations� hdr errors � number of packets containing header errors� addr errors � number of packets containing addressing errors� unkn proto � number of packets received containing unknown protocols� discards � number of discarded packets
� IP Statistics Frags:� reasm ok � number of reassembled packets� reasm req � number of requests for reassembly� reasm fails � number of reassembly failures� frag ok � number of packets fragmented successfully� frag req � number of frames requiring fragmentation� frag fails � number of packets unsuccessfully fragmented
� IP Statistics Sent:� generated � number of packets generated� no routes � number of packets that could not be routed� discards � number of packets that could not be routed that were
discarded� ICMP Statistics Rcvd:
� errors � error packets received� dst unreach � packets received with destination unreachable� time exceed � packets received with time-to-live exceeded� param probs � packets received with parameter errors� src quench � source quench packets received� redirect � receive packet redirects� echo req � echo request (ping) packets� echo rpy � echo replies received� timestamp req � requests for a timestamp� timestamp rpy � replies of timestamp requests� addr mask req � mask requests sent� addr mask rpy � mask replies sent
� ICMP Statistics Sent:� errors � error packets sent� dst unreach � packets sent with destination unreachable� time excd � packets sent with time-to-live exceeded� param probs � packets sent with parameter errors
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� src quench � source quench packets sent� redirect � send packet redirects� timestamp req � requests for a timestamp� timestamp rpy � replies to timestamp requests� addr mask req � address mask requests� addr mask rpy � address mask replies
� In Received Packets, Bytes � total number of packets and bytes received on the IP interface� Unicast Packets, Bytes � unicast packets and bytes received on the IP
interface; link-local received multicast packets (non-multicast-routed frames) are counted as unicast packets
� Multicast Packets, Bytes � multicast packets and bytes received on the IP interface which are then multicast-routed are counted as multicast packets
� In Forwarded Packets, Bytes � packets and bytes forwarded into an output IP interface
� In Total Dropped Packets, Bytes � total number of packets and bytes that were dropped on the interface; sum of all the drop reasons indented below this field� In Policed Packets � packets discarded on a receive IP interface due to
token bucket limiting� In Invalid Source Address Packets � packets discarded on a receive IP
interface due to invalid IP source address (sa-validate enabled)� In Error Packets � packets discarded on a receive IP interface due to IP
header errors� In Discarded Packets � packets discarded on the ingress interface due to
a configuration problem rather than a problem with the packet itself� In Fabric Dropped Packets � packets discarded on a receive IP interface
due to internal fabric congestion� Out Forwarded Packets, Bytes � total number of packets and bytes
forwarded out the IP interface� Unicast Packets, Bytes � unicast packets and bytes forwarded out the IP
interface� Multicast Routed Packets, Bytes � multicast packets and bytes forwarded
out the IP interface� Out Requested Packets, Bytes � packets and bytes requested to be
forwarded out an IP interface� Out Total Dropped Packets, Bytes � total number of packets and bytes that
were discarded on the egress interface; sum of all the drop reasons indented below this field� Out Scheduler Drops Committed Packets, Bytes � packets and bytes
dropped by the scheduler even though they had a committed traffic contract
� Out Scheduler Drops Conformed Packets, Bytes � packets and bytes dropped by the scheduler even though they conformed to the traffic contract
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� Out Scheduler Drops Exceeded Packets, Bytes � packets and bytes dropped by the scheduler because they exceeded the contract
� Out Policed Packets � packets discarded on the egress interface due to rate limiting
� Out Discarded Packets � packets discarded on the egress interface due to a configuration problem rather than a problem with the packet itself
� Out Fabric Dropped Packets � packets dropped due to internal fabric congestion
� Example 1host1#show ip interface detail fastEthernet 0/0
fastEthernet0/0 is up, line protocol is up
Description: boston00 fast ethernet interface
Link up/down trap is disabled
Internet address is 1.1.1.2/255.255.255.0
IP statistics:
Rcvd: 0 local destination
0 hdr errors, 0 addr errors
0 unkn proto, 0 discards
Frags: 0 reasm ok, 0 reasm req, 0 reasm fails
0 frag ok, 0 frag creates, 0 frag fails
Sent: 31656835 generated, 0 no routes, 0 discards
ICMP statistics:
Rcvd: 0 errors, 0 dst unreach, 0 time exceed
0 param probs, 0 src quench, 0 redirect,
0 echo req, 31656816 echo rpy
0 timestmp req, 0 timestmp rpy
0 addr mask req, 0 addr mask rpy
Sent: 0 errors, 0 dst unreach, 0 time excd
0 param probs, 0 src qnch, 0 redirect
0 timestamp req, 0 timestamp rpy
0 addr mask req, 0 addr mask rpy
In Received Packets 246220, Bytes 344624800
Unicast Packets 246162, Bytes 344621410
Multicast Packets 58, Bytes 3390
In Forwarded Packets 245464, Bytes 343566400
In Total Dropped Packets 756, Bytes 1058400
In Policed Packets 756
In Invalid Source Address Packets 0
In Error Packets 0
In Discarded Packets 0
In Fabric Dropped Packets 0
Out Forwarded Packets 117, Bytes 87297
Unicast Packets 117, Bytes 87297
Multicast Routed Packets 0, Bytes 0
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Out Requested Packets 117, Bytes 87297
Out Total Dropped Packets 0, Bytes 0
Out Scheduler Drops Committed Packets 0, Bytes 0
Out Scheduler Drops Conformed Packets 0, Bytes 0
Out Scheduler Drops Exceeded Packets 0, Bytes 0
Out Policed Packets 0
Out Discarded Packets 0
Out Fabric Dropped Packets 0
If you are losing packets because of fabric congestion, you can use the In Fabric Dropped Packets and Out Fabric Dropped Packets statistics to help determine the location of the bottleneck. Both statistics count the same thing—the same packets dropped because of fabric congestion—but in different directions.
At any given time, the total number of packets dropped in the fabric for all interfaces in the chassis is equal to the sum of all In Fabric Dropped Packets for all interfaces in the chassis, which equals the sum of all Out Fabric Dropped Packets for all interfaces in the chassis.
Packets not dropped for another listed reason are considered to have been dropped in the fabric. The router calculates In Fabric Dropped Packets by subtracting the total number of inbound packets dropped for all other reasons from the In Total Dropped Packets number. The router calculates Out Fabric Dropped Packets by subtracting the total number of outbound packets dropped for all other reasons from the Out Total Dropped Packets number.
The router calculates In Total Dropped Packets by subtracting In Forwarded Packets from In Received Packets. The router calculates Out Total Dropped Packets by subtracting Out Forwarded Packets from Out Received Packets. These statistics are reported as traffic is moving through the router. It is possible to get false statistics based on packets being forwarded and/or received after polling and based on which of the statistics is reported first. For example, In Forwarded Packets could be reported as greater than In Received Packets. Rather than displaying In Total Dropped Packets as a negative value, the command displays it as the sum of all drop reasons other than fabric drops; fabric drops are reported as 0, but might actually be nonzero. If you halt traffic, the In Total Dropped Packets and Out Total Dropped Packets values are always correct.
show ip interface shares� Use to display information about shared IP interfaces. � If you specify an IP interface specifier, the command displays information only
for that interface and any shared IP interfaces associated with it.
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� Field descriptions� Interface � interface specifier or name of the interface� IP-Address � IP address associated with the interface� Status � operational state of the interface� Protocol � state of the protocol running on the interface� Virtual Router � virtual router in which the interface is configured
� Example 1host1#show ip interface shares brief
Interface IP-Address Status Protocol Virtual Router
null0 255.255.255.255/32 up up
fastEthernet0/0 10.13.5.17/24 up up
loopback100 202.1.1.1/24 up up
atm4/0.1 10.1.1.1/24 up up
ip si0 Unnumbered up up vr-a
ip si1 Unnumbered up up vr-b:vrf-1
� Example 2host1#show ip interface shares brief atm 4/0.1
Interface IP-Address Status Protocol Virtual Router
atm4/0.1 10.1.1.1/24 up up
ip si0 Unnumbered up up vr-a
ip si1 Unnumbered up up vr-b:vrf-1
� Example 3 � for a description of the following fields, see the show ip address commandhost1#show ip interface shares atm 4/0.1
atm4/0.1 is up, line protocol is up
Network Protocols: IP
Unnumbered Interface on loopback100
( IP address 202.1.1.1 )
Operational MTU = 1500 Administrative MTU = 0
Operational speed = 155520000 Administrative speed = 0
Discontinuity Time = 0
Router advertisement = disabled
Administrative debounce-time = disabled
Operational debounce-time = disabled
Access routing = disabled
Multipath mode = hashed
In Received Packets 120, Bytes 12000
Unicast Packets 60, Bytes 6000
Multicast Packets 60, Bytes 6000
In Policed Packets 0, Bytes 0
In Error Packets 0
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In Invalid Source Address Packets 0
Out Forwarded Packets 101, Bytes 5252
Unicast Packets 101, Bytes 5252
Multicast Routed Packets 0, Bytes 0
Out Scheduler Drops Committed Packets 0, Bytes 0
Out Scheduler Drops Conformed Packets 0, Bytes 0
Out Scheduler Drops Exceeded Packets 0, Bytes 0
Out Policed Packets 0, Bytes 0
ip si0 is up, line protocol is up
Network Protocols: IP
Virtual Router vr-a
Layer 2 interface atm4/0.1
Unnumbered Interface on loopback100
( IP address 202.1.1.1 )
Operational MTU = 1500 Administrative MTU = 0
Operational speed = 155520000 Administrative speed = 0
Discontinuity Time = 0
Router advertisement = disabled
Administrative debounce-time = disabled
Operational debounce-time = disabled
Access routing = disabled
Multipath mode = hashed
In Received Packets 0, Bytes 0
Unicast Packets 0, Bytes 0
Multicast Packets 0, Bytes 0
In Policed Packets 0, Bytes 0
In Error Packets 0
In Invalid Source Address Packets 0
Out Forwarded Packets 101, Bytes 5252
Unicast Packets 101, Bytes 5252
Multicast Routed Packets 0, Bytes 0
Out Scheduler Drops Committed Packets 0, Bytes 0
Out Scheduler Drops Conformed Packets 0, Bytes 0
Out Scheduler Drops Exceeded Packets 0, Bytes 0
Out Policed Packets 0, Bytes 0
ip si1 is up, line protocol is up
Network Protocols: IP
Virtual Router vr-b:vrf-1
Layer 2 interface atm4/0.1
.
.
.
Out Policed Packets 0, Bytes 0
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� Example 4 � You can also display statistics for shared IP interfaces with the show ip interface commandhost1#show ip interface ip si0
ip0 is up, line protocol is up
Network Protocols: IP
Layer 2 interface atm4/0.1
Unnumbered Interface on loopback100
( IP address 202.1.1.1 )
Operational MTU = 1500 Administrative MTU = 0
Operational speed = 155520000 Administrative speed = 0
Discontinuity Time = 0
Router advertisement = disabled
Administrative debounce-time = disabled
Operational debounce-time = disabled
Access routing = disabled
Multipath mode = hashed
In Received Packets 0, Bytes 0
Unicast Packets 0, Bytes 0
Multicast Packets 0, Bytes 0
In Policed Packets 0, Bytes 0
In Error Packets 0
In Invalid Source Address Packets 0
Out Forwarded Packets 101, Bytes 5252
Unicast Packets 101, Bytes 5252
Multicast Routed Packets 0, Bytes 0
Out Scheduler Drops Committed Packets 0, Bytes 0
Out Scheduler Drops Conformed Packets 0, Bytes 0
Out Scheduler Drops Exceeded Packets 0, Bytes 0
Out Policed Packets 0, Bytes 0
show ip profile� Use to display information about a specific IP profile. � Field descriptions
� IP profile � profile name� IP address � IP address and subnet mask of the interface or none if the
interface is unnumbered� Unnumbered interface � specifier for the unnumbered interface or none if the
interface is numbered� Router � router name� Directed Broadcast � enabled or disabled� ICMP Redirects � enabled or disabled� Access Route Addition � enabled or disabled� Network Address Translation � enable or disable; domain location (inside or
outside)
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� Source-Address Validation � enabled or disabled� Ignore DF Bit � enabled or disabled� Administrative MTU � MTU size
� Examplehost1#show ip profile foo
IP profile : foo
IP address : none
Unnumbered interface : none
Router :
Directed Broadcast : Enabled
ICMP Redirects : Disabled
Access Route Addition : Enabled
Network Address Translation: Enabled, domain inside
Source-Address Validation : Enabled
Ignore DF Bit : Disabled
Administrative MTU : 0
show ip protocols� Use to display configured protocols.� Field descriptions
� For BGP:� Redistributing � protocol to which BGP is redistributing routes� Default local preference � local preference value� IGP synchronization � status of IGP synchronization: enabled, disabled� Always compare MED � status of multiexit discrimination: enabled,
disabled� Router flap damping � status of route dampening: enabled, disabled� Administrative Distance � external, internal, and local administrative
distances� Neighbor Address � IP address of the BGP neighbor� Neighbor Incoming/Outgoing update distribute list � number of the access
list for outgoing routes� Neighbor Incoming/Outgoing update prefix list � number of the prefix list
for incoming or outgoing routes� Neighbor Incoming/Outgoing update prefix tree � number of the prefix
tree for incoming or outgoing routes� Neighbor Incoming/Outgoing update filter list � number of filter list for
incoming routes� Routing for Networks � network for which BGP is currently injecting
routes� For IS-IS:
� System Id � 6-byte value of the system� IS-Type � routing type of the router: Level 1, Level 2� Distance � administrative distance for IS-IS learned routes
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� Address Summarization � aggregate addresses defined in the routing table for multiple groups of addresses at a given level or routes learned from other routing protocols
� Routing for Networks � network for which IS-IS is currently injecting routes
� For OSPF:� Router ID � OSPF process ID for the router� Distance � administrative distance for OSPF learned routes� Redistributing � protocol to which OSPF is redistributing routes� Address Summarization � aggregate addresses defined in the routing
table for multiple groups of addresses at a given level or routes learned form other routing protocols
� Routing for Networks � network for which OSPF is currently injecting routes
� For RIP:� Router Administrative State � RIP protocol state. Enable means that the
interface is allowed to send and receive updates. Disable means that the interface may be configured but it is not allowed to run yet.
� System version � RIP versions allowed for sending and receiving RIP updates. The router version is currently set to RIP1, which sends RIP version 1 but will receive version 1 or 2. If the version is set to RIP2, the router will send and receive version 2 only. The default is configured for RIP1.
� Update interval � current setting of the update timer (in seconds)� Invalid after � current setting of the invalid timer (in seconds)� hold down time � current setting of the hold down timer (in seconds)� flushed interval � current setting of the flush timer (in seconds)� Filter applied to outgoing route update � access list applied to outgoing
RIP route updates� Filter applied to incoming route update � access list applied to incoming
RIP route updates� Global route map � route map that specifies all RIP interfaces on the
router� Distance � value added to RIP routes added to the IP routing table; the
default is 120.� Interface � interface type on which RIP protocol is running� Redistributing � protocol to which RIP is redistributing routes� Routing for Networks � network for which RIP is currently injecting routes
� Examplehost1#show ip protocols
Routing Protocol is “bgp 100”
Redistributing: ospf
Default local preference is 100
IGP synchronization is enabled
Always compare MED is disabled
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Router flap damping is disabled
Administrative Distance: external 20 internal 200 local 200
Neighbor(s):
Address 1.1.1.1
Outgoing update distribute list is 2
Outgoing update prefix list is efg
Incoming update prefix tree is abc
Incoming update filter list is 1
Routing for Networks:
192.168.1.0/24
Routing Protocol is “isis isisOne”
System Id: 0000.0000.0011.00 IS-Type: level-1-2
Distance: 115
Address Summarization:
None
Routing for Networks:
fastEthernet0/0
Routing Protocol is “ospf 1” with Router ID 192.168.1.151
Distance is 110
Redistributing: isis
Address Summarization:
None
Routing for Networks:
192.168.1.0/255.255.255.0 area 0.0.0.0
Routing Protocol is “rip”
Router Administrative State: enable
System version RIP1: send = 1, receive = 1 or 2
Update interval: 30 seconds
Invalid after: 180 seconds
hold down time: 120 seconds
flushed interval: 300 seconds
Filter applied to outgoing route update is not set
Filter applied to incoming route update is not set
No global route map
Distance is 120
Interface Tx Rx Auth
fastEthernet0/0 1 1,2 none
Redistributing: ospf
Routing for Networks:
192.168.1.0/255.255.255.0
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show ip redistribute� Use to display configured route redistribution policy.� Field descriptions
� To � protocol that routes are distributed into� From � protocol that routes are distributed from� status � redistribution status� route map number � number of the route map
� Examplehost1#show ip red
To ospf, From static is enabled with route map 4
To ospf, From connected is enabled with route map 3
show ip route� Use to display the current state of the routing table, including routes not used
for forwarding.� You can display all routes, a specific route, best route to a resolved domain
name, all routes beginning with a specified address, routes for a particular protocol (BGP, IS-IS, OSPF, or RIP), locally connected routes, internal control routes, static routes, or summary counters for the routing table.
� Field descriptions� Type � type of route; protocol or other� Prefix � IP address prefix of network destination� Length � network mask length for prefix� Next Hop � IP address of the next hop to the route, whether it is a local
interface or another router� Dist � administrative distance for the route; see Table 2-3� Met � number of hops� Intf � interface type and interface specifier
� Example 1host1#show ip route
Protocol/Route type codes:
I1- ISIS level 1, I2- ISIS level2,
I- route type intra, IA- route type inter, E- route type external,
i- metric type internal, e- metric type external,
O- OSPF, E1- external type 1, E2- external type2,
N1- NSSA external type1, N2- NSSA external type2
Prefix/Length Type Next Hop Dist/Met Intf
------------- ---- -------- -------- ------
172.16.2.0/24 Bgp 192.168.1.102 20/1 fastEthernet0/0
10.10.0.112/32 Static 192.168.1.1 1/1 fastEthernet0/0
10.1.1.0/24 Connect 10.1.1.1 0/1 atm3/0.100
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� Example 2host1#show ip route static
Protocol/Route type codes:
I1- ISIS level 1, I2- ISIS level2,
I- route type intra, IA- route type inter, E- route type external,
i- metric type internal, e- metric type external,
O- OSPF, E1- external type 1, E2- external type2,
N1- NSSA external type1, N2- NSSA external type2
Prefix/Length Type Next Hop Dist/Met Intf
------------- ---- -------- -------- --------------
10.10.0.112/32 Static 192.168.1.1 1/1 fastEthernet0/0
� Example 3host1#show ip route summary
5 total routes, 720 bytes in route entries
0 isis routes
0 rip routes
1 static routes
1 connected routes
0 bgp routes
0 ospf routes
3 other internal routes
0 access routes
0 internally created access host routes
Last route added/deleted: 0.0.0.0/0 by StaticLow
At THU MAR 09 2000 05:22:49 UTC
� Example 4host1#show ip route all
Protocol/Route type codes:
I1- ISIS level 1, I2- ISIS level2,
I- route type intra, IA- route type inter, E- route type external,
i- metric type internal, e- metric type external,
O- OSPF, E1- external type 1, E2- external type2,
N1- NSSA external type1, N2- NSSA external type2
Prefix/Length Type Next Hop Dist/Met Intf
------------- ---- -------- -------- ------
0.0.0.0/0 Static 192.168.1.1 1/1 fastEthernet0/01.1.1.1/32 I2-E-i 192.168.1.105 115/10 fastEthernet0/06.6.6.0/24 Static 192.168.1.1 1/1 fastEthernet0/06.33.5.0/24 Static 0.0.0.0 1/1 loopback28.8.8.0/24 I2-E-i 192.168.1.105 115/10 fastEthernet0/09.9.9.9/32 I2-E-i 192.168.1.105 115/10 fastEthernet0/010.0.0.0/8 I2-E-i 192.168.1.105 115/10 fastEthernet0/010.10.0.156/32 Static 192.168.1.1 1/1 fastEthernet0/011.1.1.1/32 I2-E-i 192.168.1.105 115/10 fastEthernet0/011.11.11.12/32 I2-I-i 192.168.1.105 115/10 fastEthernet0/022.2.0.0/16 I2-I-i 92.168.1.105 115/10 fastEthernet0/0
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34.0.0.0/8 I2-E-i 192.168.1.105 115/10 fastEthernet0/0172.20.32.0/24 Static 192.168.1.1 1/1 fastEthernet0/0174.20.32.0/24 I2-I-i 192.168.1.105 115/20 fastEthernet0/0176.20.32.0/24 Connect 176.20.32.1 0/1 loopback1192.168.1.0/24 Connect 192.168.1.214 0/1 fastEthernet0/0201.1.1.0/24 I2-E-i 192.168.1.105 115/10 fastEthernet0/0201.2.1.0/24 I2-E-i 192.168.1.105 115/10 fastEthernet0/0201.3.1.0/24 I2-E-i 192.168.1.105 115/10 fastEthernet0/0202.1.1.1/32 I2-E-i 192.168.1.105 115/10 fastEthernet0/0207.1.1.0/24 I2-E-i 192.168.1.105 115/10 fastEthernet0/0
show ip route slot � Use to display the interface and next hop for an IP address in the routing table
of a line module. � A next hop is displayed only for protocols where ARP is used to resolve the
addresses, such as for fastEthernet, gigabitEthernet, bridged Ethernet over ATM, and so on.
� Field descriptions� IP address � address reachable via the interface� Interface � interface type and specifier associated with the IP address;
displays �Local Interface� if a special interface index is present in the routing table for special IP addresses, such as broadcast addresses
� Next Hop � IP address of the next hop router to reach the IP address; displays �---� if no next hop is associated with the IP address
� Example 1host1#show ip route slot 6 10.10.0.231
IP address Interface Next Hop
------------ ---------------- ------------
10.10.0.231 fastEthernet 6/0 10.10.0.231
� Example 2host1#show ip route slot 9 90.248.1.2
IP address Interface Next Hop
------------ ---------------- ------------
90.248.1.2 serial9/23:2 ---
� Example 3host1#show ip route slot 9 90.249.255.255
IP address Interface Next Hop
------------ ---------------- ------------
90.249.255.255 Local Interface ---
show ip static� Use to display the status of static routes in the routing table.� You can specify an IP mask that filters specific routes.� Field descriptions
� Prefix � IP address prefix� Length � prefix length� Next Hop � IP address of the next hop
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� Met � number of hops� Dist � administrative distance of the route; see Table 2-3� Tag � tag value of the route� Intf � interface type and interface specifier
� Examplehost1#show ip route static
Prefix/Length: Next Hop: Met: Dist: Tag: Intf:
10.2.0.0/24 192.168.1.1 1 1 0 ethernet6/0
10.2.1.0/24 192.168.1.1 1 1 1 ethernet6/0
172.31.1.48/32 172.18.2.2 1 1 0 atm5/1.1
show ip tcp statistics� Use to display TCP statistics.� Field descriptions
� TCP Global Statistics Connections:� attempted � number of outgoing TCP connections attempted� accepted � number of incoming TCP connections accepted� established � number of TCP connections established
� TCP Global Statistics Rcvd:� total pkts � total number of packets received� in-sequence pkts � number of packets received in sequence� bytes � number of bytes received� chksum err pkts � number of checksum error packets received� authentication err pkts � number of authentication error packets received� bad offset pkts � number of bad offset packets received� short pkts � number of short packets received� duplicate pkts � number of duplicate packets received� out of order pkts � number of packets received out of order
� TCP Global Statistics Sent:� total pkts � total number of packets sent� data pkts � number of data packets sent� bytes � number of bytes sent� retransmitted pkts � number of packets retransmitted� retransmitted bytes � number of bytes retransmitted
� TCP Session Statistics� Local addr � local address of the TCP connection� Local port � local port number of the TCP connection� Remote addr � remote address of the TCP connection� Remote port � remote port number of the TCP connection� State � current state of the TCP connection� Authentication � authentication status of the TCP connection
CHAPTER 2Configuring IP
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� TCP Session Statistics Rcvd:� total pkts � total number of packets received on the TCP connection� in-sequence pkts � number of packets received in sequence on the TCP
connection� bytes � number of bytes received on the TCP connection� chksum err pkts � number of checksum error packets received on the
TCP connection� bad offset pkts � number of bad offset packets received on the TCP
connection� short pkts � number of short packets received on the TCP connection� duplicate pkts � number of duplicate packets received on the TCP
connection� out of order pkts � number of packets received out of order on the TCP
connection� TCP Session Statistics Sent:
� total pkts � total number of packets sent on the TCP connection� data pkts � number of data packets sent on the TCP connection� bytes � number of bytes sent on the TCP connection� retransmitted pkts � number of packets retransmitted on the TCP
connection� retransmitted bytes � number of bytes retransmitted on the TCP
connection� Example
host1#show ip tcp statistics
TCP Global Statistics:
Connections: 7358 attempted, 4 accepted, 7362 established
0 dropped, 14718 closed
Rcvd: 75923 total pkts, 53608 in-sequence pkts, 3120303 bytes
0 chksum err pkts, 0 authentication err pkts, 0 bad offset pkts
0 short pkts, 0 duplicate pkts, 0 out of order pkts
Sent: 82352 total pkts, 44404 data pkts, 657095 bytes
34 retransmitted pkts, 487 retransmitted bytes
TCP Session Statistics:
Local addr: 0.0.0.0, Local port: 23
Remote addr: 0.0.0.0, Remote port: 0
State: LISTEN Authentication: None
Rcvd: 4 total pkts, 0 in-sequence pkts, 0 bytes
0 chksum err pkts, 0 bad offset pkts, 0 short pkts
0 duplicate pkts, 0 out of order pkts
Sent: 0 total pkts, 0 data pkts, 0 bytes
0 retransmitted pkts, 0 retransmitted bytes
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Local addr: 192.168.1.250, Local port: 23
Remote addr: 10.10.0.77, Remote port: 2170
State: ESTABLISHED Authentication: None
Rcvd: 61 total pkts, 34 in-sequence pkts, 41 bytes
0 chksum err pkts, 0 bad offset pkts, 0 short pkts
0 duplicate pkts, 0 out of order pkts
Sent: 64 total pkts, 45 data
Local addr: 192.168.1.250, Local port: 23
Remote addr: 10.10.0.77, Remote port: 2170
State: ESTABLISHED Authentication: None
Rcvd: 61 total pkts, 34 in-sequence pkts, 41 bytes
0 chksum err pkts, 0 bad offset pkts, 0 short pkts
0 duplicate pkts, 0 out of order pkts
Sent: 64 total pkts, 45 data pkts, 2304 bytes
0 retransmitted pkts, 0 retransmitted bytes
Local addr: 192.168.1.250, Local port: 23
Remote addr: 192.168.1.139, Remote port: 1038
State: ESTABLISHED Authentication: None
Rcvd: 295 total pkts, 159 in-sequence pkts, 299 bytes
0 chksum err pkts, 0 bad offset pkts, 0 short pkts
0 duplicate pkts, 0 out of order pkts
Sent: 281 total pkts, 210 data pkts, 3089 bytes
0 retransmitted pkts, 0 retransmitted bytes
show ip traffic� Use to display statistics about IP traffic. � You can use the ipTraffic log to show consumable IP traffic to the SRP module;
the traffic is filterable per router and IP interface. You can show ICMP, TCP, and UDP traffic with the icmpTraffic, udpTraffic, and tcpTraffic logs.
� Field descriptions� IP Statistics Rcvd:
� router Id � router ID number� total � number of frames received� local destination � frames with this router as their destination� hdr errors � number of packets containing header errors� addr errors � number of packets containing addressing errors� unkn proto � number of packets received containing unknown protocols� discards � number of discarded packets
� IP Statistics Frags:� reassembled � number of reassembled packets� reasm timed out � number of reassembled packets that timed out� reasm req � number of requests for reassembly� reasm fails � number of reassembly failures
CHAPTER 2Configuring IP
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� frag ok � number of fragmented packets reassembled successfully� frag fail � number of fragmented packets reassembled unsuccessfully� frag creates � number of packets created by fragmentation
� IP Statistics Sent:� forwarded � number of packets forwarded� generated � number of packets generated� out disc � number of outbound packets discarded� no routes � number of packets that could not be routed� routing discards � number of packets that could not be routed and were
discarded� IP Statistics Route:
� routes in table � number of routes in the routing table� ICMP Statistics Rcvd:
� total � total number of ICMP packets received� errors � number of error packets received� dst unreach � number of packets received with destination unreachable� time exceed � number of packets received with time-to-live exceeded� param probs � number of packets received with parameter errors� src quench � number of source quench packets received� redirects � number of receive packet redirects� echo req � number of echo request (ping) packets� echo rpy � number of echo replies received� timestamp req � number of requests for a timestamp� timestamp rpy � number of replies to timestamp requests� addr mask req � number of mask requests received� addr mask rpy � number of mask replies received
� ICMP Statistics Sent:� total � total number of ICMP packets sent� errors � number of error packets sent� dest unreach � number of packets sent with destination unreachable� time excd � number of packets sent with time-to-live exceeded� param prob � number of packets sent with parameter errors� src quench � number of source quench packets sent� redirects � number of send packet redirects� echo req � number of echo request (ping) packets� echo rpy � number of echo replies sent� timestamp req � number of requests for a timestamp� timestamp rpy � number of replies to timestamp requests� addr mask req � number of address mask requests sent� addr mask rpy � number of replies to address mask requests
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� UDP Statistics Rcvd:� total � total number of UDP packets received� checksum � number of checksum error packets received � no port � number of packets received for which no E-series router
application listener was listening on the destination port� UDP Statistics Sent:
� total � total number of UDP packets sent� errors � number of error packets sent
� TCP Global Statistics Connections:� attempted � number of outgoing TCP connections attempted� accepted � number of incoming TCP connections accepted� established � number of TCP connections established� dropped � number of TCP connections dropped� closed � number of TCP connections closed� currently established � number of TCP connections currently established
� TCP Global Statistics Rcvd:� total pkts � total number of TCP packets received� in-sequence pkts � number of packets received in sequence� bytes � number of bytes received� chksum err pkts � number of checksum error packets received� authentication err pkts � number of authentication error packets received� bad offset pkts � number of packets received with bad offsets� short pkts � number of short packets received� duplicate pkts � number of duplicate packets received� out of order pkts � number of packets received out of order
� TCP Global Statistics Sent:� total pkts � total number of TCP packets sent� data pkts � number of data packets sent� bytes � number of bytes sent� retransmitted pkts � number of packets retransmitted� retransmitted bytes � number of retransmitted bytes
� OSPF Statistics � provides statistics on OSPF� IGMP Statistics � provides statistics about queries, reports sent or received� ARP Statistics � not supported for this version of the router
� Examplehost1#show ip traffic
IP statistics: Router Id: 172.31.192.217
Rcvd: 97833 total, 171059 local destination
0 hdr errors, 0 addr errors
167 unkn proto, 0 discards
Frags: 4 reassembled, 30 reasm timed out, 8 reasm req
0 reasm fails, 145 frag ok, 0 frag fail
CHAPTER 2Configuring IP
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290 frag creates
Sent: 15 forwarded, 25144 generated, 0 out disc
0 no routes,0 routing discards
Route: 57680 routes in table
0 timestamp req, 0 timestamp rpy
0 addr mask req, 0 addr mask rpy
ICMP statistics:
Rcvd: 561 total, 0 errors, 15 dst unreach
0 time exceed, 0 param probs, 0 src quench
0 redirects, 0 echo req, 0 echo rpy
0 timestamp req, 0 timestamp rpy
0 addr mask req, 0 addr mask rpy
Sent: 463866 total, 0 errors, 163676 dest unreach
0 time excd, 0 param prob, 0 src quench
20 redirects, 463846 echo req, 0 echo rpy
0 timestamp req, 0 timestamp rpy
0 addr mask req, 0 addr mask rpy
UDP Statistics:
Rcvd: 93326 total, 0 checksum errors, 90610 no port
Sent: 0 total, 0 errors
TCP Global Statistics:
Connections: 7358 attempted, 4 accepted, 7362 established
0 dropped, 14718 closed
Rcvd: 75889 total pkts, 53591 in-sequence pkts, 3120283 bytes
0 chksum err pkts, 0 authentication err pkts, 0 bad offset
0 short pkts, 0 duplicate pkts, 0 out of order pkts
Sent: 82318 total pkts, 44381 data pkts, 656321 bytes
34 retransmitted pkts, 487 retransmitted bytes
OSPF Statistics:
IGMP Statistics:
ARP Statistics:
show ip udp statistics� Use to display UDP statistics.� Field descriptions
� UDP Statistics Rcvd:� total � total number of UDP packets received� checksum � number of checksum error packets received � no port � number of packets received for which no E-series router
application listener was listening on the destination port� UDP Statistics Sent:
� total � total number of UDP packets sent� errors � number of error packets sent
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� Examplehost1#show ip udp statistics
UDP Statistics:
Rcvd: 39196 total, 0 checksum errors, 29996 no port
Sent: 210 total, 0 errors
show profile brief� Use to list all profile names.� Field descriptions
� profile � profile name� Example
host1#show profile brief
Profile :
foo
trill
profile4
show route-map� Use to display the configured route maps.� The displayed information includes the instances of each access list such as
match and set commands.� Example
host1(config)#route-map westford permit 10
host1(config-route-map)#match community 44
host1(config-route-map)#set local-pref 400
host1(config-route-map)#exit
host1(config)#exit
host1#show route-map westford
route-map 1, permit, sequence 10
Match clauses:
match community 44
Set clauses:
set local-pref 400
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3
Configuring IPv6 and Neighbor DiscoveryThis chapter describes how to configure Internet Protocol version 6 (IPv6) routing and Neighbor Discovery (ND) on your E-series router.
Topic Page
Overview 3-2
References 3-3
IPv6 Packet Headers 3-3
IPv6 Addressing 3-5
Understanding Neighbor Discovery 3-9
Before You Configure IPv6 or Neighbor Discovery 3-10
IPv6 Configuration Tasks 3-11
Creating Static IPv6 Neighbors 3-17
Neighbor Discovery Configuration Tasks 3-17
Clearing IPv6 Neighbors 3-20
Monitoring IPv6 and Neighbor Discovery 3-20
CHAPTER 3Configuring IPv6 and Neighbor Discovery
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OverviewInternet Protocol version 6 (IPv6) is designed to eventually supersede IP version 4 (IPv4). The intent of this design change is not to take a radical step away from IPv4, but to enhance IP addressing and maintain other IPv4 functions that work well.
The differences between IPv4 and IPv6 include the following:
• Expanded addressing capabilities
IPv6 increases the size of the IP address from 32 bits to 128 bits. This increased size allows for a larger address space and a much larger number of addressable nodes.
• Simplified header format
Reducing some common processing costs associated with packet handling and streamlining the bandwidth cost of the larger IPv6 header, some IPv4-specific header fields either no longer exist or are now optional in the IPv6 header.
• Traffic flow labelling capabilities
The ability to label packets for specific traffic flows exists in the IPv6 packet. These labels allow for nondefault quality of service (QoS) or the possibility of “real-time” services.
• Authentication capabilities
Authentication provides the ability to use extensions for some authentication and data integrity applications.
IPv6 continues to provide the basic packet delivery service for all TCP/IP networks. As a connectionless protocol, IPv6 does not exchange control information to establish an end-to-end connection before transmitting data. Instead, just like its IPv4 predecessor, IPv6 continues to rely on protocols in other layers to establish the connection if connection-oriented services are required and to provide error detection and error recovery.
In addition to supporting a revised header structure and an expanded addressing format, the E-series router supports the following IPv6 features:
• Static routes
• ICMPv6
• Ping
• Traceroute
ReferencesE-Series Routers
3-3
• Routing policy (see Chapter 1, Configuring Routing Policy for details)
• IPv6 BRAS (see Broadband Access Configuration Guide for details).
ReferencesFor more information about IPv6, consult the following resources:
• RFC 2373 – IP Version 6 Addressing Architecture (July 1998)
• RFC 2460 – Internet Protocol, Version 6 (IPv6) (December 1998)
• RFC 2461 – Neighbor Discovery for IP Version 6 (IPv6) (December 1998)
• RFC 2462 – IPv6 Stateless Address Autoconfiguration (December 1998)
• RFC 2463 – Internet Control Message Protocol (ICMPv6) for the Internet Protocol Version 6 (IPv6) Specification (December 1998)
• RFC 2464 – Transmission of IPv6 Packets over Ethernet Networks (December 1998)
• RFC 2465 – Management Information Base for IP Version 6: Textual Conventions and General Group (December 1998)
• RFC 2466 – Management Information Base for IP Version 6: ICMPv6 Group (December 1998)
You can access these and other Internet RFCs and drafts at the following URL:
http://www.ietf.org
IPv6 Packet HeadersAn IPv6 packet is a block of data that contains a header and a payload. The header is the information necessary to deliver the packet to a destination address; the payload is the data that you want to deliver. IPv6 packets can use a standard or an extended format.
IPv4 and IPv6 Header DifferencesThe main difference between IPv4 and IPv6 resides in their headers. Figure 3-1 provides a comparison between the two protocol versions.
CHAPTER 3Configuring IPv6 and Neighbor Discovery
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Figure 3-1 IPv4 and IPv6 header comparison
Standard IPv6 HeadersIPv6 packet headers contain many of the fields found in IPv4 packet headers; some of these fields differ from IPv4. (See Figure 3-1.)
The 40-byte IPv6 header consists of the following eight fields:
• Version – Indicates the version of the Internet Protocol.
• Traffic class – Previously the type-of-service (ToS) field in IPv4, the traffic class field defines the class-of-service (CoS) priority of the packet. However, the semantics for this field (for example, DiffServ code points) are identical to IPv4.
• Flow label – The flow label identifies all packets belonging to a specific f low (that is, packet flows requiring a specific class of service [CoS]); routers can identify these packets and handle them in a similar fashion.
• Payload length – Previously the total length field in IPv4, the payload length field specifies the length of the IPv6 payload.
• Next header – Previously the protocol field in IPv4, the Next Header field indicates the next extension header to examine.
• Hop limit – Previously the time-to-live (TTL) field in IPv4, the hop limit indicates the maximum number of hops allowed.
Ver.6
Ver.6
Traffic class8 bits
Traffic class8 bits
Flow label20 bits
Flow label20 bits
Payload Length16 bits
Payload Length16 bits
Next Hdr.8 bits
Next Hdr.8 bits
Hop Limit8 bits
Hop Limit8 bits
Source Address128 bits
Source Address128 bits
Destination Address128 bits
Destination Address128 bits
32 bits
Ver.4
Ver.4 HLHL Datagram LengthDatagram LengthTOS
Datagram-IDDatagram-ID FlagsFlags Flag OffsetFlag Offset
TTLTTL ProtocolProtocol Header ChecksumHeader Checksum
Source IP AddressSource IP Address
Destination IP AddressDestination IP Address
IP Options (with padding if necessary)IP Options (with padding if necessary)
32 bits
IPv4 header
IPv6 header
IPv6 AddressingE-Series Routers
3-5
• Source address – Identifies the address of the source node sending the packet.
• Destination address – Identifies the final destination node address for the packet.
Extension HeadersIn IPv6, extension headers are used to encode optional Internet-layer information. Extension headers are placed between the IPv6 header and the upper-layer header in a packet.
IPv6 allows you to chain extension headers together by using the next header field. The next header field, located in the IPv6 header, indicates to the router which extension header to expect next. If there are no more extension headers, the next header field indicates the upper-layer header (TCP header, UDP header, ICMPv6 header, an encapsulated IP packet, or other items).
IPv6 AddressingIPv6 increases the size of the IP address from the 32 bits found in IPv4 to 128 bits. This increased size allows for a broader range of addressing hierarchies and a much larger number of addressable nodes.
In addition to the increased size, IPv6 addresses can be of different scopes that categorize what types of applications are suitable for the address. IPv6 does not support broadcast addresses, but uses multicast addresses to serve this role. In addition, IPv6 also defines a new type of address called anycast.
Address RepresentationIPv6 addresses consist of eight hexadecimal groups. Each hexadecimal group, separated by a colon (:), consists of a 16-bit hexadecimal value. The following is an example of the IPv6 format:
xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx:xxxx
A group of xxxx represents the 16-bit hexadecimal value. Each individual x represents a 4-bit hexadecimal value. The following is an example of a possible IPv6 address:
4FDE:0000:0000:0002:0022:F376:FF3B:AB3F
Note: Hexadecimal letters in IPv6 addresses are not case sensitive.
CHAPTER 3Configuring IPv6 and Neighbor Discovery
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IPv6 Address CompressionIPv6 addresses often contain consecutive hexadecimal fields of zeros. To simplify address entry, you can use two colons (::) to represent the consecutive fields of zeros when typing the IPv6 address. Table 3-1 provides compressed IPv6 address format examples.
Note: You can use two colons (::) only once in an IPv6 address to represent hexadecimal fields of consecutive zeros.
IPv6 Address PrefixAn IPv6 address prefix is a combination of an IPv6 prefix (address) and a prefix length. The prefix takes the form ipv6-prefix/prefix-length and represents a block of address space (or a network). The ipv6-prefix variable follows general IPv6 addressing rules (see RFC 2373 for details). The /prefix-length variable is a decimal value that indicates the number of contiguous, higher-order bits of the address that make up the network portion of the address. For example, 10FA:6604:8136:6502::/64 is a possible IPv6 prefix.
Address TypesIPv6 can use several types of addresses:
• Unicast – Used to identify a single interface, this release of the E-series router product supports the following unicast address types:
> Global aggregatable – Allows for aggregation of routing prefixes to limit the number of global routing table entries
> Link-local – Eliminates the need for a globally unique prefix. Local-link addresses allow communications between devices on a local link.
> Site-local – Used as private addresses to restrict communication to a domain portion.
Note: IPv6 routers must not forward packets that have site-local source or destination addresses outside the site.
Table 3-1 Compressed IPv6 formats
IPv6 Address Type Full Format Compressed Format
Unicast 10FB:0:0:0:C:ABC:1F0C:44DA 10FB::C:ABC:1F0C:44DA
Multicast FD01:0:0:0:0:0:0:1F FD01::1F
Loopback 0:0:0:0:0:0:0:1 ::1
Unspecified 0:0:0:0:0:0:0:0 ::
IPv6 AddressingE-Series Routers
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> IPv4-compatible – Contains a standard IPv4 address in the lower-order 32 bits of the address and zeros in the higher-order 96 bits of the address. For example, the format of an IPv4-compatible IPv6 address is 0:0:0:0:0:0:A.B.C.D (or condensed as ::A.B.C.D). In other words, devices using IPv6 use the entire 128-bit IPv4-compatible IPv6 address, whereas IPv4 devices use the IPv4 address embedded within the lower-order 32-bits of the address. You would use IPv4-compatible IPv6 addresses for devices that must support both IPv4 and IPv6 protocols.
• Multicast – Used for sending packets to multiple destinations. A multicast transmission sends packets to all interfaces that are part of a multicast group. The group is represented by the IPv6 destination address of the packet.
• Anycast – Used for a set of interfaces on different nodes. An anycast transmission sends packets to only one of the interfaces associated with the address, not to all of the interfaces. This interface is typically the closest interface, as defined by the routing protocol.
• Loopback – Used by a node to send an IPv6 packet to itself. An IPv6 loopback address functions the same as an IPv4 loopback address.
• Unspecified – Indicates the absence of an IPv6 address. For example, newly initialized IPv6 nodes may use the unspecified address as the source address in their packets until they receive an IPv6 address.
Note: IPv6 does not use broadcast addresses; instead, IPv6 uses multicast addresses.
Address ScopeSome unicast and multicast IPv6 addresses contain a value known as scope. This value identifies the application suitable for the address.
Unicast addresses support two types of scope—global and local. In addition, there are two types of local scope—link-local addresses and site-local addresses.
Link-local unicast addresses, identified by the first ten bits of the prefix, function within a single network link. You cannot use link-local addresses outside a network link.
Site-local unicast addresses function within a site or an intranet. A site consists of multiple network links, and site-local addresses identify nodes inside the intranet. You cannot use site-local addresses outside the site.
CHAPTER 3Configuring IPv6 and Neighbor Discovery
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Multicast addresses support 16 different types of scope, including node, link, site, organization, and global scope. A four-bit field in the prefix identifies the scope.
Address StructureUnicast addresses identify a single interface. The address consists of n bits for the prefix and 128-n bits for the interface ID.
Multicast addresses identify a set of interfaces. The address is made up of the first 8 bits of all ones, a 4-bit f lag field, a 4-bit scope field, and a 112-bit group ID.
11111111 | flgs | scop | group ID
The first octet of ones identifies the address as a multicast address. The flags field identifies whether the multicast address is a well-known address or whether it is a transient multicast address. The scope field identifies the scope of the multicast address. The 112-bit group ID identifies the multicast group.
Similar to multicast addresses, anycast addresses identify a set of interfaces. However, packets are sent to only one of the interfaces, not to all interfaces. Anycast addresses are allocated from the normal unicast address space and cannot be distinguished from a unicast address in format. Therefore, each member of an anycast group must be configured to recognize certain addresses as anycast addresses.
ICMP SupportInternet Control Message Protocol (ICMP) provides a mechanism that enables a router or destination host to report an error in data traffic processing to the original source of the packet. For this release, the E-series router supports ICMP for use in the IPv6 ping and traceroute commands.
The ping and traceroute commands help you determine destination reachability within a network.
• Use the ping ipv6 command to send an ICMP echo request packet. In the following example, the request packet is sent to address 1::1 with a data size of 200 and a timeout value of 10 seconds:
host1#ping ipv6 1::1 data-size 200 timeout 10
• Use the traceroute ipv6 command to discover routes that router packets follow when traveling to their destination. In the following
Understanding Neighbor DiscoveryE-Series Routers
3-9
example, the trace destination address is 1::1, the maximum number of hops of the trace is 20, and the timeout value is 10 seconds:
host1#traceroute ipv6 1::1 hop-limit 20 timeout 10
Understanding Neighbor DiscoveryThough not a true protocol, routers and hosts (nodes) use Neighbor Discovery (ND) messages to determine the link-layer addresses of neighbors that reside on attached links and to overwrite invalid cache entries. Hosts also use ND to find neighboring routers that can forward packets on their behalf.
In addition, nodes use ND to actively track the ability to reach neighbors. When a router (or the path to a router) fails, nodes actively search for alternatives to reach the destination.
IPv6 Neighbor Discovery corresponds to a number of the IPv4 protocols — ARP, ICMP Router Discovery, and ICMP Redirect. However, Neighbor Discovery provides many improvements over the IPv4 set of protocols. These improvements address the following:
• Router discovery – How a host locates routers residing on an attached link.
• Prefix discovery – How a host discovers address prefixes for destinations residing on an attached link. Nodes use prefixes to distinguish between destinations that reside on an attached link and those destinations that it can reach only through a router.
• Parameter discovery – How a node learns various parameters (link parameters or Internet parameters) that it places in outgoing packets.
• Address resolution – How a node uses only a destination IPv6 address to determine a link-layer address for destinations on an attached link.
• Next-hop determination – The algorithm that a node uses for mapping an IPv6 destination address into a neighbor IPv6 address (either the next router hop or the destination itself) to which it plans to send traffic for the destination.
• Neighbor unreachability detection – How a node determines that it can no longer reach a neighbor.
• Duplicate address detection – How a node determines whether an address is already in use by another node.
CHAPTER 3Configuring IPv6 and Neighbor Discovery
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Before You Configure IPv6 or Neighbor DiscoveryBefore you configure IPv6, you must create the lower-layer interfaces over which IPv6 traffic flows. In this release, the following modules support IPv6 configuration:
• ATM OC3/STM-1
• ATM OC12/STM-4
• Fast Ethernet (FE-8)
• Gigabit Ethernet (GE)
Note: This release does not support Neighbor Discovery router advertisements on Ethernet cards.
For example, to configure an ATM interface:
host1(config)#interface atm 1/0
host1(config-if)#atm sonet stm-1
host1(config-if)#no loopback
host1(config-if)#atm clock internal chassis
host1(config-if)#interface atm 1/0.10
host1(config-if)#atm pvc 10 0 20 aal5snap
Refer to E-Series Link Layer Configuration Guide, Chapter 1, Configuring ATM for information on configuring an ATM interface. Refer to E-Series Link Layer Configuration Guide, Chapter 6, Configuring Ethernet Interfaces for information on configuring an Ethernet interface.
Configuring Ethernet interfaces to function with IPv6 requires Neighbor Discovery configuration for the interface.
In this release, only the 8-port Fast Ethernet (FE-8) and Gigabit Ethernet (GE) modules support Neighbor Discovery. ND is required for IPv6 to function on Ethernet interfaces. For information about configuring Neighbor Discovery, see Neighbor Discovery Configuration Tasks.
IPv6 Configuration TasksE-Series Routers
3-11
IPv6 Configuration TasksThis section describes how to configure and maintain IPv6 interfaces.
Configuring an IPv6 License You must configure an IPv6 license before you can use any IPv6 commands on the E-series router.
license ipv6� Use to specify an IPv6 license.� Purchase an IPv6 license to allow IPv6 configuration on the E-series router.
Note: Acquire the license from Juniper Networks Customer Service or your Juniper Networks sales representative.
� Examplehost1(config)#license ipv6 <license-value>
� Use the no version to disable the license.
Creating an IPv6 Profile You can configure an IPv6 interface dynamically by creating a profile. A profile is a set of characteristics that acts as a pattern that can be dynamically assigned to an IPv6 interface. You can manage a large number of IPv6 interfaces efficiently by creating a profile with a specific set of characteristics. In addition, you can create a profile to assign an IPv6 interface to a virtual router.
A profile can contain one or more of the following characteristics:
• address – configures an IPv6 address on an interface
• mtu – configures the MTU for a network
• policy – attaches (or removes) a policy to (or from) an interface
• unnumbered – configures IPv6 on this interface without a specific address
• ipv6 virtual-router – specifies a virtual router to which interfaces created by this profile will be attached
Note: You can also configure any of these IPv6 characteristics outside the profile configuration mode.
Use the profile command from Global Configuration mode to create or edit a profile. See E-Series Link Layer Configuration Guide, Chapter 13,
CHAPTER 3Configuring IPv6 and Neighbor Discovery
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Configuring Dynamic Interfaces for information on creating profiles and on other characteristics that can be applied to the profile.
host1(config)#profile boston
host1(config-profile)#ipv6 virtual-router warf
host1(config-profile)#ipv6 unnumbered atm 3/0
ipv6 address� Use to add an IPv6 address to an interface or a subinterface.� Example
host1(config)#interface atm 1/0.25
host1(config-if)#ipv6 address 1::1/64
Note: You can use this command in Interface Configuration or Subinterface Configuration mode.
� Use the no version of this command to remove an IPv6 address.
ipv6 mtu� Use to set the MTU size of IPv6 packets sent on an interface. � The range is 128�10240.� Example
host1(config-if)#ipv6 mtu 1000
� Use the no version to restore the default MTU size.
ipv6 unnumbered� Use to set up an unnumbered interface.� An unnumbered interface does not have an IPv6 address assigned to it.
Unnumbered interfaces are often used in point-to-point connections where an IPv6 address is not required.
� This command enables IPv6 processing on an interface without your having to assign an explicit IPv6 address to the interface.
� You supply an interface location that is the type and number of another interface on which the router has an assigned IPv6 address. This interface cannot be another unnumbered interface.
� Examplehost1(config-if)#ipv6 unnumbered loopback
� Use the no version to disable IPv6 processing on an interface.
ipv6 virtual-router� Use to assign a virtual router to a profile.� You can configure a virtual router using RADIUS instead of adding one to the
profile by using the ipv6 virtual-router command.� Use the no version to remove the virtual router assignment.
IPv6 Configuration TasksE-Series Routers
3-13
Assigning a Profile To assign a profile to an interface, use the profile command from Interface mode.
profile� Use to assign a profile to a PPP interface. The profile configuration is used to
dynamically create an upper IP interface. � Example
host1(config-if)#interface atm 3/1.50
host1(config-if)#encapsulation ppp
host1(config-if)#profile boston
� Use the no version to remove the assignment from the interface.
Establishing a Static RouteYou can set a destination to receive and send traffic by a specific route through the network.
ipv6 route� Use to establish a static IPv6 route.� You can set a destination to receive and send traffic from and to a network or to
use a specific route through the network.Note: In this release, IPv6 supports only static routes and loopback configurations.
� Examplehost1(config)#ipv6 route 7fff::0/16 1::1
� Use the no version of this command to remove a static route from the routing table.
Specifying an IPv6 Hop Count LimitYou can specify the maximum number of hops that the router can use in router advertisements and all IPv6 packets.
ipv6 hop-limit� Use to set the maximum number of hops that the router can use in router
advertisements and all IPv6 packets.� Example
host1(config)#ipv6 hop-limit 50
� Use the no version to set the hop limit for IPv6 packets to 255 hops and router advertisements to zero [0] hops (or �unspecified�).
CHAPTER 3Configuring IPv6 and Neighbor Discovery
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Managing IPv6 InterfacesYou can manage IPv6 interfaces in the following ways:
• Disable or reenable an IPv6 interface.
host1(config-if)#no ipv6 enable
host1(config-if)#ipv6 enable
• Set a baseline for IPv6 interface counters.
host1#clear ipv6 interface atm 2/0
• Determine reachability within a network.
host1#ping ipv6 1::1
host1#traceroute ipv6 1::1
clear ipv6 interface� Use to set a baseline for counters on a specified IPv6 interface. � Example
host1#clear ipv6 interface atm 2/0
� There is no no version.
ipv6 enable� Use to enable or disable an IPv6 interface at any time.
Note: By default, an IPv6 interface is enabled when you first create it.
� Examplehost1(config-if)#ipv6 enable
� Use the no version of this command to disable IPv6 on an interface or a subinterface.
ping ipv6� Use to send an ICMP echo request packet to the IPv6 address that you specify.� Use the source interface keywords to specify a source interface other than the
one from which the probe originates. � Use the source address keywords to specify a source IP address other than
the one from which the probe originates. � You can specify the following options:
� packetCount � number of packets to send to the destination IPv6 address. If you specify a zero, echo requests packets are sent indefinitely.
� data-pattern � sets the type of bits contained in the packet to all ones, all zeros, a random mixture of ones and zeros, or a specific hexadecimal data pattern that can range from 0x0�0xFFFFFFFF. The default is all zeros.
� data-size � sets the number of bytes comprising the IPv6 packet and reflected in the IPv6 header in the range 0�64000; the default is 100 bytes
IPv6 Configuration TasksE-Series Routers
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� extended header attributes � set the interface type and specifier of a destination address on the router that is configured for external loopback; the command succeeds only if the specified interface is configured for external loopback
� sweep-interval � specifies the change in the size of subsequent ping packets while sweeping across a range of sizes. For example, you can configure the sweep interval to sweep across the range of packets from 100 bytes to 1000 bytes in increments equal to the sweep interval. By default the router increments packets by one byte; for example, it sends 100, 101, 102, 103, ... 1000. If the sweep interval is 5, the router sends 100, 105, 110, 115, ... 1000.
� sweep-sizes � enables you to vary the sizes of the echo packets being sent. This capability is useful for determining the minimum sizes of the MTUs configured on the nodes along the path to the destination address. This reduces packet fragmentation, which contributes to performance problems. The default is not to sweep (all packets are the same size).
� timeout � sets the number of seconds to wait for an ICMP echo reply packet before the connection attempt times out
� hop-limit � sets the time-to-live hop count in the range 1�255; the default is 255
� The following characters can appear in the display after you issue the ping command:� ! � reply received� . � timed out while waiting for a reply� ? � unknown packet type� A � admin unreachable� b � packet too big� H � host unreachable� N � network unreachable� P � port unreachable� p � parameter problem� S � source beyond scope� t � hop limit expired (TTL expired)
� Examplehost1#ping ipv6 1::1
� There is no no version.
traceroute� Use to discover the routes that router packets follow when traveling to their
destination.� You can specify:
� Destination IPv6 address� Source interface for each of the transmitted packets� Source IPv6 address for each of the transmitted packets
CHAPTER 3Configuring IPv6 and Neighbor Discovery
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� Maximum number of hops of the trace and a time-out value� Size of the IPv6 packets (not the ICMP payload) in the range 0�64000 bytes
sent with the traceroute command. Including a size might help locate any MTU problems that exist between your router and a particular device.
� Hop count in the range 1�255; the default is 32 � You can also force transmission of the packets on a specified interface
regardless of what the IPv6 address lookup indicates.� Example
host1#traceroute ipv6 1::1 timeout 10
� There is no no version.
Adding a DescriptionThe router enables you to add a text description or an alias to an IPv6 interface or subinterface. Adding a description helps you identify the interface and keep track of interface connections.
ipv6 description� Use to assign a text description or an alias to an IPv6 interface or subinterface.� The description or alias can be a maximum of 256 characters.� Use the show ipv6 interface command to display the text description.� Examples
host1(config-if)#ipv6 description boston01 ipv6 interface
host1(config-subif)#ipv6 description dallas05 ipv6 subinterface
� Use the no version to remove the text description or alias.
Removing an IPv6 ConfigurationTo remove an IPv6 configuration from the virtual router, issue the no ipv6 command.
no ipv6� Use to remove IPv6 configuration from the virtual router. � Example
host1(config)#no ipv6
Note: The E-series router automatically starts IPv6 processing when you begin configuring an IPv6 interface. However, by issuing the ipv6 command without using the no option, you can create an IPv6 processing instance with no IPv6 configuration.
Creating Static IPv6 NeighborsE-Series Routers
3-17
Clearing IPv6 RoutesTo clear IPv6 routes from the routing table, use the clear ipv6 routes command. To clear the routes for a specific IPv6 network, specify the IPv6 prefix. To clear all dynamic IPv6 routes, using the * (asterisk) option.
clear ipv6 routes� Use to clear IPv6 routes.� To clear routes in a specific IPv6 network, specify an IPv6 prefix.� To clear all dynamic IPv6 routes, use the * (asterisk) option.� Example
host1(config)#clear ipv6 routes *
� There is no no version.
Creating Static IPv6 NeighborsTo create static IPv6 neighbors, use the ipv6 neighbor command.
ipv6 neighbor� Use to create static IPv6 neighbors.� Example
host1(config)#ipv6 neighbor 1::10 fastEthernet 1/0 0002.7dfa.0034
� Use the no version of this command to delete the neighbor.
Neighbor Discovery Configuration TasksThis section describes how to configure Neighbor Discovery on IPv6 interfaces.
Note: This release supports Neighbor Discovery on 8-port Fast Ethernet and Gigabit Ethernet modules only.
Configuring Neighbor DiscoveryTo configure Neighbor Discovery:
1 Access an IPv6 interface.
host1(config)#interface fastEthernet 3/0
host1(config-if)#
CHAPTER 3Configuring IPv6 and Neighbor Discovery
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2 Configure the current IPv6 interface to send neighbor solicitations and to respond with neighbor advertisements.
host1(config)#ipv6 nd
Note: This command is redundant when configuring Neighbor Discovery over Ethernet, because router advertisements are automatically sent on Ethernet interfaces. However, unless explicitly enabled, IPv6 router advertisements are not sent on other types of interfaces.
3 (Optional) Configure the interface to retry sending neighbor solicitations using a specified interval.
host1(config-if)#ipv6 nd ns-interval 500
4 (Optional) Configure the interface to assume that a neighbor is reachable for a specified time after a reachable confirmation event.
host1(config-if)#ipv6 nd reachable-time 30000
ipv6 nd� Use to enable the IPv6 Neighbor Discovery process on an interface.� Example
host1(config)#interface fastEthernet 3/0
host1(config-if)#ipv6 nd
� Use the no version of this command to disable the Neighbor Discovery process.
ipv6 nd ns-interval� Use to specify the interval between IPv6 neighbor solicitation retransmissions
on an interface.� Example
host1(config-if)#ipv6 nd ns-interval 500
� Use the no version of this command to return the interval between neighbor solicitation retransmission to its default value (zero [0] milliseconds for router advertisements and 1000 milliseconds for Neighbor Discovery activity of the E-series router).
ipv6 nd reachable-time� Use to specify the amount of time that the E-series router can reach a remote
IPv6 node after some reachability confirmation event has occurred.� Example
host1(config-if)#ipv6 nd reachable-time 30000
� Use the no version of this command to restore the default value (zero [0] milliseconds for router advertisements and 60000 milliseconds for Neighbor Discovery activity of the E-series router).
Neighbor Discovery Configuration TasksE-Series Routers
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Configuring Proxy Neighbor AdvertisementsMuch like proxy ARP, proxy Neighbor Discovery is a means by which one interface responds to a Neighbor Discovery query on behalf of another interface.
To configure proxy Neighbor Discovery:
1 Access an IPv6 interface.
host1(config)#interface fastEthernet 0/0
host1(config-if)#
2 Enable Neighbor Discovery on the current interface.
host1(config)#ipv6 nd
Note: This command is redundant when configuring Neighbor Discovery over Ethernet, because neighbor solicitations and advertisements are automatically sent on Ethernet interfaces.
3 Enable IPv6 neighbor proxy.
host1(config-if)#ipv6 nd proxy
ipv6 nd proxy� Use to enable or disable Neighbor Discovery proxy.� Example
host1(config-if)#ipv6 nd proxy
� Use the no version of this command to disable Neighbor Discovery proxy.
Configuring Duplicate Address Detection AttemptsThe duplicate address detection feature helps to verify that a new unicast IPv6 address is unique in the network. The router sends the IPv6 address in its neighbor solicitation messages. However, the router relies on the receiving device to understand the address duplication and does not prompt a conflict if the address already exists.
The CLI allows you to specify the number of consecutive neighbor solicitation messages that the router sends from the IPv6 interface.
ipv6 nd dad attempts� Use to specify the number of consecutive neighbor solicitation messages that
the router sends from the IPv6 interface.� Use an attempt value of zero (0) to disable duplicate address detection on the
current interface.� The router suspends duplicate address detection on interfaces that are
administratively down.
CHAPTER 3Configuring IPv6 and Neighbor Discovery
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� Examplehost1(config-if)#ipv6 nd dad attempts 10
� Use the no version of this command to restore the default number of attempts to one (1).
Clearing IPv6 NeighborsTo clear dynamic IPv6 neighbors, use the clear ipv6 neighbor command. Use the include-statics keyword clears both dynamic neighbors and static neighbors. Use the statics-only keyword clears only IPv6 static neighbors.
clear ipv6 neighbors� Use to clear all dynamic IPv6 neighbors.� Use the include-statics keyword clears both dynamic neighbors and static
neighbors. Use the statics-only keyword clears only IPv6 static neighbors.� Example
host1(config)#clear ipv6 neighbors
� There is no no version.
Monitoring IPv6 and Neighbor DiscoveryThis section shows how to set an IPv6 statistics baseline and use the show commands to view your IPv6 configuration, monitor IPv6 interfaces and statistics, and view IPv6 neighbors.
Establishing a BaselineIPv6 statistics are stored in system counters. The only way to reset the system counters is to reboot the system. You can, however, establish a baseline for IPv6 statistics by setting a group of reference counters to zero.
baseline ipv6� Sets a baseline for IPv6 statistics. � The router implements the baseline by reading and storing the statistics at the
time the baseline is set and then subtracting this baseline whenever baseline-relative statistics are retrieved.
� Use the udp keyword to set a baseline for UDP statistics� Use the delta keyword with IPv6 show commands to specify that baselined
statistics are to be shown.
Monitoring IPv6 and Neighbor DiscoveryE-Series Routers
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� Examplehost1#baseline ipv6
� There is no no version.
baseline ipv6 interface� Use to set a statistical baseline for a specified IPv6 interface.� Example
host1#baseline ipv6 interface atm 2/0.100
� There is no no version.
IPv6 show CommandsYou can monitor the following aspects of IPv6 using show ipv6 commands:
You can use the output filtering feature of the show command to include or exclude lines of output based on a text string that you specify. See E-Series System Basics Configuration Guide, Chapter 2, Command Line Interface, for details.
To Display Command
General IPv6 information show ipv6
IPv6 addresses show ipv6 address
IPv6 Interfaces show ipv6 interface
IPv6 neighbors show ipv6 neighbors
IPv6 profile information show ipv6 profile
Active IPv6 protocol information show ipv6 protocols
IPv6 route redistribution configuration show ipv6 redistribute
IPv6 routes show ipv6 route
IPv6 static routes show ipv6 static
IPv6 statistics/traffic show ipv6 traffic
IPv6 UDP information show ipv6 udp statistics
IPv6 license string show license ipv6
CHAPTER 3Configuring IPv6 and Neighbor Discovery
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show ipv6� Use to display general IPv6 information. � Example
host1#show ipv6
Ipv6 Unicast Routing: Enabled
Default hop limit: not specified
Number of interfaces: 2
Default interface source address/mask: fe80::90:1a00:210:fd0/128
show ipv6 addressshow ipv6 interface
� Use to display detailed or summary information for a particular IPv6 address/interface or all interfaces.
� The default for the show ipv6 interface command is all interface types and all interfaces.
� Use brief or detail keywords with the show ipv6 interface command to display different levels of information.
� Field descriptions� Network Protocols � network protocols configured on this interface� Link local address � local IPv6 address of this interface� Internet address � external address of this interface� IP statistics Rcvd:
� local destination � frames with this router as their destination� hdr errors � number of packets containing header errors� addr errors � number of packets containing addressing errors� unkn proto � number of packets received containing unknown protocols� discards � number of discarded packets
� IP statistics Sent:� generated � number of packets generated� no routes � number of packets that could not be routed� discards � number of packets that could not be routed that were
discarded� ICMP statistics Rcvd:
� total � total number of received packets� errors � error packets received� destination unreach � packets received with destination unreachable� admin unreach � packets received because the destination was
administratively unreachable (for example, the packet encountered a firewall filter)
� parameter problem � packets received with parameter errors� time exceeded � packets received with time-to-live exceeded� pkt too big � number of packet-too-big messages received that indicate a
packet was too large to forward because of the allowed MTU size
Monitoring IPv6 and Neighbor DiscoveryE-Series Routers
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� redirects � received packet redirects� echo requests � echo request (ping) packets� echo replies � echo replies received� rtr solicits � number of received router solicitations� rtr advertisements � number of received router advertisements� neighbor solicits � number of received neighbor solicitations� neighbor advertisements � number or received neighbor advertisements� Group membership (queries, responses, reductions) � number of queries,
responses, and reduction requests received from within a group to which the interface is assigned
� ICMP statistics Sent:� total � total number of received packets� errors � error packets received� destination unreach � packets received with destination unreachable� admin unreach � packets sent because the destination was
administratively unreachable (for example, due to a firewall filter)� parameter problem � packets received with parameter errors� time exceeded � packets received with time-to-live exceeded� pkt too big � number of packet-too-big messages sent because a
received packet was too large to forward because of the allowed MTU size
� redirects � received packet redirects� echo requests � echo request (ping) packets� echo replies � echo replies received� rtr solicits � number of sent router solicitations� rtr advertisements � number of sent router advertisements� neighbor solicits � number of sent neighbor solicitations� neighbor advertisements � number of sent neighbor advertisements� Group membership (queries, responses, reductions) � number of queries,
responses, and reduction requests sent to a group of which the interface is assigned
� Operational MTU � value of the MTU� Administrative MTU � value of the MTU if it has been administratively
overridden using the configuration� Operational speed � speed of the interface� Administrative speed � value of the speed if it has been administratively
overridden using the configuration� In Received Packets, Bytes � total number of packets and bytes received on
this interface� Unicast Packets, Bytes � unicast packets and bytes received on the IPv6
interface; link-local received multicast packets (non-multicast-routed frames) are counted as unicast packets
CHAPTER 3Configuring IPv6 and Neighbor Discovery
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� Multicast Packets, Bytes � multicast packets and bytes received on the IPv6 interface which are then multicast-routed are counted as multicast packets
� In Total Dropped Packets, Bytes � total number of inbound packets and bytes dropped on this interface� In Policed Packets � packets that were received and dropped because of
rate limits� In Invalid Source Address Packets � packets received with invalid source
address (for example, spoofed packets)� In Error Packets � number of packets received with errors� In Discarded Packets � packets received that were discarded for reasons
other than rate limits, errors, and invalid source address� Out Forwarded Packets, Bytes � total number of packets and bytes that
were sent from this interface� Unicast Packets, Bytes � unicast packets and bytes that were sent from
this interface� Multicast Routed Packets, Bytes � multicast packets and bytes that were
sent from this interface� Out Total Dropped Packets � total number of outbound packets and bytes
dropped by this interface� Out Scheduler Dropped Packets, Bytes � number of outbound packets
and bytes dropped by the scheduler� Out Policed Packets, Bytes � number of outbound packets and bytes
dropped because of rate limits � Out Discarded Packets � number of outbound packets that were
discarded for reasons other than those dropped by the scheduler and those dropped because of rate limits
� Example 1host1#show ipv6 address 1::1
loopback0 line protocol IpLoopback is up, ipv6 is up
Network Protocols: IPv6
Link local address: fe80::90:1a00:210:fd0
Internet address: 1::1/64
Operational MTU 1500 Administrative MTU 0
Operational speed 100000000 Administrative speed 0
Creation type Static
Neighbor Discovery is disabled
In Received Packets 0, Bytes 0
Unicast Packets 0, Bytes 0
Multicast Packets 0, Bytes 0
In Total Dropped Packets 0, Bytes 0
In Policed Packets 0
In Invalid Source Address Packets 0
In Error Packets 0
In Discarded Packets 0
Monitoring IPv6 and Neighbor DiscoveryE-Series Routers
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Out Forwarded Packets 0, Bytes 0
Unicast Packets 0, Bytes 0
Multicast Routed Packets 0, Bytes 0
Out Total Dropped Packets 0, Bytes 0
Out Scheduler Dropped Packets 0, Bytes 0
Out Policed Packets 0
Out Discarded Packets 0
� Example 2host1#show ipv6 address detail 5::1
ATM4/0.15 line protocol Atm1483 is up, ipv6 is up
Network Protocols: IPv6
Link local address: fe80::90:1a00:4440:1d44
Internet address: 5::1/64
IP statistics:
Rcvd: 0 local destination
0 hdr errors, 0 addr errors
0 unkn proto, 0 discards
Sent: 0 generated, 0 no routes, 0 discards
ICMP statistics:
Rcvd: 2914 total, 0 errors
0 destination unreach, 0 admin unreach, 0 parameter problem
0 time exceeded, 0 pkt too big, 0 redirects
21 echo requests, 2893 echo replies
0 rtr solicits, 0 rtr advertisements
0 neighbor solicits, 0 neighbor advertisements
Group membership: 0 queries, 0 responses, 0 reductions
Sent: 2914 total, 0 errors
0 destination unreach, 0 admin unreach, 0 parameter problem
0 time exceeded, 0 pkt too big, 0 redirects
2893 echo requests, 21 echo replies
0 rtr solicits, 0 rtr advertisements
0 neighbor solicits, 0 neighbor advertisements
Group membership: 0 queries, 0 responses, 0 reductions
Operational MTU 9180 Administrative MTU 0
Operational speed 155520000 Administrative speed 0
In Received Packets 2914, Bytes 430372
Unicast Packets 2914, Bytes 430372
Multicast Packets 0, Bytes 0
CHAPTER 3Configuring IPv6 and Neighbor Discovery
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In Total Dropped Packets 0, Bytes 0
In Policed Packets 0
In Invalid Source Address Packets 0
In Error Packets 0
In Discarded Packets 0
Out Forwarded Packets 2914, Bytes 430372
Unicast Packets 2914, Bytes 430372
Multicast Routed Packets 0, Bytes 0
Out Total Dropped Packets 0, Bytes 0
Out Scheduler Dropped Packets 0, Bytes 0
Out Policed Packets 0
Out Discarded Packets 0
� Example 3host1#show ipv6 interface
ATM4/0.15 line protocol Atm1483 is up, ipv6 is up
Network Protocols: IPv6
Link local address: fe80::90:1aff:fe01:725
Internet address: 1::2/60
Operational MTU 1500 Administrative MTU 0
Operational speed 100000000 Administrative speed 0
In Received Packets 0, Bytes 0
Unicast Packets 0, Bytes 0
Multicast Packets 0, Bytes 0
In Total Dropped Packets 0, Bytes 0
In Policed Packets 0
In Invalid Source Address Packets 0
In Error Packets 0
In Discarded Packets 0
Out Forwarded Packets 5, Bytes 740
Unicast Packets 5, Bytes 740
Multicast Routed Packets 0, Bytes 0
Out Total Dropped Packets 0, Bytes 0
Out Scheduler Dropped Packets 0, Bytes 0
Out Policed Packets 0
Out Discarded Packets 0
� Example 4host1#show ipv6 int detail
ATM4/0.15 line protocol Atm1483 is up, ipv6 is up
Network Protocols: IPv6
Link local address: fe80::90:1aff:fe01:725
Monitoring IPv6 and Neighbor DiscoveryE-Series Routers
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Internet address: 1::2/60
IP statistics:
Rcvd: 0 local destination
0 hdr errors, 0 addr errors
0 unkn proto, 0 discards
Sent: 0 generated, 0 no routes, 0 discards
ICMP statistics:
Rcvd: 0 total, 0 errors
0 destination unreach, 0 admin unreach, 0 parameter problem
0 time exceeded, 0 pkt too big, 0 redirects
0 echo requests, 0 echo replies
0 rtr solicits, 0 rtr advertisements
0 neighbor solicits, 0 neighbor advertisements
Group membership: 0 queries, 0 responses, 0 reductions
Sent: 5 total, 0 errors
0 destination unreach, 0 admin unreach, 0 parameter problem
0 time exceeded, 0 pkt too big, 0 redirects
5 echo requests, 0 echo replies
0 rtr solicits, 0 rtr advertisements
0 neighbor solicits, 0 neighbor advertisements
Group membership: 0 queries, 0 responses, 0 reductions
Operational MTU 1500 Administrative MTU 0
Operational speed 100000000 Administrative speed 0
In Received Packets 0, Bytes 0
Unicast Packets 0, Bytes 0
Multicast Packets 0, Bytes 0
In Total Dropped Packets 0, Bytes 0
In Policed Packets 0
In Invalid Source Address Packets 0
In Error Packets 0
In Discarded Packets 0
Out Forwarded Packets 5, Bytes 740
Unicast Packets 5, Bytes 740
Multicast Routed Packets 0, Bytes 0
Out Total Dropped Packets 0, Bytes 0
Out Scheduler Dropped Packets 0, Bytes 0
Out Policed Packets 0
Out Discarded Packets 0
CHAPTER 3Configuring IPv6 and Neighbor Discovery
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� Example 5host1#show ipv6 interface brief
Interface IPv6-Address Status Protocol Description
---------------------- -------------------- ------- -------- ------------------
ATM4/0.15 1::2/60 up up
show ipv6 neighbors� Use to display IPv6 Neighbor Discovery cache information static entries,
dynamic entries, or both.� Field descriptions
� Prefix � IPv6 address prefix� Length � prefix length� Type � protocol type (possible route types include: Bgp, Connect, Idrp, Igrp,
Invalid, Isis, Ndisc, Ospf, Other, Rip, Static)� Dst (or Distance) � administrative distance for the route� Met (or Metric) � number of hops� Intf (or Interface) � interface type and interface specifier� NextHop � configured next hop address for this interface� IfIndex � autogenerated value for the next-hop interface
� Example 1
show ipv6 profile� Use to display information about a specific IPv6 profile. � Field descriptions
� IP profile � profile name� Unnumbered interface � specifier for the unnumbered interface or none if the
interface is numbered� Router � router name� Access Route Addition � enabled or disabled� Source-Address Validation � enabled or disabled� Administrative MTU � MTU size
� Examplehost1#show ip profile foo
IPv6 profile : foo
Unnumbered interface on : loopback 0
Router : r1
Access Route Addition : Enabled
Source-Address Validation : Disabled
Administrative MTU : 0
Monitoring IPv6 and Neighbor DiscoveryE-Series Routers
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show ipv6 protocols� Use to display configured protocols.� Field descriptions
� Local router ID � router ID of the local router� Local AS � AS number of local router� Administrative state � administrative state of the protocol� Operational state � operational state of the protocol� Shutdown in overload state � status of shutdown in an overload state� Default local preference � default value for local preference� IGP synchronization � indicates whether synchronization is enabled or
disabled� Default originate � indicates whether network 0.0.0.0 is redistributed into
BGP � Auto summary � status of autosummary� Always compare MED � status of always compare MED� Compare MED within confederation � status of compare MED within a
confederation� Advertise inactive routes � status of Advertise inactive routes� Advertise best external router to internal peers � status of Advertise best
external router to internal peers� Enforce first AS � status of Enforce first AS� Missing MED as worst � status of Missing MED as worst� Route flap dampening � status of route dampening� Log neighbor changes � status of Log neighbor changes� Fast External Fallover � status of Fast External Fallover� Maximum received AS-path length � maximum AS-path length received� BGP administrative distances � external, internal, and local BGP
administrative distances� Client-to-client reflection � whether client-to-client reflection is configured� Cluster ID � cluster IDs� Route-target filter � status of Route-target filter� Default IPv4-unicast � status of Default IPv4-unicast� Local-RIB version � RIB version� Local-FIB version � FIB version� Neighbor (s)� BGP neighbors (if configured)� Networks for which routing is occurring� Aggregate Generation for Unicast Routes
� Example 1host1#show ipv6 protocols
Routing Protocol is "bgp 100"
Local router ID 1.1.1.1, local AS 100
Administrative state is Start
Operational state is Up
CHAPTER 3Configuring IPv6 and Neighbor Discovery
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Shutdown in overload state is disabled
Default local preference is 100
IGP synchronization is enabled
Default originate is disabled
Auto summary is enabled
Always compare MED is disabled
Compare MED within confederation is disabled
Advertise inactive routes is disabled
Advertise best external route to internal peers is disabled
Enforce first AS is disabled
Missing MED as worst is disabled
Route flap dampening is disabled
Log neighbor changes is disabled
Fast External Fallover is disabled
No maximum received AS-path length
BGP administrative distances are 20 (ext), 200 (int), and 200 (local)
Client-to-client reflection is enabled
Cluster ID is 1.1.1.1
Route-target filter is enabled
Default IPv4-unicast is enabled
Local-RIB version 8. FIB version 8.
Neighbor(s):
No neighbors are configured
Routing for Networks:
Aggregate Generation for Unicast Routes:
� Example 2host1#show ipv6 protocols summary
bgp 100
show ipv6 redistribute� Use to display configured route redistribution policy.� Field descriptions
� To � protocol that routes are distributed into� From � protocol that routes are distributed from� status � redistribution status� route map name � name of the route map
� Examplehost1#show ipv6 redistribute
To bgp, From static is enabled with route map foo
To bgp, From connected is enabled without a route map
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show ipv6 route� Use to display the current state of the routing table, including routes not used
for forwarding.� You can display all routes, a specific route, detailed information about all or a
specific route, or summary counters for the routing table.� Field descriptions
� Prefix � IPv6 address prefix� Length � prefix length
� Type � protocol type (possible route types include: Bgp, Connect, Idrp, Igrp, Invalid, Isis, Ndisc, Ospf, Other, Rip, Static)� Dst (or Distance) � administrative distance for the route� Met (or Metric) � number of hops� Intf (or Interface) � interface type and interface specifier� NextHop � the configured next hop address for this interface� IfIndex � an autogenerated value for the next hop interface
� Example 1host1#show ipv6 route
Prefix/Length Type Dst/Met Intf
-------------------------------- ------- ------- --------------------
1::/16 Connect 0/0 loopback1
5::/64 Connect 0/0 ATM4/0.15
6::/64 Static 1/0 ATM4/0.15
2003::/16 Static 1/0 ATM4/0.15
� Example 2host1#show ipv6 route summary
6 total routes, 408 bytes in route entries
0 isis routes
0 rip routes
2 static routes
2 connected routes
0 bgp routes
0 ospf routes
2 other internal routes
0 access routes
0 internally created access host routes
Last route added/deleted: null by Local
At WED JAN 22 2003 09:53:33 UTC
� Example 3host1#show ipv6 route 5::/64 detail
5::/64 Type local Distance 0 Metric 0
NextHop 1::2 IfIndex 10007 Intf ATM4/0.15
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show ipv6 static� Use to display the status of static routes in the routing table.� You can specify an IP mask that filters specific routes.� Field descriptions
� Prefix � IP address prefix� Length � prefix length� Next Hop � IP address of the next hop� Dst � administrative distance of the route� Met � number of hops� Interface � interface type and interface specifier
� Examplehost1#show ipv6 static
Prefix/Length NextHop Dst/Met Interface
------------------------ ------------------------ ------- --------------------
6::/64 5::2 1/0 ATM4/0.15
2003::/16 5::1 1/0 ATM4/0.15
show ipv6 traffic� Use to display statistics about IPv6 traffic.� Field descriptions
� IPv6 statistics Rcvd:� total � total number of packets received� local destination � number of packets received with this router as their
destination� hdr errors � number of packets containing header errors� addr errors � number of packets containing addressing errors� unkn proto � number of packets received containing unknown protocols� discards � number of discarded packets
� IPv6 statistics Sent:� forwarded � number of packets forwarded� generated � number of packets generated� out disc � number of packets that could not be routed that were discarded
� IPv6 statistics Mcast:� received � number of multicast packets received� forwarded � number of multicast packets forwarded
� IPv6 statistics (Routes) � number of routes currently in the routing table� ICMPv6 statistics Rcvd:
� total � total number of received packets� errors � error packets received� destination unreach � packets received with destination unreachable
Monitoring IPv6 and Neighbor DiscoveryE-Series Routers
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� admin unreach � packets received because the destination was administratively unreachable (for example, the packet encountered a firewall filter)
� parameter problem � packets received with parameter errors� time exceeded � packets received with time-to-live exceeded� pkt too big � number of packet-too-big messages received that indicate a
packet was too large to forward because of the allowed MTU size� redirects � received packet redirects� echo requests � echo request (ping) packets� echo replies � echo replies received� rtr solicits � number of received router solicitations� rtr advertisements � number of received router advertisements� neighbor solicits � number of received neighbor solicitations� neighbor advertisements � number of received neighbor advertisements� Group membership (queries, responses, reductions) � number of queries,
responses, and reduction requests received from within a group to which the interface is assigned
� ICMP statistics Sent:� total � total number of received packets� errors � error packets received� destination unreach � packets received with destination unreachable� admin unreach � packets sent because the destination was
administratively unreachable (for example, due to a firewall filter)� parameter problem � packets received with parameter errors� time exceeded � packets received with time-to-live exceeded� pkt too big � number of packet-too-big messages sent because a
received packet was too large to forward because of the allowed MTU size
� redirects � received packet redirects� echo requests � echo request (ping) packets� echo replies � echo replies received� rtr solicits � number of sent router solicitations� rtr advertisements � number of sent router advertisements� neighbor solicits � number of sent neighbor solicitations� neighbor advertisements � number of sent neighbor advertisements� Group membership (queries, responses, reductions) � number of queries,
responses, and reduction requests sent to a group to which the interface is assigned
� UDP Statistics Rcvd:� total � total number of received packets� checksum errors � checksum error packets received� no port � no port error packets received
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� UDP Statistics Sent:� total � total number of received packets� errors � error packets received
� Examplehost1#show ipv6 traffic
IPv6 statistics:
Rcvd: 0 total, 0 local destination
0 hdr errors, 0 addr errors
0 unkn proto, 0 discards
Sent: 0 forwarded, 0 generated
0 out disc
Mcast: 0 received 0 forwarded
Routes: 7 in routing table
ICMPv6 statistics:
Rcvd: 0 total, 0 errors
0 destination unreach, 0 admin unreach, 0 parameter problem
0 time exceeded, 0 pkt too big, 0 redirects
0 echo requests, 0 echo replies
0 rtr solicits, 0 rtr advertisements
0 neighbor solicits, 0 neighbor advertisements
Group membership: 0 queries, 0 responses, 0 reductions
Sent: 3 total, 0 errors
0 destination unreach, 0 admin unreach, 0 parameter problem
0 time exceeded, 0 pkt too big, 0 redirects
0 echo requests, 0 echo replies
0 rtr solicits, 0 rtr advertisements
2 neighbor solicits, 1 neighbor advertisements
Group membership: 0 queries, 0 responses, 0 reductions
UDP Statistics:
Rcvd: 0 total, 0 checksum errors, 0 no port
Sent: 0 total, 0 errors
show ipv6 udp statistics� Use to display IPv6 UDP statistics.� Example
host1#show ipv6 udp statistics
UDP Statistics:
Rcvd: 0 total, 0 checksum errors, 0 no port
Sent: 0 total, 0 errors
Monitoring IPv6 and Neighbor DiscoveryE-Series Routers
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show license ipv6� Use to display the IPv6 license key configured on the router. � Example
host1#show license ipv6
Ipv6 license is ipv6_licence
CHAPTER 3Configuring IPv6 and Neighbor Discovery
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4
Configuring NATThis chapter describes how to configure Network Address Translation (NAT) on your E-series router.
Topic Page
Overview 4-2
NAT Configurations 4-2
Network and Address Terms 4-4
Understanding Address Translation 4-5
Address Assignment Methods 4-6
Order of Operations 4-7
References 4-7
Before You Begin 4-8
Limiting Translation Entries 4-8
Specifying Inside and Outside Interfaces 4-8
Defining Static Address Translations 4-9
Defining Dynamic Translations 4-10
Clearing Dynamic Translations 4-15
Configuration Examples 4-15
Monitoring NAT 4-23
CHAPTER 4Configuring NAT
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OverviewThe Internet faces the challenge of conserving IP address space while continuing to provide scalability in routing. Network Address Translation (NAT) helps to address these challenges by allowing the conservation of registered IP addresses within private networks and simplifying IP addressing management tasks through a form of transparent routing.
NAT allows you to translate IP addresses between two address realms (for example, between an intranet network that uses private, not publicly routable addresses and the Internet or between two overlapping, private networks). On receiving incoming traffic, the IP addresses are translated back for delivery within the private network.
Using NAT at the edge of your intranet provides the following advantages:
• Allows unregistered “private” addresses to connect to the Internet by translating those addresses into globally registered IP addresses
• Increases network privacy by hiding internal IP addresses from external networks
NAT ConfigurationsYou can configure NAT in several different ways. Each configuration method provides a solution for different configuration requirements. These methods include:
• Traditional NAT
• Bidirectional NAT
• Twice NAT
Traditional NATTraditional NAT (sometimes called outbound NAT) is the most common method of using address translation. Its primary use is translating private addresses to legal addresses for use in an external network. When configured for dynamic operation, hosts within a private network can initiate access to the external (public) network, but external nodes on the outside network cannot access the private network.
Addresses on the private network and public network must not overlap. Also, route destination advertisements on the public network (for example, the Internet) can appear within the inside network, but the
NAT ConfigurationsE-Series Routers
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NAT router does not propagate advertisements of local routes that reference private addresses out to the public network.
Two types of traditional NAT exist — basic NAT and NAPT.
Basic NATBasic NAT provides translation for IP addresses only (called a “simple” translation) and places the mapping into a NAT table. In other words, for packets outbound from the private network, the NAT router translates the source IP address and related fields (for example, IP, TCP, UDP, and ICMP header checksums). For inbound packets, the NAT router translates the destination IP address (and related checksums) for entries that it finds in its translation table.
Caution: Although it is the simplest and most common, basic NAT is the least secure translation method. By not defining the translation to the port level, and accepting return information on any port, basic NAT can leave private hosts open to port access.
NAPTNetwork Address Port Translation (NAPT) extends the level of translation beyond that of basic NAT; it modifies both the IP address and the transport identifier (for example, the TCP or UDP port number, or the ICMP query identifier) and places the mapping into the translation table (this entry is called an “extended” translation). This process combines the transport identifiers and addresses of any number of private hosts into one transport identifier of one or more external addresses.
Similar to basic NAT, for outbound packets, NAPT translates the source IP address, source transport identifier, and related checksum fields. For inbound packets, NAPT translates the destination IP address, destination transport identifier, and checksum fields.
Bidirectional NATBidirectional (or two-way) NAT uses traditional NAT in conjunction with the Domain Name System – Application Level Gateway (DNS-ALG). When using bidirectional NAT, hosts can initiate sessions from both the private network and the public network.
The translation, installed by DNS, maps private network addresses to globally unique addresses, statically or dynamically, as hosts establish connections in either direction. Hosts in the public network can access hosts in the private network by using DNS address resolution. This requires an end-to-end unique fully qualified domain name (FQDN) for
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each host. In other words, the NAT router intercepts any DNS message (using the DNS-ALG) and assigns a global address to reach the intended host.
When a public (outside) host initiates a session with a private host, the NAT router intercepts the packet and substitutes the advertised public address with the actual private (inside) address. On the return path the NAT router replaces the local private address (now the source) with the advertised public host address.
Some additional configuration may be required to allow public access from the Internet to a DNS server that resides in the private domain (see Bidirectional NAT Example on page 4-17).
The same address space requirements and routing restrictions apply to bidirectional NAT as were described for traditional NAT. The difference between these two methods is that the DNS exchange may create entries within the translation table.
Twice NATIn twice NAT, both the source and destination addresses are subject to translation as packets traverse the NAT router. For example, you would use twice NAT when you are connecting two networks in which all or some addresses in one network overlap with addresses in another network (whether the network is private or public).
Network and Address TermsThe NAT implementation defines an address realm as either inside or outside, with the router that is running NAT acting as the defining boundary between the two realms.
From a NAT perspective, an inside network is the local portion of a network that uses private, not publicly routable, IP addresses that you want to translate. An outside network is the public portion of a network that uses legitimate, publicly routable IP addresses to which you want private hosts to connect.
The terms in this section relate to those addresses you want to translate from one network realm to another. Addresses within these realms are labelled as either local or global.
When reading the following sections, keep the following in mind:
• The terms inside and outside refer to where a host resides
Understanding Address TranslationE-Series Routers
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• The terms local and global refer to where the address appears on the NAT network.
Inside Local AddressesThe inside local address is a configured IP address that is assigned to a host on the inside network. Addresses may be globally unique (not requiring translation), allocated from the private address space defined in RFC 1918, or officially allocated to some other organization.
Inside Global AddressesThe inside global address is the “translated” IP address of an inside host as seen by an outside host and network. Addresses may be allocated from a globally unique address space (often provided by the ISP, if the inside address is connected to the global Internet).
Outside Local AddressesThe outside local address is the “translated” IP address of an outside host as it appears to the inside network. Addresses may be globally unique (not requiring translation), allocated from the private address space defined in RFC 1918, or officially allocated to some other organization.
Outside Global AddressesThe outside global address is the configured, publicly routable IP address assigned to a host on the outside network.
Understanding Address TranslationAddress translation can occur under one of two general methods — inside or outside source translation.
Inside Source TranslationInside source translation is the most commonly used in NAT configuration. In this method, the NAT router performs translation between an inside (private) network address and an outside network address (for example, the Internet). The NAT router replaces the private source address with a globally unique address (either statically or dynamically). When the external destination responds, the NAT router, after successfully locating the address translation in its translation table, “untranslates” the global address (now the destination address) back to the local, private address.
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Note: Dynamic inside source translations are established by outbound traffic.
You use inside source translation in traditional and bidirectional NAT configurations.
Outside Source TranslationOutside source translation is less often used in NAT configuration because you are configuring the translation of an outside source to access an inside network. Normally, outside hosts have globally unique IP addresses, making translation unnecessary.
You use outside source translation along with inside source translation to configure translation in both directions, from both sides of the NAT router (not just translation of outbound information and “untranslation” of returning information).
Note: Dynamic outside source translations are established by inbound traffic.
Cases that require this type of translation method occur in twice NAT configurations that set up translation between two networks that contain nonunique or not publicly routable IP addresses (for example, two separate networks that use overlapping IP address blocks).
Address Assignment MethodsNAT uses one of two methods to assign IP addresses — static translation or dynamic translation.
Static TranslationsYou enter static translations as direct configuration settings that remain in the translation table until you remove them. You use static translations when you must initiate connections from both the inside and outside interfaces or when the translation is not subject to change.
Dynamic TranslationsDynamic translations use access list rules (to determine whether or not to apply NAT to incoming traffic) and NAT address pools (from which a NAT translation can use one of several available IP addresses). You use dynamic translation when you want the NAT router to initiate and manage address translation and session flows between address realms on demand.
Order of OperationsE-Series Routers
4-7
Order of OperationsTable 4-1 displays the order of operations for both inside-to-outside and outside-to-inside translation.
ReferencesFor more information about IP, consult the following resources:
• RFC 2663 – IP Network Address Translator (NAT) Terminology and Considerations (August 1999)
• RFC 2694 – DNS extensions to Network Address Translators (DNS_ALG) (September 1999)
• RFC 2993 – Architecture Implications of NAT (November 2000)
• RFC 3022 – Traditional IP Network Address Translator (Traditional NAT) (January 2001)
• RFC 3027 – Protocol Complications with the IP Network Address Translator (January 2001)
Table 4-1 NAT Order of Operations
Inside-to-Outside Translation Outside-to-Inside Translation
1 Inside (privately addressed) traffic enters the router on an interface marked as �inside.
2 A route lookup is performed.3 If the next interface is marked as
�outside,� the router sends the traffic to the server module.
4 The server module performs the appropriate translation.
5 The router forwards the packet to the appropriate egress line card.
6 The line card sends the packet as outbound traffic using a globally unique source address (inside source translation), destination address (outside source translation), or ports (NAPT).
1 Traffic from the outside, public domain enters the router.
2 All traffic from an interface that is marked �outside,� whether or not it requires NAT, is sent to the server module.
3 The server card looks for an associated NAT match.
4 If the server module:� Finds a NAT match, and the
destination interface is marked as �inside,� the server module performs the appropriate translation and sends the packet to the appropriate destination.
� Does not find a NAT match, and the destination interface is marked as �inside,� the server module drops the packet.
� Does not find a NAT match, and the destination interface is not marked as �inside,� the server module processes the packet normally for its destination.
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Before You BeginYou can configure certain IP interfaces to participate in Network Address Translation. This chapter discusses how to configure NAT to function for certain IP interfaces. For information about general IP interface configuration, see Chapter 2, Configuring IP.
Limiting Translation EntriesYou can configure the maximum number of dynamic translation entries that the translation table contains in Global Configuration mode for a given virtual router. The no version removes the configured limit and returns the maximum number of translation entries to the default (no limit).
ip nat translation max-entries� Use to specify the maximum number of dynamic translation entries that the
translation table can contain in global configuration mode for the given virtual router.
� Examplehost:VR1 (config-if) #ip nat translation max-entries 50
� Use the no version to remove the configuration limit.
Specifying Inside and Outside InterfacesYou must mark interfaces that participate in NAT translation as residing on the inside or the outside network.
Caution: Only packets routed between an inside and an outside interface are subject to translation.
You can unmark an interface by using the no version of this command.
ip nat� Use to mark an IP interface as participating in NAT translation.� Specifies on what side of the network (either inside or outside) the interface
resides.� Example
host (config-if) # ip nat inside� Use the no version to unmark the interface (the default).
Defining Static Address TranslationsE-Series Routers
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Defining Static Address TranslationsStatic address translation establishes a one-to-one mapping between a local (private) and global address. When specifying a static address translation, you issue commands to indicate how the translation is applied, along with more specific variables that further define the type of translation.
Caution: You must mark interfaces that participate in NAT translation as on the inside or the outside network. See Specifying Inside and Outside Interfaces for details.
Creating Inside Source TranslationsYou use the ip nat inside source static command to create static translations from a local IP address to a global IP address, and to “untranslate” the destination address when a packet returns from the outside network to the inside network. When configuring traditional NAT (both basic NAT and NAPT), you need only use this command alone. However, when configuring twice NAT, you must also use the ip nat outside source static command.
The ip nat inside source static command creates a simple (IP address only) or extended (IP address, protocol, and port) entry in the translation table that maps the two addresses.
ip nat inside source static� Use to create static translations for a source address when routing a packet
from the inside network to the outside network, and to �untranslate� the destination address when a packet returns from the outside network to the inside network.
� Example 1 � simple NAT table entryhost (config) # ip nat inside source static 10.1.2.3 171.69.68.10
� Example 2 � extended NAT table entryhost (config) # ip nat inside source static tcp 10.1.2.3 15 171.69.68.10 30
� Use the no version to remove the static translation and purge the associated translations from the translation table.
Note: Creating a static translation with the ip nat inside source static command allows any outside host to contact the inside host by using the inside global address of the inside host. This means that a static translation can be initiated in either direction.
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Creating Outside Source TranslationsLess commonly used, outside source translation allows you to set up translation between two nonunique or not publicly routable networks (for example, two separate networks that use overlapping IP address blocks).
This command creates a simple (IP address only) or extended (IP address, protocol, and port) entry in the translation table that maps the two addresses.
ip nat outside source static� Use to translate the source address when routing a packet from the outside
network to the inside network, and to �untranslate� the destination address when a packet travels from the inside network to the outside network.
� Example 1 � simple NAT table entryhost (config) # ip nat outside source static 171.69.68.10 10.1.2.3
� Example 2 � extended NAT table entryhost (config) # ip nat outside source static tcp 171.69.68.10 56 10.1.2.3 24
� Use the no version to remove the static translation and purge the associated translations from the translation table.
Note: Creating a static translation with the ip nat outside source static command allows any inside host to contact the outside host by using the address of the outside host. This means that a static translation can be initiated in either direction.
Defining Dynamic TranslationsTo configure dynamic translations:
• Define any access list rules that the NAT router uses to decide which packets need translation.
• Define an address pool from which the NAT router obtains addresses.
• Define inside or outside source translation rules for the NAT router to use for any NAT traffic it processes.
• Mark interfaces as inside or outside.
• (Optional) Modify any translation time-out values.
Creating Access List RulesBefore creating a dynamic translation, you should create the access list rules that you plan to apply to the translation. For information about configuring access lists, see Chapter 1, Configuring Routing Policy.
The router evaluates multiple commands for the same access list in the order they were created. An undefined access list implicitly contains a
Defining Dynamic TranslationsE-Series Routers
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rule to “permit any.” A defined access list implicitly ends with a rule to “deny any.”
Note: The access lists do not filter any packets; they determine whether or not the packet requires translation.
For reference, you can configure an access list using the access-list command.
access-list� Use to define an IP access list to permit or deny translation based on the
addresses in the packets.� Each access list is a set of permit or deny conditions for routes that are
candidates for translation (that is, moving from the inside network to the outside network).
� A zero in the wildcard mask means that the route must exactly match the corresponding bit in the address. A one in the wildcard mask means that the route does not have to match the corresponding bit in the address.
� Use the log keyword to log an Info event in the ipAccessList log whenever matching an access-list rule.
� Use the no version to delete the access list (by not specifying any other options), the specified entry in the access list, or the log for the specified access list or entry (by specifying the log keyword).
Defining Address PoolsBefore you can configure dynamic translation, you should first create an address pool. An address pool is a group of IP addresses from which the NAT router obtains an address when performing a dynamic translation. You can create address pools with either a single range or multiple, nonoverlapping ranges.
When creating a single range, you specify the optional starting and ending IP address for the range in the root ip nat pool command. However, when creating multiple, nonoverlapping ranges, you omit the optional starting and ending IP address in the root ip nat pool command; this launches the IP NAT Pool Configuration mode.
The config-ipnat-pool mode uses an address command to specify a range of IP addresses. You can repeat this command to create multiple, nonoverlapping ranges.
When creating or editing address pools, keep the following in mind:
• Specified-range starting and ending IP addresses are inclusive and must reside on the same subnet.
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• Address ranges are verified against other ranges in the specified pool to exclude range overlaps. Additional verification occurs when the pool is associated with a translation rule and the router can determine whether the rule is inside or outside.
• You cannot change the network mask if configured ranges already exist.
• The subnetwork mask excludes host addresses that end in either all zeros or all ones. These addresses are reserved as broadcast addresses.
• You cannot remove an address pool if the pool is part of a translation rule or if any of the ranges within the pool are still in use. You must issue the clear ip nat translation command to clear any ranges before you can remove the pool to which they apply.
ip nat pool� Use to create address pools.� Example 1 � creating a single, continuous range
host (config) #ip nat pool singlerange 171.69.40.1 171.69.40.100 prefix-length 30
� Example 2 � creating a multiple, discontinuous rangehost (config) #ip nat pool multiplerange prefix-length 30host (config-ipnat-pool)#address 171.69.40.110 171.69.40.115host (config-ipnat-pool)#address 171.69.40.116 171.69.40.120host (config-ipnat-pool)#exit
� The no version removes the range designation.
address� Use to specify a range of IP addresses in IP NAT Pool Configuration mode; you
can repeat the address command to create multiple ranges.� Example
host (config-ipnat-pool)#address 171.69.40.110 171.69.40.115� The no version removes the range for the current address pool.
Defining Translation RulesThe CLI allows you to define dynamic translations for inside and outside sources.
Caution: You must mark interfaces that participate in NAT translation as on the inside or the outside network. See Specifying Inside and Outside Interfaces for details.
You can create dynamic translation rules for either an inside source translation or an outside source translation. The router determines if source addresses from a named access list require translation. If they do,
Defining Dynamic TranslationsE-Series Routers
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the router translates the addresses by substituting addresses from a specified address pool.
When creating dynamic translations, keep the following in mind:
• You can associate a list with one pool at any given time. Associating a list with a different pool replaces the previous association.
• The optional overload keyword for inside source translations specifies that the router employ NAPT translation.
• You can configure dynamic NAPT for inside source translation only; you cannot configure dynamic NAPT for outside source translation.
• An access list mismatch results in the NAT router’s not translating the packet.
• An empty pool results in the NAT router’s dropping the packet.
• Access lists and pools do not have to exist when you are defining dynamic translations; you may create them after defining the dynamic translations.
Creating Dynamic Inside Source TranslationsUse the ip nat inside source list command to create a dynamic inside source translation rule. This command dynamically translates inside local source addresses to inside global addresses when packets from the inside network are routed to the outside network (and vice versa when a packet returns before a translation table entry times out). Use the overload keyword to specify that the translation create NAPT entries (protocol, port, and address) in the NAT table.
The no version of this command removes the dynamic translation rule, but does not remove any previously created translations (resulting from the rule evaluation) from the translation table. To remove active translations from the translation table, see Clearing Dynamic Translations on page 4-15.
ip nat inside source list� Use to create dynamic translations for a source address when routing a packet
from the inside network to the outside network, and to translate the destination address when a packet returns from the outside network to the inside network.
� Examplehost (config) #ip nat inside source list translation1 pool pool1
� Use the overload keyword to specify that the translation create extended entries (protocol, port, and address) in the translation table for NAPT.
� Use the no version to remove the dynamic translation rule; this command does not remove any dynamic translations from the translation table.
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Creating Dynamic Outside Source TranslationsUse the ip nat outside source list command to create a dynamic outside source translation rule. This command dynamically translates outside global source addresses to outside local addresses when packets are routed from the outside network to the inside network (and “untranslates” the destination address when a packet returns before a translation table entry times out).
The no version of this command removes the dynamic translation rule, but does not remove any previously created translations from the translation table. To remove active translations from the translation table, see Clearing Dynamic Translations.
ip nat outside source list� Use to create dynamic translations for a source address when routing a packet
from the outside network to the inside network, and to translate the destination address when a packet returns to the outside network from the inside network.
� Examplehost (config) # ip nat outside source list translation1 pool pool1
� Use the no version to remove the dynamic translation rule; this command does not remove any dynamic translations from the translation table.
Defining Translation Time-OutsDynamic translations in the translation table age out if the router does not use them. Use the ip nat translation command to change or disable NAT translation time-outs.
You can set the aging time to some value (in seconds) for any one of the specified timers:
• timeout – Dynamic simple translations, except for overloaded translations; default is 86400 seconds (24 hours).
• udp-timeout – UDP protocol extended translations; default is 300 seconds (5 minutes).
• dns-timeout – DNS-created protocol translations; default is 120 seconds. These dynamic translations are installed by the DNS but not yet used; as soon as the translation is used, the router applies the timeout.
• tcp-timeout – TCP protocol extended translations; default is 86400 seconds (24 hours).
• finrst-timeout – TCP connections terminated with reset (RST) or bidirectional finished (FIN) flags; default is 120 seconds. This time-out
Clearing Dynamic TranslationsE-Series Routers
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applies only to TCP overload translations. It more gracefully ages out closed translations.
• icmp-timeout – ICMP protocol extended translations; default is 300 seconds (5 minutes).
All time-outs for this command support a maximum value of 2147483 seconds (about 25 days).
The no version of this command resets the timer to its default value.
ip nat translation� Use to change translation time-outs for old translations in the translation table.� All time-outs for this command support a maximum value of 2147483 seconds
(about 25 days).� Example
host1 (config) # ip nat translation timeout 23200
Clearing Dynamic TranslationsUse the clear ip nat translation command to clear dynamic translations from the NAT translation table. You can remove all dynamic translations from the translation table or restrict the removal of translation entries based on the protocol, address, or port values.
clear ip nat translation� Use to clear dynamic translations from the NAT translation table.� Use an asterisk (*) to clear all dynamic translations from the translation table.� Example 1 � to clear all dynamic translations
host1 #clear ip nat translation*� Example 2 � to clear a specific port translation
host1 #clear ip nat translation tcp inside 171.69.68.10 10.1.2.3 55� There is no no version.
Configuration ExamplesThis section contains NAT configuration examples for a single virtual router configuration and NAT translation between two virtual routers.
NAPT ExampleThis example illustrates a NAPT configuration for a private network with two inside sub-networks, a field office, and a corporate office.
CHAPTER 4Configuring NAT
4-16
Both offices use private addresses. The corporate office has a dual T-3 link and a public FTP server that has a global address (that is, it does not need translation).
Figure 4-1 NAPT example
The address pool consists of three addresses (the number of addresses is small, since NAPT is used). Addresses matching the private address spaces of the corporate and field subnetworks are translated to global addresses from the pool using NAPT.
To configure this example:
1 Enter the correct virtual router context.
host1(config)#virtual-router blue
2 Mark the inside interfaces.
a First the field office:
host1:blue(config)#interface serial 2/1:1/1
host1:blue(config-interface)#ip nat inside
host1:blue(config-interface)#exit
b Then the two corporate T-3 links:
host1:blue(config)#interface serial 1/1
host1:blue(config-interface)#ip nat inside
host1:blue(config-interface)#exit
host1:blue(config)#interface serial 1/2
host1:blue(config-interface)#ip nat inside
host1:blue(config-interface)#exit
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Configuration ExamplesE-Series Routers
4-17
3 Mark the outside interface.
host1:blue(config)#interface gigabitEthernet 3/0.1
host1:blue(config-interface)#ip nat outside
host1:blue(config-interface)#exit
4 Create a static nil-translation for the FTP server on the corporate network.
host1:blue(config)#ip nat inside source static tcp 190.22.8.18 21 190.22.8.18 21
5 Create the address pool for dynamic translations.
host1:blue(config)#ip nat pool corpxyz 192.32.6.4 192.32.6.7 prefix-length 24
6 Create the access list for addresses eligible for dynamic translation.
host1:blue(config)#access-list justcorp permit 10.10.1.0 0.0.0.255
host1:blue(config)#access-list justcorp permit 10.10.2.0 0.0.0.255
7 Create the NAPT dynamic translation rule.
host1:blue(config)#ip nat inside source list justcorp pool corpxyz overload
8 Configure a default route to the outside interface.
host1:blue(config)#ip route 0.0.0.0 0.0.0.0 gigabitEthernet 3/0.1
9 Configure a null route for the inside global addresses (prevents routing loops when no matching translation exists)
host1:blue(config)#ip route 192.32.6.0 255.255.255.252 null 0
All hosts using private addresses in both the field office and the corporate office must have their addresses translated to one of the three addresses in the pool. Because we are using NAPT, the interface can use only one pool address, depending on the number of inside hosts attempting to access the outside at any given time.
Bidirectional NAT ExampleIn this example, outside hosts can initiate conversations with inside hosts through the use of a DNS server that resides on the inside network.
The inside realm uses basic NAT. The inside network uses a mix of private subnetwork address space (192.168.22/24) and registered public addresses.
CHAPTER 4Configuring NAT
4-18
Figure 4-2 Bidirectional NAT example
To configure this example:
1 Enter the correct virtual router context.
host1(config)#virtual-router blue
2 Mark the inside interface.
host1:blue(config)#interface serial 1/1:1/1
host1:blue(config-interface)#ip nat inside
host1:blue(config-interface)#exit
3 Mark the outside interface.
host1:blue(config)#interface gigabitEthernet 3/0.1
host1:blue(config-interface)#ip nat outside
host1:blue(config-interface)#exit
4 Create the translation for the DNS.
host1:blue(config)#ip nat inside source static 192.168.22.2 192.32.6.1
5 Create the address pool for dynamic translations.
host1:blue(config)#ip nat pool entA192 192.32.6.2 192.32.6.63 prefix-length 24
6 Create the access list for addresses eligible for dynamic translation (that is, private addresses).
host1:blue(config)#access-list entA permit 192.168.22.0 0.0.0.255
7 Create the dynamic translation rule.
host1:blue(config)#ip nat inside source list entA pool entA192
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Configuration ExamplesE-Series Routers
4-19
8 Configure a default route to the outside interface.
host1:blue(config)#ip route 0.0.0.0 0.0.0.0 gigabitEthernet 3/0.1
9 Configure a null route for the inside global addresses (to prevent routing loops when no matching translation exists).
host1:blue(config)#ip route 192.32.6.0 255.255.255.192 null 0
Twice NAT ExampleTwice NAT is often useful when the inside network is using a nonprivate address space (unregistered usage of global address space) and desires connectivity to the public network. Inside local addresses need to be translated to legal global addresses. Legal addresses from the outside that overlap those used on the inside network need to be translated to unused and recognizable addresses in the inside network. Both inside source and outside source translations must be configured on the NAT router.
In this example, the inside network is using the unregistered global address space of 15.12.0.0/16. Outside hosts whose addresses overlap with this sub-network that wish to access the inside network will need their global addresses translated.
Figure 4-3 Twice NAT example
To configure this example:
1 Enter the correct virtual router context.
host1(config)#virtual-router blue
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CHAPTER 4Configuring NAT
4-20
2 Mark the inside interface.
host1:blue(config)#interface fast-ethernet 6/1
host1:blue(config-interface)#ip nat inside
host1:blue(config-interface)#exit
3 Mark the Outside Interface.
host1:blue(config)#interface atm 3/0.20
host1:blue(config-interface)#ip nat outside
host1:blue(config-interface)#exit
4 Create the address pool for inside source translations.
host1:blue(config)#ip nat pool entAoutpool 12.220.1.0 12.220.255.255 prefix-length 16
5 Create the access list for addresses eligible for dynamic translation.
host1:blue(config)#access-list entAout permit 15.12.0.0 0.0.255.255
6 Create the dynamic translation rule for outbound traffic.
host1:blue(config)#ip nat inside source list entAout pool entAoutpool
7 Create the address pool for outside source translations.
host1:blue(config)#ip nat pool entAinpool 10.1.32.1 10.1.32.255 prefix-length 16
Note: Using a private address range avoids any overlap with the public network.
8 Configure the access list for global addresses that overlap with inside addresses.
host1:blue(config)#access-list entAin permit 15.12.0.0 0.0.255.255
9 Create the dynamic translation rule for inbound traffic
host1:blue(config)#ip nat outside source list entAin pool entAinpool
10 Create a route to the outside interface for inside hosts to access outside hosts that have overlapping addresses
host1:blue(config)#ip route 10.1.32.0 255.255.255.0 atm 3/0.1
Note: An inside host cannot directly access hosts on the outside network that use addresses that overlap with the inside subnetwork. However, by using DNS name resolution to reference translated addresses, inside hosts can access these outside hosts.
Configuration ExamplesE-Series Routers
4-21
11 Configure a null route for the inside global addresses (prevents routing loops when no matching translation exists)
host1:blue(config)#ip route 12.220.0.0 255.255.0.0 null 0
Cross-VRF ExampleIn MPLS VPN configurations, it may be desirable to offer public Internet access to VPN subscribers. MPLS VPNs are enabled through the use of VRFs. If a VPN is using a private or overlapping address space, we can use NAT to enable access to the public network since NAT is both VR and VRF aware. In this example, we will use the subscriber interface feature of the router in conjunction with NAT to connect the VPNs to the public network.
Figure 4-4 Cross-VRF example
VRF11 is the local (this PE) representation of the MPLS VPN and connects enterpriseA to the VPN. EnterpriseA communicates to VRFs in other PE devices (the rest of the VPN) through RFC2547bis (MPLS VPNs). The VR, of which the VRF is administratively a member, represents the public network. The interface to enterpriseA is marked as an inside interface. The normal steps for configuring inside source translation are applied. A subscriber interface is created off of the uplink to the core network and anchored in the VRF. A DA-based demultiplex matching the inside global address range is configured on the subscriber interface. The subscriber interface is marked as an outside interface.
To configure this example:
1 Enter the correct virtual routing and forwarding instance.
host1(config)#virtual-router vr1:vrf11
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CHAPTER 4Configuring NAT
4-22
2 Mark the inside interfaces.
host1:vr1:vrf11(config)#interface fast-ethernet 6/1
host1:vr1:vrf11 (config-interface)#ip nat inside
host1:vr1:vrf11 (config-interface)#exit
3 Set the primary interface to DA-type demultiplex (for subsequent shared interfaces).
host1:vr1(config)#interface atm 12/0.101
host1:vr1(config-interface)#ip demux-type da-prefix
host1:vr1(config-interface)#exit
4 Create the address pool for dynamic translations.
host1:vr1(config)#virtual-router vr1:vrf11
host1:vr1:vrf11(config)#ip nat pool entApool 128.13.44.1 128.13.44.255 prefix-length 24
5 Create the access list for addresses eligible for dynamic translation.
host1:vr1:vrf11(config)#access-list entA permit 10.16.5.0 0.0.0.255
6 Create the dynamic translation rule.
host1:vr1:vrf11(config)#ip nat inside source list entA pool entApool
7 Create the subscriber interface off the uplink.
host1:vr1:vrf11(config)#interface ip vrf11vr1
host1:vr1:vrf11(config-interface)#ip share-interface atm 12/0.101
host1:vr1:vrf11(config-interface)#ip unnumbered loopback 1
8 Configure a group of destination prefixes with which the device can communicate on the public network.
host1:vr1:vrf11(config-interface)#ip destination-prefix 128.13.44.0 255.255.255.0
9 Mark the subscriber interface as outside.
host1:vr1:vrf11(config-interface)#ip nat outside
host1:vr1:vrf11(config-interface)#exit
10 Point the default route to the shared interface.
host1:vr1:vrf11(config)#ip route 0.0.0.0 0.0.0.0 ip vrf11vr1
11 Install a null route to avoid routing loops to the inside global address.
host1:vr1:vrf11(config)#ip route 128.13.44.0 255.255.255.0 null 0
Monitoring NATE-Series Routers
4-23
Monitoring NATThis section explains how to view NAT statistics, NAT translation entries, and determine what IP interfaces have a NAT inside or outside setting.
Displaying Translation StatisticsThe show ip nat statistics command displays statistics that apply to NAT operation.
show ip nat statistics� Use to display internal NAT statistics.� Field descriptions
� Last dynamic allocation failure � completion level of any dynamic allocation failures; the number of times the router attempted dynamic allocation but reached the dynamic allocation entry limit
� Current static translation entries� Inside Source Simple � number of inside source simple static translations� Outside Source Simple � number of outside source simple static
translation entries� Inside Source Extended � number of inside source extended static
translations� Outside Source Extended � number of outside source extended static
translations� Dynamic Translation Type � dynamic translation type (inside source simple,
outside source simple, inside source extended)� Current � current number of dynamic translations of the associated
translation type� Peak � peak number of dynamic translations of the associated translation
type� Accumulated � accumulated number of dynamic translations of the
associated type; this value reflects the accumulation of dynamic translations since the last router reboot
� Failed � total number of installation attempts that failed for an associated translation type
CHAPTER 4Configuring NAT
4-24
� Examplehost1#show ip nat statistics
NAT database statistics for virtual router vr1:
--------------------------------------------------------------
Last dynamic allocation failure: normal, successful completion
Dynamic entry limit was reached 0 times
Current static translation entries:
-----------------------------------------
Inside Source Simple: 1
Outside Source Simple: 1
Inside Source Extended: 2
Outside Source Extended: 2
Dynamic Translation Type Current Peak Accumulated Failed
---------------------------- ---------- ---------- ----------- ----------
Inside Source Simple 2 2 2 0
Outside Source Simple 2 2 2 0
Inside Source Extended 2 2 2 0
Displaying Translation EntriesThe show ip nat translations command displays current translations that reside in the translation table.
Simple translation entries appear with inside/outside and local/global address information. Extended entries appear with added protocol and port numbers (or query ID).
Using verbose mode additionally provides the time since creation and time since last use for each translation entry.
show ip nat translations� Use to display current translations that reside in the NAT translation table.� Field descriptions
� Prot � protocol (TCP, UDP, or ICMP) for this translation entry; this field appears only for extended table entries
� Inside local � inside local IP address for this translation entry; this field also provides the port number, separated by a colon ( : ) for extended entries
� Inside global � inside global IP address for this translation entry; this field also provides the port number, separated by a colon ( : ) for extended entries
� Outside global � outside global IP address for this translation entry; this field also provides the port number, separated by a colon ( : ) for extended entries
� Outside local � outside local IP address for this translation entry; this field also provides the port number, separated by a colon ( : ) for extended entries
Monitoring NATE-Series Routers
4-25
� Time since creation � amount of time elapsed since the translation entry appeared in the translation table
� Time since last use � amount of time elapsed since the translation entry was used
� Example 1host1#show ip nat translation
Prot Inside local Inside global Outside global Outside local
---- ------------------ ------------------ ----------------- -----------------
20.0.0.3 30.0.0.3 --- ---
21.0.0.3 30.208.0.3 --- ---
21.0.0.4 30.208.0.4 --- ---
--- --- 50.0.0.3 70.0.0.3
--- --- 51.0.0.3 70.208.0.3
--- --- 51.0.0.4 70.208.0.4
UDP --- --- 50.50.0.3:87 70.50.0.3:8108
UDP 22.0.0.4:63 30.224.0.3:4097 --- ---
UDP 22.0.0.3:63 30.224.0.3:4096 --- ---
TCP --- --- 50.50.0.3:80 70.50.0.3:8008
UDP 20.50.0.3:87 30.50.0.3:8108 --- ---
TCP 20.50.0.3:80 30.50.0.3:8008 --- ---
� Example 2host1#show ip nat translation verbose
Time Time
Inside Outside Outside since since
Prot Inside local global global local creation last use
---- ------------ ----------- ----------- ----------- ------------ ------------
20.0.0.3 30.0.0.3 --- --- 00:04:50 00:00:01
21.0.0.3 30.208.0.3 --- --- 00:02:12 00:00:01
21.0.0.4 30.208.0.4 --- --- 00:02:12 00:00:01
--- --- 50.0.0.3 70.0.0.3 00:03:24 Never
--- --- 51.0.0.3 70.208.0.3 00:01:44 00:00:01
--- --- 51.0.0.4 70.208.0.4 00:01:44 00:00:01
UDP --- --- 50.50.0.3:8 70.50.0.3:8 00:03:10 Never
7 108
UDP 22.0.0.4:63 30.224.0.3: --- --- 00:02:12 00:00:01
4097
UDP 22.0.0.3:63 30.224.0.3: --- --- 00:02:12 00:00:01
4096
TCP --- --- 50.50.0.3:8 70.50.0.3:8 00:03:10 Never
0 008
UDP 20.50.0.3:87 30.50.0.3:8 --- --- 00:03:35 Never
108
TCP 20.50.0.3:80 30.50.0.3:8 --- --- 00:03:35 Never
008
CHAPTER 4Configuring NAT
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Part 3Internet Protocol Routing
5
Configuring IP MulticastingIP multicasting allows a device to send packets to a group of hosts rather than to a list of individual hosts. This chapter describes how to configure IP multicasting on the E-series router.
Topic Page
Overview 5-2
References 5-3
Before You Begin 5-4
Enabling IP Multicasting 5-4
Deleting Multicast Forwarding Entries 5-4
Reverse-Path Forwarding 5-5
Multicast Packet Forwarding 5-6
Monitoring IP Multicast Settings 5-8
IGMP 5-15
IGMP Proxy 5-29
PIM 5-34
DVMRP 5-59
BGP Multicasting 5-74
Investigating Multicast Routes 5-74
CHAPTER 5Configuring IP Multicasting
5-2
Overview IPv4 defines three types of addresses: unicast, broadcast, and multicast. Each type of address enables a device to send datagrams to selected recipients:
• A unicast address enables a device to send a datagram to a single recipient.
• A broadcast address enables a device to send a datagram to all hosts on a subnetwork.
• A multicast address enables a device to send a datagram to a specified set of hosts, known as a multicast group, in different subnetworks.
Multicast IP packets contain a class D address in the Destination Address fields of their headers. A class D address is the IP address of a multicast group. Refer to Chapter 2, Configuring IP, and to IGMP, later in this chapter, for information about class D addresses.
IP multicasting improves network efficiency by allowing a host to transmit a datagram to a targeted group of receivers. For example, a host may want to send a large video clip to a group of selected recipients. It would be time-consuming for the host to unicast the datagram to each recipient individually. If the host broadcasts the video clip throughout the network, network resources are not available for other tasks. The host uses only the resources it needs by multicasting the datagram.
Routers use multicast routing algorithms to determine the best route and transmit multicast datagrams throughout the network. The E-series router supports a number of IP multicasting protocols on virtual routers (VRs). Each VR handles the interoperability of IP multicasting protocols automatically. To start multicast operation on a VR, you access the context for that VR and configure the desired protocols on the selected interfaces. Table 5-1 lists the protocols the router supports and the function of each protocol.
Table 5-1 Function of multicast protocols on a router
Protocol Function
Internet Group Membership Protocol (IGMP)
Discovers hosts that belong to multicast group.
Protocol Independent Multicast Protocol (PIM)
Discovers other multicast routers that should receive multicast packets.
Distance Vector Multicast Routing Protocol (DVMRP)
Routes multicast datagrams within autonomous systems.
ReferencesE-Series Routers
5-3
The router supports up to 16,384 multicast forwarding entries (multicast routes) at any time.
ReferencesThis implementation of IP multicasting meets the following specifications:
• A “traceroute” Facility for IP Multicast – draft-ietf-idmr-traceroute-ipm-07.txt (January 2001 expiration)
• An Overview of Source-Specific Multicast (SSM) – draft-ietf-ssm-overview-05.txt (November 2003 expiration)
• Distance Vector Multicast Routing Protocol – draft-ietf-idmr-dvmrp-v3-10.txt (February 2001 expiration)
• IGMP-based Multicast Forwarding (“IGMP Proxying”) – draft-ietf-magma-igmp-proxy-00.txt (May 2002 expiration)
• Protocol Independent Multicast MIB for IPv4 – draft-ietf-idmr-pim-mib-10.txt (July 2000 expiration)
• RFC 2236 – Internet Group Management Protocol, Version 2 (November 1997)
• RFC 2362 – Protocol Independent Multicast-Sparse Mode (PIM-SM): Protocol Specification (June 1998)
• RFC 2858 – Multiprotocol Extensions for BGP-4 (June 2000)
• RFC 2932 – IPv4 Multicast Routing MIB (October 2000)
• RFC 2933 – Internet Group Management Protocol MIB (October 2000)
• RFC 3376 – Internet Group Management Protocol (October 2002)
• Source-Specific Multicast for IP – draft-ietf-ssm-arch-03.txt (November 2003 expiration)
• Source-Specific Protocol Independent Multicast in 232/8 – draft-ietf-mboned-ssm232-05.txt (November 2003 expiration)
BGP Multicasting Protocol Routes multicast datagrams between autonomous systems.
Table 5-1 Function of multicast protocols on a router (continued)
Protocol Function
CHAPTER 5Configuring IP Multicasting
5-4
Note: IETF drafts are valid for only 6 months from the date of issuance. They must be considered as works in progress. Please refer to the IETF Web site at http://www.ietf.org for the latest drafts.
Before You BeginYou can configure IP multicasting on IP interfaces. For information about configuring IP interfaces, see Chapter 2, Configuring IP.
Enabling IP MulticastingIn this implementation, IP multicasting works on VRs. By default, IP multicasting is disabled on a VR. To enable IP multicasting on a VR, access the context for a VR, and then issue the ip multicast-routing command.
ip multicast-routing� Use to enable IP multicast routing on the VR.� By default, IP multicasting is disabled on the VR. In the disabled state, all
multicast protocols are disabled, and the VR forwards no multicast packets.� Example
host1(config)#ip multicast-routing
� Use the no version to disable IP multicast routing on the VR.
Deleting Multicast Forwarding EntriesYou can clear one or more forwarding entries from the multicast routing table. However, if you do so, the entries may reappear in the routing table if they are rediscovered.
clear ip mroute� Use to delete IP multicast forwarding entries.� If you specify an *, the router clears all IP multicast forwarding entries.� If you specify the IP address of a multicast group, the router clears all multicast
forward entries for that group.� If you specify the IP address of a multicast group and the IP address of a
multicast source, the router clears the multicast entry that matches that group and source.
� Examplehost1:boston#clear ip mroute *
� There is no no version.
Reverse-Path ForwardingE-Series Routers
5-5
Reverse-Path ForwardingIP multicasting uses reverse-path forwarding (RPF) to verify that a router receives a multicast packet on the correct incoming interface. The RPF algorithm allows a router to accept a multicast datagram only on the interface from which the router would send a unicast datagram to the source of the multicast datagram.
Figure 5-1 illustrates RPF in a network where all routers run dense-mode multicasting protocols. Routers that receive a multicast datagram associated with a group for which they have no hosts return prune messages upstream toward the source of the datagram. Upstream routers do not forward subsequent multicast datagrams to routers from which they receive prune messages. This technique creates a source-rooted tree (SRT), also known as a shortest-path tree (SPT) — a structure that connects the source of a datagram to subnetworks of a multicast group through the shortest path. For more information on dense-mode protocols, see PIM DM, later in this chapter.
Figure 5-1 Reverse path forwarding in a dense-mode environment
When all routers in a network are running sparse-mode multicast protocols, the routers forward a multicast datagram only to other routers with downstream members of the groups associated with the datagram. Routers running sparse-mode protocols forward multicast traffic only when explicitly requested to do so, whereas routers running dense-mode protocols forward multicast traffic except when explicitly requested not to do so. For more information on sparse-mode protocols, see PIM SM, later in this chapter.
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CHAPTER 5Configuring IP Multicasting
5-6
RPF may take place through static routes, dynamic routes, or local subnets. You can define static routes for this purpose and view information associated with RPF routes.
Multicast Packet ForwardingMulticast packet forwarding is based on the source (S) of the multicast packet and the destination multicast group address (G). For each (S,G) pair, the router accepts multicast packets on an incoming interface (IIF), which satisfies the RPF check (RPF-IIF). The router drops packets received on IIFs other than the RPF-IIF and notifies the routing protocols that a packet was received on the wrong interface.
The router forwards packets received on the RPF-IIF to a list of outgoing interfaces (OIFs). The list of OIFs is determined by the exchange of routing information and local group membership information. The router maintains mappings of (S,G, IIF) to {OIF1, OIF2…} in the multicast routing table.
You can enable two or more multicast protocols on an IIF. However, only one protocol can forward packets on that IIF. The protocol that forwards packets on an IIF owns that IIF. A multicast protocol that owns an IIF also owns the (S,G) entry in the multicast routing table.
ip rpf-route� Use to customize static routes that the router may use for RPF.� Specify the IP address and subnet mask of the destination network.� Specify either a next-hop IP address or an interface type and specifier, such as
atm 3/0. For details about interface types and specifiers, see E-Series Command Reference Guide, About This Guide.
� Optionally, specify the distance (number of hops) to the next-hop address.� Optionally, specify a route�s tag number to identify a particular route in the
routing table.� Example
host1(config)#ip rpf-route 11.1.0.0 255.255.0.0 atm4/1.1 56 tag 25093
� Use the no version to remove the static route.
show ip rpf-route� Use to display routes that the router can use for RPF.� Specify the IP address and the network mask to view routes to a particular
destination.� Specify a unicast routing protocol to view routes associated with that protocol.
Multicast Packet ForwardingE-Series Routers
5-7
� Field descriptions� Proto
� Connect � subnet directly connected to the interface� Static � static route� protocol-name � route learned through the named protocol
� Prefix � value of the logical AND of the IP address of the destination network and the subnet address
� Length � length of the subnet mask in bits� Next Hop � IP address of the next hop for this route� Dist � distance configured for this route� Met � learned or configured cost associated with this route� Intf � type of interface and interface specifier for the next hop. For details
about interface types and specifiers, see E-Series Command Reference Guide, About This Guide.
� Examplehost1#show ip rpf-route
Proto: Prefix/Length: Next Hop: Dist/Met: Intf:
Connect 10.5.0.0/16 10.5.3.149 0/1 fastEthernet0/0
Static 11.0.0.0/8 21.1.1.2 1/1 atm4/0.1
Connect 21.1.1.0/24 21.1.1.2 0/1 atm4/0.1
Connect 25.25.25.25/32 25.25.25.25 0/1 loopback0
Disabling RPF ChecksBy default, the router accepts multicast packets for each (S,G) pair on an incoming interface (IIF), which satisfies the RPF check (RPF-IIF). When the router performs RPF checks, only the interface that first accepts traffic for an (S,G) pair accepts subsequent traffic for that pair. If traffic stops coming on that interface and starts arriving on another interface, the router does not accept or forward the traffic.
Some network configurations require the router to accept traffic on any interface that is the next-hop point of an equal-cost multipath (ECMP) route. To do so, you can disable the RPF check on a specified set of (S,G) pairs by issuing the ip multicast-routing disable-rpf-check command.
When you disable RPF checks, the router accepts multicast packets for (S,G) pairs on any incoming interface of an ECMP route. When the router has added the new route to its multicast routing table, it will then accept multicast packets for these pairs on any interface in the virtual router and forward them accordingly. Multicast routes established before you issue this command are not affected.
CHAPTER 5Configuring IP Multicasting
5-8
ip multicast-routing disable-rpf-check� Use to disable RPF checks for specified (S,G) pairs.� Specify a standard IP access list that defines the (S,G) pairs.� Example
host1(config)#ip multicast-routing disable-rpf-check boston-list
� Use the no version to restore the default situation, in which the router performs RPF checks for all (S,G) pairs.
Using Unicast Routes for RPFYou can use the ip route-type command to specify that IS-IS, OSPF, or RIP routes should be available for RPF. Routes available for RPF appear in the multicast view of the routing table.
ip route-type� Use to specify whether IS-IS, OSPF, or RIP routes are available only for unicast
forwarding, only for multicast reverse-path forwarding checks, or for both.� Use the show ip rpf-routes command to view the routes available for RPF.� By default, IS-IS, OSPF, and RIP routes are available both for unicast
forwarding and multicast reverse-path forwarding checks.� Example
host1(config)#router ospf
host1(config-router)#ip route-type multicast
� There is no no version.
Monitoring IP Multicast SettingsTo display general information about the IP multicasting configuration on the router, use the following commands:
• show ip mroute
• show ip multicast protocols
• show ip multicast routing
show ip mroute� Use to display information about all or specified multicast forwarding entries.� Specify a multicast group IP address or both a multicast group IP address and
a multicast source IP address to display information about particular multicast forwarding entries.
� Use the summary option to see a summary rather than a detailed description.� Use the count option to display the number of multicast forwarding entries.
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� Use the statistics option to display statistics for packets received through all multicast forwarding entries that the router has added to the multicast routing table and established on the appropriate line modules.
� Field descriptions� (S,G) � IP addresses of the multicast source and the multicast group� Uptime � length of time in days minutes:hours:seconds format that the (S,G)
pair has been active� Expires � length of time in days minutes:hours:seconds format for which the
(S,G) pair will be active� RPF Route � IP address and prefix of the RPF route� Incoming interface � type and specifier of the incoming interface for the RPF
route� Neighbor � IP address of the neighbor� Owner � owner of the route
� Local � route belonging to the local interface� Static � static route� Other protocols � route established by a protocol such as RIP or OSPF
� Incoming Interface List � list of incoming interfaces on the router. Details include:� Type of interface and its specifier� Action that the interface takes with packets: accept or discard� Multicast protocol that owns the interface� Time that the interface has been active in this multicast forwarding entry,
in days minutes:hours:seconds format� Time that the interface will cease to be active in this multicast forwarding
entry, in days minutes:hours:seconds format� Outgoing Interface List � list of outgoing interfaces on the router. Details
include:� Type of interface and its specifier� Action that the interface takes with packets: forward� Protocol running on the interface: PIM, DVMRP, or IGMP� Time that the interface has been active in this multicast forwarding entry,
in days minutes:hours:seconds format� Time that the interface will cease to be active in this multicast forwarding
entry, in days minutes:hours:seconds format� Counts � numbers of types of source group mappings
� (S,G) � number of (S,G) entries� (*,G) � number of (*,G) entries
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� Examplehost1#show ip mroute
IP Multicast Routing Table
(S, G) uptime d h:m:s[, expires d h:m:s]
RPF route: addr/mask, incoming interface
neighbor address, owner route-owner
Incoming interface list:
Interface (addr/mask), State/Owner [(RPF IIF)]
Outgoing interface list:
Interface (addr/mask), State/Owner, Uptime/Expires
(10.0.10.1, 225.1.1.1) uptime 0 00:10:31
RPF route: 10.0.10.0/24, incoming interface atm5/3.1010
neighbor 10.0.10.8, owner Local
Incoming interface list:
atm5/3.1010 (10.0.10.8/24), Accept/Pim (RPF IIF)
Outgoing interface list:
atm5/1.108 (108.0.8.5/8), Forward/Pim, 0 00:02:52/never
atm5/1.109 (107.0.8.4/8), Forward/Pim, 0 00:10:07/never
show ip mroute count� Use to display information about the number of groups and sources.� Specify a multicast group IP address or both a multicast group IP address and
a multicast source IP address to display information about a particular multicast forwarding entry.
� Field descriptions � Counts � numbers of types of source group mappings
� (S,G) � number of (S,G) entries� (*,G) � number of (*,G) entries
� Example host1#show ip mroute count
IP Multicast Routing Table
Counts: 2 (S, G) entries
0 (*, G) entries
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show ip mroute statistics� Use to display statistics for packets received through multicast routes that the
router has added to the multicast routing table and established on the appropriate line modules.
� Specify a multicast group IP address or both a multicast group IP address and a multicast source IP address to display information about a particular multicast forwarding entry.
� Field descriptions� See show ip mroute command for descriptions of all fields except the
statistics field.� StatisticsNote: The display shows statistics after the VR has added the multicast route to the multicast routing table and established the route on the appropriate line module. Statistics for interactions before the route is established on the line module are not displayed.
� Received � number of packets and bytes that the VR received for this multicast route
� Forwarded � number of packets and statistics that the VR has forwarded for this multicast route
� Rcvd on OIF � number of packets and statistics that the VR has received on the OIF for this multicast route
#show ip mroute statistics
IP Multicast Routing Table
(S, G) uptime d h:m:s[, expires d h:m:s]
RPF route: addr/mask, incoming interface
neighbor address, owner route-owner
Incoming interface list:
Interface (addr/mask), State/Owner [(RPF IIF)]
Outgoing interface list:
Interface (addr/mask), State/Owner, Uptime/Expires
(11.0.0.1, 225.1.1.1) uptime 0 00:00:24
RPF route: 11.0.0.0/8, incoming interface ATM5/1.200
neighbor 21.1.1.1, owner Netmgmt
Incoming interface list:
ATM5/1.200 (21.2.2.2/8), Accept/Pim (RPF IIF)
Outgoing interface list:
ATM5/1.300 (31.2.2.2/8), Forward/Pim, 0 00:00:24/never
Statistics:
Received : 19 pkts, 9880 bytes
Forwarded : 19 pkts, 9880 bytes
Rcvd on OIF: 0 pkts
Counts: 1 (S, G) entries
0 (*, G) entries
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show ip mroute summary� Use to display a summary of all or specified multicast routes.� Specify a multicast group IP address or both a multicast group IP address and
a multicast source IP address to display information about a particular multicast forwarding entry.
� Field descriptions � Group Address � IP address of the multicast group� Source Address � IP address of the multicast source� RPF Route � IP address and network mask of the RPF route� RPF Iif � type and identifier for the incoming interface for the RPF route� #Oifs � number of outgoing interfaces� Counts � numbers of types of (S,G) mappings
� (S,G) � number of (S,G) entries� (*,G) � number of (*,G) entries
� Example host1#show ip mroute summary
IP Multicast Routing Table
Group Address Source Address RPF route RPF Iif #Oifs
--------------- --------------- --------- ------------- ----
224.0.1.39 52.1.1.1 51.1.1.1/32 Register IIF 0
224.0.1.40 51.1.1.1 51.1.1.1/32 loopback1 1
Counts: 2 (S, G) entries
0 (*, G) entries
show ip multicast protocols� Use to display information about multicast protocols enabled on the router.� Use the brief option to display a summary of information rather than a detailed
description.� Field descriptions
� Protocol � name of the multicast protocol� Type � mode of the multicast protocol
� For DVMRP � dense� For PIM � sparse, dense, or sparse-dense� For IGMP � local
� Interfaces � registered � number of interfaces on which the protocol is configured� owned � number of interfaces that a protocol owns. If you configure only
IGMP on an interface, IGMP owns the interface. However, if you configure IGMP and either PIM or DVMRP on the same interface, PIM or DVMRP owns the interface.
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� Registered interfaces � includes the following information about interfaces on which the protocol is configured� Types and identifiers of interfaces. For details about interface types and
specifiers, see E-Series Command Reference Guide, About This Guide.� Protocols configured on the interface and the protocol that owns the
interface. If you configure only IGMP on an interface, IGMP owns the interface. However, if you configure IGMP and PIM or DVMRP on the same interface, PIM or DVMRP owns the interface.
� Count � number of multicast protocols on the VR� Example
host1:2#show ip multicast protocols
Multicast protocols:
Protocol Pim
Type: Sparse Dense
Interfaces: 2 registered, 2 owned
Registered interfaces:
atm3/1.2 (40.2.2.2/8) local Igmp owner Pim
loopback2 (52.1.1.1/32) owner Pim
Protocol Igmp
Type: Local
Interfaces: 1 registered, 0 owned
Registered interfaces:
atm3/1.2 (40.2.2.2/8) local Igmp owner Pim
Count: 2 protocols
show ip multicast protocols brief� Use to display a summary of information about multicast protocols enabled on
the router.� Field descriptions
� Protocol � name of the multicast protocol� Registered Interfaces � number of interfaces on which the protocol is
configured.� Owned Interfaces � number of interfaces that a protocol owns. If you
configure only IGMP on an interface, IGMP owns the interface. However, if you configure IGMP and either PIM or DVMRP on the same interface, PIM or DVMRP owns the interface.
� Type � mode of the multicast protocol� For DVMRP � dense� For PIM � sparse, dense, or sparse-dense� For IGMP � local
� Count � number of multicast protocols on the VR
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� Examplehost1#show ip multicast protocols brief
show ip multicast protocols brief
Protocol Registered Owned Type
Interfaces Interfaces
--------- ---------- ---------- -------------------
Pim 2 2 Sparse Dense
Igmp 1 0 Local
Count: 2 protocols
show ip multicast routing� Use to display information about the status of IP multicasting on the VR� Example
host1#show ip multicast routing
Multicast forwarding is enabled on this router
Support for Multicast Router InformationWhen you enable multicast routing on a virtual router, the router now acts as a multicast router information (mrinfo) server. This feature enables the E-series router to respond to mrinfo requests from other network hosts. Specifically, E-series virtual routers respond to DVMR ask neighbors and DVMR ask neighbors2 requests.
Each virtual router responds to mrinfo requests with a list of multicast interfaces and their IP addresses. If appropriate, the virtual router also supplies the following information for each interface:
• Interface is currently not functional (down)
• Interface is disabled, either because IP is not configured on it or because it has been disabled through the software
• Interface is the IGMP querier for this subnet
• Information about PIM neighbors
If PIM is configured on the interface, the virtual router supplies a list of the interface’s PIM neighbors and indicates which neighbors are leaf neighbors.
• Information about DVMRP and GRE tunnels
If the interface is an endpoint of a tunnel, the virtual router specifies the IP address of the endpoint of the tunnel.
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IGMPIP hosts use Internet Group Management Protocol (IGMP) to report their multicast group memberships to neighboring routers. Similarly, multicast routers, such as the E-series router, use IGMP to discover which of their hosts belong to multicast groups.
The IPv4 address scheme assigns class D addresses for IP multicasting. IGMP is the protocol that uses these addresses, which can be in the range 224.0.0.0 to 239.255.255.255. The following addresses have specific functions or are unavailable:
• 224.0.0.0 is reserved, and you cannot assign it to a group.
• 224.0.0.1 is the all-hosts address – a packet sent to this address reaches all hosts on a subnet.
• 224.0.0.2 is the all-routers address – a packet sent to this address reaches all routers on a subnet.
This implementation of IGMP complies with IGMP versions 1, 2, and 3. IGMPv3 allows for source-specific join and leave messages and is backward compatible with IGMPv1, IGMPv2, and IGMPv3.
IGMP OperationIGMPv2 mode interfaces exchange the following types of messages between routers and hosts:
• Group membership queries
• Group membership reports
• Leave group membership messages
IGMPv3 mode interfaces exchange the following types of messages with IGMPv3 hosts:
• Group membership queries
• IGMPv3 group membership reports
Group Membership QueriesA multicast router can be a querier or a nonquerier. There is only one querier on a network at any time. Multicast routers monitor queries from other multicast routers to determine the status of the querier. If the querier hears a query from a router with a lower IP address, it relinquishes its role to that router.
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IGMPv1 and IGMPv3 mode interfaces send two types of group membership queries to hosts on the network:
• General queries to the all-hosts group address (224.0.0.1)
• Specific queries to the appropriate multicast group address
IGMPv3 mode interfaces send the following type of queries to IGMPv3 hosts:
• Group-specific and source-specific queries
The purpose of a membership group query is to discover the multicast groups to which a host belongs.
IGMPv2 and IGMPv3 group membership queries have a Max Response Time field. This response time is the maximum that a host can take to reply to a query.
Group Membership ReportsWhen a host receives a group membership query, it identifies the groups associated with the query and determines to which groups it belongs. The host then sets a timer, with a value less than the Max Response Time field in the query, for each group to which it belongs.
When the timer expires, the host multicasts a group membership report to the group address. When a multicast router receives a report, it adds the group to the membership list for the network and sets a timer to the group membership interval. If this timer expires before the router receives another group membership report, the router determines that the group has no members left on the network.
If the router does not receive any reports for a specific multicast group within the maximum response time, it assumes that the group has no members on the network. The router does not forward subsequent multicasts for that group to the network.
IGMPv3 supports an extended report format that allows you to report multiple groups and source lists in a single report.
Leave Group Membership MessagesWhen a host leaves a group, it sends a leave group membership message to multicast routers on the network. A host generally addresses leave group membership messages to the all-routers group address, 224.0.0.2.
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Configuring Static and Dynamic IGMP InterfacesThe router supports static and dynamic IGMP interfaces. Unlike static interfaces, dynamic interfaces are not restored when you reboot the router. For some protocols, dynamic layers can build on static layers in an interface; however, in a dynamic IGMP interface, all the layers are dynamic. See Figure 5-2 for examples of static and dynamic IGMP interfaces.
Figure 5-2 Static and dynamic IGMP interfaces
Static IGMP interfaces are configured with software such as the CLI or an SNMP application; dynamic IGMP interfaces are configured with a profile. A profile comprises a set of attributes for an interface; a profile for dynamic IGMP interfaces contains attributes for configuring all the layers in the interface.
You define a profile using the same CLI commands that you use to configure a static IGMP interface; however, the mode in which you use the commands differs. Use the commands in Interface Configuration mode to configure a static IGMP interface and in Profile Configuration mode to define a profile.
When you have defined a profile, you can apply it to an interface or a group of interfaces. Profiles provide an efficient method of creating and managing large numbers of dynamic interfaces. For detailed information about creating and assigning profiles, see E-Series Link Layer Configuration Guide, Chapter 13, Configuring Dynamic Interfaces. When you create a profile for dynamic IGMP interfaces, specify attributes for configuring all layers in the interface.
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You use the following IGMP commands to configure a static IGMP interface. You also use these commands to define the attributes for the IGMP layer when you create a profile for dynamic IGMP interfaces.
• ip igmp
• ip igmp group limit
• ip igmp immediate-leave
• ip igmp last-member-query-interval
• ip igmp promiscuous
• ip igmp querier
• ip igmp querier-timeout
• ip igmp query-interval
• ip igmp query-max-response-time
• ip igmp robustness
• ip igmp static-include
• ip igmp static-exclude
• ip igmp static-group
• ip igmp version
The following sections describe the tasks associated with these commands.
Enabling IGMP on an InterfaceYou must start IGMP on each interface that you want to use the protocol. You can configure IGMP and either PIM or DVMRP on the same interface. If you configure only IGMP on an interface, the router considers that IGMP “owns” that interface. If you configure IGMP and either PIM or DVMRP on an interface, the router considers that PIM or DVMRP owns the interface.
For networks that use only IGMPv1, you can configure an interface to operate in IGMPv1 mode. However, IGMPv2 and IGMPv3 interfaces will support IGMPv1 hosts. In an IGMPv1 network, you must configure one interface to act as a querier. In an IGMPv2 or IGMPv3 network, the querier is the router with the lowest IP address.
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To start IGMP, complete the following steps:
1 Enable IGMP on the interface (IGMPv2 is the default version).
2 (IGMPv1 or IGMPv3) Specify the IGMP version for the interface.
3 (IGMPv1 only) Specify that the interface will act as the querier for the network.
ip igmp� Use to enable IGMP on an interface and sets the IGMP version to IGMPv2.
Use the ip igmp version command to specify a different IGMP version. � Example
host1:boston(config-if)#ip igmp
� Use the no version to disable IGMP on an interface.
ip igmp querier� Use to specify that this IGMPv1 interface will act as a querier.
Note: This command is valid only for interfaces on which you configured IGMPv1.
� Examplehost1:boston(config-if)#ip igmp querier
� Use the no version to restore the default situation, in which the interface does not act as a querier.
ip igmp version � Use to set the IGMP version (1, 2, or 3) for the interface.� Example
host1:boston(config-if)#ip igmp version 1
� Use the no version to set the version to the default, IGMPv2.
Configuring IGMP Settings for an InterfaceWhen you start IGMP on an interface, it operates with the default settings. You can, however, modify:
• The method that the router uses to remove hosts from multicast groups (IGMPv2 and IGMPv3 interfaces only)
• The time interval at which the querier multicasts group membership queries
• The time that a querier waits before sending a new query to hosts from which it receives leave group membership messages
• The time that a new querier waits before sending query messages after it assumes responsibility from another querier
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• The time that a host can take to reply to a query (maximum response time)
• The number of times that the router sends each IGMP messages from this interface
ip igmp immediate-leave� Use to specify that when the router receives a leave group membership
message from a host associated with this interface, the router will immediately remove that host from the multicast group.Caution: Issue this command only on IGMPv2 and IGMPv3 interfaces to which one IGMP host is connected. If there is more than one IGMP host connected to a LAN through the same interface, and one host sends a leave group message, the router will remove all hosts on the interface from the multicast group. The router will lose contact with the hosts that should remain in the multicast group until they send join requests in response to the router�s next general group membership query.
� Examplehost1:boston(config-if)#ip igmp immediate-leave
� Use the no version to restore the default situation, in which the router removes a host from a multicast group if that host does not return a group membership report within a certain length of time of receiving a group membership query from the router.
ip igmp last-member-query-interval� Use to specify the last-member-query-interval value, in tenths of a second.
When the router receives an IGMPv2 leave message or an IGMPv3 state change report, it sends out a query and expects a response within the time specified by this value.
� Using a lower value allows members to leave groups more quickly.� Example
host1:boston(config-if)#ip igmp last-member-query-interval 90
� Use the no version to restore the default, 10-tenths of a second (1 second).
ip igmp querier-timeout� Use to set the time in seconds that the interface waits before sending query
messages after it becomes the querier.� Example
host1:boston(config-if)#ip igmp querier-timeout 200
� Use the no version to set the time to the default, twice the query interval.
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ip igmp query-interval� Use to specify how often the interface sends group membership queries.� Example
host1:boston(config-if)#ip igmp query-interval 100
� Use the no version to set the polling interval to the default, 125 seconds.
ip igmp query-max-response-time� Use to specify the period in tenths of a second during which the host is
expected to respond to a group membership query.� IGMPv2 and IGMPv3 include this value in IGMP query messages sent out on
the interface.� You cannot set this value on interfaces running IGMPv1.� Using a lower value allows members to join and leave groups more quickly.� Example
host1:boston(config-if)#ip igmp query-max-response-time 120
� Use the no version to restore the default, 10-tenths of a second (1 second).
ip igmp robustness� Use to specify the number of times that the router sends each IGMP message
from this interface.� Use a higher value to ensure high reliability from IGMP.� Specify a number in the range 1�4.� Example
host1:boston(config-if)#ip igmp robustness 2
� Use the no version to restore the default, 3.
Assigning a Multicast Group to an InterfaceYou can assign an interface to send and receive all traffic for a particular multicast group. This feature allows you to control the IGMP traffic and to test the behavior of multicast protocols in the network.
ip igmp static-group� Use to send and receive all traffic for a multicast group from a specific interface. � The interface sets no timers for this group.� Example
host1:boston(config-if)#ip igmp static-group 225.1.2.3
� Use the no version to remove the group from the interface.
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Specifying Multicast Groups You can use a standard IP access list to specify the multicast groups that a host can join.
ip igmp group limit� Use to restrict hosts on this subnet to joining only multicast groups that appear
on the specified IP access list.� Example
host1:boston(config-if)#ip igmp access-group boston-list
� Use the no version to disassociate the interface from an access list and to allow hosts on the interface to join any multicast group.
Limiting the Number of Accepted IGMP GroupsBy default, there is no limit on the number of IGMP groups that an IGMP interface can accept. However, you can manage multicast traffic on the router by restricting the number of IGMP groups accepted by:
• A specific port on an I/O module
• A specific IGMP interface
If you set limits for both a port and interfaces on that port, the router uses the lower of the two limits when determining how many IGMP groups an interface can accept. For example, if you set a limit of 10 groups for the port and 15 groups for each interface, the router allows only 10 groups to be accepted among the interfaces.
However, if you set a limit for a port and that limit is lower than the number of groups currently accepted by the interfaces on that port, the router does not disassociate the groups from the interfaces. The router enforces the new limit on the port when the number of groups associated with the interfaces falls to that limit. For example, if the interfaces on the port have accepted a total of 15 groups, and you set a limit of 10 groups on the port, the router does not disconnect any of the groups and does not allow the interfaces to accept any more groups. Over time, some groups leave the interfaces and, eventually, a maximum of ten groups remains connected.
ip igmp group limit� Use to limit the number of IGMP groups that an interface can accept.� Example:
host1:boston(config-if)#ip igmp group limit 5
� Use the no version to restore the default situation, in which there is no limit on the number of IGMP groups that an interface can accept.
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multicast group port limit� Use to limit the number of IGMP groups that a port can accept.� Specify the identifier for the port in slot/port format and the maximum number of
IGMP groups that interfaces can accept.� slot � number of the chassis slot in the range 0�6 (ERX-7xx models) and
0�13 (ERX-14xx models)� port � port number on the I/O module
� Examples:host1(config)#multicast group port 3/0 limit 5
� Use the no version to restore the default situation, in which there is no limit on the number of IGMP groups that a port can accept.
Including and Excluding TrafficIGMPv3 extends IGMPv2 functionality with the ability to include or exclude specific multicast traffic sources. That is, with IGMPv3, hosts signal (S,G) pairs that they want to include or exclude.
For hosts that cannot signal group membership dynamically, you can use the ip igmp static-include or ip igmp static-exclude command to either statically include or exclude multicast traffic (respectively).
IGMPv3 is the industry-designated standard protocol for hosts to signal channel subscriptions in Source Specific Multicast (SSM). For additional information about SSM, see PIM SSM later in this chapter.
ip igmp static-exclude� Use to statically exclude the IGMP (S,G) membership for a host that is not
capable of dynamically signalling group membership. � Example:
host1:boston(config-if)#ip igmp static-exclude 10.1.1.5 225.1.2.3
� Use the no version to remove the static designation.
ip igmp static-include� Use to statically include the IGMP (S,G) membership for a host that is not
capable of dynamically signalling group membership.� Example:
host1:boston(config-if)#ip igmp static-include 10.1.1.1 225.1.2.3
� Use the no version to remove the static designation.
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Accepting IGMP Reports from Remote SubnetsBy default, IGMP interfaces accept IGMP reports only from associated subnets. You can configure the router to accept IGMP reports from subnets that are not associated with its interfaces. The igmp promiscuous command in Router Configuration mode specifies whether or not interfaces on the router should accept IGMP reports from indirectly connected subnets. To override this global setting on a particular interface, use the ip igmp promiscuous command in Interface Configuration mode.
Example In the following example, the router is configured to accept IGMP reports from indirectly connected subnets on all interfaces. The interface on port 0 of the line module in slot 4 is then configured to accept IGMP reports only from directly connected subnets.
host1(config)#virtual-router boston
host1:boston(config)#router igmp
host1:boston(config-router)#igmp promiscuous
host1:boston(config-router)#exit
host1:boston(config)#interface serial 4/0
host1:boston(config-if)#ip igmp promiscuous off
igmp promiscuous� Use to allow all IGMP interfaces on the router to accept IGMP reports from
hosts on any subnet.� Example
host1:boston(config-router)#igmp promiscuous
� Use the no version to allow IGMP interfaces on the router to accept IGMP reports only from hosts on their associated subnets.
ip igmp promiscuous� Use to specify whether or not the interface should accept IGMP reports from
hosts on any subnet. � Use the on keyword to enable the interface to accept IGMP reports from
hosts on any subnet.� Use the off keyword to allow the interface to accept IGMP reports only from
hosts on subnets associated with this interface� Example
host1:boston(config-if)#ip igmp promiscuous on
� Use the no version mode to configure an IGMP interface to use the Router Configuration mode setting to determine the subnets from which it can accept IGMP reports.
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Disabling and Removing IGMP You can disable and reenable IGMP on the VR. You can also remove IGMP from the VR and recreate it on the VR.
igmp disable� Use to disable IGMP on a VR.� Example
host1(config)#virtual-router boston
host1:boston(config)#router igmp
host1:boston(config-router)#igmp disable
� Use the no version to enable IGMP on a VR.
router igmp� Use to create and enable IGMP on a VR or to access IGMP Router
Configuration mode.� Example
host1(config)#virtual-router boston
host1:boston(config)#router igmp
� Use the no version to delete IGMP and IGMP proxy from the VR.
Monitoring IGMP You can establish a reference point for IGMP statistics by setting the statistics counters to zero.
To display IGMP parameters, use the show commands described in this section.
baseline ip igmp� Use to set the counters for IGMP statistics to zero.� Example
(host1)#baseline ip igmp
� There is no no version.
show ip igmp� Use to display IGMP information for a VR.� Field descriptions
� Administrative state � status of IGMP in the software: enabled or disabled� Operational state � status of IGMP on the VR: enabled or disabled� Total interfaces � number of interfaces on which you started IGMP� Enabled � number of interfaces on which IGMP is enabled� Disabled � number of interfaces on which IGMP is disabled
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� Learnt groups � number of multicast groups that the VR has discovered� IGMP Statistics Rcvd � statistics for IGMP messages received
� Total � number of IGMP messages received� Checksum errors � number of IGMP messages received with checksum
errors� Unknown types � number of messages received that are not group
membership queries, group membership reports, or leave group membership messages
� Queries � number of group member queries� Reports � number of group membership reports� Leaves � number of leave group membership messages
� IGMP Statistics Sent � number of group member queries sent
host1:boston#show ip igmp
Routing Process IGMP, Administrative state enabled, Operational state enabled
2 total interfaces, 2 enabled, 0 disabled
2 learnt groups
IGMP Statistics:
Rvcd: 1 total, 0 checksum errors, 0 unknown types
0 queries, 1 reports, 0 leaves
Sent: 11 total
show ip igmp groups� Use to display statically joined and directly connected groups learned through
IGMP.� Field descriptions
� Grp Address � address of the multicast group� Interface � interface that discovered the multicast group� State � IGMP version on the interface� ExpTim � time, in seconds, at which the router decides there are no more
members of this group� v1HTim � time at which the router decides there are no more IGMPv1
members of a group. If this value is 0, the interface has received no IGMPv1 reports for the group.
� Examplehost1:boston#show ip igmp groups
Grp Address Interface State ExpTim v1HTim
----------- --------------- ---------- ------ ------
225.1.1.1 fastEthernet0/0 Version2 never 0
232.1.1.1 fastEthernet0/0 Version2 359 0
Count: 2 Groups
(Note: 225.1.1.1 is a “static group”)
IGMPE-Series Routers
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show ip igmp interface� Use to display IGMP information for interfaces on which you enabled IGMP.� Specify the brief keyword to see a summary of the information.� Specify the count keyword to see the number of IGMP interfaces.� Specify the group address keyword to see information for interfaces that
belong to that group.� Field descriptions
� Interface � type of interface and interface specifier. For details about interface types and specifiers, see E-Series Command Reference Guide, About This Guide.
� Address � IP address of the interface� Administrative state � status of the interface in the software: enabled or
disabled� Operational state � physical status of the interface: enabled or disabled� Version � IGMP version� State � function of the interface: querier or nonquerier� Query Interval � time interval at which this interface sends query messages� Other querier present interval � time that the interface waits before declaring
itself as the querier� Maximum response time � time interval during which this interface expects a
host to respond� Last member query interval � time that this interface waits before sending a
new query to a host that sends a group leave message� Robustness � number of times this interface sends IGMP messages � Information about whether interface accepts IGMP reports from hosts on any
subnet� Interface defaults to global promiscuous mode � interface uses the setting
of the igmp promiscuous command to determine whether it accepts IGMP reports from hosts on any subnet
� Information about standard IP access lists configured with the ip igmp group limit command� � access list specified � No inbound access group � no access list specified
� Immediate Leave � setting of the ip igmp immediate-leave command: enabled or disabled
� Max-Group limit � number of IGMP groups that the interface can accept, as configured with the ip igmp group limit command
� Group Count � number of IGMP groups that the interface has accepted� Interface statistics Rcvd � information about IGMP messages received on
this interface� Reports � number of group membership reports received� Leaves � number of group leave messages received� Wrong Version Queries � number of group membership queries received
from devices running a different version of IGMP
CHAPTER 5Configuring IP Multicasting
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� Interface statistics Sent � number of IGMP messages this interface has sent� Interface statistics Groups learned � number of groups this interface has
discovered� Count � total number of IGMP interfaces
� Example host1:boston#show ip igmp interface
Interface ATM2/1.15 address 15.0.0.2/255.255.255.0
Administrative state enabled, Operational state enabled
Interface parameters:
Version 2
State Querier
Query Interval 125 secs, 53 secs before the next query
Other querier present interval 250 secs
Maximum response time 100 (in 10ths of a second)
Last member query interval 10 (in 10ths of a second)
Robustness 3
Interface defaults to global promiscuous mode
No inbound access group
Immediate Leave: disabled
Max-Group limit: No Limit
Group Count: 1
Interface statistics:
Rcvd: 0 reports, 0 leaves, 0 wrong version queries
Sent: 1 queries
Groups learned: 1
Counts: 0 down, 0 init state, 1 querier, 0 non-querier, 1 Total
show ip igmp interface brief� Use to display a summary of IGMP information for interfaces on which you
enabled IGMP.� Field descriptions
� Interface � type of interface and interface specifier. For details about interface types and specifiers, see E-Series Command Reference Guide, About This Guide.
� Intf Address � IP address of the interface� Ver � IGMP version� State � function of the interface: querier or nonquerier� Querier � IP address of the querier on the network to which this interface
connects� QTime � time interval at which this interface sends query messages� QPTime � time that the interface waits before declaring itself as the querier
IGMP ProxyE-Series Routers
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� Example host1:boston#show ip igmp interface brief
Interface Intf Address Ver State Querier QTime QPTime
-------------- ---------- --- ------ ------------- ----- ---
fastEthernet0/0 192.168.1.250/24 2 Querier 192.168.1.250 28 0
atm3/0.2 21.1.1.1/8 2 Querier 21.1.1.1 26 0
Count: 2 interfaces
show multicast group limit� Use to display the number of IGMP groups that ports have accepted, and if
configured, the maximum number of groups that ports can accept. � Only ports that have accepted IGMP groups and ports for which you have
configured a limit for the number of IGMP groups appear in this display.� Field descriptions
� Port � identifier of the port in slot/port format� slot � number of the chassis slot in the range 0�6 (ERX-7xx models) and
0�13 (ERX-14xx models)� port � port number on the I/O module
� limit � maximum number of IGMP groups that the port can accept. A value of -1 indicates that no limit has been specified.
� count � actual number of IGMP groups the port has accepted� Example:
host1:boston#show multicast group limit
Port limit count
--------- ----- -----
2/0 5 0
2/1 -1 1
IGMP ProxyIGMP proxy enables the router to issue IGMP host messages on behalf of hosts that the router discovered through standard IGMP interfaces. The router acts as a proxy for its hosts. The E-series router supports IGMP proxy versions 2 and 3.
OverviewFigure 5-3 shows a router in an IGMP proxy configuration. You enable IGMP proxy on one interface, which connects to a router closer to the root of the tree. This interface is the upstream interface. The router on the upstream interface should be running IGMP.
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You enable IGMP on the interfaces that connect the router to its hosts that are farther away from the root of the tree. These interfaces are known as downstream interfaces.
Figure 5-3 Upstream and downstream interfaces
As described in IGMP Operation, earlier in this chapter, hosts interact with the router through the exchange of IGMP messages. Similarly, when you configure IGMP proxy, the router interacts with the router on its upstream interface through the exchange of IGMP messages. However, when acting as the proxy, the router performs the host portion of the IGMP task on the upstream interface as follows:
• When queried, sends group membership reports to the group.
• When one of its hosts joins a multicast address group to which none of its other hosts belong, sends unsolicited group membership reports to that group.
• When the last of its hosts in a particular multicast group leaves the group, sends an unsolicited leave group membership report to the all-routers group (244.0.0.2).
Configuring IGMP ProxyTo configure a downstream interface, enable IGMP on that interface. To configure IGMP proxy on the router, complete the following tasks:
1 Enable IP multicasting.
2 Identify the interface that you want to act as the upstream interface.
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IGMP ProxyE-Series Routers
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3 Enable IGMP proxy on that interface.
4 (Optional) Specify how often the router should send unsolicited reports to routers on the upstream interface.
5 (Optional) Specify how long the router should assume that there is an IGMPv1 querier router on the subnet after the router receives an IGMP v1 query on this interface.
ip igmp-proxy� Use to enable IGMP proxy on an interface. � You can specify either IGMP proxy version 2 or 3. The default is version 2.
Note: You can enable only one upstream interface.
� The interface for which you enable IGMP proxy is the upstream interface.� Example
host1(config)#ip multicast-routing
host1(config-if)#ip igmp-proxy
� Use the no version to disable IGMP proxy on an interface.
ip igmp-proxy unsolicited-report-interval� Use to specify how often the upstream interface should transmit unsolicited
reports.Note: Issue this command only on the upstream interface. Otherwise, this command will have no effect.
� Examplehost1(config-if)#ip igmp-proxy unsolicited-report-interval 600
� Use the no version to transmit unsolicited reports using the default value, 400 seconds.
ip igmp-proxy V1-router-present-time� Use to specify how long the router assumes that there is an IGMPv1 querier
router on the subnet after the router receives an IGMP V1 query on this interface.Note: Issue this command only on the upstream interface. Otherwise, this command will have no effect.
� Examplehost1(config-if)#ip igmp-proxy V1-router-present-time 600
� Use the no version to set the time to the default value, 10 seconds.
CHAPTER 5Configuring IP Multicasting
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Setting the IGMP Proxy BaselineYou can set the counters for the numbers of queries received and reports sent on the upstream interface to zero. This feature allows you to establish a reference point for IGMP proxy statistics.
baseline ip igmp-proxy interface� Use to set the counters for the numbers of queries received and reports sent on
the upstream interface to zero.Note: Issue this command only on the upstream interface. Otherwise, this command will have no effect.
� Example (host1)#baseline ip igmp-proxy interface
� There is no no version.
Monitoring IGMP Proxy To display IGMP proxy parameters, use the following show commands.
show ip igmp-proxy� Use to display IGMP proxy parameters for a VR.� Field descriptions
� Routing Process � IGMP proxy protocol� Administrative state � state of IGMP proxy in the software� Operational state � operational state of IGMP proxy: enabled or disabled� Total interfaces � number of IGMP proxy interfaces on the VR; currently only
one upstream interface per VR� State � operational state of the IGMP proxy interfaces: up or down� Multicast group � number of multicast groups associated with IGMP proxy
interfaces� Example
host1#show ip igmp-proxy
Routing Process IGMP Proxy, Administrative state enabled, Operational state enabled
total 1 upstream interface, state enabled
6 multicast group
show ip igmp-proxy groups� Use to display information about multicast groups that IGMP proxy reported.� Field descriptions
� Grp Address � address of the multicast group� Interface � type and identifier of the upstream interface associated with the
multicast group
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� Member State� Idle � interface is going to send a group membership report to respond to
a group membership query for this group� Delay � interface has responded to the latest group membership query for
this group� Count � total number of multicast groups associated with this interface
� Example 1host1#show ip igmp-proxy groups
Grp Address Interface Member State
--------------- --------------- --------------
225.1.1.1 atm3/0.2 Idle
225.1.1.2 atm3/0.2 Idle
225.1.1.3 atm3/0.2 Idle
225.1.1.4 atm3/0.2 Idle
225.1.1.5 atm3/0.2 Idle
225.1.1.6 atm3/0.2 Idle
count 6
� Example 2host1#show ip igmp-proxy group 225.1.1.1
Grp Address Interface Member State
--------------- --------------- --------------
225.1.1.1 atm3/0.2 Idle
� Example 3host1#show ip igmp-proxy group count
Count: 6 groups
show ip igmp-proxy interface� Use to display information about the interface on which you configured IGMP
proxy.� To view information about a particular interface, enter an interface type and
specifier, such as atm 3/0. For details about interface types and specifiers, see E-Series Command Reference Guide, About This Guide.
� Specify the brief option to display a summary rather than a detailed description.
� Field descriptions� Interface � type of upstream interface. For details about interface types, see
E-Series Command Reference Guide, About This Guide.� Address � address of upstream interface� Administrative state � state of upstream interface in the software: enabled or
disabled� Operational state � physical state of upstream interface: enabled or disabled� Version � IGMP version on this interface
CHAPTER 5Configuring IP Multicasting
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� State � presence of IGMPv1 routers on the same subnet as this upstream interface
� Unsolicited report interval � time interval at which this upstream interface sends unsolicited group membership report
� Version 1 router present timeout � how long the upstream interface assumes there is an IGMPv1 router on the subnet after that interface receives an IGMPv1 group membership query
� multicast group � number of multicast groups associated with this upstream interface
� Interface statistics Rcvd � statistics for messages received on this interface� v1 queries � number of IGMPv1 group membership queries received� v2 queries � number of IGMPv2 group membership queries received� v1 report � number of IGMPv1 group membership reports received� v2 report � number of IGMPv1 group membership reports received
� Interface statistics Sent � statistics for messages sent from this interface� v1 reports � number of IGMPv1 leave group reports sent � v2 reports � number of IGMPv2 leave group reports sent� leaves � number of leave group membership messages sent
� Examplehost1#show ip igmp-proxy interface atm 3/0.2
Interface atm3/0.2 address 21.1.1.1/255.0.0.0
Administrative state enabled, Operational state enabled
Interface parameters:
Version 2
State No v1 Router Present
Unsolicited report interval 10 secs
Version 1 router present timeout 400 secs
0 multicast group
Interface statistics:
Rcvd: 0 v1 query, 6 v2 queries
0 v1 report, 0 v2 report
Sent: 0 v1 report, 48 v2 reports, 0 leave
PIMProtocol Independent Multicast (PIM) is the protocol that allows multicast routers to identify other multicast routers that should receive packets. This implementation of PIM supports PIM dense mode (PIM DM), PIM sparse mode (PIM SM), PIM sparse-dense mode (PIM S-DM), and PIM Source-Specific Multicast (PIM SSM).
Figure 5-4 represents how PIM builds an (S,G) entry in an SRT. When multiple routers are connected to a multiaccess network, one router must assume the role of the designated router (DR). The DR receives data from
PIME-Series Routers
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the source on interface 1/0 and multicasts the data to its downstream neighbors on interfaces 1/1, 2/0, and 2/1. In the DR routing table, the entry for this operation lists the source as the IP address of the source and the group as the IP address of the multicast group.
Neighbors exchange hello messages periodically to determine the DR. The router with the highest network layer address assumes the role of the DR. If the DR subsequently receives a hello message from a neighbor with a higher network layer address, that neighbor becomes the DR.
Figure 5-4 Source-rooted tree
PIM DMPIM DM uses a reverse path multicast, f lood and prune mechanism. The protocol was developed for situations that meet one or more of the following criteria:
• Sources and receivers are close together, and there are many more receivers than senders.
• There is a constant stream of multicast data.
• There is a lot of multicast data.
Dense-mode routing protocols use SRT algorithms. An SRT algorithm establishes a tree that connects each source in a multicast group to the members of the group. All traffic for the multicast group passes along this tree.
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Figure 5-5 illustrates how PIM DM works. When a source sends a multicast packet to a first-hop router, the first-hop router multicasts that packet to its neighbors. Those neighbors in turn forward the packet to their neighbors and their hosts that belong to the multicast group. If a neighbor has no hosts that belong to the multicast group and has no other PIM neighbors, it returns a prune message to the first-hop router. The first-hop router does not multicast subsequent packets for that group to neighbors who respond with prune messages.
Figure 5-5 PIM DM operation
Overriding PrunesIf a host on a previously pruned branch wants to join a multicast group, it sends an IGMP message to its first-hop router. The first-hop router then sends a graft message upstream.
PIM routers send join messages on multiaccess interfaces to override prune messages. For example, if a PIM router sent a prune message to indicate that it had no hosts for a multicast group, and one of its hosts subsequently wants to send a packet to that group, the router sends a join message to the first-hop router.
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Preventing DuplicationIf there are parallel paths to a source, duplicate packets can travel through different routers downstream to the network. If a forwarding router receives a multicast packet on its outgoing interface, the router knows that the packet is a duplicate and notifies the upstream routers. See Figure 5-6.
Figure 5-6 Detecting duplication
The upstream routers responsible for the duplication send assert messages to determine which router should be the forwarder. Downstream routers listen to the assert messages to discover which router becomes the forwarder.
PIM SMThis implementation of PIM SM supports the following features:
• Rendezvous point (RP) routers
• DRs and DR election
• Join/prune messages, hello messages, assert messages, register messages
• Switching from a shared tree to an SPT
• (*,*,RP) support for interoperation with dense-mode protocols
• RPF checks of multicast entries when unicast routing configuration changes
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CHAPTER 5Configuring IP Multicasting
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• Timers for tree maintenance
• Border, null, RPT, SPT, and wildcard f lags
• Remote neighbors
PIM SM was developed for situations that meet one or more of the following criteria:
• The multicast group contains few receivers.
• Multicast traffic is infrequent.
• WANs separate sources and receivers.
Sparse-mode routing protocols use shared trees. In a shared tree, sources forward multicast datagrams to a directly connected router, the DR. The DR encapsulates the datagram and unicasts it to an assigned RP router, which then forwards the datagram to members of multicast groups.
Figure 5-7 PIM SM operation
In PIM SM, an RP announces a source and establishes paths from the source to members of a multicast group before multicasting any datagrams. RPs transmit join messages to become part of the shared tree that allows distribution of packets to the multicast group.
However, when a source starts multicasting datagrams, PIM SM can switch to an SRT—known in PIM SM as an SPT—to improve the network’s efficiency. Although shared trees minimize the traffic in the
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PIME-Series Routers
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network and the costs associated with unnecessary transmission of data, the routes in a shared tree may be longer than those in an SPT. See Figure 5-8.
The DRs on the network determine when the source switches from a shared tree to an SPT. A DR switches to the SPT when it receives a certain number of packets, which you can configure using the ip pim-spt threshold command. This command has a default value of zero, which causes a DR to switch to an SPT immediately after it receives it first multicast data packet.
When all DRs associated with a specific RP router have switched to the SPT, the RP router sends a join/prune message toward the multicast source. When the multicast source receives this message, it starts sending multicast data through the SPT.
Figure 5-8 Shared tree versus SPT
Joining GroupsA host’s DR sends join messages to the RP when that host wants to join a group. When a host wants to leave a group, it communicates with its DR through IGMP. When the DR no longer has any hosts that belong to a particular group, it sends a prune message to the RP.
Remote NeighborsYou can create remote neighbors in PIM SM. This feature enables an E-series router to establish neighbor adjacencies with other E-series
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routers through a pair of unidirectional interfaces, such as the endpoints of an MPLS tunnel. Multicasting over BGP/MPLS VPNs is achieved via PIM SM remote neighbors. Figure 5-9 shows an example in which two E-series routers, called boston and chicago, are remote neighbors connected by two unidirectional MPLS tunnels.
Figure 5-9 PIM remote neighbors connected by MPLS tunnel
On each E-series router, you must specify the location of the interface that PIM uses as the source address for the connection to the remote neighbor. You must also specify that the other router is a remote neighbor, and identify the IP address of the other router that PIM uses as the source address for the connection from the remote neighbor.
Bear the following issues in mind when configuring remote neighbors:
• A route to the source RP must exist in the unicast view of the routing table to ensure that the PIM router can detect the remote neighbor. For information about configuring routes in the unicast routing tables, see the chapters on unicast routing protocols in this book and E-Series Routing Protocols Configuration Guide, Vol. 2, Chapter 1, Configuring BGP Routing.
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• A route to the source must be present in the multicast view of the IP routing table to ensure that the PIM router can perform an RPF check for that source in a VPN.
To add a route to the multicast IP routing table across a VPN, you can:
> Configure a multicast static route by issuing the ip rpf-route command (see Multicast Packet Forwarding, earlier in this chapter).
> Configure BGP to add its unicast routes to the multicast IP routing table by issuing the ip route-type both command. (see E-Series Routing Protocols Configuration Guide, Vol. 2, Chapter 1, Configuring BGP Routing)
> Configure OSPF or RIP to learn the route through the protocol’s remote neighbor features (see Chapter 8, Configuring RIP and Chapter 9, Configuring OSPF).
If a route is more specific than the route used to reach the remote neighbor originally, OSPF and RIP do not insert that route in the unicast and multicast views of the IP routing table. This feature prevents OSPF and RIP from masking the original route. If you require PIM to use such a route to reach a remote neighbor, add that route to the multicast view of the IP routing table using one of the methods described in the preceding paragraphs.
TimersPIM SM uses timers to maintain the networking trees. PIM SM routers poll their neighbors and hosts for various pieces of information at set intervals. If a PIM SM router does not receive information from a neighbor or host within a specific time, known as the hold time, it removes the associated information from its routing tables.
You can configure how often an interface sends hello messages (hello interval) and how often routers send RP announce messages (RP announce interval). The hold-time associated with hello messages is 3.5 times the hello interval and the holdtime associated with RP announce messages is 2.5 times the RP announce interval.
All other timers are fixed and take the default values recommended in:
RFC 2934 – Protocol Independent Multicast MIB for IPv4 (October 2000)
CHAPTER 5Configuring IP Multicasting
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PIM S-DMIn PIM S-DM, if an RP is not known for a group, the router sends data using PIM DM. However, if the router discovers an RP or you configure an RP statically, PIM SM takes over.
You can configure both PIM DM and PIM SM commands in PIM S-DM.
PIM SSMPIM SSM is an extension of the PIM protocol. Using SSM, a client can receive multicast traffic directly from the source. PIM SSM uses PIM SM functionality to create an SPT between the client and the source, but builds the SPT without using an RP.
By default, the SSM group multicast address is limited to the IP address range 232.0.0.0 to 232.255.255.255. However, you can extend SSM operations into another class D range by including the address statement at the [edit routing-options multicast ssm-groups] hierarchy level.
Advantages that an SSM-configured network has over a traditionally configured PIM SM network include the following:
• No need for shared trees or RP mapping (no RP is required)
• No need for RP-to-RP source discovery through Multicast Source Discovery Protocol (MSDP)
• Simplified administrative deployment; you need only configure PIM SM on all router interfaces and issue the necessary SSM commands (including specifying IGMPv3 on the receiver LAN)
• Support for source lists; you can use source lists, supported in IGMPv3, where only specified sources send traffic to the SSM group.
In a PIM SSM-configured network, the E-series router subscribes to an SSM channel (by means of IGMP version 3), announcing a desire to join group G and source S. The directly connected PIM SM router, the designated router (DR) of the receiver, sends an (S,G) join message to its RPF neighbor for the source. For PIM SSM, the RP is not contacted in this process by the receiver (as happens in normal PIM SM operations).
Enabling and Disabling PIM on a VRBy default, PIM is disabled. To enable PIM on a VR:
1 Enable multicast routing.
2 Create a VR, or access the VR context.
PIME-Series Routers
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3 Create and enable PIM processing.
host1(config)#virtual-router boston
host1:boston(config)#router pim
To disable PIM processing on a router, use the pim disable command.
pim disable� Use to disable PIM processing. By default, PIM processing is enabled.� Example
host1:boston(config-router)#pim disable
� Use the no version to reenable PIM processing.
router pim� Use to create and enable PIM processing on a VR or to access Router
Configuration mode.� Example
host1:boston(config)#router pim
� Use the no version to remove PIM from the VR.
Enabling PIM on an InterfaceYou can enable PIM on an interface in one of the allowed modes and specify how often the interface should send hello messages to neighbors.
You can configure PIM and IGMP on the same interface. If you configure IGMP and PIM on an interface, the router considers that PIM owns the interface.
Note: You cannot configure DVMRP and PIM on the same interface.
ip pim� Use to enable PIM on an interface.� Example
host1(config-if)#ip pim sparse-dense-mode
� Use the no version to disable PIM on an interface.
ip pim query-interval� Use to specify how often the router should send hello messages to neighbors.� Example
host1(config-if)#ip pim query-interval
� Use the no version to restore the default setting, 30 seconds.
CHAPTER 5Configuring IP Multicasting
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Configuring an RP Router for PIM SM and PIM S-DMWhen you use the router for PIM SM or PIM S-DM, some VRs must act as RP routers. You can configure static RP routers or configure the router to assign RP routers automatically.
To configure the router to assign RP routers automatically, you must define several VRs as RP routers and one VR as an RP mapping agent. RP routers send their announcement messages to the RP mapping agent, which assigns groups to RP routers and resolves any conflicts. The RP mapping agent notifies neighbors of the RP assigned to each group.
Configuring a Static RP RouterIf you want to control PIM more tightly, you can configure a static RP router. To do so:
1 Configure an access list that details the multicast groups that will use the static RP router.
host1(config)#access-list boston permit 224.0.0.0 15.255.255.255
2 Specify a static RP router.
host1(config)#ip pim rp-address 122.0.0.1 1
Configuring an Auto-RP Router for PIM SMTwo multicast groups, 224.0.1.39 and 224.0.1.40, are reserved for forwarding auto-RP messages through the network. When you configure an auto-RP router for PIM SM, you must assign a static RP router to these two groups. You can then specify an RP mapping agent for other multicast groups.
To configure an auto-RP router for PIM SM:
1 Configure a static RP to have priority over the auto-RP for the groups that send auto-RP multicast messages.
host1(config)#access-list 11 permit 224.0.1.39 0.0.0.0
host1(config)#access-list 11 permit 224.0.1.40 0.0.0.0
host1(config)#ip pim rp-address 192.48.1.22 76 override
2 Assign an RP mapping agent.
host1(config)#ip pim send-rp-discovery scope 23 loopback 1
3 Configure routers to send auto-RP announcement messages to the mapping agent.
host1(config)#ip pim send-rp-announce loopback 2 scope 16 group-list 1
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Configuring an Auto-RP Router for PIM S-DMIn PIM S-DM mode, you must prevent routers from advertising auto-RP messages to the multicast groups 224.0.1.39 and 224.0.1.40, which are reserved for forwarding auto-RP messages through the network. To configure an auto-RP router for PIM S-DM:
1 Assign an RP mapping agent.
host1(config)#ip pim send-rp-discovery scope 23 loopback 1
2 Configure an access list that details the multicast groups that will use the static RP router.
host1(config)access-list boston permit 224.0.0.0 15.255.255.255
3 Prevent routers from advertising auto-RP messages to the multicast groups that are reserved for forwarding auto-RP messages through the network.
host1(config)#access-list 1 deny 224.0.1.39
host1(config)#access-list 1 deny 224.0.1.40
4 Configure routers to send auto-RP announcement messages to the mapping agent.
host1(config)#ip pim send-rp-announce loopback 2 scope 23 group-list boston interval 200
ip pim rp-address� Use to specify a static PIM RP router.� Specify a standard IP access list of multicast groups to control which multicast
groups should use this RP router.� Specify the override keyword if you want this static RP router to have priority
over auto-RP routers.� Example
host1(config)#ip pim rp-address 192.48.1.22 76 override
� Use the no version to clear the filter from this interface.
ip pim send-rp-announce� Use to send auto-RP announcement messages from a router you configured
as an RP.� Specify an interface type and specifier, such as atm 3/0. For details about
interface types and specifiers, see E-Series Command Reference Guide, About This Guide. The auto-RP announcement messages will contain the IP address for the interface you specify.
� Specify the number of hops for which the announcement is valid. The default value is 64.
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� Specify an access list that details which multicast groups the RP should include in announcement messages.
� Specify a time interval in the range 1�65536 seconds to control how often the router sends announcements. The default is 60 seconds.
� Examplehost1(config)#ip pim send-rp-announce loopback 2 scope 23 group-list boston interval 200
� Use the no version to clear the specified filters from this interface.
ip pim send-rp-discovery scope� Use to configure the router as an RP mapping agent, which records
RP-to-group mappings and notifies PIM DRs about the mappings.� Specify the number of hops for which the RP discovery message is valid. The
default value is 64.� To assign an interface from which the router should send auto-RP discovery
messages, specify an interface type and specifier, such as atm 3/0. For details about interface types and specifiers, see E-Series Command Reference Guide, About This Guide.
� Examplehost1(config)#ip pim send-rp-discovery scope 23 loopback 1
� Use the no version to stop the router from acting as an RP mapping agent.
Switching to an SPT for PIM SMPIM SM initiates multicasting using a shared tree. You can configure PIM SM to switch to an SPT when a source starts sending multicast messages, or you can prevent PIM SM from switching to an SPT. Multicasting over an SPT may be more efficient than multicasting over a shared tree (see PIM SM, earlier in this chapter).
ip pim spt-threshold� Use to specify when PIM SM switches from a shared tree to an SPT.� Specify a nonzero integer or the keyword infinity to prevent PIM SM from
switching to an SPT.� Specify a value of 0 to configure PIM to switch to an SPT when a source starts
sending multicast messages.� Example
host1(config)#ip pim spt-threshold 4
� Use the no version to restore the default, 0.
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Configuring PIM SM Remote NeighborsYou must use PIM SM remote neighbors to run multicast services over BGP/MPLS VPNs.
Note: If you want to run IP multicasting over MPLS tunnels in a VRF, you must issue the ip mpls vpn-interface per-label command. IP multicasting over MPLS tunnels in a VRF is not supported in the default mode, in which MPLS allocates VPN interfaces per next hop. See E-Series Routing Protocols Configuration Guide, Vol. 2, Chapter 3, Configuring BGP/MPLS VPNs.
To configure a pair of E-series routers to act as PIM remote neighbors:
1 On one router, specify that the other router will be a remote neighbor, and identify the IP address of the interface on the other router that is used for the connection to this router.
host1(config-router):boston#remote-neighbor 10.2.23.45 sparse-mode
2 Specify the location of the local interface whose address is used as the source address for the PIM connection to a remote neighbor.
host1(config-router-rn):boston#update-source atm 2/1.108
3 (Optional) Specify how often the router should send hello messages to the remote neighbor.
host1(config-router-rn):boston#query-interval 40
4 Repeat steps 2 to 3 for the other router.
query-interval� Use to specify how often the router should send hello messages to remote
neighbors.� Example
host1(config-router-rn)#ip pim query-interval 40
� Use the no version to restore the default setting, 30 seconds.
remote-neighbor� Use to specify a remote neighbor for PIM sparse mode.� Specify the IP address of the interface on the remote neighbor that PIM uses as
the source address for the connection to this router.� Example
host1(config-router)#remote-neighbor 10.25.100.14 sparse-mode
� Use the no version to remove the remote neighbor and any attributes configured for the remote neighbor.
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update-source� Use to specify the PIM interface whose local address is used as the source
address for the PIM connection to a remote neighbor. � You can use the same source address to form neighbor adjacencies with more
than one PIM remote neighbor.� You must use the IP address of this interface when issuing the
remote-neighbor command on the remote neighbor.� Example
host1(config-router-rn)#update-source loopback 5
� Use the no version to delete the source address from the connection to the remote neighbor.
Configuration ExampleThis example uses the configuration shown in Figure 5-9. Two E-series routers called router boston and router chicago are running PIM and are connected by MPLS tunnels. To configure the routers as PIM remote neighbors:
1 Specify that router chicago will be a remote neighbor of router boston, and identify the IP address on router chicago that will transmit datagrams to router boston.
boston(config-router)#remote-neighbor 10.2.23.45 sparse-mode
2 Specify the location of the interface that will transmit datagrams from router boston to router chicago.
boston(config-router-rn)#update-source atm 2/1.108
3 Specify that router boston will send hello messages to router chicago every 40 seconds.
boston(config-if)#ip pim query-interval 40
4 Specify that router boston will be a remote neighbor of router chicago, and identify the IP address on router boston that will transmit datagrams to router chicago.
chicago(config-router)#remote-neighbor 172.16.78.3 sparse-mode
5 Specify the location of the interface that will transmit datagrams from router chicago to router boston.
chicago(config-router-rn)#update-source atm 2/1.95
6 Specify that router chicago will send hello messages to router boston every 40 seconds.
chicago(config-if)#ip pim query-interval 40
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Configuring PIM SSM To configure PIM SSM, you enable PIM SSM on the router and define the SSM range of IP multicast addresses.
To use PIM SSM, IGMPv3 must be configured on CPE-facing interfaces to receivers, and PIM SM must be configured on CPE-facing interfaces to sources and on core-facing interfaces. After configuring SSM, you can use the show ip pim sparse-mode sg-state command to display SSM group membership information.
To configure PIM SSM:
1 Enable PIM SSM on the E-series router, and specify the access list that defines the SSM address range.
host1(config)#ip pim ssm range 15
2 Enable PIM SM on the CPE-facing interface.
3 Enable IGMPv3 on the core-facing interface.
ip pim ssm � Use to enable PIM SSM and define the SSM range of IP multicast addresses.
� Example
host1(config)#access-list 15 permit 212.100.13.85
host1(config)#ip pim ssm range 15
� Use the no version to disable SSM.
Removing PIMTo remove PIM from a VR, use the no router pim command.
router pim� Use to create and enable PIM processing on a VR or to access Router
Configuration mode.� Example
host1:boston(config)#router pim
� Use the no version to remove PIM from the VR.
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Resetting PIM Counters and MappingsYou can use the clear ip pim commands to reset PIM counters and mappings.
clear ip pim auto-rp� Use to clear the group-to-RP router mappings the router learned through
auto-RP.� Specify the IP address of an RP to clear the group-to-RP mappings for a
particular RP. If you do not specify an IP address, the router clears the group-to-RP mappings on all RP routers learned through auto-RP.
� Examplehost1(config)#clear ip pim auto-rp 192.34.56.7
� There is no no version.
clear ip pim interface count� Use to clear the counters for multicast packet statistics on all interfaces or a
specified interface.� Specify an interface type and identifier, such as atm 3/0 to clear the counters on
that interface. For details about interface types and specifiers, see E-Series Command Reference Guide, About This Guide.
� If you do not specify an interface, the router clears the counters on all interfaces.
� Examplehost1(config)#clear ip pim interface atm 3/0.5 count
� There is no no version.
clear ip pim remote-neighbor count� Use to clear the counters for remote neighbor statistics on all interfaces or the
specified interface.� Specify the IP address of an interface to clear the counters for that interface.� If you do not specify an interface, the router clears the counters on all
interfaces.� Example
host1(config)#clear ip pim remote-neighbor 10.2.5.8 count
� There is no no version.
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Monitoring PIM You can display information about PIM events and parameters.
Monitoring PIM EventsYou can use the debug PIM commands to view information about PIM events.
debug ip pim� Use to show information on the selected event.� To control the type of events displayed, specify a severity level.� To control how much information to display, specify a verbosity level.� Example
host1#debug ip pim events severity 1 verbosity low
� Use the no version to disable the display.
undebug ip pim� Use to turn off the display of information previously enabled with the debug ip
pim command.host1#undebug ip pim events
� There is no no version.
Monitoring PIM SettingsYou can use the show ip pim commands to display information about PIM settings.
show ip pim auto-rp� Use to display information about RP routers and the RP mapping agent in a
PIM SM environment.� Field descriptions
� Configured with ttl � number of hops for which the RP discovery message is valid
� Using interface addr � IP address of the interface from which the router sends RP discovery messages
� Interval � time interval at which the router sends RP discovery messages� PIM auto-RP candidate RP mapping(s) � routers that the RP mapping agent
is evaluating to determine an RP router for this interface
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� Example 1host1:1#show ip pim auto-rp
This PIM router is an Auto RP mapping agent.
Configured with ttl 64
[ Using interface addr 121.0.0.1, interval 60 ].
PIM AutoRP candidate RP mapping(s)
� Example 2host1:1#show ip pim auto-rp
This PIM router is _not_ an Auto RP mapping agent.
PIM AutoRP candidate RP mapping(s)
Candidate RP 122.0.0.1
Group(s) 224.0.0.0/4, AutoRP, ttl 64, interval 60, from access List 1
Candidate RP 122.0.0.1
Group(s) 224.0.1.39/32 (negative), AutoRP, ttl 64, interval 60, from access List 1
Candidate RP 122.0.0.1
Group(s) 224.0.1.40/32 (negative), AutoRP, ttl 64, interval 60, from access List 1
show ip pim dense-mode sg-state� Use to display information for each (Source, Group) entry for PIM DM.� Field descriptions
� (Source, Group) pair � IP addresses of multicast source and group� EntryExpires � time until the (S,G) pair entry expires� RPF Route � reverse-path forwarding route� IIF � IP address of incoming interface� UpNbr � IP address of upstream neighbor� Pruned Oifs � outgoing interfaces that have been pruned
� Address � IP address of outgoing interface� IfId � index of the interface� Pruned due to � reason for prune: assert or explicit prune� Pruned time remaining � time in seconds until the prune expires
� Examplehost1:8#show ip pim dense-mode sg-state
PIM DM route table and pruned oif information
<122.0.0.1, 224.0.1.39> EntryExpires: 99
RPF Route: 122.0.0.0/255.0.0.0 IIF: 107.0.8.4 UpNbr: 107.0.4.8
Pruned Oifs:
Address: 108.0.8.5 IfId: 95
Pruned due to assert
Pruned time remaining 129
<130.0.0.2, 224.0.1.39> EntryExpires: 100
RPF Route: 130.0.0.0/255.0.0.0 IIF: 107.0.8.4 UpNbr: 107.0.4.8
Pruned Oifs:
Address: 108.0.8.5 IfId: 95
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Pruned due to assert
Pruned time remaining 130
<121.0.0.1, 224.0.1.40> EntryExpires: 102
RPF Route: 121.0.0.0/255.0.0.0 IIF: 107.0.8.4 UpNbr: 107.0.4.8
Pruned Oifs:
Address: 108.0.8.5 IfId: 95
Pruned due to assert
Pruned time remaining 133
show ip pim interface� Use to display information about PIM interfaces.� Specify no keywords or variables to display information about all PIM
interfaces.� Provide an interface type and specifier (such as atm 3/0) to display information
about that interface only. For details about interface types and specifiers, see E-Series Command Reference Guide, About This Guide.
� Specify the summary keyword to view the number of configured, enabled, and disabled PIM DM, PIM SM, and PIM S-DM interfaces.
� Specify the count keyword to view the number of multicast packets that the interface has sent and received.
� Field descriptions� Interface Addr � IP address of the interface� Interface Name � type and identifier of the interface. For details about
interface types and specifiers, see E-Series Command Reference Guide, About This Guide.
� Ver � version of PIM running on this interface� Mode � PIM mode running on this interface: sparse, dense, or sparse-dense� Nbr Count � number of neighbors connected to this interface� Hello Intvl � time interval at which the interface sends hello messages to
neighbors� DR Address � address of the DR� SM � number of PIM SM interfaces� DM � number of PIM DM interfaces� SM/DM � number of PIM S-DM interfaces
� enabled � number of interfaces administratively enabled� disabled � number of interfaces administratively disabled
� ControlPkt Count In | Out � PIM messages received on and sent from this interface� Hello � number of hello messages� JoinPrune � number of join and prune messages� Assert � number of assert messages
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� Exampleshost1#show ip pim interface
PIM Interface Table
Interface Addr Interface Name Ver Mode Nbr Hello DR Addr
Count Intvl
108.0.8.5 atm2/1.108 2 SparseDense 1 30 108.0.8.5
107.0.8.4 atm2/1.109 2 SparseDense 1 30 107.0.8.4
111.0.8.9 atm2/0.110 2 SparseDense 1 30 111.0.9.8
110.0.8.12 loopback8 2 SparseDense 0 30 110.0.8.12
host1#show ip pim interface summary
PIM Interface Summary
SM: 0, 0 enabled, 0 disabled
DM: 0, 0 enabled, 0 disabled
SM/DM: 1, 0 enabled, 1 disabled
host1#show ip pim interface count
PIM Interface Count
Interface Addr Interface Name ControlPktCount In|Out
Hello JoinPrune Assert
192.32.10.20 ATM3/0.20 0 0 0
0 0 0
show ip pim neighbor� Use to display information about PIM neighbors that the router discovered.� Provide an interface type and specifier (such as atm 3/0) to display information
about that interface only. For details about interface types and specifiers, see E-Series Command Reference Guide, About This Guide.
� Field descriptions� Neighbor Addr � IP address of the neighbor� Interface Name � type and specifier of the interface to which the neighbor
connects. For details about interface types and specifiers, see E-Series Command Reference Guide, About This Guide.
� Uptime � time since the router discovered this neighbor� Expires � time available for the neighbor to send a hello message to the
interface. If the neighbor does not send a hello message during this time, it will no longer be a neighbor.
� Ver � version of PIM that the neighbor is running� Mode � PIM mode that the neighbor is using: dense, sparse, or
sparse-dense
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� Examplehost1#show ip pim neighbor
PIM Neighbor Table
Neighbor Addr Interface Name Uptime Expires Ver Mode
107.0.4.8 atm2/1.109 1d15:47:35 00:01:41 2 SparseDense
108.0.5.8 atm2/1.108 1d15:47:34 00:01:42 2 SparseDense
111.0.9.8 atm2/0.110 1d15:48:02 00:01:44 2 SparseDense
show ip pim remote-neighbor� Use to view information about PIM remote neighbors.� Field descriptions
� Remote Nbr Addr � IP address of remote neighbor� OurEnd Addr � IP address of local interface, such as the local endpoint of a
tunnel, that transmits data to remote neighbor� Ver � version of PIM running on the local interface� Mode � PIM mode running on the local interface; always PIM sparse mode� Nbr Count � number of remote neighbors detected: 0 or 1� Hello Intvl � time interval at which the interface sends hello messages to
neighbors� DR Addr � address of DR� In interface � type and identifier of the interface on which PIM router receives
packets from remote neighbor. For details about interface types and specifiers, see E-Series Command Reference Guide, About This Guide.
� Out interface � type and identifier of the interface on which PIM router sends packets to remote neighbor. For details about interface types and specifiers, see E-Series Command Reference Guide, About This Guide.
host1:boston#show ip pim remote-neighbor
PIM RemoteNbr Table
RemoteNbr Addr OurEnd Addr Ver Mode Nbr Hello DR Addr
Count Intvl
10.2.23.45 172.16.78.3 2 Sparse 1 30 192.168.3.41
In interface : atm2/1.109
Out interface: atm2/1.108
show ip pim rp � Use to display information about PIM group-to-RP mappings.� Specify the address of a group to view PIM group-to-RP mappings for a
particular group.� To display all RP-to-group mappings that the router has recorded, specify the
mapping keyword.� Field descriptions
� Group � prefix of the multicast group� RP � IP address of RP router for the multicast group� priority � this field is not functional
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� via Auto RP/static RP � method by which the RP router was assigned� expiryTime � time in seconds at which the RP mapping becomes invalid,
unless the mapping agent reassigns the RP router to this group� Example
host1:8#show ip pim rp mapping
PIM Group-to-RP mapping(s)
Group(s) 224.0.0.0/4
RP 122.0.0.1, priority 0, via AutoRP, expiryTime 88
Group(s) 224.0.1.39/32 (negative)
RP 122.0.0.1, priority 0, via AutoRP (Negative), expiryTime 88
Group(s) 224.0.1.40/32 (negative)
RP 122.0.0.1, priority 0, via AutoRP (Negative), expiryTime 88
show ip pim rp-hash� Use to show which RP router a multicast group is using.� Field descriptions
� Group � multicast group� RP � RP router for the multicast group� priority � this field is not functional� via Auto RP/static RP � method by which the RP router was assigned� expiryTime � time in seconds at which the RP mapping becomes invalid,
unless it is renewed by the mapping agent� Example
host1:2#show ip pim rp-hash 232.1.1.1
Group(s) 224.0.0.0/4
RP 122.0.0.1, priority 0, via AutoRP, expiryTime 128
show ip pim sparse-mode sg-state� Use to display information for each (S,G) entry for PIM SM and PIM SMM. � Field descriptions
� Group-to-RP mapping � IP addresses and network mask of the multicast group
� RP � IP address of RP router� SSM group � indicates that this is an SSM group
� RPF route � IP address and network mask of the RPF route� IIF� IP address of the incoming interface for the RPF route� UpNbr � IP address of the upstream neighbor� Oifs � outgoing interface� Auto RP Discovery SELF oif � indicates that RP router for this group was
assigned through auto-RP� Register Oif to RP � IP address of RP router for the outgoing interface;
suppressed for SSM� Address � IP address of outgoing interface
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� Interface � type and specifier of the interface. For details about interface types and specifiers, see E-Series Command Reference Guide, About This Guide.
� Joined as � type of mapping� (S,G) � mapping from a specific source to a specific group� (*,G) � mapping from any source to a specific group� (*,*,RP) � mapping from any source to any group
� Join expires � number of seconds before the (S,G) membership expires� Count of entries � total count of (S,G) pair mappings
� Examplehost1:2#show ip pim sparse-mode sg-state
PIM SM route table and oif information
<*, 224.0.1.40>
Group-to-RP mapping: 224.0.0.0/240.0.0.0 RP: 123.0.0.1
RPF Route: 123.0.0.0/255.0.0.0 IIF: 106.0.7.3 UpNbr: 106.0.3.7
Oifs:
Auto RP Discovery SELF oif.
Joined as <*, G>
<*, 225.1.2.3>
Group-to-RP mapping: 224.0.0.0/240.0.0.0 RP: 123.0.0.1
RPF Route: 123.0.0.0/255.0.0.0 IIF: 106.0.7.3 UpNbr: 106.0.3.7
Oifs:
Address: 78.7.7.7 Interface: loopback7
Local group membership present.
<*, 235.1.1.1>
Group-to-RP mapping: 224.0.0.0/240.0.0.0 RP: 123.0.0.1
RPF Route: 123.0.0.0/255.0.0.0 IIF: 106.0.7.3 UpNbr: 106.0.3.7
Oifs:
Address: 78.7.7.7 Interface: loopback7
Local group membership present.
<118.1.33.34, 232.0.0.1>
SSM Group
RPF Route: 118.1.0.0/255.255.0.0 IIF: 118.1.0.1 (Directly attached)
Oifs:
Register Oif to RP: 141.0.0.2 suppressed for SSM Group.
Address: 134.0.0.1 Interface: ATM3/0.104
Joined as <S, G> Join Expires: 161
<118.1.33.35, 232.0.0.1>
SSM Group
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RPF Route: 118.1.0.0/255.255.0.0 IIF: 118.1.0.1 (Directly attached)
Oifs:
Register Oif to RP: 141.0.0.2 suppressed for SSM Group.
Address: 134.0.0.1 Interface: ATM3/0.104
Joined as <S, G> Join Expires: 161
<10.0.1.8, 235.1.1.1> EntryExpires: 143
Group-to-RP mapping: 224.0.0.0/240.0.0.0 RP: 123.0.0.1
RPF Route: 10.0.0.0/255.0.0.0 IIF: 106.0.7.3 UpNbr: 106.0.3.7
Oifs:
Address: 78.7.7.7 Interface: loopback7
Joined as <*, G>
Count of entries - <S, G> : 2
<*, G> : 1
<*, *, RP>: 0
show ip pim sparse-mode unicast-route� Use to display the unicast routes that PIM SM is using.� Field descriptions
� Route � IP address and network mask for the unicast route� RpfNbr � RPF neighbor� Iif � incoming interface for the unicast route� Pref � preference for the unicast route� Metric � value of metric for the unicast route (type of metric varies with the
unicast protocol)� Count of entries � number of unicast routes that PIM SM is using.
� Examplehost1:2#show ip pim sparse-mode unicast-route
PIM SM unicast route table information
Route RpfNbr Iif Pref Metric
---------------------------------------------------------------------------
122.0.0.0 /255.0.0.0 122.0.0.1 255 1
Count of entries: 1
show ip pim spt-threshold� Use to display the threshold for switching to the shortest path tree at a PIM DR.� Field descriptions
� Access List Name � name of the IP access list that specifies the groups to which the threshold applies
� SptThreshold (in kbps) � value at which PIM SM should switch from a shared tree to an SPT. A value of infinity indicates that PIM SM should never switch to an SPT.
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host1:2#show ip pim spt-threshold
Access List Name SptThreshold(in kbps)
-------------------------------------------------------
1 infinity
DVMRP
Note: PIM has gained general acceptance among a large number of multicast-enabled networks. We recommend that you use PIM rather than DVMRP for applications that are not otherwise required to run DVMRP.
The router supports Distance Vector Multicast Routing Protocol (DVMRP) on VRs to forward multicast datagrams through a network. DVMRP is an interior gateway protocol that supports operations within an autonomous system, but not between autonomous systems. The multicast backbone of the Internet, MBone, uses DVMRP to forward multicast datagrams.
DVMRP is a dense-mode multicasting protocol and therefore uses a broadcast and prune mechanism. The protocol builds an SRT in a similar way to PIM DM (see Figure 5-3). DVMRP routers flood datagrams to all interfaces except the one that provides the shortest unicast route to the source. DVMRP uses pruning to prevent unnecessary sending of multicast messages through the SRT.
A DVMRP router sends prune messages to its neighbors if it discovers that:
• The network to which a host is attached has no active members of the multicast group.
• All neighbors, except the next-hop neighbor connected to the source, have pruned the source and the group.
When a neighbor receives a prune message from a DVMRP router, it removes that neighbor from its (S,G) pair table, which provides information to the multicast forwarding table.
If a host on a previously pruned branch wants to join a multicast group, it sends an IGMP message to its first-hop router. The first-hop router then sends a graft message upstream.
Identifying NeighborsIn this implementation of DVMRP, a neighbor is a directly connected DVMRP router. When you enable DVMRP on an interface, the associated VR adds information about local networks to its DVMRP
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routing table. The VR then sends probe messages periodically to learn about neighbors on each of its interfaces. To ensure compatibility with other DVMRP routers that do not send probe messages, the VR also updates its DVMRP routing table when it receives route report messages from such routers.
Advertising RoutesAs its name suggests, DVMRP uses a distance vector routing algorithm. Such algorithms require that each router periodically inform its neighbors of its routing table. DVMRP routers advertise routes by sending DVMRP report messages. For each network path, the receiving router picks the neighbor advertising the lowest cost and adds that entry to its routing table for future advertisement.
The cost or metric for this routing protocol is the hop count back to the source. The hop count for a network device is the number of routers on the route between the source and that network device.
Table 5-2 shows an example of the routing table for a DVMRP router.
The DVMRP router maintains a (S,G) pair table that provides information to the multicast forwarding table. The (S,G) pair table is based on:
• Information from the DVMRP routing table
• Information learned from prune messages
• If IGMP and DVMRP are on the same interface, group information learned from IGMP
The (S,G) pair table includes a route from each subnetwork that contains a source to each multicast group of which that source is a member. These routes can be static or learned routes. Table 5-3 shows an example of the (S,G) pair table for DVMRP.
Table 5-2 Sample routing table for a DVMRP router
Source Subnet
Subnet Mask From Router Metric
Time Before Entry Is Deleted from Routing Table
Input Port
Output Port
143.2.0.0 255.255.0.0 143.32.44.12 4 85 3/0 4/0, 4/1
143.3.0.0 255.255.0.0 143.2.55.23 2 80 3/1 4/0, 4/1
143.4.0.0 255.255.0.0 143.78.6.43 3 120 3/1 4/0, 4/1
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Enabling DVMRP on a VRBy default, DVMRP is enabled on the router. To enable DVMRP on a VR:
1 Enable multicast routing.
2 (Optional) Create a VR or access a VR context.
Note: If you do not specify a VR, you can configure DVMRP on the default router.
You must now enable and configure DVMRP on one or more interfaces. See Activating DVMRP on an Interface. You can also set DVMRP limits for the VR. See Configuring DVMRP Limits.
Example host1(config)#ip multicast-routing
host1(config)#virtual-router boston
Activating DVMRP on an InterfaceBy default, DVMRP is not activated on an interface. Configuring any DVMRP parameter on an interface automatically activates DVMRP on that interface. You can also activate DVMRP on an interface and use the default parameters.
ip dvmrp� Use to activate DVMRP on an interface.� This command automatically creates and enables DVMRP processing on the
current VR.� Issuing this command identifies this interface as one that DVMRP owns.
Table 5-3 Example of DVMRP (S,G) pair table
Source Subnet
Multicast Group
Time Before Entry Is Deleted from Routing Table Input Port Output Port
143.2.0.0 230.1.2.3 85 3/0 4/0, 4/1
230.2.3.4 75 3/0 4/0, 4/1
230.3.4.5 60 3/0 4/1
230.4.5.6 90 a
a No value for the input port indicates that the interface is associated with a protocol other than DVMRP.
4/0
143.3.0.0 230.1.2.3 80 3/1 4/0, 4/1
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� Examplehost1:boston(config-if)#ip dvmrp
� Use the no version to remove DVMRP from an interface.
Configuring DVMRP LimitsYou can configure DVMRP and IGMP on the same interface. If you configure IGMP and DVMRP on an interface, the router considers that DVMRP owns the interface.
Note: You cannot configure DVMRP and PIM on the same interface.
When you have enabled DVMRP processing on a VR, you can configure the following settings for that VR:
• The number of routes that the VR advertises on each interface.
• A maximum number of DVMRP routes at which the router generates a system log warning message and an SNMP trap.
ip dvmrp route-hog-notification� Use to set the number of DVRMP routes that the router can record before it
generates a system log warning message.� The warning allows you to identify routers that are injecting large numbers of
routes into the MBone.� Example
host1:boston(config)#ip dvmrp route-hog-notification 5000
� Use the no version to revert to the default, 10,000 routes.
ip dvmrp route-limit� Use to limit the number of routes that the router can advertise on each
interface.� Example
host1:boston(config)#ip dvmrp route-limit 5000
� Use the no version to restore the default, 7000 routes.
Filtering DVMRP ReportsYou can configure an interface to accept only reports with routes that appear on a standard IP access list. You can refine the set of accepted routes further, by defining a second access list of neighbors who can supply the specified routes.
For example, suppose you define an access list that specifies that the router accepts only reports for the route 172.16.2.0/24. You then define a
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second access list that specifies that only neighbors 192.168.1.1 and 193.168.1.1 can supply this route. If neighbor 192.168.2.2 supplies the route, the DVMRP router rejects this report.
You can also modify the value (distance) that the router associates with a DVMRP route when it computes the RPF interface for the source of a multicast packet. By default, the router associates a distance of 0 with DVMRP routes; this value indicates that the router should use DVMRP, rather than a unicast routing protocol, to transport multicast datagrams.
However, in a configuration where PIM discovers multicast routes and a unicast routing protocol performs RPF lookups, you can increase the administrative distance to favor the unicast protocol.
For information about defining access lists, see Chapter 1, Configuring Routing Policy.
ip dvmrp accept-filter� Use to filter routes in DVMRP reports in accordance with a standard IP access
list. � Specify a standard IP access list of sources for which the interface will accept
routes.� To favor a unicast routing protocol, specify a DVMRP administrative distance.� To restrict the neighbors from whom reports for routes on the first list will be
accepted, specify a neighbor list.� Example
host1:boston(config-if)#ip dvmrp accept-filter boston-list 4 neighbor-list boston-neighbors
� Use the no version to disable a filter.
Configuring DVMRP Summary AddressesYou can configure an interface to advertise a summary address with a known metric rather than a more specific route. DVMRP advertises the summary address if the DVMRP routing table contains a more specific route that matches the address and mask of the summary address.
If you want to advertise all routes rather than a summary, disable automatic summarization on the interface. By default, the router automatically summarizes DVMRP routes. DVMRP automatic summarization maps a unicast subnet route to a classful network number route when the subnet has a different network number from the IP address of the interface (or tunnel) over which the advertisement travels. If the interface is unnumbered, the router compares the network number of the numbered interface to the IP address to which the unnumbered interface points.
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If you configure a summary address on an interface and do not disable automatic summarization, the interface advertises the least specific address.
ip dvmrp auto-summary� Use to reenable the router to summarize routes automatically for this interface.
By default, automatic summarization is enabled.� Example
host1:boston(config-if)#ip dvmrp auto-summary
� Use the no version to disable automatic summarization for this interface.
ip dvmrp summary-address� Use to advertise DVMRP summary addresses on an interface. By default, an
interface advertises only summary addresses generated by automatic summarization.
� If you configure multiple overlapping summary addresses on an interface, the one with the shortest mask takes preference.
� The default metric value is 1.� Example
host1:boston(config-if)#ip dvmrp summary-address 192.48.1.2 255.255.255.0 metric 1
� Use the no version to stop advertising a summary address on the interface.
Changing the Metric for a RouteThe metric for DVMRP is hop count. For example, a route with two hops over a slow serial line is preferable to a route with three hops over a faster optical line.
The router increments DVMRP routes in incoming reports by a default metric of one and in outgoing reports by a default of 0. You can change the metric for an interface to promote or demote the preference for associated routes.
ip dvmrp metric-offset� Use to adjust the number of hops associated with a route. This action specifies
that the route is more efficient or less efficient than an alternative route.� Use the in keyword to specify the number of hops by which the router
increments a DVMRP route advertised in incoming DVMRP reports. This option is the default.
� Use the out keyword to specify the number of hops by which the router increments a DVMRP route advertised in outgoing DVMRP reports.
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� Examplehost1:boston(config-if)#ip dvmrp metric-offset in 3
� Use the no version to revert to the default settings: 1 for incoming reports and 0 for outgoing reports.
Importing Routes from Other ProtocolsYou can import routing information from other protocols into the DVMRP routing table. Only routes that appear in the RPF table can be imported. To do so:
1 If you want to use IS-IS, OSPF, or RIP routes, make those routes available to multicasting protocols. See Using Unicast Routes for RPF, earlier in this chapter.
2 Access Router Configuration mode.
3 Specify a route map.
4 Import information from one type of routing domain into another.
redistribute� Use to import information from another type of routing domain to the DVMRP
domain. Only routes that appear in the RPF table can be imported.� Specify the source protocol from which routes are being redistributed. It can be
one of the following keywords: bgp, isis, ospf, static, and connected. � Use the static keyword to redistribute static IP multicast routes into DVMRP. � Use the keyword connected to redistribute routes that are established
automatically in the RPF table when another multicast routing protocol, such as PIM, is enabled on an interface.
� Use the route-map keyword to configure the route map to filter imported routes from the source routing protocol to the current routing protocol. If you do not specify the route-map option, all routes are redistributed. If you specify the route-map option, but no route map tags are listed, no routes will be imported.
� Example: Importing routing information from BGP into DVMRPhost1:boston(config-router)#redistribute bgp 100 route-map boston-map
� Use the no version of this command to disable redistribution.
route-map� Use to specify a route map.
host1:boston(config-router)#route-map boston-map atm 3/2
� Use the no version to delete the route map. If you do not specify an interface, it removes the global route map if one exists.
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router dvmrp� Use to create and enable DVMRP processing on a VR or to access DVMRP
Router Configuration mode.� Example
host1:boston(config)#router dvmrp
� Use the no version to remove DVMRP from the VR.
Specifying Routes to Be AdvertisedBy default, if DVMRP owns an interface, that interface advertises all DVMRP routes it has learned to its neighbors. You can specify the routes that the interface advertises by issuing the ip dvmrp announce-filter command in conjunction with a standard IP access list. The IP access list defines the DVMRP routes that will be advertised.
ip dvmrp announce-filter� Use to specify the DVMRP routes that an interface will advertise. � Specify a standard IP access list of routes that the interface will advertise.� Example
host1:boston(config-if)#ip dvmrp announce-filter boston-list
� Use the no version to allow the interface to advertise all DVMRP routes that it has learned.
Preventing Dynamic Route DistributionBy default, if you make changes to a route map, the router dynamically redistributes the routes in DVMRP. To prevent this dynamic redistribution, use the disable-dynamic-redistribute command.
disable-dynamic-redistribute� Use to halt the dynamic redistribution of routes that are initiated by changes to
a route map. � Dynamic redistribution is enabled by default.� Example
host1(config-router)#disable-dynamic-redistribute
� There is no no version.
Exchanging DVMRP Unicast RoutesDVMRP maintains its own unicast routing table, based on distance vector calculations. The routing table defines the best-known distance to each destination and how to get there. The router updates the tables by
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exchanging information with its neighbors. The DVMRP routing table is used solely for RPF lookups.
By default, if DVMRP owns an interface, that interface exchanges DVMRP unicast routes with its neighbors, and you cannot disable the exchange of routes. However, you can enable and disable the exchange of DVMRP unicast routes on interfaces that DVMRP does not own.
When an interface exchanges DVMRP routes, the router obtains routes from DVMRP report messages and stores them in its DVMRP routing table. Other multicast protocols, such as PIM, can then use these routes for RPF lookups. With this feature, PIM can use the DVMRP routing table even when the router is not running DVMRP.
All interfaces, including tunnels, support DVMRP unicast routing. DVMRP tunnels use DVMRP multicast routing to support DVMRP unicast routing.
ip dvmrp unicast-routing� Use to enable the exchange of DVMRP unicast routes on an interface not
owned by DVMRP.� Example
host1:boston(config-if)#ip dvmrp unicast-routing
� Use the no version to disable the exchange of DVMRP unicast routes on an interface not owned by DVMRP.
Disabling and Removing DVMRPYou can disable DVMRP on a VR or an interface without removing the configuration. You can also remove DVMRP from a VR or an interface.
disable� Use to disable DVMRP processing on a VR without removing the DVMRP
configuration. By default, DVMRP processing is enabled.� Example
host1:boston(config-router)#disable
� Use the no version to reenable DVMRP processing on a VR.
ip dvmrp disable� Use to disable DVMRP processing on an interface without removing the
DVMRP configuration.� Example
host1:boston(config-if)#ip dvmrp disable
� Use the no version to reenable DVMRP on an interface.
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ip dvmrp� Use to activate DVMRP on an interface.� This command automatically creates and enables DVMRP processing on the
current VR.� Issuing this command identifies this interface as one that DVMRP owns.� Example
host1:boston(config-if)#ip dvmrp
� Use the no version to remove DVMRP from an interface.
router dvmrp� Use to create and enable DVMRP processing on a VR or to access Router
Configuration mode.� Example
host1:boston(config)#router dvmrp
� Use the no version to remove DVMRP from the VR.
Deleting DVMRP RoutesYou can clear one or more routes from the DVMRP routing table. However, if you do so, the routes may reappear in the routing table if they are rediscovered.
clear ip dvmrp routes� Use to delete DVMRP routes from the routing table.� If you do not specify any options, the router removes all routes except those
associated with its own interfaces from the DVMRP table.� If you specify an IP address but not a subnet mask, the router removes the
longest route to that IP address from the DVMRP table.� If you specify a subnet mask, the router removes that specific route from the
DVMRP table.� Example
host1:boston#clear ip dvmrp routes
Configuring DVMRP TunnelsDVMRP tunnels allow the exchange of IP multicast traffic between routers separated by networks that do not support multicast routing. For information about DVMRP tunnels, see Chapter 6, Configuring IP Tunnels.
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Monitoring DVMRP You can establish a reference point for DVMRP statistics by setting the statistics counters to zero.
You can display DVMRP information with the show ip dvmrp commands.
baseline ip dvmrp� Use to set the counters for IGMP statistics to zero.� Example
(host1)#baseline ip dvmrp
show ip dvmrp� Use to display DVMRP information for a VR. � Field descriptions
� Dvmrp Admin State � state of DVMRP in the software: enabled or disabled� Mcast Admin State � state of multicasting in the software: enabled or
disabled� Dvmrp Version � version of DVMRP with which this software is compatible� GenerationID � a number the router generates each time it reboots; when
the number changes, neighbors discard all information previously learned from the router
� NumRoutes � number of routes in the DVMRP routing table� NumTrigdRts � number of routes waiting to be advertised, because a
parameter for the route changed� ReachableRoutes � number of routes that the router can currently reach � RouteHogNotification � number of DVMRP routes that the router can record
before it generates a system log warning message� RouteLimit � maximum number of routes that the router can advertise on
each interface� Send-S32-Prunes-Only � indicates whether or not the router sends only
S-32 prunes � True � router sends only S-32 prunes and grafts to ensure compatibility
with other protocols, such as PIM� False � router sends S-32 and S/Prefix grafts and prunes
� Examplehost1:boston>show ip dvmrp
Routing Process DVMRP - Distance Vector Multicast Routing Protocol
Dvmrp Admin State: Enabled
Mcast Admin State: Enabled
Dvmrp Version: 3.255
GenerationID: 0x39aa07d3
NumRoutes: 7
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NumTrigdRts: 0
ReachableRoutes: 7
RouteHogNotification: 10000
RouteLimit: 7000
Send-S32-Prunes-Only: false
show ip dvmrp interface� Use to display DVMRP parameters for the specified interfaces.� Field descriptions
� Interface � type and identifier of the interface connected to a source. For details about interface types and specifiers, see E-Series Command Reference Guide, About This Guide.
� SourceAddress � IP address of the interface or, for an unnumbered interface, address of the loopback interface
� Network/Mask � network and mask of the subnet on which the interface resides
� Received Bad Packets/RBdPk � number of bad packets received on this interface
� Received Bad Routes/RBdRt � number of bad routes received on this interface
� Routes Sent/SntRt � number of bad routes advertised on this interface� Administrative State � configured state of DVMRP on this interface: enabled
or disabled� Summary Address � specific summary address that this interface should
advertise� auto-summary � status of automatic summarization: enabled or disabled� metric-offset in � number of hops by which the router increments a DVMRP
route advertised in incoming DVMRP reports� metric-offset out � number of hops by which the router increments a DVMRP
route advertised in outgoing DVMRP reports� accept-filter(s) � names of IP access lists that specify the sources for which
the interface accepts routes.� Example 1
host1:v3#show ip dvmrp interface
Interface: atm5/0.14
SourceAddress: 14.0.1.1
Network/Mask: 14.0.1.1/8
Received Bad Packets: 0
Received Bad Routes: 0
Routes Sent: 2
Administrative State: Enabled
Summary Address(es)
None Configured
auto-summary: Enabled
metric-offset in: 1
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metric-offset out: 0
accept-filter(s): None Configured
� Example 2host1:boston#show ip dvmrp interface brief
Interface SourceAddress Network/Mask RBdPk RBdRt SntRt
atm5/0.14 14.0.1.1 14.0.1.1/8 0 0 2
atm5/0.15 15.0.1.1 15.0.1.1/8 0 0 2
show ip dvmrp mroute� Use to display information about DVMRP routes to multicast groups.� Field descriptions
� For each (S,G) pair:� No Upstream Prune � router has sent no prune messages for this group� Uptime � time, in seconds, that this (S,) pair entry has been in the routing
table� RPF Interface � interface that provides the shortest path back to the
source� Outgoing interface list � types and identifiers of interfaces through which
the VR forwards DVMRP messages, such as atm3/0. For details about interface types and specifiers, see E-Series Command Reference Guide, About This Guide.
� Example host1:boston#show ip dvmrp mroute
IP DVMRP Multicast Routing Table
(40.0.0.0/16, 228.1.1.1) Uptime: 77
Upstream Prune: none
RPF Interface
atm5/0.40
Outgoing interface list:
atm5/0.31
show ip dvmrp neighbor� Use to display information about DVMRP neighbors.� Field descriptions
� Interface � interface type and identifier, such as atm3/0. For details about interface types and specifiers, see E-Series Command Reference Guide, About This Guide.
� Neighbor Address/NbrAddress � IP address of the neighbor� Neighbor upTime/UpTime � length of time, in seconds, that this router has
been a neighbor� Neighbor Major Version/Maj � major number of the DVMRP version on the
neighbor� Neighbor Minor version/Min � minor number of the DVMRP version on the
neighbor
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� Neighbor capabilities/Cap � capability of the neighbor� Prune/P � ability to send prune messages� GenerationId/G � ability to create a GenID number� Mtrace/M � ability to trace multicast routes� Netmask/N � ability to send prunes and grafts with a network mask
address� Neighbor State/State � status of the communications with the neighbor
� Active � router is able to communicate with this neighbor� Down � neighbor is down� Ignoring � router is not accepting message from this neighbor� Oneway � router is receiving messages from the neighbor, but the
neighbor does not include the router�s IP address in the messages. This state can indicate a starting transition, or a problem.
� Generation ID � number that the neighbor generates each time it boots; when the number changes, the VR discards all information previously learned from the router.
� Routes Received � number of routes learned from this neighbor� Bad Routes Received � number of bad routes received from this neighbor� Bad Packets Received � number of bad packets received from this neighbor
� Example 1host1:boston#show ip dvmrp neighbor
Neighbor Address: 14.0.0.1
Interface: atm5/0.14
Neighbor upTime: 28
Neighbor Major Version: 3
Neighbor Minor Version: 255
Neighbor Capabilities: Prune GenerationId Mtrace NetMask
Neighbor State: Active
Geneneration ID: 0x3a13fbc2
Routes Received: 1
Bad Routes Received 0
Bad Packets Received: 0
� Example 2host1:v3#show ip dvmrp neighbor brief
Interface NbrAddress UpTime Maj Min Cap State
atm5/0.14 14.0.0.1 32 3 255 PGMN Active
atm5/0.15 15.0.0.1 34 3 255 PGMN Active
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show ip dvmrp route� Use to display information about DVMRP routes.� Specify an IP address to display the best route to that address.� Specify an IP address and subnet mask to display the route that exactly
matches this IP address and subnet mask� Specify an interface type and specifier to display routes associated with that
interface.� Specify the brief keyword to view a summary of information.� Field descriptions
� Prefix � IP address of the network� Length � length of the subnet mask for the network� usNbr/Owner � IP address of the upstream neighbor associated with this
route or a description of the origin of the route� DVMRP Local � route is associated with a directly attached network� DVMRP Aggregate � route is an aggregate route determined by
summarization� Metric � metric associated with this interface for this route� ExpireTime � time until the VR starts the process for removing the route� UpTime � length of time the route has been in the DVMRP routing table� Interface � type and identifier for the interface, such as atm3/0. For details
about interface types and specifiers, see E-Series Command Reference Guide, About This Guide.
� Examplehost1:boston>show ip dvmrp route
Prefix/Length usNbr/Owner Metric ExpireTime UpTime Interface
14.0.0.0/8 Dvmrp Local 1 Never 18 atm5/0.14
Downstream Interface(s)
Interface
atm5/0.15
15.0.0.0/8 Dvmrp Local 1 Never 18 atm5/0.15
Downstream Interface(s)
None
25.0.0.0/8 14.0.0.1 2 129 11 atm5/0.14
Downstream Interface(s)
Interface
atm5/0.15
host1:v3#show ip dvmrp route brief
Prefix/Length usNbr/Owner Metric ExpireTime UpTime Interface
14.0.0.0/8 Dvmrp Local 1 Never 26 atm5/0.14
15.0.0.0/8 Dvmrp Local 1 Never 26 atm5/0.15
25.0.0.0/8 14.0.0.1 2 121 19 atm5/0.14
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show ip dvmrp routeNextHop� Use to display information about the next hop.� Field descriptions
� addr � IP address of the next-hop router� mlen � mask length of the next-hop router� ifIndex � SNMP ifIndex for the interface that connects to the next hop� Type � description of the next-hop router
� leaf � neighbor with no downstream neighbors� branch � neighbor with downstream neighbors
� Examplehost1:boston>show ip dvmrp routeNextHop
addr/mlen ifIndex Type
172.16.0.0/16 4 leaf
172.17.0.0/16 4 leaf
172.18.0.0/16 3 leaf
172.19.0.0/16 3 leaf
172.19.0.0/16 4 branch
BGP MulticastingBGP multicasting (MBGP) is an extension of the BGP unicast routing protocol. Many of the functions available for BGP unicasting are also available for MBGP.
The MBGP extensions specify that BGP can exchange information within different types of address families. The address families available are unicast IPv4, multicast IPv4, and VPN-IPv4. When you enable BGP, the router employs unicast IPv4 addresses by default.
You should be thoroughly familiar with BGP before configuring MBGP. See E-Series Routing Protocols Configuration Guide, Vol. 2, Chapter 1, Configuring BGP Routing, for detailed information on BGP and MBGP.
Investigating Multicast RoutesYou can use the mtrace command to trace the path that multicast packets take from a source to a destination through a multicast group address. This command is similar to the traceroute command for investigating unicast routes.
mtrace� Use this command to trace the path that multicast packets take to a destination. � Specify the unicast IP address of the source for the packets.
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� To direct the packets to a particular destination, specify the unicast address for that destination. If you do not specify a destination, the router traces the route from the device on which you issue the command.
� To direct the packets through a particular multicast group address, specify that multicast group address. If you do not specify a multicast group address, the router traces the route through the MBone audio multicast group.
� To send the trace to a particular device, specify the IP address of that device. If you do not specify a response address, the router sends the trace to an IP address on the router.
� To investigate a problem at a particular point in the route, specify the maximum number of hops for the trace.
� The trace starts at the destination and works back to the source. The default number of hops is 64.
� Field descriptions� Tracing multicast route from a.a.a.a to b.b.b.b for group c.c.c.c using
response address d.d.d.d � a description of the trace as follows:� a.a.a.a � IP address of the source� b.b.b.b � IP address of the destination� c.c.c.c � IP address of the multicast group� d.d.d.d � IP address on the router to which the router will send the trace
� Received mtrace response packet of length n � length of the response packet in bytes
� Each line of the trace has the following format: hops. ip-address protocol threshold � hops � number of hops from the destination to this intermediate router� ip-address � IP address of the intermediate router� protocol � multicast protocol running on the intermediate router. A value
of 12 indicates IGMP; other values comply with A �traceroute� Facility for IP Multicast � draft-ietf-idmr-traceroute-ipm-07.txt (July 2000).
� FwdingCode � forwarding information or error associated with this hop. For example, RPF iif indicates that the request arrived on the expected RPF interface for this source group. For more information about the forwarding information or error codes, see A �traceroute� Facility for IP Multicast � draft-ietf-idmr-traceroute-ipm-07.txt (July 2000).
� Examplehost1#mtrace 100.4.4.4 40.1.1.1 232.1.1.1
Tracing multicast route from 100.4.4.4 to 40.1.1.1 for group 232.1.1.1 using response address 10.6.129.56
(Press ^c to stop.)
Received mtrace response packet of length 88
1. 40.1.1.1 Protocol: PIM(3) FwdingCode: RPF iif(9)
2. 21.2.2.2 Protocol: PIM(3) FwdingCode: Reached RP(8)
� There is no no version.
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6
Configuring IP TunnelsIP tunnels provide a way of transporting datagrams between routers separated by networks that do not support all the protocols that those routers support. This chapter describes how to configure IP tunnels on the E-series router.
Topic Page
Overview 6-2
Line Module Requirements 6-2
Managing TSMs 6-3
References 6-3
Configuration Tasks 6-3
Monitoring IP Tunnels 6-8
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OverviewThe E-series router supports static IP tunnels. An IP tunnel is a virtual point-to-point connection between two routers. See Figure 6-1. To establish an IP tunnel, you specify a tunnel type and name, and then configure an interface on each router to act as an endpoint for the tunnel.
Figure 6-1 IP tunneling
The E-series router supports the following types of IP tunnels:
• Generic Routing Protocol (GRE) tunnels
• Distance Vector Multicast Routing Protocol (DVMRP) tunnels, also known as IP in IP tunnels
GRE TunnelsGRE encapsulates IP packets to enable data transmission through an IP tunnel. The resulting encapsulated packet contains a GRE header and a delivery header. Consequently, the packet requires more processing than an IP packet, and GRE can be slower than native routing protocols.
DVMRP TunnelsDVMRP tunnels allow the exchange of IP multicast traffic between routers separated by networks that do not support multicast routing. For information about DVMRP, see Chapter 5, Configuring IP Multicasting.
Line Module RequirementsTo create IP tunnels, you must install a Tunnel Service line module (TSM) in the E-series router. For information about installing TSMs in the E-series router, see the E-Series Installation and User Guide.
Unlike other line modules, the TSM does not pair with a corresponding I/O module that contains ingress and egress ports. The TSM receives data from, and transmits data to, other line modules with ingress and
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Managing TSMsE-Series Routers
6-3
egress ports. However, you must assign interfaces on other line modules or loopback interfaces to act as source endpoints for the tunnel.
All line modules forward traffic to tunnels. For information about which line modules accept traffic for tunnels, see E-Series Installation and User Guide, Chapter 13, Protocol Support.
Managing TSMsFor information about TSM redundancy and tunnel distribution, see E-Series Physical Layer Configuration Guide, Chapter 9, Managing Tunnel Service and IPSec Service Interfaces.
ReferencesFor more information about IP tunnels, see the following documents:
• RFC 791 – Internet Protocol DARPA Internet Program Protocol Specification (September 1981)
• RFC 1700 – Assigned Numbers (October 1994)
• RFC 1701 – Generic Routing Encapsulation (October 1994)
• RFC 1702 – Generic Routing Encapsulation over IPv4 Networks (October 1994)
• RFC 2003 – IP Encapsulation within IP (October 1996)
• RFC 2784 – Generic Routing Encapsulation (GRE) (March 2000)
Configuration TasksTo configure an IP tunnel:
1 Create or select a physical or loopback interface.
This interface acts as an anchor for the source of the tunnel.
2 Assign an IP address to the physical or loopback interface.
3 Create a tunnel interface.
4 Set the source address for the tunnel.
5 Set the destination address for the tunnel.
6 (Optional) Enable error checking across a GRE tunnel.
7 Set the maximum transmission unit (MTU) size for the tunnel.
CHAPTER 6Configuring IP Tunnels
6-4
Note: On TSM interfaces, issue only the commands listed below. Do not configure protocols such as Multilink PPP or Multilink Frame Relay on TSM interfaces.
interface tunnel� Use to create an IP tunnel interface.� Specify the type and name of the tunnel you want to create.� You can establish the tunnel on a virtual router other than the current virtual
router.� Example
host1(config)#interface tunnel dvmrp:boston-tunnel-1 transport-virtual-router boston
� Use the no version to remove the tunnel.
tunnel checksum� Use to enable checksum computation across a GRE tunnel.� Checksum computation is not supported for DVMRP tunnels.� Selecting this feature causes the E-series router to drop corrupted packets it
receives on the tunnel interface.� Example
host1(config)#interface tunnel gre:tunnel2
host1(config-if)#tunnel checksum
� Use the no version to disable the checksum option.
tunnel destination� Use to configure the remote end of the tunnel.� Specify either the IP address of an interface on the remote router or the
hostname of the remote router.� The IP address is the address for the destination interface.� The hostname is the name of the destination interface.
� Example 1host1(config)#interface tunnel dvmrp:tunnel2
host1(config-if)#tunnel destination 192.13.7.1
� Example 2host1(config)#interface tunnel dvmrp:tunnel2
host1(config-if)#tunnel destination remoteHost
� Use the no version to remove the destination of a tunnel.
tunnel mtu� Use to set the MTU for the tunnel.� Specify a value in the range 1024 to 10240 bytes.
Configuration TasksE-Series Routers
6-5
� Examplehost1(config-if)#tunnel mtu 7500
� Use the no version to restore the default, 10240 bytes.
tunnel source� Use to configure the source of the tunnel.� Specify either the primary IP address or the type and specifier of an interface. � Do not specify an unnumbered interface.� Example 1
host1(config)#interface tunnel dvmrp:boston-tunnel-1
host1(config-if)#tunnel source 192.10.2.1
� Example 2host1(config)#interface tunnel dvmrp:boston-tunnel-1
host1(config-if)#tunnel source atm 5/0.12
� Use the no version to remove the source of a tunnel.
Configuration Example In this example, two GRE tunnel interfaces are configured on different virtual routers of an E-series router. The source of the first tunnel interface matches the destination of the second tunnel interface and vice versa.
1 Configure a virtual router called boston that will support one end of the tunnel.
host1#virtual-router boston
2 Configure a physical or loopback interface for the end of the tunnel on virtual router boston.
The IP address of this interface appears in the header of tunneled frames and is used for forwarding traffic.
host1:boston#interface atm 12/0.5
host1:boston(config-if)#ip address 10.5.5.5 255.255.255.0
3 Configure the tunnel interface on virtual router boston.
a Create the tunnel interface.
host1:boston(config)#interface tunnel gre:ChicagoTunnel
b Configure the source and destination points of the tunnel interface.
host1:boston(config-if)#tunnel source 10.5.5.5
host1:boston(config-if)#tunnel destination 10.6.6.6
CHAPTER 6Configuring IP Tunnels
6-6
c Set the MTU for the tunnel.
host1:boston(config-if)#tunnel mtu 8000
d Configure the IP address of the tunnel interface.
host1:boston(config-if)#ip address 10.7.7.7 255.255.255.0
4 Configure a virtual router called chicago that will support the other end of the tunnel.
host1(config)#virtual-router chicago
5 Configure a physical or loopback interface for the end of the tunnel on virtual router chicago.
host1:chicago(config)#interface atm 12/1.5
host1:chicago(config-if)#ip address 10.6.6.6 255.255.255.0
6 Configure the tunnel interface on virtual router chicago.
a Create the tunnel interface.
The name of the tunnel interface can differ from the tunnel interface configured in step 3.
host1:chicago(config-if)#interface tunnel gre:BostonTunnel
b Configure the source and destination points of the tunnel interface.
The destination of this tunnel interface matches the source of the tunnel interface configured in step 3 and vice versa.
host1:chicago(config-if)#tunnel source 10.6.6.6
host1:chicago(config-if)#tunnel destination 10.5.5.5
c Set the MTU for the tunnel.
The MTU must match the MTU configured in step 3.
host1:chicago(config-if)#tunnel mtu 8000
d Configure the IP address of the tunnel interface.
host1:chicago(config-if)#ip address 10.9.9.9 255.255.255.0
Configuring IP Tunnels to Forward IP FramesWhen a line module receives IP frames destined for a tunnel, the module forwards the frames to the TSM. The TSM encapsulates the frames and forwards them to the tunnel through an interface determined by a route lookup of an IP frame. The source and destination addresses in the IP frame are the source and destination addresses of the tunnel.
Configuration TasksE-Series Routers
6-7
Similarly, when a line module receives traffic from a tunnel, the module forwards the traffic to the TSM for deencapsulation. After deencapsulation, the TSM forwards the resultant IP frames to an interface determined by a route lookup.
When you have configured a tunnel interface, treat it in the same way as any IP interface on the router. For example, you can configure static IP routes or enable routing protocols on the tunnel interface. The IP configurations you apply to the tunnels control how traffic travels through the network.
Preventing Recursive TunnelsIf routing information about the tunnel network combines with routing information about the transport networks (the networks that the tunnel services), a recursive tunnel can occur. In this case, the routing table defines the tunnel itself as the best path to a tunnel destination. To prevent recursive tunnels, differentiate routing information for the tunnel network and the transport networks with one or both of the following techniques:
• Use different routing protocols for the tunnel network and the transport networks.
• Define a static route to the tunnel destination.
Note: If you define a static route to a tunnel destination, be careful not to create routing loops.
Figure 6-2 illustrates how to prevent recursive tunnels by using different routing protocols for the tunnel network and the transport networks.
Figure 6-2 Transport and tunnel networks using different routing protocols
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CHAPTER 6Configuring IP Tunnels
6-8
Monitoring IP TunnelsYou can monitor DVMRP and GRE tunnels by using the following commands.
show dvmrp tunnel� Use to display information about DVMRP tunnels.� Optionally, specify the detail keyword to view detailed information about
tunnels.� Optionally, specify the state keyword and the state of the tunnel (disabled,
down, enabled, lower-down, not-present, up) to view the number of tunnels in a specific state.
� Optionally, specify a tunnel name to view the state of a specific tunnel.� Optionally, specify an IP address to view the number of tunnels associated with
that IP address.� Optionally, specify an IP address with the virtual-router keyword and the name
of the virtual router to view the number of tunnels associated with that IP address on the virtual router.
� Field descriptions� Tunnel status
� up � tunnel is operational� down � tunnel is not operational� not-present � tunnel is not operational, because the hardware (such as a
line module) supporting the tunnel is inaccessible� Tunnel name � name of the tunnel� Tunnel mtu � maximum transmission unit for the tunnel� Tunnel source address � IP address of the source of the tunnel� Tunnel destination address � IP address of the destination of the tunnel� Tunnel transport virtual router � virtual router associated with the tunnel� Tunnel up/down trap is enabled � indicates whether or not the E-series
router sends traps to SNMP when the operational state of the tunnels changes
� Tunnel server location � location of the TSM in slot/port format. The port is internal to the TSM.
� Tunnel administrative state � configured state of the tunnel: up or down� Statistics � details of packets received or transmitted by the tunnel� Packets � number of packets received or transmitted by the tunnel� Octets � number of octets received or transmitted by the tunnel� Discards � number of packets not accepted by the tunnel� Errors � number of packets with errors received or transmitted by the tunnel� Data rx � received data� Data tx � transmitted data
Monitoring IP TunnelsE-Series Routers
6-9
� Example 1host1#show dvmrp tunnel
DVMRP tunnel boston1 is up
1 DVMRP tunnel found
� Example 2host1#show dvmrp tunnel detail
DVMRP tunnel boston1 is up
Tunnel operational configuration
Tunnel name is 'boston1'
Tunnel mtu is '10240'
Tunnel source address is '0.0.0.0'
Tunnel destination address is '0.0.0.0'
Tunnel transport virtual router is vr1
Tunnel up/down trap is enabled
Tunnel server location is 4/0
Tunnel administrative state is up
Statistics packets octets discards errors
Data rx 0 0 0 0
Data tx 0 0 0 0
1 DVMRP tunnel found
� Example 3host1#show dvmrp tunnel state enabled
DVMRP tunnel boston1 is up
1 DVMRP tunnel found
� Example 4host1#show dvmrp tunnel virtual-router vr1 ip 0.0.0.0
DVMRP tunnel boston1 is up
1 DVMRP tunnel found
show dvmrp tunnel summary� Use to display a summary of information about DVMRP tunnels.� Field descriptions
� Administrative status� enabled � tunnel is available for use� disabled � tunnel is not available for use
� Operational status� up � tunnel is operational� down � tunnel is not operational� not-present � tunnel is not operational, because the hardware (such as a
line module) supporting the tunnel is inaccessible
CHAPTER 6Configuring IP Tunnels
6-10
� Examplehost1#show dvmrp tunnel summary
Administrative status enabled disabled
1 0
Operational status up down not-present
1 0 0
show gre tunnel� Use to display information about a GRE tunnel or a list of GRE tunnels.� Optionally, specify the detail keyword to view detailed information about
tunnels.� Optionally, specify the state keyword and the state of the tunnel (disabled,
down, enabled, lower-down, not-present, up) to view the number of tunnels in a specific state.
� Optionally, specify a tunnel name to view the state of a specific tunnel.� Optionally, specify an IP address to view the number of tunnels associated with
that IP address.� Optionally, specify an IP address with the virtual-router keyword and the name
of the virtual router to view the number of tunnels associated with that IP address on the virtual router.
� Field descriptions� Tunnel name � name of the tunnel� Tunnel mtu � maximum transmission unit for the tunnel� Tunnel source address � IP address of the source of the tunnel� Tunnel destination address � IP address of the destination of the tunnel� Tunnel transport virtual router � virtual router associated with the tunnel� Tunnel checksum option � state of the checksum feature: enabled or
disabled� Tunnel up/down trap is enabled � indicates whether or not the E-series
router sends traps to SNMP when the operational state of the tunnels changes
� Tunnel server location � location of the TSM in slot/port format. The port is internal to the TSM.
� Tunnel administrative state � configured state of the tunnel: up or down� Statistics � details of packets received or transmitted by the tunnel� Packets � number of packets received or transmitted by the tunnel� Octets � number of octets received or transmitted by the tunnel� Discards � number of packets not accepted by the tunnel� Errors � number of packets with errors received or transmitted by the tunnel� Data rx � received data� Data tx � transmitted data
� Example 1host1#show gre tunnel
3 GRE tunnels found
Monitoring IP TunnelsE-Series Routers
6-11
� Example 2host1#show gre tunnel detail
Tunnel operational configuration
Tunnel name is 'vr1'
Tunnel mtu is '10240'
Tunnel source address is '10.0.0.2'
Tunnel destination address is '10.0.0.1'
Tunnel transport virtual router is vr1
Tunnel checksum option is disabled
Tunnel up/down trap is enabled
Tunnel server location is 4/0
Tunnel administrative state is up
Statistics packets octets discards errors
Data rx 0 0 0 0
Data tx 0 0 0 0
Tunnel operational configuration
Tunnel name is 'default'
Tunnel mtu is '10240'
Tunnel source address is '10.0.0.1'
Tunnel destination address is '10.0.0.2'
Tunnel transport virtual router is default
Tunnel checksum option is disabled
Tunnel up/down trap is enabled
Tunnel server location is 4/0
Tunnel administrative state is up
Statistics packets octets discards errors
Data rx 0 0 0 0
Data tx 0 0 0 0
Tunnel operational configuration
Tunnel name is 'london2'
Tunnel mtu is '10240'
Tunnel source address is '0.0.0.0'
Tunnel destination address is '0.0.0.0'
Tunnel transport virtual router is vr1
Tunnel checksum option is disabled
Tunnel up/down trap is enabled
Tunnel server location is 4/0
Tunnel administrative state is up
Statistics packets octets discards errors
Data rx 0 0 0 0
Data tx 0 0 0 0
3 GRE tunnels found
CHAPTER 6Configuring IP Tunnels
6-12
� Example 3host1#show gre tunnel state up
GRE tunnel VR1 is up
GRE tunnel default is up
GRE tunnel london2 is down
3 GRE tunnels found
Example 4
host1#show gre tunnel virtual-router vr1 ip 10.0.0.1
GRE tunnel VR1 is up
1 GRE tunnel found
show gre tunnel summary� Use to display a summary of information about GRE tunnels.� Field descriptions
� Administrative status� enabled � tunnel is available for use� disabled � tunnel is not available for use
� Operational status� up � tunnel is operational� down � tunnel is not operational� not-present � tunnel is not operational, because the hardware (such as a
line module) supporting the tunnel is inaccessible� Example
host1#show gre tunnel summary
Administrative status enabled disabled
3 0
Operational status up down not-present
3 0 0
7
IP Reassembly for TunnelsThis chapter describes IP packet reassembly for tunneled protocols on the E-series router.
Overview Tunneling protocols provide a method of forwarding packets of a particular protocol through a network of a different protocol type. For example, L2TP can transport a protocol such as PPP through a routed IP network. This capability requires a pair of devices that define the endpoints of the tunnel. Packets entering the tunnel are processed and encapsulated at the ingress endpoint, and packets exiting the tunnel are processed and de–capsulated at the egress endpoint.
When packets are tunneled through an IP network, simple IP forwarding is performed. The IP forwarding process may require fragmentation within the tunnel, which means that a packet that enters a tunnel whole may reach the egress endpoint as fragments. Because tunnel processing requires each packet to exit the tunnel in the same form in which it entered, if fragmented packets are not reassembled before the tunnel egress processing is performed, they are dropped.
Topic Page
Overview 7-1
Configuring IP Reassembly 7-2
Monitoring IP Reassembly 7-3
CHAPTER 7IP Reassembly for Tunnels
7-2
For example, in Figure 7-1, traffic is tunneled through an IP network that has four hops. Because the MTU of the link between routers B and C is smaller than that of previous hops, some packets are fragmented. Router D must reassemble the packets before tunnel egress processing and decapsulation are performed.
Figure 7-1 Tunneling through an IP network that fragments packets
Reassembly Processing Within the System Tunnel Server modules (TSMs) perform IP reassembly on the E-series router. The E-series router can perform reassembly of IP packets it receives on DVMRP, GRE, IPSec, and L2TP tunnels.
Because IP reassembly is required only on tunnel egress packets, the router performs reassembly only on packets in which the IP destination address is local to the router and in which the underlying protocol is one of the supported tunneling protocols.
Configuring IP Reassembly To set up IP reassembly, you enable it on a virtual router basis. Also, on a systemwide basis, you can control how the router handles checking of sequence numbers in data packets that it receives on L2TP tunnels.
ip tunnel reassembly� Use to enable the reassembly of fragmented IP tunnel packets that are
received on the current virtual router. � Note that you configure tunnel reassembly on VPN routing and forwarding
routers independent of the tunnel reassembly configuration on the parent virtual router.
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Monitoring IP ReassemblyE-Series Routers
7-3
� Example � enables reassembly for virtual router vr12 and disables reassembly for virtual router vr8host1:vr12(config)#ip tunnel reassembly
host1:vr12(config)#virtual-router vr8
host1:vr8(config)#no ip tunnel reassembly
� Use the no version to return IP tunnel reassembly to the default, disabled.
l2tp ignore-receive-data-sequencing� Use to prevent sequence number checking for data packets received on all
L2TP tunnels in the router. This command does not affect the insertion of sequence numbers in packets sent from the router.
� We recommend that you set up the router to ignore sequence numbers in received data packets if you are using IP reassembly. Because IP reassembly may reorder L2TP packets, out-of-order packets may be dropped if sequence numbers are being used on L2TP data packets.
� Examplehost1(config)#l2tp ignore-receive-data-sequencing
� Use the no version to cause the router to check sequence numbers on received L2TP data packets.
Monitoring IP Reassembly The router keeps several statistics that are useful for diagnostic purposes. These statistics are organized by virtual router, and some are broken out by protocol as well. You can display statistics for a single virtual router or for all virtual routers.
show ip tunnel reassembly statistics� Use to display reassembly statistics. � Statistics are displayed for the current virtual router unless you include the all
keyword, which causes the router to display statistics for all virtual routers.� Statistics are displayed in brief form unless you include the detail keyword. � Field descriptions
� Tunnel IP reassembly � status of the IP reassembly feature: enabled, disabled
� Fragments Received � total fragments received for all tunneling protocols� Packets Reassembled � number of packets reassembled; detailed display
includes number of packets reassembled for each protocol� Reassembly Errors � errors in completing reassembly; detailed display
includes types of reassembly errors� Reassembly Discards � number of packets discarded because they were not
reassembled; detailed displays include the cause of discard
CHAPTER 7IP Reassembly for Tunnels
7-4
� Example 1 � show reassembly statistics for the default virtual routerhost1:vr0#show ip tunnel reassembly statistics
Tunnel IP Reassembly Statistics for Virtual Router: default
Tunnel IP Reassembly enabled
Total Fragments Received: 2685
Total Packets Reassembled: 1231
Reassembly Errors: 32
Reassembly Discards: 1422
� Example 2 � shows detailed reassembly statistics for the default virtual routerhost1:vr0#show ip tunnel reassembly statistics detail
Tunnel IP Reassembly Statistics for Virtual Router: default
Tunnel IP Reassembly enabled
Total Fragments Received: 2685
Total Packets Reassembled: 1231
L2TP: 324
GRE: 871
L2F: 36
IPSec: 0
Total Reassembly Errors: 22
Fragmentation Errors: 0
Too Many Fragments: 0
Out of Resources: 0
Packet Too Big: 0
Reassembly Timeout: 22
Reassembly Disabled Discards: 1422
8
Configuring RIPThis chapter describes how to configure the Routing Information Protocol (RIP) on your E-series router.
OverviewRIP is an interior gateway protocol (IGP) typically used in small, homogeneous networks. RIP uses distance-vector routing to route information through IP networks.
Distance-vector routing requires that each router simply inform its neighbors of its routing table. For each network path, the receiving router picks the neighbor advertising the lowest metric, then adds this entry into its routing table for readvertisement.
Any host that uses RIP is assumed to have interfaces to one or more networks. These networks are considered to be directly connected networks. RIP relies on access to certain information about each of these networks. The most important information is the network’s metric.
Topic Page
Overview 8-1
References 8-2
Features 8-3
Before You Run RIP 8-6
Configuration Tasks 8-7
Using RIP Routes for Multicast RPF Checks 8-18
Remote Neighbors 8-19
Monitoring RIP 8-22
CHAPTER 8Configuring RIP
8-2
RIP MetricRIP uses the hop count as the metric (also known as cost) to compare the value of different routes. The hop count is the number of routers that data packets must traverse between RIP networks. Metrics range from 0 for a directly connected network to 16 for an unreachable network. This small range prevents RIP from being useful for large networks.
RIP MessagesRIP exchanges routing information via User Datagram Protocol (UDP) data packets. Each RIP router sends and receives datagrams on UDP port number 520, the RIP version 1/RIP version 2 port. All communications intended for another router’s RIP process area are sent from the RIP port.
Every RIP message contains a RIP header that consists of a command and a version number. The router supports RIP version 1 (RIPv1) and RIP version 2 (RIPv2) extensions.
RIP employs the following message types:
• Request – A request for the responding router to send all or part of its routing table.
• Response – A message containing all or part of the sender’s routing table. This message is sent in response to a request or is an unsolicited routing update generated by the sender.
The RIP request and response messages also contain a list of route entries. Each route entry contains the following:
• Address Entry Identifier – The type of address
• Destination IP address – The destination address of the message
• Cost to reach the destination – A value between 1 and 15, which specifies the current metric for reaching the destination
ReferencesFor more information about RIP, consult the following resources:
• RFC 1058 – Routing Information Protocol (June 1998)
• RFC 2453 – RIP Version 2 (November 1998)
FeaturesE-Series Routers
8-3
FeaturesSome of the major RIP features supported by the router include:
Route TagsA route tag is a field in a RIP message that allows boundary routers in an autonomous system (AS) to exchange information about external routes. Route tags provide a method of separating internal RIP routes (routes within the RIP routing domain) from external RIP routes, which may have been imported from an EGP (exterior gateway protocol) or another IGP (interior gateway protocol).
Routers supporting protocols other than RIP should be configurable to allow the route tags to be configured for routes imported from different sources. For example, routes imported from BGP should be able to have their route tags set to the number of the ASs from which the routes were learned.
AuthenticationRIPv1 does not support authentication. If you are sending and receiving RIPv2 packets, you can enable RIP authentication on an interface.
The router provides the simple authentication scheme for RIPv2. Because authentication is a per message function and only one 2-octet field is available in the RIP message header, authentication uses the space of an entire RIP message.
The first 20-byte entry in a RIP authentication message contains an address family identifier value of 0xffff and a route tag value of 2. If the 0xffff address family is present in the RIP message, the remaining 16 octets of the entry contain a plain text password. If the password is fewer than 16 octets, it must be left-justified and padded to the right with nulls (0x00).
Authentication is applied per RIP interface. You can specify either text or MD5 authentication. Text authentication uses a simple password that must be shared by the neighbors receiving updates or requests. If they do
RIP version 1 multicast addressing
RIP version 2 route summarization
route tags split horizon
authentication equal-cost multipath
subnet masks remote neighbors
next hop poison reverse
CHAPTER 8Configuring RIP
8-4
not have this password, the neighbors reject all updates or requests from the router. MD5 authentication uses a shared key to encrypt the RIP message. The neighbors must have the MD5 key to decrypt the message and encrypt a response.
Note: Do not use text authentication when security is important, because the router sends the unencrypted password in every RIP packet it sends.
Example 1 The following example shows how to use password authentication:
host1(config)#interface fastEthernet 0/0
host1(config-if)#ip rip send version 2
host1(config-if)#ip rip authentication mode text
host1(config-if)#ip rip authentication key ke6G72mV
Example 2 The following example shows how to use MD5 authentication:
host1(config)#interface fastEthernet 0/0
host1(config-if)#ip rip send version 2
host1(config-if)#ip rip authentication mode md5 8
host1(config-if)#ip rip authentication key sf43nBScE9
Subnet MasksThe Subnet Mask field of a RIP message contains the subnet mask that is applied to the IP address to set the nonhost portion of the address. If the subnet mask field in a RIP message contains a zero, then no subnet mask was included for the entry.
On an interface where a RIPv1 router may hear and operate on information in a RIPv2 routing entry, the following rules apply:
• Information internal to one network must never be advertised into another network.
• Information about a more specific subnet may not be advertised where RIPv1 routers would consider it a host route.
• Supernet routes (routes where a netmask is less specific than the natural network mask) must not be advertised where they could be misinterpreted by RIPv1 routers.
Next HopThe Next Hop field in a RIP message contains the next IP address where a packet is sent. A value of zero in this field indicates that the next address the packet should be sent to is the router that originally sent the RIP message.
FeaturesE-Series Routers
8-5
MulticastingTo reduce unnecessary load on hosts that are not listening to RIPv2 messages, an IP multicast address is used for periodic broadcast messages. The IP multicast address is 224.0.0.9.
Route SummariesYou can summarize routes reported by RIP to reduce the size of the routing table and the amount of traffic resulting from RIP updates. Configuring a RIP summary will cause that prefix to be advertised with the associated metric regardless of the presence of more-specific prefixes. Any more-specific prefixes will not be advertised when they are covered by the summary. You can choose the degree of summarization by using a prefix tree to specify the number of bits to report for routes matching a route map. Alternatively, you can explicitly specify routes for RIP to summarize.
Prefix TreeExample
The following example shows how to configure a 16-bit route summary:
1 Specify a route map for RIP in Router Configuration mode.
host1#configure t
Enter configuration commands, one per line. End with CNTL/Z.
host1(config)#router rip
host1(config-router)#route-map 1
host1(config-router)#exit
2 Define a route map associated with a prefix tree.
host1(config)#
host1(config)#route-map 1
host1(config-route-map)#match-set
host1(config-route-map)#match-set summary prefix-tree boston
host1(config-route-map)#exit
host1(config)#
3 Set the conditions for summarization in the prefix tree, including which routes are summarized and how many bits of the network addresses are preserved as the network prefix.
host1(config)#ip prefix-tree boston permit 2.1.0.0/16
This example summarizes routes for networks addressed by 2.1.x.x. The first 16 bits of the network address are preserved in the summary. For example, routes 2.1.3.0, 2.1.2.0, and 2.1.1.0 would all be summarized as 2.1.0.0.
CHAPTER 8Configuring RIP
8-6
StaticSummaryExample
You can use the ip summary-address command to specify routes that RIP will summarize.
host1(config-router)#ip summary-address 4.4.0.0 255.255.0.0 5
host1(config-router)#ip summary-address 4.3.0.0 255.255.0.0 6
Split HorizonSplit horizon is a mechanism to aid in preventing routing loops when distance-vector routing protocols such as RIP are employed in broadcast networks. When split horizon is enabled, the router cannot advertise information about routes on an interface from which the information originates. Split horizon is enabled by default on the router.
You can disable split horizon and enable poison reverse routing updates that advertise routes originating on the interface, but for each of these routes the metric is set to infinity to explicitly advertise that these networks are not reachable.
Equal-Cost MultipathRIP supports equal-cost multipath (ECMP) and installs into the routing table multiple entries for paths to the same destination. Each of these multiple paths to a given destination must have the same cost as the others, but a different next hop.
Applying Route MapsYou can apply a policy to redistributed routes with the route-map command. See Chapter 1, Configuring Routing Policy, for more information on route maps. You can use the table-map command to apply a route map to RIP routes that are about to be added to the IP routing table.
Before You Run RIPAt least one IP address must be configured on your router for RIP to run.
Configuration TasksE-Series Routers
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Configuration TasksTo configure RIP:
1 Create a RIP process by enabling RIP.
host1(config)#router rip
2 (Optional) Configure the global RIP version. RIPv1 is used by default.
host1(config-router)#version 2
3 (Optional) Do one of the following:
• Associate a network with a RIP routing process and optionally configure RIP for the network.
host1(config-router)#network 10.2.1.0 255.255.255.0
host1(config-if)#ip rip
host1(config-if)#ip rip receive version 1
host1(config-if)#ip rip send version 2
host1(config-if)#ip rip authentication mode text
host1(config-if)#ip rip authentication key klaatu42
• Associate the RIP routing process with an interface specified by an IP address or with an unnumbered interface, and configure RIP for the interface.
host1(config-router)#address 10.2.1.1
host1(config-router)#address 10.2.1.1 receive version 1
host1(config-router)#address 10.2.1.1 send version 2
host1(config-router)#address 10.2.1.1 authentication mode text
host1(config-router)#address 10.2.1.1 authentication key 31barada
Each configuration step is optional, and includes the following:
• (Optional) Specify a RIP receive version for an interface. By default, RIP interfaces on your router receive both RIPv1 and RIPv2.
• (Optional) Specify a RIP send version for an interface. By default, RIP interfaces on your router send only RIPv1.
• (Optional) Specify an authentication mode and authentication password or key. This step is permitted only if both receive version and send version are set to RIPv2.
4 (Optional) Enable RIP to advertise a default route.
host1(config-router)#default-information originate
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5 (Optional) Specify a default metric for advertised routes.
host1(config-router)#default-metric 5
6 (Optional) Set the administrative distance for advertised routes.
host1(config-router)#distance 150
7 (Optional) Control the dynamic distribution of routes caused by changes to an associated route map.
host1(config-router)#disable-dynamic-redistribute
8 (Optional) Adjust RIP timers.
host1(config-router)#timers update 20
host1(config-router)#timers invalid 60
host1(config-router)#timers holddown 60
host1(config-router)#timers flush 90
9 (Optional) Specify maximum number of ECMP paths.
host1(config-router)#maximum-paths 2
10 (Optional) Summarize routes.
Use a prefix tree to specify the number of bits to report for routes matching a route map:
host1(config)#ip prefix-tree boston permit 10.10.2.0/24
host1(config-router)#route-map 4
host1(config-route-map)#match-set summary prefix-tree boston
Alternatively, explicitly specify routes for RIP to summarize:
host1(config-router)#ip summary-address 4.4.0.0 255.255.0.0 5
host1(config-router)#ip summary-address 4.3.0.0 255.255.0.0 6
11 (Optional) Redistribute routes from other protocols into RIP, or from RIP to other protocols.
host1(config-router)#redistribute rip 5
host1(config-router)#route-map 4
host1(config-router)#redistribute bgp 100 route-map 4
12 (Optional) Enable unicast communication with RIP neighbors.
host1(config-router)#neighbor 10.10.21.100
host1(config-router)#passive-interface atm atm 2/0.16
13 (Optional) Set the debounce time for interfaces brought down by some event.
host1(config-router)#debounce-time 30
Configuration TasksE-Series Routers
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14 (Optional) Prevent RIP from purging the routing table for interfaces brought down by some event.
host1(config-router)#interface-event-disable
15 (Optional) Prevent RIP from sending a more-specific route if a less-specific route has a better metric.
host1(config-router)#send-more-specific-routes-disable
16 (Optional) Prevent RIP from sending triggered updates.
host1(config-router)#triggered-update-disable
17 (Optional) Apply a table map to modify route distance.
host1(config-router)#table-map dist1
Relationship Between address and network CommandsIf you use the network command to configure a RIP network, use the ip rip commands to configure the RIP attributes for that network. Do not use the address commands.
If you use the address command to configure a RIP network, use the address commands to configure the RIP attributes for that network. Do not use the ip rip commands.
Note: The network and ip rip commands are maintained for industry compatibility. You can configure all your RIP interfaces with the address commands. You cannot configure unnumbered interfaces with the network and ip rip commands.
address� Use to configure RIP to run on the interface specified by the IP address or on
an unnumbered interface. Use the address commands to configure RIP attributes on the network.
� Configures RIP with the default values: Send version is RIPv1, receive version is RIPv1 and RIPv2, authentication is not enabled.
� Examplehost1(config-router)#address 10.2.1.1
� Use the no version to delete the RIP interface.
address authentication key� Use to specify either the simple password for text authentication or the
encryption/decryption key for MD5 authentication. The key is a string of up to 16 alphanumeric characters and can be mixed uppercase and lowercase.
� You can specify whether the key is entered in unencrypted or encrypted format. If you do not specify which, the string is assumed to be unencrypted.
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� Examplehost1(config-router)#address 10.2.1.1 authentication key ke6G72mV
� Use the no version to clear all authentication keys.
address authentication mode� Use to specify the authentication mode.� Specify text to send a simple text password to neighbors. If a neighbor does
not have the same password, requests and updates from this router are rejected.
� Specify md5 keyID to send an MD5 hash to neighbors. Neighbors must share the MD5 key to decrypt the message and encrypt the response.
� Examplehost1(config-router)#address 10.2.1.1 authentication mode text
� Use the no version to remove authentication from all RIP interfaces.
address receive version� Use to restrict the RIP version that the router can receive on an interface. The
default is to receive both RIPv1 and RIPv2.� Example
host1(config-router)#address 10.2.1.1 receive version 1
� Use the no version to restore the default value, 1 2.
address send version� Use to restrict the RIP version that the router can send on an interface. The
default is to send only RIPv1.� Example
host1(config-router)#address 10.2.1.1 send version 2
� Use the no version to restore the default value, 1.
clear ip rip redistribution� Use to clear all the routes that have previously been redistributed into RIP.� Example
host1#clear ip rip redistribution
� There is no no version.
debounce-time� Use to control the interval RIP waits before bringing back up an interface that
was brought down by some event.� The interval can range from 0�60 seconds.
Configuration TasksE-Series Routers
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� Examplehost1(config-router)#debounce-time 30
� Use the no version to restore the default value, 10.
default-information originate� Use to enable RIP to advertise a default route (0.0.0.0/0) if the default route
exists in the IP routing table. � If the default route does not exist, you must configure it using the ip route
command, or specify the always keyword. The always keyword causes RIP to always advertise the default route, and creates it if it is not present in the IP routing table.
� Examplehost1(config-router)#default-information originate
� Use the no version to disable advertisement of the default route.
default-metric� Use to configure RIP to apply this metric when advertising routes on all
subsequently created interfaces. � Configuring a default metric lowers the priority of the routes.� Use a metric from 1 to 16. � Example
host1(config-router)#default-metric 5
� Use the no version to restore the default value, 0.
disable� Use to disable RIP processing.� Example
host1(config-router)#disable
� Use the no version to enable RIP processing.
disable-dynamic-redistribute� Use to halt the dynamic redistribution of routes that are initiated by changes to
a route map. � Dynamic redistribution is enabled by default.� Example
host1(config-router)#disable-dynamic-redistribute
� Use the no version to reenable dynamic redistribution.
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distance� Use to set the administrative distances for routes. The default is 120.� Example
host1(config-router)#distance 150
� Use the no version to restore the default value, 120.
distribute-list� Use to apply a specific access list to incoming or outgoing RIP route updates.� An IP access list acts as a filter. Refer to the access list command in the
E-Series Command Reference Guide A to M for more information.� Example
host1(config-router)#distribute-list 5 incoming
� Use the no version to stop application of the distribute list.
interface-event-disable� Use to configure RIP to purge the routing table for interfaces that were brought
down by some event.� Example
host1(config-router)#interface-event-disable
� Use the no version to restore the default condition, wherein RIP does not automatically purge the routing table for down interfaces.
ip prefix-tree� Use to create a prefix tree to match routes to be summarized by a route map;
specifies a tree entry�a deny or permit clause for a network address.� The prefix tree name can be up to 32 characters long.� Example
host1(config)#ip prefix-tree boston42 permit 10.10.2.0/24
� Use the no version to remove the specified prefix tree or the specified tree entry.
ip rip� Use to configure RIP on the network interface specified with the network
command.� Configures RIP with the default values: Send version is RIPv1, receive version
is RIPv1 and RIPv2, authentication is not enabled. � Example
host1(config-if)#ip rip
� Use the no version to delete the RIP interface.
Configuration TasksE-Series Routers
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ip rip authentication key� Use to specify either the simple password for text authentication or the
encryption/decryption key for MD5 authentication. The key is a string of up to 16 alphanumeric characters and can be mixed uppercase and lowercase.
� You can specify whether the key is entered in unencrypted or encrypted format. If you do not specify which, the string is assumed to be unencrypted.
� Examplehost1(config-if)#ip rip authentication key ke6G72mV
� Use the no version to clear all authentication keys.
ip rip authentication mode� Use to specify the authentication mode.� Specify text to send a simple text password to neighbors. If a neighbor does
not have the same password, requests and updates from this router are rejected.
� Specify md5 keyID to send an MD5 hash to neighbors. Neighbors must share the MD5 key to decrypt the message and encrypt the response.
� Examplehost1(config-if)#ip rip authentication mode text
� Use the no version to remove authentication from all RIP interfaces.
ip rip receive version� Use to restrict the RIP version that the router can receive on an interface. The
default is both RIPv1 and RIPv2.� Example
host1(config-if)#ip rip receive version 1
� Use the no version to restore the default value, 1 2.
ip rip send version� Use to restrict the RIP version that the router can send on an interface. The
default is RIPv1. � Example
host1(config-if)#ip rip send version 2
� Use the no version to restore the default value, 1.
ip split-horizon� Use to configure the split horizon feature and poison reverse features for the
interface. Enabled by default, split horizon prevents the RIP router from advertising routes from the originating interface.
� Poison reverse routing updates are disabled by default; when enabled, they set the metric for routes originating on the interface to infinity, thus explicitly advertising that the network is not reachable. This helps to prevent routing loops.
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� In most configurations, you will want to accept the default condition.� Example
host1(config-if)#no ip split-horizon
� Use the no version to disable split horizon and enable poison reverse routing updates.
ip summary-address� Use to specify an IP address and network mask to identify which routes to
summarize.� You can optionally specify a metric associated with the summary address. The
default metric is 1.� Example
host1(config-router)#ip summary-address 4.4.0.0 255.255.0.0 5
host1(config-router)#ip summary-address 4.3.0.0 255.255.0.0 6
� Use the no version to stop summarization for the specified routes.
match-set summary prefix-tree� Use to specify a prefix tree that summarizes routes for a particular route map.� Use the ip prefix-tree command to set the conditions of the prefix tree,
including which routes to summarize and how many bits of the network address to preserve.
� Examplehost1(config-route-map)#match-set summary prefix-tree boston
� Use the no version to disable the use of the prefix tree by the route map.
maximum-paths� Use to control the maximum number of parallel routes that RIP can support.� RIP installs multiple equal-cost paths to a given destination only if each has a
different next hop.� The maximum number of routes can range from 1�16. � Example
host1(config-router)#maximum-paths 2
� Use the no version to restore the default value, 4.
Configuration TasksE-Series Routers
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neighbor� Use to specify a RIP neighbor to which the router sends unicast messages. � You must also use the passive-interface command to specify the interface as
passive, thereby restricting the interface to unicast RIP messages.� Example
host1(config-router)#neighbor 10.10.21.100
� Use the no version to remove the neighbor.
network� Use to associate a network with a RIP routing process. Use the ip rip
commands to configure RIP attributes on the network.� You supply a network mask to the new address so that RIP runs on that specific
network.� If you do not specify an interface�s network, the network is not advertised in any
RIP updates.� You can specify either the standard subnet mask or the inverse subnet mask.� Example 1
host1(config-router)#network 10.2.1.0 255.255.255.0
� Example 2host1(config-router)#network 10.2.1.0 0.0.0.255
� Use the no version to disable RIP on the specified interface.
passive-interface� Use to disable the transmission of multicast RIP messages on the interface.� RIP messages are unicast to a RIP neighbor on the interface if the interface is
present in the IP routing table as the next-hop interface to the configured neighbor.
� Examplehost1(config-router)#passive-interface atm atm 2/0.16
� Use the no version to reenable the transmission of RIP multicast messages on the specified interface.
redistribute� Use to redistribute information from a routing domain other than RIP into the
RIP domain.� Example 1
host1(config)#router rip 5
host1(config-router)#redistribute bgp 100 route-map 4
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� Specify the source protocol from which routes are being redistributed. It can be one of the following keywords: bgp, isis, ospf, static [ip], and connected. Use the static keyword to redistribute IP static routes; optionally add the ip keyword when redistributing into IS-IS. The keyword connected refers to routes that are established automatically by virtue of having enabled IP on an interface. For routing protocols such as OSPF and IS-IS, these routes will be redistributed as external to the AS.
� Use the route-map keyword to interrogate the route map to filter the importation of routes from the source routing protocol to the current routing protocol. If you do not specify the route-map option, all routes are redistributed. If you specify the route-map option, but no route map tags are listed, no routes will be imported.
� Use to redistribute routes from RIP into other non-RIP routing domains.� Example 2
host1(config)#router bgp 100
host1(config-router)#redistribute rip 5
� Use the no version to disable redistribution.
route-map� Use to specify a route map for RIP.� Example
host1(config)#router rip
host1(config-router)#route-map 4
� Use the no version to delete the route map. If you do not specify an interface, it removes the global route map if it exists.
router rip� Use to enable RIP routing protocol and specify a RIP process for IP, or to
access Router Configuration mode.� Specify only one RIP process per router.� Example
host1(config)#router rip
� Use the no version to delete the RIP process and removes the configuration from your router.
send-more-specific-routes-disable� Use to configure RIP to send a less-specific route in preference to a
more-specific route if the less-specific route has a metric.� Example
host1(config-router)#send-more-specific-routes-disable
� Use the no version to restore the default condition, wherein RIP always sends a more-specific route in preference to a less-specific route, even if the less-specific route has a metric.
Configuration TasksE-Series Routers
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table-map� Use to apply a policy to modify distance, metric, or tag values of RIP routes
about to be added to the IP routing table.� The new route map is applied to all routes currently in and those subsequently
placed in the forwarding table. Previously redistributed routes are redistributed with the changes caused by the route map.
� To remove from the forwarding table any old routes that are now disallowed by the specified route map, you must refresh the IP routing table with the clear ip routes * command.
� Examplehost1(config)#route-map dist1 permit 5
host1(config-route-map)#match community boston42
host1(config-route-map)#set distance 33
host1(config-route-map)#exit
host1(config)#router rip 100
host1(config-router)#table-map dist1
host1(config-router)#exit
host1(config)#exit
host1#clear ip routes *
� Use the no version to halt application of the route map.
timers� Use to configure RIP timers.� The router supports the following RIP timers:
� update � interval in seconds at which routing updates are sent. The default is 30 seconds.
� invalid � interval in seconds after which a route is declared invalid (null). Set this value to at least three times the update value. The default is 180 seconds.
� holddown � interval in seconds during which routing information about better paths is suppressed. Set this value to at least three times the update value. The default is 120 seconds.
� flush � interval in seconds that must pass before a route is removed from the routing table. Set this value greater than the invalid value. The default is 300 seconds.
� Exampleshost1(config-router)#timers update 20
host1(config-router)#timers invalid 60
host1(config-router)#timers holddown 60
host1(config-router)#timers flush 90
� Use the no version to restore the default values, 30 180 120 300.
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triggered-update-disable� Use to prevent RIP from sending triggered routing updates.� Example
host1(config-router)#triggered-update-disable
� Use the no version to restore the default condition, wherein RIP does sends triggered routing updates.
version� Use to specify the global RIP version. The default is RIPv1.� To change the RIP version on a specific interface, use the ip rip receive
version and the ip rip send version commands, or the address receive version and address send version commands.
� Examplehost1(config-router)#version 2
� Use the no version to revert to the default value, 1.
Using RIP Routes for Multicast RPF ChecksYou can use the ip route-type command to specify whether RIP routes are available for only unicast forwarding protocols or only multicast reverse path forwarding (RPF) checks. Routes available for unicast forwarding appear in the unicast view of the routing table, whereas routes available for multicast RPF checks appear in the multicast view of the routing table.
ip route-type� Use to specify whether RIP routes are available only for unicast forwarding,
only for multicast reverse path forwarding checks, or for both.� Use the show ip route command to view the routes available for unicast
forwarding.� Use the show ip rpf-routes command to view the routes available for multicast
reverse path forwarding checks.� By default, RIP routes are available for both unicast forwarding and multicast
reverse path forwarding checks.� Example
host1(config)#router rip
host1(config-router)#ip route-type unicast
� Use the no version to restore the default value, both.
Remote NeighborsE-Series Routers
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Remote NeighborsYou can create RIP remote neighbors to enable the router to establish neighbor adjacencies through unidirectional interfaces, such as MPLS tunnels, rather than the standard practice of using the same interface for receipt and transmission of RIP packets. The remote neighbor can be more than one hop away through intermediate routes that are not running RIP. RIP uses the interface associated with the best route to the remote neighbor to reach the neighbor. A best route to the neighbor must exist in the IP routing table.
You must explicitly configure remote neighbors on the RIP routers to specify the remote neighbor with which the router will form an adjacency and the source IP address the router will use for RIP packets destined to its peer remote neighbor.
To form an adjacency with its remote neighbor, the router sends all RIP packets to the remote neighbor as unicast packets with the destination IP address equal to the source IP address of the remote neighbor. The loopback interface associated with the source IP address for the remote neighbor acts as a logical RIP interface for the neighbor.
To prevent routing loops, you can disable split horizon and enable poison reverse routing updates.
The remote-neighbor command to specify the remote neighbors is mandatory. Configuration of all other remote-neighbor attributes is optional.
authentication key� Use to specify the password for text authentication and the key for MD5
authentication for RIP remote-neighbor interface. � This command is supported only in RIPv2. Authentication is disabled by
default.� Example
host1(config-router-rn)#authentication key 0 jun27ior
� Use the no version to clear the key for the remote-neighbor interface.
authentication mode� Use to specify the authentication mode for the remote neighbor interface.� Specify text to send a simple text password to remote neighbors. If a remote
neighbor does not have the same password, requests and updates from this router are rejected.
� Specify md5 keyID to send an MD5 hash to remote neighbors. Remote neighbors must share the MD5 key to decrypt the message and encrypt the response.
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� This command is supported only in RIPv2. Authentication is disabled by default.
� Examplehost1(config-router-rn)#authentication mode text
� Use the no version to remove authentication from the RIP remote-neighbor interface.
distribute-list� Use to apply a specific access list to either incoming or outgoing RIP route
updates on the RIP remote-neighbor interface.� An IP access list acts as a filter. Refer to the access list command in the
E-Series Command Reference Guide A to M for more information.� Example
host1(config)#distribute-list 5 in
� Use the no version to stop application of the distribute list.
exit-remote-neighbor� Use to exit from the Remote Neighbor Configuration mode and return to Router
Configuration mode.� Example
host1(config-router-rn)#exit-remote-neighbor
� There is no no version.
receive version� Use to restrict the RIP version that the router can receive on a RIP
remote-neighbor interface. The default is to receive both RIPv1 and RIPv2.� The off keyword overrides any other specified option; for example, configuring
both 1 and off or both 2 and off has the same result as configuring only off. � Example
host1(config-router-rn)#receive version 1
� Use the no version to restore the default value, 1 2.
remote-neighbor� Use to configure a RIP remote neighbor.� Example
host1(config-router)#remote-neighbor 10.25.100.14
� Use the no version to remove the remote neighbor and any attributes configured for the remote neighbor.
Remote NeighborsE-Series Routers
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send version� Use to restrict the RIP version that the router can send on an interface. The
default is to send only RIPv1.� Example
host1(config-router-rn)#send version 1
� Use the no version to restore the default value, 1.
split-horizon� Use to configure the split horizon and poison reverse features for RIP remote
neighbors. � Split horizon is enabled by default; poison reverse routing updates are disabled
by default. � Poison reverse routing updates set the metric for routes originating on the
interface to infinity, thus explicitly advertising that the network is not reachable. This helps to prevent routing loops.
� Examplehost1(config-router-rn)#no split-horizon
� Use the no version to disable the split horizon and enable poison reverse routing updates.
time-to-live� Use to configure a hop count by setting the value of the time-to-live field used
by packets sent to a RIP remote neighbor.� Example
host1(config-router-rn)#time-to-live 12
� Use the no version to restore the default value, 16.
update-source� Use to specify the RIP interface whose local address is used as the source
address for the RIP connection to a remote neighbor. � The source address assigned to a remote neighbor must be unique. If you
configure a RIP router to form neighbor adjacencies with two RIP remote neighbors, then the RIP router must have two unique local source IP addresses, one for each of its remote neighbors.
� Examplehost1(config-router-rn)#update-source atm 2/0.17
� Use the no version to delete the source address from the connection to the remote neighbor.
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Monitoring RIPTwo sets of commands enable you to monitor RIP operation on your router: the debug and the show commands. Both sets of commands provide information about your router’s RIP state and configuration.
The task you are performing with each of these monitoring commands is basically the same for each command; that is, you are requesting information. The results of this request may vary. For instance, the debug commands provide information about problems with the network or the router, whereas the show commands provide information about the actual state and configuration of your router.
debug CommandsThe debug commands provide information about the following RIP items:
• General events, such as creating a RIP process or removing RIP from an interface
• Routing events, such as when two RIP routers exchange routes
debug ip rip� Use to display information on selected RIP events. This command has many
keywords that allow you to specify a variety of RIP events.� You can set the level of severity for the events you want displayed; specify the
desired descriptive term or a corresponding number (0�7).� You can set the verbosity of the messages you want displayed: low, medium,
high.� Example
host1#debug ip rip events
� Use the no version to cancel the display of any information on the designated variable.
undebug ip rip� Use to cancel the display of information on a selected event.� The same RIP variables can be designated as in the debug ip rip command.� Example
host1#undebug ip rip events
� There is no no version.
Monitoring RIPE-Series Routers
8-23
show CommandsUse the show commands to monitor the following types of RIP information:
• Configuration
• IP-related information
• Global counters
• Counters for a specified network
• Statistics
You can set a statistics baseline for RIP interfaces by using the baseline ip rip command.
You can specify a VRF instance for the show ip rip commands. You can use the output filtering feature of the show command to include or exclude lines of output based on a text string you specify. See E-Series System Basics Configuration Guide, Chapter 2, Command Line Interface, for details.
baseline ip rip� Sets a statistics baseline for RIP interfaces. � The router implements the baseline by reading and storing the statistics at the
time the baseline is set and then subtracting this baseline whenever baseline-relative statistics are retrieved.
� Use the optional delta keyword with the show ip rip statistics command to specify that baselined statistics are to be shown.
� Examplehost1#baseline ip rip
� There is no no version.
show ip rip� Use to display RIP information.� Specify vrf vrfName to limit the display to a specific VRF.� Use the ifconfig keyword to display address and interface configuration
information instead of the default operational data.� Field descriptions
� Router Administrative State � displays the RIP state. Enable means the router is allowed to send and receive updates. Disable means that RIP might be configured but it is not allowed to run yet.
� System version RIP1 � RIP versions allowed for sending and receiving RIP updates. The router version is currently set to RIP1, which sends RIPv1 but will receive RIPv1 or RIPv2. If it is set to RIP2, it will send and receive RIPv2 only. The default is configured for RIP1.
CHAPTER 8Configuring RIP
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� Incoming filters � access list applied to incoming route updates� Outgoing filters � access list applied to outgoing route updates� Global route map � route map that specifies all RIP interfaces on the router� Default metric � value for redistributed routes. The default is 1. This global
value is superseded by metrics applied to a RIP interface.� Distance � value added to RIP routes added to the IP routing table. The
default is 120.� Number of route changes � number of times the router has been told to
route changes by its peers� Number of route queries � number of times the router has received route
requests from other routers� Update interval � current setting of the update timer (in seconds)� Invalid interval � current setting of the invalid timer (in seconds)� Hold down time � current setting of the hold-down timer (in seconds)� Flush interval � current setting of the flush timer (in seconds)� Network � IP address of a network on which RIP is running� Netmask � network mask applied to the network address� Address/status/interface � values listed for each network that is running RIP� Send version � version of RIP used for sending updates� Receive version � version of RIP accepted in received updates� Authentication mode � password or MD5 authentication, or none� Default metric � metric value applied to the RIP interface. The default is 1.� Outgoing access-list � name of the access list applied to outgoing routes� Incoming access-list � name of the access list applied to incoming routes� Outgoing route-map � name of the route map applied to outgoing routes� Received bad packets � number of bad packets received� Received bad routes � number of bad routes received� Triggered updates sent � number of triggered updates sent; triggered
updates are sent before the entire RIP routing table is sent; triggered by events such as adding a new RIP route or redistribution
� Received updates � number of updates received� Example
host1#show ip rip
Routing Information Protocol
Router Administrative State = enable
System version RIP1: send = 1, receive = 1 or 2
No filter is applied to outgoing route update for all interfaces
No filter is applied to incoming route update for all interfaces
No global route map
Default metric = 1
Distance = 120
Number of route changes = 0
Monitoring RIPE-Series Routers
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Number of route queries = 0
Update interval = 30 (secs)
Invalid interval = 180 (secs)
Hold down time = 120 (secs)
Flush interval = 300 (secs)
Network netmask
10.2.1.0 255.255.255.0
10.2.1.32, Rip is up, fastEthernet0/0
Send version = 1
Receive version = 1,2
Authentication mode = none
Default metric = 1
Access-list applied to outgoing route = none
Access-list applied to incoming route = none
Route-map applied to outgoing route = none
Received bad packet = 0
Received bad routes = 0
Triggered updates sent = 0
Received updates = 0
170.100.100.2, Rip is up, fastEthernet0/0
Send version = 1
Receive version = 1,2
Authentication mode = none
Default metric = 1
Access-list applied to outgoing route = none
Access-list applied to incoming route = none
Route-map applied to outgoing route = none
Received bad packet = 0
Received bad routes = 0
Triggered updates sent = 0
Received updates = 0
show ip rip brief � Use to display limited RIP information.� Specify vrf vrfName to limit the display to a specific VRF.� Field descriptions
� IP Address � IP address of the interface where RIP is running� Tx � transmit version of RIP on this interface, which can override the router
configuration � Rx � receive version of RIP on this interface� Auth � type of authentication, password (text) or MD5� Met � current value is the same as the router one (the default metric). Based
on MIB 2 for RIP, the interface�s route metric can be set individually.� AccList O/I � access list applied to outgoing/incoming RIP route updates� RtMap � identifier for the route map that specifies a summary of RIP routes
CHAPTER 8Configuring RIP
8-26
� Status � status of RIP, either up or down� Intf � interface type on which RIP is running
� Examplehost1#show ip rip brief
IP Address Tx Rx Auth Met AccList O/I RtMap Status Intf
10.2.1.32 1 1,2 none 1 no/no no up fastEthernet0/0
10.10.1.2 1 1,2 none 1 no/no no up serial5:1/1:1
show ip rip database� Use to display the route entries in the RIP routing table.� Specify vrf vrfName to limit the display to a specific VRF.� Specify the active keyword to limit the display to active routes learned via RIP
updates.� Specify the inactive keyword to limit the display to routes that the router will
discard in the immediate future.� Field descriptions
� Prefix � IP address prefix� Length � prefix length� ttl � (time to live) indicates how many seconds the specific route remains in
the routing table. If an entry reaches 0, it is removed from the routing table.� Met � metric that RIP uses to rate the value of different routes (hop count).
The hop count is the number of routers that can be traversed in a route.� Next Hop � next IP address where a packet is sent. A value of zero in this
field indicates that the next address the packet should be sent to is the router that originally sent the RIP message.
� Intf � interface that the route has learned� Example
host1#show ip rip database
Prefix/Length: ttl Met: Next Hop Intf:
3.0.0.0/8 0 1 72.30.100.2 tm2/1.100
9.20.0.0/17 0 2 172.30.100.1 tm2/1.100
10.2.1.0/24 0 2 172.30.100.1 tm2/1.100
Monitoring RIPE-Series Routers
8-27
show ip rip network� Use to display the networks associated with the RIP routing process.� Specify vrf vrfName to limit the display to a specific VRF.� Field descriptions
� network � IP address of a network on which RIP is running� netmask � network mask applied to the network address
� Examplehost1#show ip rip network
Network netmask
10.2.1.0 255.255.255.0
172.30.100.0 255.255.255.0
172.30.200.0 255.255.255.0
show ip rip peer� Use to display limited information about each RIP neighbor.� Specify vrf vrfName to limit the display to a specific VRF.� Field descriptions
� Time since last update received � time in seconds since an update was received from this peer
� Peer version � version of IS-IS running on the peer� Bad packets received � number of bad packets received from the peer� Bad routes received � number of bad routes received from the peer
� Examplehost1#show ip rip peer
192.168.1.102
Time since last update received = 24
Peer version = 1
Bad packet received = 0
Bad routes received = 0
192.168.1.151
Time since last update received = 24
Peer version = 1
Bad packet received = 0
Bad routes received = 0
192.168.1.158
Time since last update received = 15
Peer version = 1
Bad packet received = 0
Bad routes received = 0
192.168.1.250
Time since last update received = 7
Peer version = 2
Bad packet received = 0
Bad routes received = 0
CHAPTER 8Configuring RIP
8-28
show ip rip statistics� Use to display global and session statistics counters for RIP. If you specify an
IP address, statistics for that interface are displayed in addition to the global RIP statistics.
� Specify vrf vrfName to limit the display to a specific VRF.� Use the optional delta keyword to specify that baselined statistics are to be
shown. You must use the baseline ip rip command to set a baseline.� Field descriptions
� Number of route changes � number of times the router has been told to route changes by its peers
� Number of route queries � number of times the router has received route requests from other routers
� Received bad packets � number of bad packets received from the peer� Received bad routes � number of bad routes received from the peer� Triggered updates sent � number of triggered updates sent; triggered
updates are sent before the entire RIP routing table is sent; triggered by events such as adding a new RIP route or redistribution
� Received updates � number of updates received� Example
host1#show ip rip statistics
Number of route changes = 23
Number of route queries = 0
� Examplehost1#show ip rip statistics 10.2.1.32
Number of route changes = 901
Number of route queries = 0
fastEthernet 0/0, 10.2.1.32
Received bad packet = 0
Received bad routes = 0
Triggered updates sent = 2
Received updates = 41
show ip rip summary-address� Use to display the specified summary address or all summary addresses for
RIP.� Field descriptions
� Summary Address � address summarizing RIP routes� Mask � network mask specified in the ip summary-address command to
identify which routes to summarize� Metric � metric advertised with the summary RIP prefix
Monitoring RIPE-Series Routers
8-29
� Examplehost1#show ip rip summary-address
Summary Address Mask Metric
4.3.0.0 255.255.0.0 3
4.4.0.0 255.255.0.0 5
CHAPTER 8Configuring RIP
8-30
9
Configuring OSPFThis chapter provides information for configuring the Open Shortest Path First (OSPF) routing protocol on your E-series router.
Topic Page
Overview 9-2
References 9-4
Features 9-5
Configuration Tasks 9-8
Enabling OSPF 9-9
Aggregating OSPF Networks 9-12
Configuring OSPF Interfaces 9-13
Configuring OSPF Areas 9-19
Configuring Authentication 9-22
Configuring Additional Parameters 9-27
Configuring OSPF for NBMA Networks 9-34
Traffic Engineering 9-35
Using OSPF Routes for Multicast RPF Checks 9-37
OSPF and BGP/MPLS VPNs 9-37
Remote Neighbors 9-37
Disabling and Reenabling Incremental SPF 9-40
Configuring OSPF Traps 9-41
Monitoring OSPF 9-42
CHAPTER 9Configuring OSPF
9-2
OverviewOSPF is an interior gateway protocol (IGP) that runs within a single autonomous system (AS). Exterior gateway protocols (EGP), such as Border Gateway Protocol (BGP), exchange routing information between ASs.
OSPF is a link-state routing protocol, similar to the Intermediate System-to-Intermediate System (IS-IS) routing protocol. It advertises the states of its local network links. This distinguishes OSPF from some IGPs, such as Routing Information Protocol (RIP). A distance vector protocol, such as RIP, advertises the distances (that is, the number of hops) to each known destination within the network.
Each participating OSPF router within the AS has an identical database describing the AS’s topology. Each individual piece of this database is a particular router’s local state. From this database, OSPF calculates a routing table by constructing a shortest-path tree.
OSPF learns the best routes to reachable destinations. It can quickly perceive changes in the topology of an AS and, after a short convergence period, calculate new loop-free routes. This protocol has been designed expressly for the TCP/IP Internet environment, including explicit support for classless interdomain routing (CIDR) and the tagging of externally derived routing information.
This chapter provides direction for customizing basic OSPF settings if you need to do so. For detailed information on the OSPF commands, see the E-Series Command Reference Guide N to Z.
TermsTable 9-1 defines commonly used OSPF terms.
Table 9-1 OSPF-related terms
Term Meaning
adjacency The relationship between selected neighboring routers for exchanging routing information. Not every pair of neighboring routers is adjacent.
area An OSPF area is a collection of network segments interconnected by routers. It is a region in an OSPF routing domain.
area border router (ABR) A router that sits on the edge of an OSPF area and routes link state advertisements (LSAs) between areas.
area ID A unique number that identifies an area. Typically, an IP address.
OverviewE-Series Routers
9-3
authentication Contains verification information and is 64 bits long.
authentication type A simple password is an example. All OSPF protocol exchanges are authenticated. The authentication type is configurable on a per-area basis.
autonomous system (AS) A group of routers using a common routing protocol to exchange routing information.
autonomous system boundary router (ASBR)
An OSPF router that redistributes routes from other autonomous systems.
classless interdomain routing (CIDR)
CIDR replaces the traditional class structure of IP addresses. In CIDR, an IP network is represented by a prefix and a notation that indicate the IP address and mask�for example, 10.12.8.3/16
designated router Generates an LSA for the network. Performs other special responsibilities in running the protocol.
domain A collection of routers that use a common IGP constitutes an OSPF routing domain.
flooding The distribution and synchronization of the link-state database between OSPF routers.
hello protocol Establishes and maintains neighbor relationships. Also, dynamically discovers neighboring routers on broadcast networks.
interior gateway protocol (IGP)
A routing protocol that routers within an AS use to exchange information.
link state advertisement (LSA)
A unit of data that describes the local state of a router or network. LSAs are flooded throughout the routing domain.
neighboring routers Routers that have interfaces to a common network.
nonbroadcast network A network that has no broadcast capability but supports more than two routers.
Not-so-stubby area (NSSA)
Similar to a stub area but can also import selected external LSAs.
router ID A 32-bit number that uniquely identifies a router within an AS�for example, 10.10.1.5
stub area An area that does not get flooded with external LSAs but does carry intra-area and interarea routes and a default route.
virtual link A logical link between two backbone routers where the link tunnels through a nonbackbone area.
Table 9-1 OSPF-related terms (continued)
Term Meaning
CHAPTER 9Configuring OSPF
9-4
Figure 9-1 illustrates the topology of an OSPF routing domain.
Figure 9-1 OSPF topology
ReferencesIf you need more information about the OSPF protocol, consult the following resources:
• E-Series Release Notes, Appendix A, System Maximums – See the Release Notes corresponding to your software release for information on maximum values.
• RFC 2328 – OSPF Version 2 (April 1998)
• RFC 2370 – The OSPF Opaque LSA Option (July 1998)
• Traffic Engineering Extensions to OSPF Version 2 – draft-katz-yeung-ospf-traffic-09.txt (April 2003 expiration)
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FeaturesE-Series Routers
9-5
Note: IETF drafts are valid for only 6 months from the date of issuance. They must be considered as works in progress. Please refer to the IETF Web site at http://www.ietf.org for the latest drafts.
FeaturesThe following sections provide a brief description of key OSPF features supported in our implementation of OSPF.
Intra-area, Interarea, and External RoutesYou can split up an OSPF AS into areas. Doing this reduces the size of the link-state database (LSDB). Each OSPF area runs as a separate network and maintains its own LSDB. OSPF computes routes only to destinations within the area and does not f lood routes beyond the area boundaries.
Routing PriorityOSPF areas receive routes based on priority. Table 9-2 lists the routing priority.
If you use the redistribute command to import routes from other protocols or sources, the routes default to external type 2. You can specify a route map with the redistribute command to modify the type.
Table 9-2 Routing priority
Priority Type Description
1 (highest) Intra-area Intra-area routing. Refers to routing within a single OSPF area.
2 Interarea Interarea routing. Refers to routing between OSPF areas within a single OSPF routing domain.
3 External External type 1. Refers to routing from other protocols that can be imported into the OSPF domain and readvertised by OSPF as type 1 external.Type 1 metric is comparable to the link-state metric; the cost is equal to the sum of the internal costs plus the external cost.
4 (lowest) External External type 2. Refers to routing from other protocols that can be imported into the OSPF domain and readvertised by OSPF as type 2 external.Type 2 metric is much larger than the cost of any intra-AS path; the cost is equal to the external cost. This is the OSPF default.
CHAPTER 9Configuring OSPF
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Alternatively, you can use the metric-type keyword with the redistribute command to specify the type.
Virtual LinksEach OSPF area must be directly connected to the backbone area. The backbone is responsible for distributing routing information between nonbackbone areas. All routers in the backbone must be contiguous, but they need not be physically adjacent. You can configure backbone routers to be logically adjacent by creating OSPF virtual links.
AuthenticationOSPF supports three modes of authentication:
• Null authentication – Implies no authentication is in use
• Simple password authentication – Requires a 64-bit unencrypted password in each OSPF packet
• Cryptographic authentication – Uses a shared secret key that is configured on each router on a network. RFC 2328 defines the use of OSPF cryptographic authentication with the MD5 algorithm.
Opaque LSAsOSPF opaque LSAs provide a generalized way of extending OSPF. The router generates opaque LSAs to carry traffic engineering (TE) information, accepts them from other routers, and floods them accordingly. OSPF uses the TE information to build a database from which paths can be computed for MPLS label-switched paths.
Route LeakageRoutes can be leaked into OSPF or from OSPF as follows:
• Route leakage into OSPF – When another routing protocol adds a new route to the routing table, or when a static route is added to the routing table, OSPF can be informed through the redistribute commands. When OSPF learns the new route, it f loods the information into the routing domain using external LSAs.
• Route leakage from OSPF – OSPF adds routing information to the routing table, which is used in forwarding IP packets.
FeaturesE-Series Routers
9-7
Equal-Cost MultipathOSPF inherently supports the notion of equal-cost multipath (ECMP). When building the shortest-path tree, OSPF calculates all paths of equal cost to a given destination. If equal-cost paths exist, OSPF inserts into the routing table the next hops for all equal-cost paths to a destination.
OSPF MIBSee the JUNOSe Software CD, shipped with your router, for complete information on the OSPF Management Information Base (MIB) supported by your router. In the MIBs folder you will find information on all supported standard and Juniper Networks E-series enterprise (proprietary) MIBs. OSPF does not act as a host within the router and therefore does not support the ospfIfMetric and ospfHost tables.
Interacting with Other Routing ProtocolsOSPF interacts seamlessly with other routing protocols.
With IS-ISOSPF was developed originally from an early version of the IS-IS intradomain routing protocol. OSPF can receive IS-IS routing information. See Chapter 10, Configuring IS-IS.
With RIPE-series routers can simultaneously run OSPF and RIP. When doing so, OSPF routes are preferred over RIP. In general, use of the OSPF protocol is preferred because of its robustness, responsiveness, and decreased bandwidth requirements. See Chapter 8, Configuring RIP.
With BGPThe default expectation is that your routing environment is an AS running OSPF and exchanging BGP routes with other ASs. See E-Series Routing Protocols Configuration Guide, Vol. 2, Chapter 1, Configuring BGP Routing.
CHAPTER 9Configuring OSPF
9-8
Configuration Tasks Configuring OSPF calls for careful coordination among a variety of routers:
• Routers internal to a single area
• Routers that link multiple areas within a single routing domain; these routers are called area border routers (ABRs).
• Routers that link multiple routing domains; these routers are called autonomous system boundary routers (ASBRs).
To configure OSPF:
1 Enable OSPF.
2 Configure and aggregate network ranges.
3 Create the router’s OSPF network interfaces.
4 Define the OSPF areas attached to the router.
Configuring OSPF InterfacesYou can create OSPF interfaces in the following ways:
• You can issue the network area command, which creates OSPF interfaces for all IP interfaces with IP addresses within the specified range.
• You can issue the address area command, which creates an OSPF interface in the specified area that sits on top of the IP interface at the given IP address (or on the unnumbered interface, if that is specified).
Note: Do not enable OSPF on any unidirectional interfaces (such as an MPLS tunnel) because it will never be able to form an adjacency.
You can delete OSPF interfaces in the following ways:
• You can issue the no network area command, which deletes all OSPF interfaces within the specified range.
• If the OSPF interface was created with the address area command, you can issue the no address area command to delete the specified interface.
• You can issue the no ip address command to delete the IP interface associated with the OSPF interface and also the OSPF interface itself.
Note: If an OSPF interface is configured on top of an IP interface and you delete the IP interface, the corresponding OSPF interface is also deleted. The previously
Enabling OSPFE-Series Routers
9-9
configured network range, however, is not deleted. You must issue the no network area command to delete the range.
Enabling OSPFWhen you enable OSPF on your router, you can create either a range of OSPF interfaces or a single OSPF interface.
Creating a Range of OSPF InterfacesTo create a range of OSPF interfaces:
1 Create an OSPF routing process.
2 Create the range of IP addresses associated with the routing process and the corresponding OSPF interfaces.
3 Assign an area ID associated with each range of IP addresses.
Each router running OSPF has a database describing a map of the routing domain. This map needs to be identical in all participating routers.
network area� Use to configure a range of OSPF interfaces and their related area.� If the specified range matches one or more of the IP addresses configured for
IP interfaces, one or more corresponding OSPF interfaces are created and placed in the specified area.
� Create address ranges that do not overlap; you can attach only the same range of interfaces to a single area.
� You cannot use this command for unnumbered interfaces.� If the range specified by this command includes an address on an interface that
is being referred to by unnumbered interfaces, all of the unnumbered interfaces will begin trying to form adjacencies. If this behavior is not intended, you must reevaluate the interface assignment or the range specified by the command.
� Example 1 shows the creation of one OSPF interface in the backbone area:host1(config-if)#ip address 2.2.2.1 255.255.0.0
host1(config-if)#ip address 2.2.1.1 255.255.0.0 secondary
host1(config)#router ospf 2
host1(config-router)#network 2.2.2.0 0.0.0.255 area 0
CHAPTER 9Configuring OSPF
9-10
� Example 2 shows the creation of two OSPF interfaces, one in the backbone area and one in a non-backbone area:host1(config-if)#ip address 2.2.2.1 255.255.255.0
host1(config-if)#ip address 2.2.1.1 255.255.255.0 secondary
host1(config)#router ospf 2
host1(config-router)#network 2.2.2.0 0.0.0.255 area 0
host1(config-router)#network 2.2.1.0 0.0.0.255 area 1
This sequence of commands creates two OSPF ranges (2.2.2.0/24 and 2.2.1.0/24), with each range belonging to a different area. Area 0 is configured for 2.2.2.0/24, and area 1 is configured for 2.2.1.0/24. This sequence also creates two OSPF interfaces: one in the backbone area (area 0) using IP address 2.2.2.1, the second in a nonbackbone area (area 1) using IP address 2.2.1.1. This command also creates the two areas if they do not already exist.
� Use the no version to delete OSPF interfaces, ranges, and areas.Note: The configured network range is not active for summarization until you activate this range for summaries by issuing the area range command. The only range that is active by default if you do not issue the area range command is the network that matches the IP interface�s network exactly. (In other words, by default the exact network of the IP interface is going to be summarized into other areas.)
Note: Active for summarization means that the network range is summarized through area summaries�for ABRs only. See the Aggregating OSPF Networks section in this chapter.
ospf enable� Use to enable OSPF on the router.� OSPF is enabled by default.� Example
host1(config-router)#ospf enable
� The no version of this command is obsolete and may be removed in the future. Use the ospf shutdown command to disable OSPF on the router.
router ospf� Use to set an OSPF process ID.� The process ID can be any positive integer 1�65535. � You must assign a unique ID for each OSPF routing process.� From a virtual router context you can specify a VRF name. Doing so changes
the context to that of the specified VRF and remains so until you exit from the OSPF router context.
� Examplehost1(config)#router ospf 5
� Use the no version to end the designated OSPF routing process.
Enabling OSPFE-Series Routers
9-11
Creating a Single OSPF InterfaceTo create a single OSPF interface:
1 Create an OSPF routing process.
2 Create the OSPF interface associated with the IP interface at the specified address.
Each router running OSPF has a database describing a map of the routing domain. This map needs to be identical in all participating routers.
address area� Use to create an interface in an area on which OSPF runs, on top of the IP
interface at the specified IP address.� You can specify either an IP address or an unnumbered interface.� Configures OSPF with the default values. You can configure the interface with a
nondefault value by using the other address commands. You must first issue the address area command before issuing any other address commands. See Configuring OSPF Interfaces in this chapter for more information.
� Examplehost1(config-router)#address 10.10.32.100 area 0.0.0.0
� Use the no version to delete the OSPF interface.
ospf enable� Use to enable OSPF on the router.� OSPF is enabled by default.� Example
host1(config-router)#ospf enable
� The no version of this command is obsolete and may be removed in the future. Use the ospf shutdown command to disable OSPF on the router.
router ospf� Use to set an OSPF process ID.� The process ID can be any positive integer 1�65535. � You must assign a unique ID for each OSPF routing process.� Example
host1(config)#router ospf 5
� Use the no version to end the designated OSPF routing process.
CHAPTER 9Configuring OSPF
9-12
Aggregating OSPF NetworksYou can aggregate OSPF networks at the border of an OSPF area by using the area range command. You can also aggregate OSPF networks when entering the border of the OSPF domain by using the summary-address command.
area range� Use to aggregate OSPF routes at an OSPF area border.� Use only for ABRs.� You can configure multiple instances of the area range command for a single
OSPF area.� The following example shows the steps you must take to create an area range.
1 Configure the interface�s IP address(es) using the ip address command.2 Enable OSPF using the router ospf command.3 Configure the network area with the network area command.4 Configure the area range with the area range command.
� Examplehost1(config-if)#ip address 2.2.10.1 255.255.255.0
host1(config-if)#ip address 2.2.11.1 255.255.255.0 secondary
host1(config)#router ospf 2
host1(config-router)#network 2.2.0.0 0.0.255.255 area 0
At this point, the OSPF process is configured with two OSPF interfaces. If your router is an ABR, two networks must be summarized: 2.2.10.0/24 and 2.2.11.0/24.host1(config-router)#area 0 range 2.2.0.0 255.255.0.0
After you enter this area range command, only the aggregated range 2.2.0.0/16 is going to be summarized.
� By default, the range of configured networks is advertised in type 3 (summary) LSAs.
� Use the do-not-advertise keyword to prevent advertisement of configured networks.
� Use the command no area area-id (with no other keywords) to remove the specified area from the configuration.
� Use the summary-address command to summarize external routes being redistributed into OSPF.
� Use the no version to disable the aggregation of routes at the OSPF area border.
summary-address� Use to aggregate external routes at the border of the OSPF routing domain.� Use only for ASBRs.
Configuring OSPF InterfacesE-Series Routers
9-13
� The ASBR advertises one external route as an aggregate for all redistributed routes that are covered by the address.
� For OSPF, this command summarizes only routes from other routing protocols that are being redistributed into OSPF.
� With this command, you can reduce the load of advertising many OSPF external routes by specifying a range that includes some (or all) of these external routes.
� Examplehost1(config-router)#summary-address 10.1.0.0 255.255.0.0
� Use the area range command for route summarization between OSPF areas.� Use the no version to restore the default.
Configuring OSPF InterfacesYou can configure OSPF attributes for either a single OSPF network using the address commands, or for all OSPF networks on a particular media interface using the ip ospf commands.
OSPF MTU size is negotiated rather than configured. OSPF database description exchange uses the interface MTU to signal the largest OSPF MTU that can be sent over an OSPF interface without fragmentation.
Perform the following tasks to configure OSPF attributes for the OSPF network(s):
• Set the cost.
• Set the dead interval.
• Set the hello interval.
• Set router priority.
• Set the retransmit interval.
• Set the transmit delay.
Note: Before using the address or ip ospf commands, see Precedence of Commands on p 9-18 for information on the relationship between these commands.
address CommandsYou can use the address area command to create a new OSPF interface. Use the other address commands to configure parameters for OSPF interfaces that already exist.
Note: You must first issue the address area command before issuing any other address command.
CHAPTER 9Configuring OSPF
9-14
Note: The address commands configure OSPF attributes for a single OSPF network. The ip ospf commands configure OSPF attributes for all OSPF networks in the given interface context�for example, in a multinet environment where multiple IP networks sit on top of an Ethernet interface.
address area� Use to create a new OSPF interface and configure the area ID. � The interface can have an IP address, or it can be unnumbered.� Example
host1(config-router)#address 10.12.10.2 area 3
� You must first issue the address area command before issuing any other address commands.
� Use the no version to delete the area ID from the specified interface.
address cost� Use to specify the cost metric for the interface. The cost is used in calculating
the SPF routing table and can range from 0�65535.� The interface can have an IP address, or it can be unnumbered.� Example
host1(config-router)#address unnumbered area 3
host1(config-router)#address unnumbered atm 4/0.1 cost 50
� Use the no version to reset the path cost to the default value, 10.
address dead-interval� Use to specify the time period that the router�s neighbors should wait without
seeing hello packets from the router before they declare the router to be down.� The dead interval can range from 1�65535 seconds, and is advertised by the
router�s hello packets.� For the OSPF routers to become adjacent, the dead interval must be identical
on each router.� The interface can have an IP address, or it can be unnumbered.� Example
host1(config-router)#address 192.168.10.32 area 6
host1(config-router)#address 192.168.10.32 dead-interval 60
� Use the no version to reset the dead interval to the default value, 40.
address hello-interval� Use to specify the interval between hello packets that the router sends on the
interface.� The hello interval can range from 1�65535 seconds.� The interface can have an IP address, or it can be unnumbered.
Configuring OSPF InterfacesE-Series Routers
9-15
� Examplehost1(config-router)#address 192.168.1.1 area 5
host1(config-router)#address 192.168.1.1 hello-interval 25
� Use the no version to reset the hello interval to the default value, 10.
address passive-interface� Use to disable the transmission of routing updates on the interface, meaning
that OSPF routing information is neither sent by nor received through the interface.
� The interface can have an IP address, or it can be unnumbered.� Example
host1(config-router)#address 192.168.100.20 area 5
host1(config-router)#address 192.168.100.20 passive-interface
� Use the no version to reenable the transmission of routing updates.
address priority� Use to specify the router priority, an 8-bit number from 1 to 255. Used in
determining the designated router for the particular network. � Applies only to nonbroadcast multiaccess (NBMA) networks. Every broadcast
and NBMA network has a designated router. � The interface can have an IP address, or it can be unnumbered.� Example
host1(config-router)#address unnumbered area 6
host1(config-router)#address unnumbered loopback 0 priority
� Use the no version to restore the default value, 1.
address retransmit-interval� Use to specify the time between LSA retransmissions for the interface when an
acknowledgment for the LSA is not received. � Specify an interval in the range 1�65535 seconds; the default value is 5.� The interface can have an IP address, or it can be unnumbered.� Example
host1(config-router)#address 192.168.10.200 area 6
host1(config-router)#address 192.168.10.200 retransmit-interval
� Use the no version to restore the default value, 5.
address transmit-delay� Use to specify the estimated time it takes to transmit a link-state update packet
on the interface. � Specify an interval in the range 1�65535 seconds; the default value is 1.
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� The interface can have an IP address, or it can be unnumbered.� Example
host1(config-router)#address 10.100.25.38 area 7
host1(config-router)#address 10.100.25.38 transmit-delay
� Use the no version to restore the default value, 1.
ip ospf CommandsThe ip ospf commands have two effects on interface configuration. These effects apply to all ip ospf commands:
• Configuration per logical IP interface (for example, Fast Ethernet 0/1.3 or ATM 5/0.1):
The ip ospf command configures the specified OSPF parameter(s) for all networks configured on the given IP interface—for example, all multinetted addresses on an interface.
The no version of the command resets the specified parameter(s) to unspecified.
If the no version of the command takes effect, then for the specified IP interface there is no default value for the specified parameter(s). The parameter is set back to unspecified values. However, the value of the specified parameter for the OSPF interface is set back to the default value or the value previously specified by the address command.
• Configuration per OSPF interface:
The ip ospf command configures the specified OSPF parameter(s) for each OSPF interface which sits on top of the IP interface.
The no version of the command restores the specified parameter(s) to the default value(s).
Note: If you use ip ospf commands to configure OSPF interfaces, you must first have created the interfaces with the network area command.
Note: The ip ospf commands configure OSPF attributes for all OSPF networks in the given interface context�for example, in a multinet environment where multiple IP networks sit on top of an Ethernet interface. The address commands configure OSPF attributes for a single OSPF interface.
ip ospf cost� Use to configure the cost of sending a packet on the network.� Cost is a metric value in the range 0�65535; the default value is 1.� The router LSA advertises the link-state metric as the link cost.
Configuring OSPF InterfacesE-Series Routers
9-17
� Examplehost1(config)#interface fastethernet 0/0
host1(config-if)#ip ospf cost 50
� Use the no version to reset the path cost to the default value, 1.
ip ospf dead-interval� Use to configure the interval since the last hello packet was seen.� Specify an interval in the range 1�65535 seconds; the default value is 40.� For the OSPF routers to become adjacent, the dead interval must be identical
on each router.� The router�s hello packets advertise this interval.� Example
host1(config-if)#ip ospf dead-interval 60
� Use the no version to restore the default value, 40.
ip ospf hello-interval� Use to configure the interval between hello packets.� Specify an interval in the range 1�65535 seconds; the default value is 10.� For the OSPF routers to become adjacent, the hello interval has to be identical
on each router.� Example
host1(config-if)#ip ospf hello-interval 8
� Use the no version to restore the default value, 10.
ip ospf priority� Use to configure the router�s priority.� Select a priority level in the range 0�255; the default value is 1.� This setting determines the designated router for the particular network.� A router whose priority is set to 0 cannot be a designated router.� Configure priority only for interfaces to multiaccess networks.� Example
host1(config-if)#ip ospf priority 2
� Use the no version to restore the default value, 1.
ip ospf retransmit-interval� Use to configure the time interval between retransmission of an LSA.� Specify an interval in the range 1�65535 seconds; the default value is 5.� Example
host1(config-if)#ip ospf retransmit-interval 10
� Use the no version to return to the default value, 5.
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ip ospf transmit-delay� Use to configure the time it takes to transmit a link-state update on the
interface.� This is the time between transmissions of LSAs.� Specify an interval in the range 1�65535 seconds; the default value is 1.� In setting the time, consider the interface�s transmission and propagation
delays.� Example
host1(config-if)#ip ospf transmit-delay 4
� Use the no version to return to the default value, 1.
Comparison ExampleSuppose you configure a range of OSPF interfaces with the network area command as follows:
host1(config)#interface fastEthernet 0/0
host1(config-if)#ip address 1.1.1.1 255.255.255.0
host1(config-if)#ip address 2.2.2.2 255.255.255.0 secondary
host1(config-if)#exit
host1(config)#router ospf 1
host1(config-router)#network 1.1.1.0 0.0.0.255 area 0
host1(config-router)#network 2.2.2.0 0.0.0.255 area 0
If you want to specify the cost, you can do so for both interfaces simultaneously:
host1(config)#interface fastEthernet 0/0
host1(config-if)#ip ospf cost 30
You can use address commands to create a third OSPF interface over the Ethernet interface. When you specify a cost, it is set for only that interface:
host1(config)#interface fastEthernet 0/0
host1(config-if)#ip address 3.3.3.3 255.255.255.0 secondary
host1(config-if)#exit
host1(config)#router ospf 1
host1(config-router)#address 3.3.3.3 area 0
host1(config-router)#address 3.3.3.3 cost 25
Precedence of CommandsFor a single OSPF interface, when you modify the same OSPF attribute by issuing both the ip ospf command and the address command, the value configured with the address command takes precedence. In other words, the most specific command for a single OSPF interface takes precedence.
Configuring OSPF AreasE-Series Routers
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Consider the following example. Suppose you have a numbered IP interface with an IP address of 10.10.1.1/24 sitting on top of Fast Ethernet interface 0/0. Configure a single OSPF interface on top of the IP interface.
host1(config)#router ospf 100
host1(router-config)#address 10.10.1.1 area 0
The default cost for this OSPF interface is 10. Change the cost for this OSPF interface using the address cost command:
host1(router-config)#address 10.10.1.1 cost 45
The cost for OSPF interface 10.10.1.1 is now 45.
Now use the ip ospf cost command to change the cost for this OSPF interface:
host1(config)#int fastEthernet 0/0
host1(config-if)#ip ospf cost 23
The cost of OSPF interface 10.10.1.1 does not change. The previously issued address cost command is more specific for the interface and takes precedence over the ip ospf cost command. You must use the address cost command if you want to change the cost again:
host1(router-config)#address 10.10.1.1 cost 23
Configuring OSPF AreasYou can divide your OSPF routing domain into OSPF areas. Doing this provides the following benefits:
• Reduces resource demands placed on routers and links
• Reduces the router CPU usage by the OSPF routing calculation
• Reduces the amount of memory used for link state databases
• Hides subnets within areas from the rest of the routing domain
• Increases routing security within the area
You must attach each area in your routing domain to an area called the backbone area (0.0.0.0).
Disadvantages to using OSPF areas include the following:
• Areas hide information, which may result in less-than-optimal data paths.
• Creating areas complicates the task of configuring OSPF routing domains.
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You can optionally define an area to be a stub area or a not-so-stubby area. You can configure virtual links for areas that are not directly connected to a backbone area.
areano area
� There is no affirmative version of this command; there is only a no version.� Example
host1(config-router)#no area 47.0.0.0
� Use the no version to remove the specified area only if no OSPF interfaces are configured in the area.
area default-cost� Use to configure the cost for the default summary route sent into a stub area.� Cost is a metric value in the range 1�65535; the default value is 1.� Use only on an ABR attached to a stub area.� Provides the metric for the summary default route that the ABR generates into
the stub area.� Example
host1(config-router)#area 47.0.0.0 default-cost 1
� Use the no version to remove the configured default route cost.
area nssa� Use to configure the area as an NSSA.� An NSSA is like a stub area, but it can also import external AS routes in a
limited way.� To cause NSSA border routers to generate a type 7 default LSA in the OSPF
database if there is a default route in the routing table, you must specify the default-information-originate option.
� You can specify a metric cost, metric type, or a route map to be applied to the generated type 7 default LSAs.
� Examplehost1(config-router)#area 35.0.0.0 nssa
� Use the no version to remove the NSSA designation from the area, to stop the generation of type 7 default LSAs, or to stop the application of the specified metric cost, metric type, or a route map to the type 7 default LSAs.
area stub� Use to configure a stub area. Stub areas do not get flooded with external LSAs
but do carry a default route, intra-area routes, and interarea routes. This reduces the size of the area's OSPF database and decreases memory usage for external routers in the stub area.
� You must configure each router in a stub area as belonging to the stub area.
Configuring OSPF AreasE-Series Routers
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� You cannot configure virtual links across a stub area.� Stub areas cannot contain ASBRs.� Example
host1(config-router)#area 47.0.0.0 stub
� Use the no version to disable this function.
area virtual-link� Use to configure an OSPF virtual link.� A virtual link is used for areas that do not have a direct connection to the
backbone area.� To have configured virtual links, the router itself must be an ABR.� Virtual links are identified by the router ID of the other endpoint, which is also
an ABR.� The two endpoint routers must be attached to a common area, called the virtual
link�s transit area.� Virtual links are part of the backbone and behave as if they were unnumbered
point-to-point networks between the two routers.� A virtual link uses the intra-area routing of its transit area to forward packets.� Example
host1(config-router)#area 27.0.0.0 virtual-link 27.8.4.2
� Use the no version to remove an OSPF virtual link.
area virtual-link dead-interval� Use to set the time in seconds to wait before declaring a neighbor down after
not receiving packets from that neighbor.� Specify an interval in the range 1�65535 seconds; the default value is 40.� Example
host1(config-router)#area 27.0.0.0 virtual-link 27.8.4.2 dead-interval 10
� Use the no version to remove the virtual link�s dead interval.
area virtual-link hello-interval� Use to configure the hello interval on an OSPF virtual link.� Specify an interval in the range 1�65535 seconds; the default value is 10.� The hello interval is the time between the transmission of hello packets.� The hello interval must be the same for all routers attached to a common
network.� Example
host1(config-router)#area 27.0.0.0 virtual-link 27.8.4.2 hello-interval 10
� Use the no version to remove the virtual link�s hello interval.
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area virtual-link retransmit-interval� Use to configure the retransmission interval on an OSPF virtual link.� The retransmit interval is the time between retransmissions of link-state
advertisements for adjacencies belonging to the interface.� Specify an interval in the range 1�65535 seconds; the default value is 5.� Set the value greater than the expected round-trip delay. � Example
host1(config-router)#area 27.0.0.0 virtual-link 27.8.4.2 retransmit-interval 6
� Use the no version to remove the interface�s retransmit interval.
area virtual-link transmit-delay� Use to configure the estimated time it takes to transmit a link-state update
packet on the virtual link.� Specify an interval in the range 1�65535 seconds; the default value is 1. � Example
host1(config-router)#area 27.0.0.0 virtual-link 27.8.4.2 transmit-delay 1
� Use the no version to remove the interface�s transmit delay.
automatic-virtual-link� Use to enable an automatic virtual link configuration.� If enabled, then backbone connectivity is ensured by the automatic creation of
a virtual link between this backbone router that has an interface to a common nonbackbone area and other backbone routers that have interfaces to a common nonbackbone area.
� Examplehost1(config-router)#automatic-virtual-link
� Use the no version to disable an automatic virtual link.
Configuring AuthenticationThe router supports the following authentication capabilities:
• Null authentication
• Simple password authentication
• MD5 authentication
The MD5 algorithm takes as input a message of arbitrary length and produces a 128-bit fingerprint or message digest of the input. MD5 is used to create digital signatures. It is a one-way hash function, meaning
Configuring AuthenticationE-Series Routers
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that it takes a message and converts it into a fixed string of digits, called a message digest.
When using a one-way hash function, you can compare a calculated message digest with the message digest that is decrypted using a public key (password). The key verifies that the message has not been tampered with. This comparison process is called a hashcheck.
Note: You must first issue the address area command before issuing any other address command.
Authentication RequirementsIf you configure either simple password or MD5 authentication, the password or authentication key must be the same on both sides of an adjacency. When you change the password or key on one side of an established adjacency, you must also change it on the other side within the dead interval. This enables a hello packet that has the latest authentication information to be sent before the dead interval expires. If the packet is not sent within the dead interval, the adjacency breaks down and is not reestablished until both sides of the adjacency have the same password or key.
address authentication-key� Use to assign a password used by neighboring routers for OSPF simple
password authentication.� The interface can have an IP address, or it can be unnumbered.� You can specify whether the key is entered in unencrypted or encrypted format.
If you do not specify which, the string is assumed to be unencrypted.� The password, or key, is a character string up to 8 characters in length.� Example
host1(config-router)#address 10.12.10.2 authentication-key 9rdf7
� Use the no version to delete the password from the specified interface.
address authentication message-digest� Use to specify that MD5 authentication is used for the OSPF interface.� You must configure the MD5 key ID and password with the address
message-digest-key md5 command.� Switching between authentication types does not delete a configured MD5 key
ID or password; only using the no version of that configuration command can delete the MD5 key ID and password.
� Examplehost1(config-router)#address 10.12.10.2 authentication message-digest
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� Use the no version to set authentication for the interface to none without removing any configured MD5 key. You could subsequently apply MD5 authentication to the interface without having to reconfigure the key.
address authentication-none� Use to disable authentication on the interface.� The interface can have an IP address, or it can be unnumbered.� Example
host1(config-router)#address 192.168.10.32 authentication-none
� The no version has no effect.
address message-digest-key md5� Use to enable OSPF MD5 authentication and configure the MD5 key.� The MD5 key is a character string up to 16 characters long. You must also
specify a key identifier and whether the key is entered in unencrypted or encrypted format. If you do not specify which, the string is assumed to be unencrypted.
� Configures an interface already created, or creates a new OSPF interface and configures the MD5 key. The interface can have an IP address, or it can be unnumbered.
� Examplehost1(config-router)#address 10.1.1.1 message-digest-key 1 md5 0 9mwk6gdr76
� Use the no version to delete the MD5 key.
area virtual-link authentication-key� Use to configure a simple password for a virtual link. � You can specify whether the key is entered in unencrypted or encrypted format.
If you do not specify which, the string is assumed to be unencrypted.� The password can be up to eight characters long.� Example
host1(config-router)#area 27.0.0.0 virtual-link 27.3.4.5 authentication-key sadsa29c
� Use the no version to remove the password.
area virtual-link authentication message-digest� Use to specify that MD5 authentication is used for the particular virtual link.� You must configure the MD5 key ID and password with the area virtual-link
message-digest-key md5 command.� Switching between authentication types does not delete a configured MD5 key
ID or password; only using the no version of that configuration command can delete the MD5 key ID and password.
Configuring AuthenticationE-Series Routers
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� Examplehost1(config-router)#area 27.0.0.0 virtual-link 27.2.3.4 authentication message-digest
� Use the no version to set authentication for the virtual link to none without removing any configured MD5 key. You could subsequently apply MD5 authentication to the virtual link without having to reconfigure the key.
area virtual-link authentication-none� Use to specify that no authentication is used for the particular virtual link.� Example
host1(config-router)#area 27.0.0.0 virtual-link 27.2.3.4 authentication-none
� The no version has no effect.
area virtual-link message-digest-key md5� Use to enable MD5 authentication and to configure MD5 keys for virtual links.� The MD5 key is a character string up to 16 characters long. You must also
specify a key identifier and whether the key is entered in unencrypted or encrypted format. If you do not specify which, the string is assumed to be unencrypted.
� Examplehost1(config-router)#area 27.0.0.0 virtual-link 327.3.4.5 message-digest-key 2 md5 rc45lsm2c
� Use the no version to remove the password.
ip ospf authentication-key� Use to configure a type 1 authentication (a simple password) on the interface.� Neighboring OSPF routers use the password to access the router�s interface.� Use the same password on all neighboring routers on the same network.� Use this password only when you enable authentication for the interface.� You can specify whether the key is entered in unencrypted or encrypted format.
If you do not specify which, the string is assumed to be unencrypted.� Use a password that is a continuous string up to 8 characters long.� Example
host1(config-if)#ip ospf authentication-key yourpwd
� Use the no version to remove the password on the interface.
ip ospf authentication message-digest� Use to specify the authentication method for the interface as MD5.� You must configure the MD5 key ID and password with the ip ospf
message-digest-key md5 command.
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� Switching between authentication types does not delete a configured MD5 key ID or password; only using the no version of that configuration command can delete the MD5 key ID and password.
� Examplehost1(config-if)#ip ospf authentication message-digest
� Use the no version to set authentication for the interface to none without removing any configured MD5 key. You could subsequently apply MD5 authentication to the interface without having to reconfigure the key.
ip ospf authentication-none� Use to specify that no authentication is used for the OSPF interface.� Example
host1(config-if)#ip ospf authentication-none
� The no version has no effect.
ip ospf message-digest-key md5� Use to enable MD5 authentication on the OSPF interface and configure the
MD5 key.� The MD5 key is a character string up to 16 characters long. You must also
specify a key identifier and whether the key is entered in unencrypted or encrypted format. If you do not specify which, the string is assumed to be unencrypted.
� Examplehost1(config-if)#ip ospf message-digest-key 3 md5 0 tre987is
� Use the no version to delete an MD5 key from the OSPF interface.Note: If all the MD5 keys have been deleted, the authentication type is still MD5, but you need to configure MD5 keys.
Note: To disable MD5 authentication for the interface, use the ip ospf authentication-none command.
Note: To display the password only in encrypted text, use the service password-encryption command.
Configuring Additional ParametersE-Series Routers
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Configuring Additional ParametersThe commands presented in this section include both OSPF-specific commands and routing protocol–independent commands that are not limited to OSPF. You can use these commands to perform the tasks listed in Table 9-3.
access-listroute-map
� Use the access-list command to create a standard or extended access list.� Use the route-map command to create a route map.� For detailed information on configuring access lists and route maps, see
Chapter 1, Configuring Routing Policy.� Example
1 Configure three static routes:host1(config)#ip route 20.20.20.0 255.255.255.0 192.168.1.0
host1(config)#ip route 20.20.21.0 255.255.255.0 192.168.1.0
host1(config)#ip route 20.21.0.0 255.255.255.0 192.168.1.0
2 Configure an access list with filters on routes 20.20.20.0/24 and 20.20.21.0/24:host1(config)#access-list boston permit 20.20.0.0 0.0.255.255
3 Configure a route map which matches the previous access list and applies a metric type 1 (OSPF):host1(config)#route-map boston
host1(config-route-map)#match ip address boston
host1(config-route-map)#set metric-type type-1
4 Configure redistribution of the static routes into OSPF with route map boston:host1(config)#router ospf 2
host1(config-router)#redistribute static route-map boston
Table 9-3 Additional configuration tasks
Filter and apply policy to routes. Set the maximum paths.
Set a baseline for statistics. Enable automatic cost calculation.
Set the redistribution routes. Enable logs for OSPF neighbor changes.
Set the distance for OSPF routes. Set SPF hold time.
Administratively disable OSPF. Set a default metric.
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5 Use the show ip ospf database command to verify the effect of the redistribution (the two static routes matching the route map are redistributed as external type 1):
host1#show ip ospf database
OSPF Database
Router Link States (Area 0.0.0.0)
Link ID ADV Router Age Seq# Checksum
192.168.1.250 192.168.1.250 3 0x80000006 0x39a1
192.168.254.7 192.168.254.7 220 0x80000169 0xd2b5
Network Link States (Area 0.0.0.0)
Link ID ADV Router Age Seq# Checksum
192.168.1.214 192.168.254.7 220 0x80000001 0xe0f2
AS External Link States
Link ID ADV Router Age Seq# Checksum
20.20.20.0 192.168.1.250 3 0x80000001 0x6045
20.20.21.0 192.168.1.250 3 0x80000001 0x554f
� Use the no version of the access-list command to remove the access list or the specified entry in the access list.
� Use the no version of the route-map command to remove an entry.
baseline ip ospf� Use to set a baseline for OSPF statistics and counters.� The following example first displays the output of the show ip ospf command
shown before you run the baseline ip ospf command; then, the execution of the baseline ip ospf command; and finally, the display of the show ip ospf command run after you execute the baseline ip ospf command.� The output of the show ip ospf command run before the baseline ip ospf
command reflects the up-to-date packet counters.� The output of the show ip ospf delta command run after you run the
baseline ip ospf command reflects the baseline set for OSPF statistics and counters.
� There is no no version. � Example
host1#show ip ospf
Routing Process OSPF 1 with Router ID 5.106.7.1
OSPF Statistics:
Rcvd: 217935 total, 0 checksum errors
8987 hello, 8367 database desc, 188 link state req
159898 link state updates, 40484 link state acks
Sent: 265026 total, 0 pkts dropped
8927 hello, 8341 database desc, 53 link state req
158571 link state updates, 89134 link state acks
Supports only single TOS(TOS0) routes
SPF schedule delay 0 secs, Hold time between two SPFs 3 secs
Configuring Additional ParametersE-Series Routers
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Maximum path splits 1
Area BACKBONE(0.0.0.0)
Area is a transit area
SPF algorithm executed 425 times
ABR count 0
ASBR count 1
LSA Count 12
Number of interfaces in this area is 24
Area ranges are:
Number of active areas in this router is 1
1 normal, 0 stub, 0 NSSA.
host1#baseline ip ospf
host1#show ip ospf delta
Routing Process OSPF 1 with Router ID 5.106.7.1
OSPF Statistics:
Rcvd: 0 total, 0 checksum errors
0 hello, 0 database desc, 0 link state req
0 link state updates, 0 link state acks
Sent: 0 total, 0 pkts dropped
0 hello, 0 database desc, 0 link state req
0 link state updates, 0 link state acks
Supports only single TOS(TOS0) routes
SPF schedule delay 0 secs, Hold time between two SPFs 3 secs
Maximum path splits 1
Area BACKBONE(0.0.0.0)
Area is a transit area
SPF algorithm executed 425 times
ABR count 0
ASBR count 1
LSA Count 12
Number of interfaces in this area is 24
Area ranges are:
Number of active areas in this router is 1
1 normal, 0 stub, 0 NSSA.
clear ip ospf redistribution� Use to clear all the routes that have been previously redistributed into OSPF.� Example
host1#clear ip ospf redistribution
� There is no no version.
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default-information originate� Use to generate a default route into an OSPF routing domain.� When you use this command to redistribute routes into an OSPF routing
domain, the router automatically becomes an ASBR.� An ASBR, however, does not, by default, generate a default route into the
OSPF routing domain. The software must have a default route before it generates one, except when you have specified the always keyword.
� You can specify a metric for the route or specify that the route be OSPF external type 1 or 2.
� Examplehost1(config)#router ospf 1
host1(config-router)#default-information originate route-map 5
� Use the no version to disable this feature.
disable-dynamic-redistribute� Use to halt the dynamic redistribution of routes that are initiated by changes to
a route map. � Dynamic redistribution is enabled by default.� Example
host1(config-router)#disable-dynamic-redistribute
� Use the no version to reenable dynamic redistribution.
distance� Use to configure the administrative distance for OSPF routes.� Example
host1(config-router)#distance ospf external 60
� Default settings:� Intra-area routes � 110� Interarea routes � 112� External routes � 114
� Use the no version to restore the default values noted above.
ip ospf shutdown� Use to disable OSPF on the interface.� Example
host1(config-if)#ip ospf shutdown
� Use the no version to enable OSPF on the interface.
Configuring Additional ParametersE-Series Routers
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maximum-paths� Use to control the maximum number of parallel routes that OSPF can support.� The maximum number of routes can range from 1�16. � The default for OSPF is 4 paths.� To enable equal-cost multipath (ECMP) for OSPF, you need to specify a value
for maxPaths greater than 1.� Example
host1(config-router)#maximum-paths 2
� Use the no version to restore the default value, 4.
ospf auto-cost reference-bandwidth� Use to calculate OSPF interface cost according to bandwidth.� Sets the OSPF metric for an interface according to the bandwidth specified.� Affects OSPF metrics only for OSPF interfaces created after its execution.� This command�s value overrides the cost resulting from the command.� If you want this command to apply to OSPF interfaces already configured, you
need to bounce the existing interfaces: Use the no network and then the network command for the selected OSPF interfaces.
� Examplehost1(config-router)#ospf auto-cost reference-bandwidth 1000
� If you issue this command, the metric is calculated as follows:OSPF metric = bandwidth*1,000,000/link speedFor the previous example, a 64K link will get a metric of 15625, while a T1 link will have a metric of 647. The minimum value for the metric is 1.
� If you never issue the ospf auto-cost reference-bandwidth command, OSPF calculates the cost as 108/link speed.
� Use the no version to assign cost based only on the interface type.
ospf log-adjacency-changes� Use to configure the router to send a log message when the state of an OSPF
neighbor changes.� Example
host1(config-router)#ospf log-adjacency-changes severity 3 verbosity low
� Use the no version to halt logging of neighbor changes.
ospf shutdown� Use to administratively disable OSPF on the router.� Example
host1(config-router)#ospf shutdown
� Use the no version to reenable OSPF on the interface.
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passive-interface� Use to disable the transmission of routing updates on the interface, meaning
that OSPF routing information is neither sent by nor received through the interface.
� The specified interface appears as a stub network in the OSPF domain.� By default, OSPF is enabled on a configured OSPF interface.� Example
host1(config-router)#passive-interface ethernet 1/0
� Use the no version to reenable the transmission of OSPF routing updates on the specified interface.
redistribute� Use to redistribute information from a routing domain other than OSPF into the
OSPF domain.� You can set the OSPF metric type�type 1 or type 2�and set a metric for all
redistributed routes.� Example 1
host1(config)#router ospf 5
host1(config-router)#redistribute bgp route-map 4
� If you do not specify route-map, all routes are redistributed. By default, all routes are imported as external type 2 routes.
� If you do specify route-map but do not list any route map tags, no routes are imported.
� Use to redistribute routes from OSPF into other non-OSPF routing domains.� Example 2
host1(config)#router bgp 100
host1(config-router)#redistribute ospf 5
� Use the no version to disable redistribution.
table-map� Use to apply a policy to modify distance, metric, metric type, route type, or tag
values of OSPF routes about to be added to the IP routing table.� The new route map is applied to all routes currently in and those subsequently
placed in the forwarding table. Previously redistributed routes are redistributed with the changes caused by the route map.
� To remove from the forwarding table any old routes that are now disallowed by the specified route map, you must refresh the IP routing table with the clear ip routes * command.
Configuring Additional ParametersE-Series Routers
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� Examplehost1(config)#route-map dist1 permit 5
host1(config-route-map)#match community boston42
host1(config-route-map)#set distance 33
host1(config-route-map)#exit
host1(config)#router ospf 100
host1(config-router)#table-map dist1
host1(config-router)#exit
host1(config)#exit
host1#clear ip routes *
� Use the no version to halt application of the route map.
timers spf� Use to configure the time between two consecutive SPF calculations.� Set the time (in seconds) in the range 1�5; the default value is 3.� If you set the hold time to 0, there is no delay between two consecutive SPF
calculations. They can be done one immediately after the other.� Example
host1(config-router)#timers spf 2
� Use the no version to return to the default value, 3.
Default MetricsAlthough the router does not support a default-metric command, the redistribute command provides two ways to set a default metric for redistributed routes.
You can simply configure a metric with the redistribute command to apply to all routes redistributed from the specified source protocol:
host1(config)#router ospf 5
host1(config-router)#redistribute bgp metric 5
Alternatively, you can create one or more route maps that set the metric and apply them selectively to redistributed routes:
host1(config)#access-list 1 permit any any
host1(config)#route-map defmetric
host1(config-route-map)#match ip address 1
host1(config-route-map)#set metric 10
host1(config-route-map)#exit
host1(config)#router ospf 5
host1(config-router)#redistribute bgp route-map defmetric
host1(config-router)#redistribute isis route-map defmetric
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See Chapter 1, Configuring Routing Policy, for information on configuring route maps.
Configuring OSPF for NBMA NetworksYou can configure OSPF nonbroadcast multiaccess (NBMA) networks. You can configure your OSPF network type as NBMA, regardless of the default medium. This is useful when, for example, you have routers in your network that do not support multicast addressing.
You must use the neighbor command to specify the router’s OSPF neighbors.
To configure OSPF for an NBMA network:
1 Configure an interface network type as NBMA for OSPF.
host1(config-subif)#ip ospf network non-broadcast
2 Exit Interface Configuration mode. Enter Global Configuration mode.
host1(config-subif)#exit
3 Configure an OSPF routing process, and enter Router Configuration mode.
host1(config)#router ospf 5
4 Specify an OSPF neighbor, and optionally assign a priority number or poll interval to the neighbor.
host1(config-router)#neighbor 10.12.14.1 priority 5 poll-interval 180
5 Repeat step 4 for each neighbor in the OSPF network.
If you want to configure the network type for a specific interface or OSPF area, rather than for all OSPF interfaces, you can use the address network command rather than the ip ospf network command.
address network � Use to configure the network type on a specific OSPF interface or for a specific
OSPF area to a type other than the default for the medium.� You must first issue the address area command before issuing the address
network command. � Use the no version to restore the default value for the medium.
Traffic EngineeringE-Series Routers
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ip ospf network� Use to configure the network type on all OSPF interfaces on the OSPF network
to a type other than the default for the medium.� Use the no version to restore the default value for the medium.
neighbor � Use to configure OSPF neighbors on the NBMA network. � Specify priority and poll interval only for routers that are eligible to become the
designated router or backup designated router�that is, a router with a nonzero router priority value. The default priority value is 0, and the default polling interval is 120 seconds.
� Use the no version to remove the neighbor or restore the default values 0 and 120.
Traffic EngineeringTraffic engineering (TE) enables more effective use of network resources by providing for the setup of explicitly routed Multiprotocol Label Switching (MPLS) label-switched paths (LSPs) that satisfy resource and administrative constraints. You can use OSPF to exchange link resource and traffic-engineering administrative information between routers. OSPF uses this information to calculate paths in the network that satisfy the administrative constraints. MPLS can then set up LSPs along these paths. Refer to E-Series Routing Protocols Configuration Guide, Vol. 2, Chapter 2, Configuring MPLS, for a detailed discussion of MPLS.
Configuring OSPF for TEFor OSPF to support TE, you must issue both of the following commands:
• mpls traffic-eng area – Enables the router to flood TE resource and administrative information in the specified area using type 10 opaque LSAs. These LSAs have an area-wide scope and therefore are flooded only within the indicated area.
• mpls traffic-eng router-id – Designates a router as TE capable and specifies the address of a stable router interface as the router ID of the node for TE purposes. The TE router ID serves as the tunnel endpoint for tunnels terminating at the node. Each node advertises its TE router ID in type 10 LSAs.
By default, OSPF always uses the MPLS tunnel to reach the MPLS endpoint. Best paths determined by SPF calculations are not considered. You can enable the consideration of best paths by issuing the mpls spf-use-any-best-path command. As a result, OSPF considers metrics
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for IGP paths and the tunnel metric, and might forward traffic along a best path, through the MPLS tunnel, or both.
You can use the show ip ospf database opaque-area command to display information about TE opaque LSAs.
For OSPF routes to use established MPLS tunnels as next hops—so that traffic can be mapped to use these tunnels—you must configure the tunnels with the tunnel mpls autoroute announce ospf command. See E-Series Routing Protocols Configuration Guide, Vol. 2, Chapter 2, Configuring MPLS, for information on configuring MPLS on a router.
mpls spf-use-any-best-path� Use to enable SPF calculations to consider the IGP (OSPF) best paths as well
as the MPLS tunnel for forwarding traffic to the MPLS endpoint. � By default, the MPLS tunnel is always selected for traffic to the tunnel endpoint;
IGP paths are not considered. For traffic beyond the endpoint, the tunnel is considered equally with any other path.
� Example host1(config-router)#mpls spf-use-any-best-path
� Use the no version to disable the use of IGP best paths.
mpls traffic-eng area� Use to enable flooding of MPLS TE link information into the specified OSPF
area. Flooding is disabled by default.� Example
host1(config-router)#mpls traffic-eng area 0
� Use the no version to disable flooding.
mpls traffic-eng router-id� Use to specify a stable interface to be used as a router ID for MPLS TE.
Typically you specify a loopback interface to provide the greatest stability, because this is flooded to all nodes. The interface acts as the destination node for tunnels originating at other nodes.
� Example host1(config-router)#mpls traffic-eng router-id loopback 0
� Use the no version to remove the interface as a router ID.
Using OSPF Routes for Multicast RPF ChecksE-Series Routers
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Using OSPF Routes for Multicast RPF ChecksYou can use the ip route-type command to specify whether OSPF routes are available for only unicast forwarding protocols or only multicast reverse path forwarding (RPF) checks. Routes available for unicast forwarding appear in the unicast view of the routing table, whereas routes available for multicast RPF checks appear in the multicast view of the routing table.
ip route-type� Use to specify whether OSPF routes are available only for unicast forwarding,
only for multicast reverse path forwarding checks, or for both.� Use the show ip route command to view the routes available for unicast
forwarding.� Use the show ip rpf-routes command to view the routes available for multicast
reverse path forwarding checks.� By default, OSPF routes are available for both unicast forwarding and multicast
reverse path forwarding checks.� Example
host1(config)#router ospf
host1(config-router)#ip route-type unicast
� Use the no version to restore the default value, both.
OSPF and BGP/MPLS VPNsSome network topologies will use OSPF as the routing protocol between CE and PE routers in BGP/MPLS VPNs. See E-Series Routing Protocols Configuration Guide, Vol. 2, Chapter 3, Configuring BGP/MPLS VPNs, for information on configuring OSPF for this purpose.
Remote NeighborsYou can create OSPF remote neighbors to enable the router to establish neighbor adjacencies through unidirectional interfaces, such as MPLS tunnels, rather than the standard practice of using the same interface for receipt and transmission of OSPF packets. The remote neighbor can be more than one hop away through intermediate routers that are not running OSPF. OSPF uses the interface associated with the best route to reach the remote neighbor. A best route to the neighbor must exist in the IP routing table.
You must explicitly configure a remote neighbor on an OSPF router. You must specify the remote neighbor with which the router will form an
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adjacency and the source IP address the router will use for OSPF packets destined to its peer remote neighbor.
To form an adjacency with its remote neighbor, all OSPF packets are sent to the remote neighbor as unicast packets with the destination IP address equal to the source IP address of the remote neighbor. Use the update-source loopback command to assign the source IP address to a remote neighbor.
The connection between two remote neighbors is treated as an unnumbered point-to-point link that resides in the same area as that to which the pair of remote neighbors belongs.
The rules of OSPF adjacency must be followed for remote neighbors to form an adjacency with each other; for example, the neighbors must be in the same OSPF area and have the same hello interval and dead interval, and so on.
Once you have used the remote-neighbor command to specify the remote neighbors and the update-source loopback to assign the source IP address, you must set a TTL value with the ttl command, because a remote neighbor can be more than one hop away. Configuration of all other remote-neighbor attributes is optional.
authentication-key� Use to enable simple password authentication and assign a password for
communication with OSPF remote neighbors.� Example
host1(config-router-rn)#authentication-key 0 br549hee
� Use the no version to delete the password.
authentication message-digest� Use to specify that MD5 authentication is to be used on the OSPF remote
neighbor interface.� Example
host1(config-router-rn)#authentication message-digest
� There is no no version.
authentication-none� Use to specify that no authentication is to be used on the OSPF remote
neighbor interface.� Example
host1(config-router-rn)#authentication-none
� There is no no version.
Remote NeighborsE-Series Routers
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cost� Use to specify a cost metric for the OSPF remote-neighbor interface; the metric
is used in the calculation of the SPF routing table.� The default value is 10 if there is no route to the remote neighbor; otherwise,
the default is calculated based on the bandwidth of the physical interface used to reach the remote neighbor and the OSPF autocost reference bandwidth.
� Examplehost1(config-router-rn)#cost 235
� Use the no version to restore the default value, as described above.
dead-interval� Use to set the time period that the OSPF router waits without seeing hello
packets from a remote neighbor before declaring the neighbor to be down.� Example
host1(config-router-rn)#dead-interval 180
� Use the no version to restore the default value, 40 seconds.
hello-interval� Use to set the interval between hello packets that the router sends on the
OSPF remote-neighbor interface. � Specify a value in the range 1�65535 seconds; the default value is 40.� Example
host1(config-router-rn)#hello-interval 15
� Use the no version to restore the default value, 40.
message-digest-key md5� Use to enable MD5 authentication for the OSPF remote-neighbor interface and
configure the MD5 key. � Example
host1(config-router-rn)#message-digest-key 42 md5 0 sal29ute
� If you delete all MD5 keys, MD5 authentication is still enabled; you must either configure an MD5 key or disable MD5 authentication with the authentication-none command.
� Use the no version to delete the MD5 key.
remote-neighbor� Use to configure an OSPF remote neighbor.� Example
host1(config-router)#remote-neighbor 10.25.100.14 area 35672
� Use the no version to remove the remote neighbor and any attributes configured for the remote neighbor.
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retransmit-interval� Use to set the time between LSA retransmissions for the OSPF
remote-neighbor interface when an acknowledgment for the LSA is not received.
� Specify a value in the range 1�3600 seconds; the default value is 5.� Example
host1(config-router-rn)#retransmit-interval 10
� Use the no version to restore the default value, 5.
transmit-delay� Use to set the estimated time it takes to transmit a link state update packet on
the OSPF remote-neighbor interface. � Specify a value in the range 0�3600 seconds; the default value is 1 second. � Example
host1(config-router-rn)#transmit-delay 3
� Use the no version to restore the default value, 1.
ttl� Use to configure a hop count by setting the value of the time-to-live field used
by packets sent to an OSPF remote neighbor.� Specify a value in the range 1�255 seconds; the default value is 1 second. � Example
host1(config-router-rn)#ttl 35
� Use the no version to restore the default value, 1.
update-source� Use to specify the loopback interface whose local IP address is used as the
source address for the OSPF connection to a remote neighbor. � Example
host1(config-router-rn)#update-source loopback 1
� Use the no version to delete the source address from the connection to the remote neighbor.
Disabling and Reenabling Incremental SPFBy default, when changes occur to a type 5 or type 7 LSA, OSPF recalculates new, loop-free routes for only the LSAs that change. When a subset of LSAs in the external link-state database change, a full recalculation is not necessary. However, the CLI allows you to disable incremental SPF, allowing the router to perform a full SPF on all external LSAs in the link-state database.
Configuring OSPF TrapsE-Series Routers
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disable-incremental-external-spf� Use to disable incremental external SPF on the router. When issued, this
command results in a full SPF when an event occurs to trigger an external SPF.� Example
host1(config-router)#disable-incremental-external-spf
� Use the no version to reenable incremental SPF on this router.
Configuring OSPF TrapsYou can use the traps command to specify OSPF traps. This command allows you to specify all or any number of the following trap settings:
• virtIfStateChange – to indicate any state change on an OSPF virtual interface
• nbrStateChange – to indicate any state change on a nonvirtual OSPF neighbor
• virtNbrStateChange – to indicate any state change on a virtual OSPF neighbor
• ifConfigError – to indicate any configuration mismatch with a nonvirtual neighbor
• virtIfConfigError – to indicate any configuration mismatch with a virtual neighbor
• ifAuthFailure – to indicate any authentication failure on a nonvirtual interface
• virtIfAuthFailure – to indicate any authentication failure on a virtual interface
• ifRxBadPkt – to indicate the receipt of a packet that the router cannot parse
• virtIfRxBadPkt – to indicate the receipt of a packet on a virtual interface that the router cannot parse
• txRetransmit – to indicate the retransmittal of a packet on a nonvirtual interface
• virtTxRetransmit – to indicate the retransmittal of a packet on a virtual interface
• originateLsa – to indicate the origination of a new LSA by this router
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• maxAgeLsa – to indicate that an LSA in this router LSDB has reached MaxAge
• ifStateChange – to indicate a state change on an OSPF interface
traps� Use to specify traps for OSPF. � Example
host1(config-router-rn)#traps all
� Use the no version to delete the specified trap, group of traps, or all traps.
Monitoring OSPFTwo sets of commands enable you to monitor OSPF operation on your router: the debug and the show commands. Both sets of commands provide information on your router’s OSPF state and configuration.
The task you are performing with each of these monitoring commands is basically the same for each command; that is, you are requesting information. The results of this request may vary. For instance, the debug commands provide information on problems with the network or the router, whereas the show commands provide information on the actual state and configuration of your router.
debug CommandsThe debug commands provide information on the following OSPF items:
• Adjacencies
• Designated router
• General events
• Link-state advertisements
• Neighbors
• Packets received
• Packets sent
• Route events
• SPF events
Monitoring OSPFE-Series Routers
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debug ip ospf� Use to display information on selected OSPF events. This command has many
keywords that allow you to specify a variety of OSPF events.� You can set the level of severity for the events you want displayed: 0�7.� You can set the verbosity of the messages you want displayed: low, medium,
high.� Example
host1#debug ip ospf adj
� Use the no version to cancel the display of any information on the designated variable.
ospf log-adjacency-changes� Use to enable the logging of changes in the state of an OSPF neighbor.� Example
host1(config-router)#ospf log-adjacency-changes
� Use the no version to disable the logging of changes in the state of an OSPF neighbor.
undebug ip ospf� Use to cancel the display of information on a selected event.� The same OSPF variables can be designated as in the debug ip ospf
command.� Example
host1#undebug ip ospf adj
� There is no no version.
show CommandsThe show commands provide information on the following OSPF items:
• Routing processes
• Border routers
• Database
• Interfaces
• Neighbors
• Virtual links
• Internal statistics
• MPLS tunnels and opaque LSAs
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You can use the output filtering feature of the show command to include or exclude lines of output based on a text string you specify. See E-Series System Basics Configuration Guide, Chapter 2, Command Line Interface, for details.
show ip ospf� Use to display general information about OSPF routing processes.� Field descriptions
� Routing process � process ID, router ID, domain ID� OSPF administrative state � enabled or disabled� OSPF operational state � enabled or disabled� Incremental External SPF � on or off� Router � router types: internal, area border, or autonomous system
boundary routers� OSPF Statistics � packets sent and received� TOS type � number of types of service supported� SPF timers � timers configured on the router� Maximum path splits � maximum equal-cost paths supported� Areas � areas configured and their parameters� Number of areas � number of areas in the router
� Examplehost1#show ip ospf
Routing Process OSPF 1 with Router ID, 2.2.2.2, Domain ID 0.0.0.0
OSPF administrative state is enabled
OSPF operational state is enabled
Incremental External SPF is OFF
Automatic virtual links configuration is enabled
Ospf set trap field disabled
Router is an Area Border Router (ABR)
OSPF Statistics:
Rcvd: 35 total, 0 checksum errors
20 hello, 9 database desc, 3 link state req
24 link state updates, 8 link state acks
Sent: 51 total, 0 pkts dropped
2155 hello, 6 database desc, 3 link state req
32 link state updates, 10 link state acks
LSA discard count: 0
Supports only single TOS(TOS0) routes
SPF schedule delay 0 secs, Hold time between two SPFs 3 secs
Maximum path splits 4
Area 0.0.0.1
SPF algorithm executed 20 times
ABDR count 1
Monitoring OSPFE-Series Routers
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ASBDR count 0
LSA Count 2
Number of interfaces in this area is 2
Area ranges are:
Area 0.0.0.3
SPF algorithm executed 20 times
ABDR count 1
ASBDR count 0
LSA Count 3
Number of interfaces in this area is 1
Area ranges are:
Number of active areas in this router is 2
2 normal, 0 stub, 0 NSSA.
show ip ospf border-routers� Use to display a list of OSPF border routers.� Field descriptions
� Destination � destination's router ID� Next Hop � next hop toward the destination� Router Type � router type of the destination: either an ABR or ASBR or both � Route Type � type of this route: either an intra-area or interarea route� Area � area ID of the area that this route is learned from
� Examplehost1#show ip ospf border-routers
Destination NEXT HOP Interface Router Type Route Type Area
5.5.0.250 5.5.6.250 fastethernet0 ABR/ASBR INTRA 0.0.0.0
5.5.0 250 4.4.4.250 fastethernet0 ABR/ASBR INTRA 0.0.0.1
6.6.6.250 4.4.4.13 fastethernet0 ABR INTRA 0.0.0.1
show ip ospf database� Use to display either the full OSPF database or a summary of it.� Field descriptions
� Link ID � link-state ID of the LSA: � for router links, set to the router�s OSPF router ID� for network links, set to the IP interface address of the network�s
designated router� for type 3 summary LSAs, set to an IP network number� for type 4 summary LSAs, set to an ASBR�s router ID� for type 5 externals, set to an IP network number
� Adv Router � advertising router�s ID� Age � link-state age� Seq# � link-state sequence number (detects old or duplicate LSAs)� Checksum � Fletcher checksum of the complete contents of the LSA
CHAPTER 9Configuring OSPF
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� Examplehost1#show ip ospf database
OSPF Database
Router Link States (Area 0.0.0.0)
Link ID ADV Router Age Seq# Checksum
5.1.101.1 5.1.101.1 932 0x80000069 0x102f
192.168.1.13 192.168.1.13 1763 0x80000099 0xaa4e
192.168.1.10 192.168.1.10 285 0x80000087 0xada6
192.168.1.11 192.168.1.11 401 0x80000087 0xaba5
192.168.24.6 192.168.24.6 622 0x800005bf 0x6087
Network Link States (Area 0.0.0.0)
Link ID ADV Router Age Seq# Checksum
56.56.56.220 5.6.6.1 499 0x80000069 0x26a0
192.168.1.12 192.168.254.6 622 0x8000009e 0xebc2
Summary Link States (Area 0.0.0.0)
Link ID ADV Router Age Seq# Checksum
4.4.4.0 5.5.0.250 497 0x8000005a 0x2ca6
4.4.4.0 192.168.1.13 528 0x80000059 0x 45d
AS Summary Link States (Area 0.0.0.0)
Link ID ADV Router Age Seq# Checksum
5.5.0.250 192.168.1.13 491 0x80000002 0xe9d4
AS External Link States
Link ID ADV Router Age Seq# Checksum
8.8.8.0 5.5.0.250 502 0x8000005f 0x2d67
Router Link States (Area 0.0.0.1)
Link ID ADV Router Age Seq# Checksum
5.5.0.250 5.5.0.250 498 0x80000067 0xdec1
192.168.1.13 192.168.1.13 505 0x800000a5 0x3b32
Network Link States (Area 0.0.0.1)
Link ID ADV Router Age Seq# Checksum
4.4.4.13 192.168.1.13 505 0x80000001 0x410b
5.1.0.0 192.168.1.13 940 0x80000059 0x82c4
5.2.0.0 5.5.0.250 495 0x80000001 0x51bf
5.2.0.0 192.168.1.13 932 0x80000059 0x76cf
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5.3.0.0 5.5.0.250 495 0x80000001 0x45ca
5.3.0.0 192.168.1.13 932 0x80000059 0x6ada
56.56.56.0 5.5.0.250 495 0x80000062 0xc469
AS Summary Link States (Area 0.0.0.1)
Link ID ADV Router Age Seq# Checksum
5.5.0.250 5.5.0.250 496 0x800000001 0x51c0
show ip ospf database opaque-area� Use to display lists of information about the TE opaque LSAs.� The TE router address LSA describes a stable IP address on the originating
router that can be used for TE purposes�such as setting up TE LSPs to this address.
� The TE link LSA describes TE information about an interface on the originating router.
� Field descriptions� LS age � age of LSA� Options � optional capabilities supported by the described portion of the
routing domain � LS Type � type of LSA; opaque area TE router address or opaque area TE
link LSA� Link State ID � link-state ID of the opaque LSA� Advertising Router � router ID of the router that originated the LSA� LS Seq Number � link-state sequence number to identify duplicate or old
LSIDs� Checksum � checksum of the complete contents of the LSA� Length � length of the LSA in bytes� TE router ID � TE router ID of the originating router� Link type � point-to-point or multiaccess� Link ID � for point-to-point interfaces, this is the router ID of the router at the
remote end; for multiaccess interfaces, this is the address of the DR� Local Address � IP address of the local interface for the link� Remote Address � IP address of the remote (neighbor�s) interface for the
link� TE Metric � link metric for traffic engineering purposes; can be different from
the standard OSPF link� Max BW � maximum bandwidth that can be used on this link in this direction� Max Reservable BW � maximum bandwidth that can be reserved on this
link; can exceed the maximum bandwidth in the event of oversubscription� Max Unreserved BW � amount of bandwidth not yet reserved at each of the
eight priority levels; each value is less than or equal to the maximum reservable bandwidth
� Color � bitmask that specifies the administrative group membership for this link; a link that is a member of more than one group will have multiple bits set
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� Examplehost1#show ip ospf database opaque-area
Opaque-area Link States (Area 0.0.0.0)
LS age: 914
Options: (TOS-capable, No Type7-LSA, ExternalRoutingCapability, No
Multicast Capability, No External Attributes LSA)
LS Type: Opaque-Area (TE Router Address)
Link State ID: 1.0.0.0(Instance)
Advertising Router: 100.1.1.1
LS Seq Number: 0x80000003
Checksum: 0xd293
Length: 28
TE Router-ID: 100.1.1.1
LS age: 919
Options: (TOS-capable, No Type7-LSA, ExternalRoutingCapability, No
Multicast Capability, No External Attributes LSA)
LS Type: Opaque-Area (TE Links)
Link State ID: 1.0.0.1(Instance)
Advertising Router: 100.1.1.1
LS Seq Number: 0x80000003
Checksum: 0xf66e
Length: 124
Link Type: P2P
Link ID: 1744896257
Local Address 14.1.1.2
Remote Address 14.1.1.1
TE Metric 0
Max BW 1000 kb/sec (125000 Bps)
Max Reservable BW 1000 kb/sec (125000 Bps)
Max Unreserved BW : pri 0 1000 kb/sec (125000 Bps)
Max Unreserved BW : pri 1 1000 kb/sec (125000 Bps)
Max Unreserved BW : pri 2 1000 kb/sec (125000 Bps)
Max Unreserved BW : pri 3 1000 kb/sec (125000 Bps)
Max Unreserved BW : pri 4 1000 kb/sec (125000 Bps)
Max Unreserved BW : pri 5 1000 kb/sec (125000 Bps)
Max Unreserved BW : pri 6 1000 kb/sec (125000 Bps)
Max Unreserved BW : pri 7 1000 kb/sec (125000 Bps)
Color 0
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show ip ospf interface� Use to display a list of OSPF interfaces.� Field descriptions
� Interface value (fastEthernet) � status of the physical link and the operational status of the protocol
� Internet Address � interface IP address� Area � area identifier: IP address� Network type � broadcast, NBMA, Point-to-Point, or Point-to-Multipoint� Authentication type � none, simple, or MD5� Interface cost � metric for OSPF transmission� Transmit Delay � time between transmissions from the specified interface� Interface State � current state of the specified interface� Priority � router�s priority on the specified interface� Designated Router � designated router ID and respective interface IP
address� Backup Designated Router � designated router ID and respective interface
IP address of the backup router� Interface timer intervals � configuration of timer intervals: Hello, Dead, Wait,
and Retransmit � Neighbors � number of neighbors and their state; adjacent neighbors
� Examplehost1#show ip ospf interface
FastEthernet0 is up, OSPF line protocol is up
OSPF interface configuration:
Internet Address 192.168.1.250, Area 0.0.0.0
Network type BROADCAST, No authentication
Cost: 1
Transmit Delay is 1 sec, Interface State DROTHER, Priority 1
Designated Router (Interface address) 192.168.1.107
Backup Designated Router (Interface address) 192.168.1.214
Timer intervals configured, Hello 10, Dead 40, Wait 120, Retransmit 5
Neighbor Count is 2, Adjacent neighbor count is 2
Adjacent with neighbor 192.168.1.107 (Designated Router)
Adjacent with neighbor 192.168.254.7 (Backup Designated Router)
show ip ospf internal-statistics� Use to display internal OSPF statistics, such as allocation failures for different
OSPF components.� Field descriptions
� LSA bytes allocated � number of bytes allocated for LSAs� Router LSA bytes allocated � number of bytes allocated for router LSAs� Summary bytes allocated � number of bytes allocated for summary LSAs
CHAPTER 9Configuring OSPF
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� Neighbor RTX bytes allocated � number of bytes allocated for neighbor retransmissions
� Timers bytes allocated � number of bytes allocated for OSPF timers� Ospf total bytes free � total number of bytes free � Ospf heap total bytes allocated � total number of bytes allocated from the
OSPF heap� Neighbor allocation failures � number of neighbor allocation failures � LSA allocation failures � number of LSA allocation failures� LSA HDR allocation failures � number of LSA header allocation failures� DB Request allocation failures � number of database request allocation
failures � RTX allocation failures � number of neighbor retransmission allocation
failures� LS Ack allocation failures � number of LSA acknowledgment packet
allocation failures� DD pkt allocation failures � number of database description packet allocation
failures� OSPF interface allocation failures � number of interface allocation failures� OSPF general packet allocation failures � number of general packet
allocation failures� Example
host1#show ip ospf internal-statistics
Routing Process OSPF 1 with Router ID 5.72.3.1
Internal OSPF Statistics, bytes allocated/free:
LSA bytes allocated:216
Router LSA bytes allocated:936
Summary bytes allocated:0
Neighbor RTX bytes allocated:0
Timers bytes allocated:352
Ospf total bytes free:824368
Ospf heap total bytes allocated:1048576
Internal OSPF Statistics, allocation failures:
Neighbor allocation failures:0
LSA allocation failures:0
LSA HDR allocation failures:0
DB Request allocation failures:0
RTX allocation failures:0
LS Ack allocation failures:0
DD pkt allocation failures:0
OSPF interface allocation failures:0
OSPF general packet allocation failures:0
Monitoring OSPFE-Series Routers
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show ip ospf neighbors� Use to display information on OSPF neighbors on a per-interface basis.� Field descriptions
� Neighbor ID � neighbor�s router ID� Pri � router priority of neighbor� State � OSPF neighbor�s state
� DR � designated router� BDR � backup designated router� DR Other � neighbor to a designated router or a backup designated
router� Dead Time � interval since last hello packet from neighbor� Address � IP address of the neighbor�s interface� Interface � name of the specified interface and its port number
� Examplehost1#show ip ospf neighbors
Neighbor ID Pri State Dead Time Address Interface
10.0.8.1 1 TWO-WAY/DR Other 00:00:39 10.0.76.1 fastEthernet11/0
10.0.71.1 1 FULL/DR 00:00:42 10.0.76.2 fastEthernet11/0
10.0.96.1 1 FULL/BDR 00:00:28 10.0.76.4 fastEthernet11/0
show ip ospf remote-neighbor interface� Use to display all interfaces that are associated with OSPF remote neighbors. � Example
host1#show ip ospf remote-neighbor interface
OSPF remote-neighbor 221.221.221.221 interface configuration:
Update-source loopback0
Remote-neighbor reachable: yes
Area 0.0.0.0
Network type POINT-TO-POINT, No authentication
Cost: 1
Transmit Delay is 1 sec, Interface State POINT-TO-POINT, Priority 1
No designated router on this network
No backup designated router on this network
Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
Neighbor Count is 1, Adjacent neighbor count is 1
Adjacent with neighbor 221.221.221.221
show ip ospf spf-log� Use to display how often and why the router has run a full SPF calculation.� Field descriptions
� Intra SPF log � log for SPF calculations run to compute intraarea LSAs � Inter SPF log � log for SPF calculations run to compute interarea LSAs
CHAPTER 9Configuring OSPF
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� External SPF log � log for SPF calculations run to compute routes outside the OSPF routing domain
� When � amount of time since a full SPF calculation took place given in hours:minutes:seconds; the previous 20 calculations are logged
� Duration � number of milliseconds to complete this SPF run; the elapsed time is in actual clock time, not CPU time
� LSA Router Id � whenever a full SPF calculation is triggered by a new LSA, the router ID is stored in the router
� Triggers � list of reasons that triggered a full SPF calculation� Example
host1#show ip ospf spf-log
Intra SPF log
When Duration LSA Router Id Triggers
00:04:42 0.000 23.23.23.3 Protocol Off
00:04:38 0.000 23.23.23.3 LSA Add
00:04:34 0.000 12.12.12.2 LSA Add
00:04:30 0.010 23.23.23.3 LSA Update
00:03:51 0.000 23.23.23.3 Protocol Off
00:03:47 0.000 23.23.23.3 LSA Add
00:03:43 0.000 12.12.12.2 LSA Add
00:03:39 0.000 23.23.23.3 LSA Update
Inter SPF log
When Duration LSA Router Id Triggers
00:04:46 0.010 23.23.23.3 Protocol Off
00:04:42 0.000 23.23.23.3 LSA Add
00:04:38 0.000 12.12.12.2 LSA Add
00:04:34 0.000 23.23.23.3 LSA Update
00:03:55 0.000 23.23.23.3 Protocol Off
00:03:51 0.000 23.23.23.3 LSA Add
00:03:47 0.000 12.12.12.2 LSA Add
00:03:43 0.000 23.23.23.3 LSA Update
External SPF log
When Duration LSA Router Id Triggers
00:04:47 0.000 23.23.23.3 Protocol Off
00:04:43 0.000 23.23.23.3 LSA Add
00:04:39 0.000 12.12.12.2 LSA Add
00:04:35 0.010 23.23.23.3 LSA Update
00:03:56 0.000 23.23.23.3 Protocol Off
00:03:52 0.000 23.23.23.3 LSA Add
00:03:48 0.000 12.12.12.2 LSA Add
00:03:44 0.000 23.23.23.3 LSA Update
Monitoring OSPFE-Series Routers
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show ip ospf virtual-links� Use to display the parameters and the current state of OSPF virtual links.� Field descriptions
� Virtual link to router � identifies the OSPF neighbor and the current state of the virtual link
� Transmit Delay � time between transmissions from the specified interface� Timer intervals � timer intervals configured for the link: Hello, Dead, and
Retransmit� Example
host1#show ip ospf virtual-links
Virtual link to router 192.168.1.13 in state POINT-TO-POINT
Transmit Delay is 1 sec
Timer intervals configured, Hello 10 sec, Dead 40 sec, Retransmit 5 sec
CHAPTER 9Configuring OSPF
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10
Configuring IS-ISThis chapter describes how to configure Intermediate System-to-Intermediate System (IS-IS) routing on your E-series router.
OverviewIS-IS is a dynamic routing protocol developed by the International Organization for Standardization (ISO) and commonly referred to as ISO 10589. The original development of IS-IS was done at Digital Equipment Corporation for Phase V DECnet. The motivation to standardize IS-IS, however, was through the efforts of the American National Standards Institute (ANSI) X3S3.3 Network and Transport Layers Committee.
Topic Page
Overview 10-1
References 10-10
Features 10-11
Before You Run IS-IS 10-11
Configuration Tasks 10-11
Enabling IS-IS 10-12
Configuring IS-IS Interface-Specific Parameters 10-14
Configuring Global IS-IS Parameters 10-20
Configuring IS-IS for MPLS 10-35
Using IS-IS Routes for Multicast RPF Checks 10-36
Monitoring IS-IS 10-37
CHAPTER 10Configuring IS-IS
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Similar to the Open Shortest Path First (OSPF) routing protocol, IS-IS is a link-state protocol. It builds a complete and consistent picture of a network’s topology by sharing link-state information across all network Intermediate System (IS) devices.
The IS-IS routing protocol provides routing for pure Open Systems Interconnection (OSI) environments. IS-IS as implemented on the E-series router supports IP networks and enables you to configure IS-IS as an IP routing protocol only. In IS-IS, networks are partitioned into routing domains, which are further divided into areas. A two-level hierarchical routing design is used. With this model, routing is referred to as level 1, level 2, or both level 1 and level 2.
TermsOSI internetworking has its own terminology. A number of terms used in IS-IS routing discussions are defined in Table 10-1.
Table 10-1 IS-IS terms
Term Meaning
area A group of contiguous networks and their attached hosts. Area boundaries are normally assigned by a network administrator.
complete sequence number PDU (CSNP)
PDU sent by designated router to ensure database synchronization
Connectionless-mode Network Protocol (CLNP)
An OSI network layer protocol used by CLNS to handle data at the transport layer; the OSI equivalent of IP
Connectionless Network Service Protocol (CLNS)
An OSI network layer service that enables data transmission without establishing a circuit and that routes messages independently of any other messages.
end system (ES) Any nonrouting network node or host
intermediate system (IS) A router
level 1 routing � Routing within an area� Level 1 routers (or intermediate systems) track all the
individual links, routers, and end systems within a level 1 area.
� Level 1 routers do not know the identity of routers or destinations outside their area.
� A level 1 router forwards all traffic for destinations outside its area to the nearest level 2 router within its area.
OverviewE-Series Routers
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level 2 routing � Routing between areas� Level 2 routers know the level 2 topology and know
which addresses are reachable via each level 2 router.� Level 2 routers track the location of each level 1 area.� Level 2 routers are not concerned with the topology
within any level 1 area (for example, the details internal to each level 1 area).
� Level 2 routers can identify when a level 2 router is also a level 1 router within the same area.
� Only a level 2 router can exchange packets with external routers located outside its routing domain.
link-state PDU (LSP) PDU broadcast by link-state protocols that contains information about neighbors and path costs; used to maintain routing tables; also known as link-state advertisement
network entity title (NET) ISO network addresses used by CLNS networks; an identifier of a network entity in an end system or intermediate system. A NET consists of an area address (routing domain), system identifier, and selector.
network service access point (NSAP)
Hierarchical network address that specifies the point at which network services are made available to a transport layer entity in the OSI reference model. A valid NSAP address is unique and unambiguously identifies a single system.
protocol data unit (PDU) OSI term equivalent to packet, containing protocol control information and, possibly, user data. This chapter uses the term packet interchangeably with PDU.
routing domain A collection of connected areas that provide full connectivity to all end systems located within them. A routing domain is partitioned into areas.
system identifier Uniquely identifies a system within an area
Table 10-1 IS-IS terms (continued)
Term Meaning
CHAPTER 10Configuring IS-IS
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Figure 10-1 illustrates some of the terms described in Table 10-1 above.
Figure 10-1 Overview of IS-IS topology
ISO Network Layer AddressesISO network layer addresses are f lexible enough to make routing feasible in a worldwide Internet. Network layer addresses in ISO and IP are hierarchical and clearly identify level 1 and level 2 areas. These addresses can be up to 20 octets long; any packet that contains an address has one additional octet to specify the length of the address.
An ISO address—also known as the NSAP address—is broken into three parts: the area address, the system identifier (ID), and the NSAP selector.
The area address defines the routing domain and the area within the routing domain. The length of the ID field can be from 1 to 8 octets and uses a single fixed length for any one routing domain. The selector field is always 1 octet long. Usually, all end systems within the same area have the same area address. Some areas can have multiple addresses. The NSAP address is defined by the network entity title (NET) during configuration.
Level 1 RoutingA level 1 router looks at a packet’s area address and compares it with a destination address. If the area portion of the destination address matches
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OverviewE-Series Routers
10-5
its own area’s address, the level 1 router uses the ID portion of the address to route the packet. If the area portion of the address does not match, the level 1 router routes the packet to a level 2 router within its area.
Level 2 RoutingLevel 2 routers do not look at an area’s internal structure, but simply route toward an area based on the area address. It is common for a level 2 router to also be a level 1 router in a particular area; these routers are sometimes referred to as level 1-2 routers. See Figure 10-1.
Dynamic Hostname ResolutionThe system identifier of the NSAP address identifies a node in a network. System operators often find symbolic hostnames to be easier to use and remember than the system identifier. However, a static mapping of hostname to system identifier requires every router to maintain a table of the mappings; each table must contain the hostnames and system identifiers of every router in the network. The static mapping must be managed by router operators, and every change or addition of a mapping requires all the tables to be updated. Consequently, the static tables are likely to become rapidly outdated.
The router supports dynamic resolution of hostnames to system identifiers. You can use the clns host command to map the hostname to the NSAP address, and therefore to the system ID. This mapping is inserted in the dynamic hostname type-length-value tuple (TLV type 137), and subsequently advertised when LSPs are transmitted. The value field contains the hostname, preferably the fully qualified domain name (FQDN) of the host, or a subset of the FQDN. You can display the TLV by issuing the show isis database detail command.
AuthenticationThe router supports hash function-based message authentication code (HMAC) MD5 authentication for IS-IS to prevent unauthorized routers from injecting false routing information into your network or forming adjacencies with your router.
Authentication is disabled by default. When you enable IS-IS MD5 authentication, the router creates secure digests of the packets, encrypted according to the HMAC MD5 message-digest algorithms. The digests are inserted into the packets from which they are created. Depending on the commands you issue, the digests can be inserted into hello packets, link-state PDUs, complete sequence number PDUs, and partial sequence number PDUs.
CHAPTER 10Configuring IS-IS
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CommandsThe area-message-digest-key command specifies an HMAC MD5 key that the router uses to create a message digest of each level 1 packet—LSPs, CSNPs, and PSNPs—transmitted by area routers. Using MD5 authentication for area routers protects against unauthorized routers injecting false routing information into the area portions of your network.
The domain-message-digest-key command specifies an HMAC MD5 key that the router uses to create a message digest of each level 2 packet—LSPs, CSNPs, and PSNPs—transmitted by domain routers. Using MD5 authentication for domain routers protects against unauthorized routers injecting false routing information into the routing domain portions of your network.
The isis message-digest-key command specifies an HMAC MD5 key that the router uses to create a message digest of level 1 or level 2 hello packets on the interface. Level 1 packets are the default. Using MD5 authentication on interfaces protects against intrusion by preventing unauthorized routers from forming adjacencies with your router.
Example Suppose authentication is configured on router LA and router SanDiego, but not on router SanJose, as shown in Figure 10-2. Router LA and router SanDiego accept packets from each other because they contain message digests generated by an accepted key. Router SanJose accepts packets from router LA and router SanDiego, and simply ignores the message digest included in their packets. Router LA and router SanDiego reject packets from router SanJose because those packets do not include a message digest.
Figure 10-2 Packet flow between routers with and without authentication set
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OverviewE-Series Routers
10-7
Specifying Start and Stop TimingWith each of the MD5 commands, you can specify when the router will start and stop accepting packets that include a digest made with this key. You can also specify when the router will start and stop generating packets that include a digest made with this key. If you specify a time for any of these actions, you can further specify the day, month, and year. The default times are as follows:
• Start accepting keys (startAcceptTime) – current time
• Stop accepting keys (stopAcceptTime) – never
• Start generating keys (startGenTime) – current time plus 2 minutes
• Stop generating keys (stopGenTime) – never
If you specify times, you must follow these guidelines to achieve appropriate timing between the actions:
• startAcceptTime must be less than startGenTime.
• stopGenTime must be less than stopAcceptTime.
• When a new key replaces an old one, the startGenTime time for the new key must be less than or equal to the stopGenTime time of the old key.
For example, suppose you configure authentication on router A and router B. If the startGenTime for router A is earlier than the startAcceptTime for router B, router B does not accept packets from router A until the current time matches its startAcceptTime.
The router accepts any packet authenticated with a key you have defined if the packet is received within the period defined for the key by its startAcceptTime and stopAcceptTime. If more than one key has been defined for that period, the router determines which key to use by comparing the startGenTime with the current time. When the startGenTime of a key matches the current time, the router starts using this key to transmit packets and stops using the previous key.
Example host1(config-router)#area-message-digest-key 1 hmac-md5 mr942s7n start-accept 08:00:00 start-generate 9:00:00 stop-accept 23:00:00 stop-generate 22:59:59
host1(config-router)#area-message-digest-key 2 hmac-md5 dsb38h5f start-accept 08:00:00 start-generate 0:00:00 stop-accept 23:00:00 stop-generate 22:59:59
Both key 1 and key 2 are configured to be accepted between 08:00:00 and 23:00:00. When the current time reaches 09:00:00, the router begins using key 1 to transmit packets. When the current time reaches 10:00:00,
CHAPTER 10Configuring IS-IS
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the router begins using key 2 to transmit packets; key 1 is no longer used. Key 2 will continue to be used until a new key is configured and the new key's startGenTime matches the current time on the router.
Halting MD5 AuthenticationTo prevent key expiration from causing your network to revert to an unauthenticated condition, you cannot halt MD5 authentication by using the timers. When the stopGenTime time for a key is reached, the router does not stop generating the key if it was the last key issued. You must delete all keys to halt authentication. Use the no version of the command to delete a key.
Managing and Replacing KeysA key has an infinite lifetime if you do not specify stopGenTime and stopAcceptTime. (As noted above, if the last key expires, the router continues to generate that key.) Many system operators choose to roll their keys over on a regular basis, such as every month. If you determine that a key is no longer secure, you should configure a new key immediately. We recommend the following practice for configuring new keys:
1 Configure the new key on all routers in the IS-IS network.
2 Verify that the new key is working.
3 Delete the old key from every router.
Each key has an associated key-ID that you specify. The key-ID is sent with the message digest, so that the receiving routers know which key was used to generate the digest. You also use the key-ID to delete a key.
Extensions for Traffic EngineeringThe router supports new-style TLV tuples described in the Internet draft, IS-IS Extensions for Traffic Engineering. The router ID TLV (TLV type 134) contains the ID of the router that originates the LSP, providing a stable address that can always be referenced regardless of the state of node interfaces.
The extended IP reachability TLV (type 135) carries IP prefixes and is similar to the IP reachability TLVs (types 128 and 130). The extended IS reachability TLV (type 22) contains information about a series of IS neighbors and is similar to the IS neighbor TLV (type 2).
The older TLVs—2, 128, 130—each have a narrow metric field, providing for metric values ranging only from 0–63. The new TLVs—22
OverviewE-Series Routers
10-9
and 135—have a new data structure that includes a wide metric field of 3 bytes (extended IS reachability; configurable) or four bytes (extended IP reachability; calculated). Both new TLVs provide for the use of sub-TLVs to carry more information about IS neighbors; however, only the extended IS reachability TLV currently has defined sub-TLVs, such as IPv4 interface and neighbor addresses.
Use the metric-style commands to configure what style the router generates and accepts. The following behaviors are supported:
• Generates and accepts only old-style metrics
• Generates only old-style metrics, but accepts old style and new style
• Generates and accepts both old-style and new-style metrics (this option consumes the most system resources)
• Generates only new-style metrics, but accepts old style and new style
• Generates and accepts only new-style metrics
Refer to the Internet draft, IS-IS Extensions for Traffic Engineering, for more information about these extensions.
Integrated IS-ISThe E-series router supports the Integrated IS-IS version of IS-IS. Integrated IS-IS provides a single routing algorithm to route both TCP/IP and OSI Connectionless Network Protocol (CLNP) packets. This design adds IP-specific information to the OSI IS-IS routing protocol. It supports IP subnetting, variable subnet masks, type of service (ToS), and external routing.
Integrated IS-IS allows for the mixing of routing domains; that is, IP-only routers, OSI-only routers, and dual (IP and OSI) routers. OSI and IP packets are forwarded directly over the link layer services without needing mutual encapsulation. The E-series router supports IS-IS only for the routing and forwarding of TCP/IP packets. Forwarding of OSI packets is not supported.
Equal-Cost MultipathIS-IS supports equal-cost multipath (ECMP) and installs into the routing table multiple entries for paths to the same destination. Each of these multiple paths to a given destination must have the same cost as the others, but a different next hop.
CHAPTER 10Configuring IS-IS
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ReferencesFor more information about the IS-IS protocol, consult the following resources:
• E-Series Release Notes, Appendix A, System Maximums – refer to the Release Notes corresponding to your software release for information on maximum values.
• ISO International Standard 8473-1:1993 – Information technology – Protocol for providing the connectionless-mode network service
• ISO International Standard 9542:1988 (E) – Information processing systems – Telecommunications and information exchange between systems – End System-to-Intermediate System Routing Exchange Protocol for use in conjunction with the protocol for providing the connectionless-mode network service (ISO 8473)
• ISO/IEC 10589:1992 – Information technology – Telecommunications and information exchange between systems – Intermediate System-to-Intermediate System Intra-Domain Routing Exchange Protocol for use in conjunction with the protocol for providing the connectionless-mode network service (ISO 8473)
• Extended Ethernet Frame Size Support – draft-ietf-isis-ext-eth-01.txt (November 2001 expiration)
• IS-IS Extensions for Traffic Engineering – draft-ietf-isis-traffic-04.txt (August 2001 publication)
• Management Information Base for IS-IS – draft-ietf-isis-wg-mib-10.txt (April 2003 expiration)
• RFC 1195 – Use of OSI IS-IS for Routing in TCP/IP and Dual Environments (December 1990)
• RFC 2763 – Dynamic Hostname Exchange Mechanism for IS-IS (February 2000)
• RFC 2966 – Domain-wide Prefix Distribution with Two-Level IS-IS (October 2000)
• RFC 2973 – IS-IS Mesh Groups (October 2000)
• Routing IPv6 with IS-IS – draft-ietf-isis-ipv6-03.txt (April 2003 expiration)
Note: IETF drafts are valid for only 6 months from the date of issuance. They must be considered as works in progress. Please refer to the IETF Web site at http://www.ietf.org for the latest drafts.
FeaturesE-Series Routers
10-11
FeaturesSome of the major IS-IS features supported by the router include:
• Optimization of route leaking from level 1 to level 2
• Equal-cost paths maximum 32 equal paths
• Adjacency and LSP overrun
• Dynamic resolution of hostnames to system IDs
• Mesh groups
• Configurable LSP transmit and throttle intervals
• Route redistribution policies based on access lists between IS-IS levels
• Three-way handshake for point-to-point adjacencies
• HMAC MD5 authentication
• Support for bigger metric TLVs
• Domain-wide prefix distribution
• Traffic engineering for MPLS
Before You Run IS-ISAt least one IP address/router ID must be configured on your router for IS-IS to run.
Configuration TasksConfigure Integrated IS-IS by completing the tasks in the order presented below. You must enable IS-IS. All other tasks are optional.
1 Enable IS-IS.
2 Configure selected IS-IS interface-specific parameters.
3 Configure selected global IS-IS parameters.
4 Configure selected IS-IS parameters for monitoring and debugging purposes.
5 Configure IS-IS parameters to enable CLNS packets to be recognized by your router and to monitor CLNS information.
CHAPTER 10Configuring IS-IS
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Enabling IS-ISWhen enabling IS-IS, you must create an IS-IS routing process and assign it to specific interfaces rather than to networks. You can specify only a single IS-IS process per router.
To enable IS-IS routing enter Global Configuration mode, and follow this procedure:
1 Specify an IS-IS process for IP. In this example, f loor12 is specified as the tag name.
host1(config)#router isis floor12
The router is now in Router Configuration mode.
2 Configure Network Entity Titles (NETs) for the routing process that specify the ISO network address.
host1(config-router)#net 47.0010.0000.0000.0000.0001.0001.1111.1111.1111.00
3 Enter Interface Configuration mode, and specify the interface that you want to actively route IS-IS.
host1(config)#interface atm 2/0
4 Specify the IS-IS process to apply to the interface. Use the tag name from step 1.
host1(config-if)#ip router isis floor12
You can repeat steps 3 and 4 to apply the IS-IS process to multiple interfaces.
ip router isis� Use to configure an IS-IS routing process on an IP interface.� Before the IS-IS router process is useful, you must assign a NET with the net
command, and enable some interfaces with IS-IS.� Use the tag parameter to specify a meaningful name for a routing process. It
must be unique among all IP routing processes for a given router. If you choose not to specify a tag name, a null tag is assumed, and the process is referenced with a null tag. Use the same tag name for ip router isis as you did for the router isis command.
� Examplehost1(config-if)#ip router isis floor12
� Use the no version to disable IS-IS for IP on the interface.
Enabling IS-ISE-Series Routers
10-13
net� Use to configure a NET for a specified routing process. The NET defines the
ISO address and consists of an area address or ID, a system ID, and a selector.
� You must configure a minimum of one NET. � You are allowed a maximum of three NETs per router. � You can manually add multiple area IDs by adding multiple NETs with the same
system ID.� There is no default value; net must be configured for an IS-IS process to start.� Multiple NETs can be temporarily useful when there has been a network
reconfiguration where either multiple areas are merged, or one area is in the process of being split into more areas. Multiple area addresses enable you to renumber an area slowly, without needing to set aside time to renumber areas all at once.
� When you use IS-IS to do IP routing only, a NET must be configured to instruct the router about its system ID and area ID.
� ExampleIf you are configuring a router with the area ID 47.0005.80ff.f800.0000.0001.0001 and the system ID 0000.0c11.1111, you would enter it as shown. The last byte of the NET is the N-selector byte and is always 0.host1(config-router)#net 47.0010.0000.0000.0000.0001.0001.1111.1111.1111.00
� Use the no version to remove a specific NET. Remember that you must specify the NET. The last NET cannot be removed.
router isis� Always use the router isis command to enable the IS-IS routing protocol and
to specify an IS-IS process for IP.� Specify only one IS-IS process per router.� Use the tag parameter to specify a meaningful name for a routing process. If
you choose not to specify a tag name, a null tag is assumed, and the process is referenced with a null tag.
� Examplehost1(config)#router isis floor12
� Use the no version to disable IS-IS routing.
CHAPTER 10Configuring IS-IS
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Summary Examplehost1(config)#router isis floor12
host1(config-router)#net 47.0010.0000.0000.0000.0001.0001.1111.1111.1111.00
host1(config-router)#exit
host1(config)#interface atm 2/0
host1(config-if)#ip router isis floor12
host1(config-router)#exit
host1(config-if)#interface atm 2/1
host1(config-if)#ip router isis floor12
Configuring IS-IS Interface-Specific ParametersYou can change IS-IS interface-specific parameters; most can be configured independently of other attached routers. You are not required to alter any interface parameters; however, some parameters must be consistent across all routers in your network. If you change certain values from the defaults, you must configure them on multiple interfaces and routers.
You can configure IS-IS interfaces as follows:
• Set an HMAC MD5 authentication password on an interface.
• Configure the IS-IS link-state metrics.
• Set the advertised complete sequence number PDU (CSNP) interval.
• Set the advertised hello interval and hello multiplier.
• Set the LSP transmission interval.
• Set the retransmission interval.
• Set the retransmission throttle interval.
• Specify the designated router election.
• Specify the interface circuit type.
• Configure a passive interface.
In the following command guidelines, notice that many parameters are preset to a default value. If that parameter has been modified from its default, use the no version of the command to restore its default value.
Configuring IS-IS Interface-Specific ParametersE-Series Routers
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isis authentication-key� Use to specify a password associated with an interface for authentication of
IS-IS hellos. � You can specify whether the password is for level 1 or level 2 hellos.� Example
host1(config-if)#isis-authentication-key 0 red5flower6
� Use the no version to delete the password.
isis circuit-type� Use to specify adjacency levels on a specified interface; however, normally, you
do not need to use this command.� Configure a router as a level 1-only, a level 1�level 2 system, or a level 2-only
system.� Configure some interfaces to be level 2-only for routers that are between areas.
This prevents wasting bandwidth by sending out unused level 1 hellos.� On point-to-point interfaces, the level 1 and level 2 hellos are in the same
packet.� Level 1-2 is the default.� Example
host1(config-if)#isis circuit-type level-2-only
� Use the no version to restore the default value, level-1-2.
isis csnp-interval� Configure the isis csnp-interval level for a specified interface. The level can
be configured independently for level 1 and level 2.� For LAN interfaces: the default value is 10 seconds, which you probably do not
need to change. For WAN interfaces: the default value is 0 seconds or disabled.
� On point-to-point subinterfaces use isis csnp-interval in conjunction with the isis mesh-group command.
� Completed sequence number PDUs are sent by the designated router to maintain database synchronization.
� Example host1(config-if)#isis csnp-interval 30 level-1
� Use the no version to restore the default value.
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isis hello-intervalisis hello-multiplier
� Use the isis hello-interval command to set the length of time (in seconds) between hello packets sent on a specific interface. Configure independently for level 1 and level 2, except on point-to-point interfaces because only a single type of hello packet is sent on serial links. For this reason, it is independent of levels 1 and 2. For example, you can specify an optional level for Frame Relay multiaccess networks.
� Use the isis hello-multiplier command to set a number by which to multiply the hello interval seconds. This number determines the total holding time transmitted in the IS-IS hello packet. The default is 3. Use when hello packets are frequently lost and IS-IS adjacencies are failing unnecessarily.� Holding time � time a neighbor waits for another hello packet before
declaring the neighbor is down. It determines how quickly a failed link or neighbor is identified so that routes can be recalculated.
� Raise the hello multiplier and lower the hello interval simultaneously to make the hello protocol more reliable without increasing the time required to detect a link failure.
� Examplehost1(config-if)#isis hello-interval 6 level-1
host1(config-if)#isis hello-multiplier 10 level-1
� Use the no version to restore a default value.
isis lsp-interval� Use to configure the delay between successive IS-IS link-state PDU (LSP)
transmissions. � You can choose an interval in the range 1�4294967295 milliseconds. For
example, setting 100 milliseconds allows 10 packets per second.� The default value is 33 milliseconds.� If your network has many IS-IS neighbors and interfaces, a particular router
may have difficulty with the CPU load imposed by LSP transmission and reception. If this is the case, you can reduce the LSP transmission rate by issuing this command.
� Examplehost1(config-if)#isis lsp-interval 100
� Use the no version to restore the default value, 33.
isis message-digest-key� Use to configure HMAC MD5 authentication for an interface. � Generates a secure, encrypted message digest of level 1 or level 2 hello
packets and inserts the digest into the packet from which it is created. Level 1 is the default.
� You can specify whether the key is entered in unencrypted or encrypted format. If you do not specify which, the string is assumed to be unencrypted.
Configuring IS-IS Interface-Specific ParametersE-Series Routers
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� Examplehost1(config-if)#isis message-digest-key 3 hmac-md5 wdi6c3s39n level-2
� For point-to-point interfaces, configure keys only for level 1, because only one hello packet is sent (at level 1), not one at level 1 and one at level 2. Keys configured at level 2 are ignored for point-to-point interfaces.
� Use the no version to delete the MD5 key, specified by the key ID, from the interface.
isis metric� Use to configure a cost for a specified interface. � You can select a number in the range 0�63 if you configured the router with the
metric-style narrow command. You can select a number in the range 0�16277215 if you configured the router with the metric-style transition or the metric-style wide command.
� The default value is 10. The default metric is the value assigned when no quality of service (QoS) routing is performed.
� You can configure the default metric for a specified interface by selecting level 1 or level 2 routing. This resets the metric only for level 1 or level 2 routing, respectively.
� We recommend that you configure metrics on all interfaces that are related to link speed. If you do not, the IS-IS metrics are simply hop-count-like metrics.
� Examplehost1(config-if)#isis metric 20 level-2
� Use the no version to restore the default value, 10.
isis priority� Use to set the priority of use for your designated router. � You can configure an individual priority for level 1 and level 2 by choosing a
priority level in the range 0�127.� The default priority level is 64.� Specifying the level 1 or level 2 keyword resets the priority only for level 1 or
level 2 routing, respectively.� Priorities are used to determine which router in the network is the designated
intermediate system (DIS); the router with the highest priority becomes the DIS. Priorities are advertised in hellos.
� IS-IS has no backup designated router. Setting the priority to 0 reduces the chance of this router becoming the DIS, but does not prevent it. If a router with a higher priority is identified, it takes over the role from the current DIS. When priorities are equal, the highest MAC address breaks the tie and becomes the DIS.
� Example host1(config-if)#isis priority 80 level-1
� Use the no version to restore the default value, 64.
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isis retransmit-interval� Use to configure the number of seconds between the retransmission of IS-IS
LSPs with the same LSP ID for point-to-point links.� You can select an interval in the range 1�65535 seconds.� The default value is 5 seconds.� Specify a number greater than the expected round-trip delay between any two
routers on your network.� Always specify conservatively; otherwise, excessive retransmission will result.� Because retransmissions occur only when LSPs are dropped, when you set
isis retransmit-interval to a higher value, it has little effect on reconvergence. � You should set to a higher value when routers have many neighbors and/or
more paths over which LSPs can be flooded.� Use a large value for serial lines.� Example
host1(config-if)#isis retransmit-interval 60
� Use the no version to restore the default value, 5.
isis retransmit-throttle-interval� Use to configure the maximum rate at which IS-IS LSPs are retransmitted on
point-to-point links. The interval is the number of milliseconds between packets.� You can choose an interval in the range 0�65535 milliseconds.� The default delay value is 33 milliseconds.� The isis retransmit-throttle-interval is the maximum rate at which IS-IS LSPs
are retransmitted. It is different from isis lsp-interval, which is the rate at which LSPs are transmitted on the interface; and it is different from isis retransmit-interval, which is the period between successive retransmissions of the same LSP. Use all three commands with each other to control the load of routing traffic from one router to its neighbors.
� Typically, you can set this interval for very large networks with many LSPs and many interfaces as a way of controlling LSP retransmission traffic.
� Example host1(config-if)#isis retransmit-throttle-interval 300
� Use the no version to restore the default value, 33.
Configuring IS-IS Interface-Specific ParametersE-Series Routers
10-19
passive-interface� Use to configure an IS-IS interface such that its IP address is advertised in its
link-state PDUs, but no IS-IS packets are sent from or received on the interface.
� Example The following commands configure loopback 0 as a passive interface and enable IS-IS on subinterfaces ATM 2/0.1 and ATM 2/1.1. IS-IS advertises the IP address of loopback 0 in its link-state PDUs, but runs only on ATM 2/0.1 and ATM 2/1.1:host1(config)#router isis floor12
host1(config-router)#net 47.0010.0000.0000.0000.0001.0001.1111.1111.1111.00
host1(config-router)#passive-interface loopback 0
host1(config-router)#exit
host1(config)#interface atm 2/0.1
host1(config-if)#ip router isis floor12
host1(config-if)#exit
host1(config)#interface atm 2/1.1
host1(config-if)#ip router isis floor12
You can override the passive-interface configuration simply by issuing the complementary command. For example, suppose you issue the following commands after the previous configuration:host1(config-router)#passive-interface atm 2/0.1
host1(config-router)#exit
host1(config)#interface loopback 0
host1(config-if)#ip router isis floor12
Now IS-IS advertises the IP address of ATM 2/0.1 in its link-state PDUs, but runs only on loopback 0 and ATM 2/1.1.
� You can also accomplish the equivalent of the passive-interface command by using the redistribute command to redistribute a connected route to level 1.
� Use the no version to delete the passive interface.
Summary Examplehost1(config-router)#passive-interface loopback 0
host1(config-if)#interface atm 8/0.500
host1(config-if)#isis metric 20 level-2
host1(config-if)#isis csnp-interval 30 level-1
host1(config-if)#isis hello-interval 6 level-1
host1(config-if)#isis hello-multiplier 10 level-1
host1(config-if)#isis lsp-interval 100
host1(config-if)#isis retransmit-interval 60
host1(config-if)#isis retransmit-throttle-interval 300
host1(config-if)#isis priority 80 level-1
host1(config-if)#isis circuit-type level-2-only
CHAPTER 10Configuring IS-IS
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Configuring Global IS-IS ParametersThis section describes the commands you can use to globally configure optional IS-IS parameters.
• Set the maximum number of parallel routes.
• Set the mesh group.
• Suppress installation of default routes to level 1-2 routers.
In the following command guidelines, notice that many parameters are preset to a default value. Use the no version of those commands to restore default values.
Setting Authentication PasswordsYou can configure HMAC MD5 authentication either for an area or for a domain.
area-authentication-key� Use to specify a password used by neighboring routers for authentication of
IS-IS level 1 LSPs, CSNPs, and PSNPs. � You can specify whether the key is entered in unencrypted or encrypted format.
If you do not specify which, the string is assumed to be unencrypted.� Example
host1(config-router)#area-authentication-key 0 bigtree
� Use the no version to delete the password.
area-message-digest-key� Use to configure HMAC MD5 authentication for an area. � Generates a secure, encrypted message digest of level 1 packets (LSPs,
CSNPs, and PSNPs) and inserts the digest into the packet from which it is created.
� You can specify whether the key is entered in unencrypted or encrypted format. If you do not specify which, the string is assumed to be unencrypted.
� Example host1(config-router)#area-message-digest-key 1 hmac-md5 kd4s8hnEK
� Use the no version to delete the MD5 key specified by the key ID.
domain-authentication-key� Use to specify a password used by neighboring routers for authentication of
IS-IS level 2 LSPs, CSNPs, and PSNPs. � You can specify whether the key is entered in unencrypted or encrypted format.
If you do not specify which, the string is assumed to be unencrypted.
Configuring Global IS-IS ParametersE-Series Routers
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� Examplehost1(config-router)#domain-authentication-key 8 4kl6n39us
� Use the no version to delete the password.
domain-message-digest-key� Use to configure HMAC MD5 authentication for a domain. � Generates a secure, encrypted message digest of level 2 packets (LSPs,
CSNPs, and PSNPs) and inserts the digest into the packet from which it is created.
� You can specify whether the key is entered in unencrypted or encrypted format. If you do not specify which, the string is assumed to be unencrypted.
� Example host1(config-router)#domain-message-digest-key 4 hmac-md5 4bFjt7es
� Use the no version to delete the MD5 key specified by the key ID.
Configuring RedistributionYou can specify how IS-IS redistributes routes received from other routing protocols, redistributes routes according to new policies, and controls redistribution of routes with access lists and route maps.
access-listroute-map
� Use the access-list command to create a standard or extended access list.� Use the route-map command to create a route map.� For detailed information about configuring access lists and route maps, see
Chapter 1, Configuring Routing Policy.� Example
1 Configure three static routes:host1(config)#ip route 20.20.20.0 255.255.255.0 192.168.1.0
host1(config)#ip route 20.20.21.0 255.255.255.0 192.168.1.0
host1(config)#ip route 20.21.0.0 255.255.255.0 192.168.1.0
2 Configure an access list with filters on routes 20.20.20.0/24 and 20.20.21.0/24:host1(config)#access-list boston permit 20.20.0.0 0.0.255.255
3 Configure a route map that matches the previous access list and applies an internal metric type:host1(config)#route-map 1
host1(config-route-map)#match ip address 1
host1(config-route-map)#set metric-type internal
CHAPTER 10Configuring IS-IS
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4 Configure redistribution into IS-IS of the static routes with route map 1:host1(config)#router isis testnet
host1(config-router)#redistribute static ip route-map 1
5 Use the show isis database command to verify the effect of the redistribution (the two static routes matching the route map are redistributed as level 2 internal routes):host1#show isis database detail l2
IS-IS Level-2 Link State Database
LSPID LSP Seq Num LSP Checksum LSP Holdtime ATT/P/OL
0000.0000.6666.00-00 0x000002B7 0x3E1F 1198 0/0/0
Area Address: 47.0005.80FF.F800.0000.0001.0001
NLPID: 0xcc
IP Address: 192.168.1.105
Metric: 10 IS 0000.0000.6666.01
Metric: 10 IS 0000.0000.3333.00
Metric: 10 IS 0000.0000.7777.00
Metric: 30 IP 20.20.21.0 255.255.255.0
Metric: 30 IP 20.20.20.0 255.255.255.0
� Use the no version of the access-list command to remove the access list or the specified entry in the access list.
� Use the no version of the route-map command to remove an entry.
clear ip isis redistribution� Use to clear all the routes that have been previously redistributed into IS-IS and
redistribute them using the current policy configured. � Use when you have made changes to route maps or access lists that affect
how routes are redistributed to IS-IS.� Example
host1#clear ip isis redistribution
� There is no no version.
disable-dynamic-redistribute� Use to halt the dynamic redistribution of routes that are initiated by changes to
a route map. � Dynamic redistribution is enabled by default.� Example
host1(config-router)#disable-dynamic-redistribute
� Use the no version to reenable dynamic redistribution.
redistribute� Use to redistribute routes from other routing protocols in the routing table to
IS-IS. IS-IS advertises these routes within its level 1 and level 2 LSPs.� The default is no source protocol defined for redistribution.
Configuring Global IS-IS ParametersE-Series Routers
10-23
� This command can accomplish the same results as the passive-interface command by redistributing a connected route to level 1.
� Example host1(config-router)#redistribute static ip
� Use the no version to disable redistribution.
Redistributing Routes Between LevelsThe two-level routing hierarchy of IS-IS can lead to suboptimal path selection in certain situations. Because a level 1 router by default has knowledge only of level 1 routes, traffic from a level 1 router to a router in another area passes through the nearest level 1-2 router as its next hop. Consider the topology shown in Figure 10-3.
Figure 10-3 Example of level 1 and level 2 routing
In this example, Router 4 in Area 1 considers Router 2 to be its next hop for interarea traffic, and Router 5 considers Router 3 to be its next hop for interarea traffic. Traffic from Router 4 to Router 8 passes through Router 2, requiring a total of five hops to the destination: Routers 2, 1, 3, 9, and 8. Similarly, five hops are required for traffic from Router 5 to Router 7.
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CHAPTER 10Configuring IS-IS
10-24
Neither of these paths is optimal. For example, it would be shorter for traffic from Router 4 to take the four-hop path: Routers 5, 3, 9, and 8.
You can configure IS-IS to redistribute routes between the routing levels; this is sometimes known as route leaking between levels. The redistribute isis ip command enables you to specify a route filter (an access list) and the direction of leakage, as shown in the following example:
host1(config)#access-list leakList permit ip 100.0.0.0 0.255.255.255 any
host1(config)#router isis 1
host1(config-router)#redistribute isis ip level-1 into level-2 distribute-list leakList
host1(config-router)#redistribute isis ip level-2 into level-1 distribute-list leakList
redistribute isis ip� Use to redistribute routes from level 1 to level 2 or from level 2 to level 1. � Use the access list command to create a route filter to apply to the
redistribution.� Example
host1(config-router)#redistribute isis ip level-1 into level-2 distribute-list leakList
� Use the no version to stop redistribution of routes between the specified levels.
Controlling Granularity of Routing InformationYou can force the distribution of level 2 routing information to level 1 routers in other areas to improve the quality of the resulting routes, but at the cost of reduced scalability.
distribute-domain-wide� Use to increase the granularity of routing information within a domain.� Domainwide prefix distribution enables a routing domain running with both level
1 and level 2 IS routers to distribute IP prefixes from level 2 to level 1 between areas.
� The major advantage for using domainwide prefix distribution is to improve the quality of the resulting routes within a domain by distributing more specific information.
� The major disadvantage of using domainwide prefix distribution is that it affects the scalability of IS-IS. When used, it increases the number of prefixes throughout the domain, causing increased memory consumption, transmission requirements, and computation requirements throughout the domain.
Configuring Global IS-IS ParametersE-Series Routers
10-25
� A trade-off decision must be made between scalability and optimality.host1(config-router)#distribute-domain-wide
� Use the no version to halt the distribution of routes from level 2 to level 1.
Configuring Metric Type Extensions to IS-IS traffic engineering enable the use of bigger metrics. You can specify whether your router accepts, generates, or accepts and generates only old-style metrics, only new-style metrics, or both.
metric-style narrow� Use to specify that the router generates and accepts only old-style TLV tuples.� Old-style TLVs refers to TLVs having metrics with a narrow (six-bit) field that
range in value from 0�63. New-style TLVs refers to TLVs having metrics with a wider field, as provided for in current extensions to IS-IS traffic engineering.
� Use the transition option to accept old-style and new-style metrics; only old-style metrics are generated.
� Specify whether the command applies to level 1, level 2, or both.� Example
host1(config-router)#metric-style narrow level-2
� Use the no version to restore the default, which is to generate and accept only old-style TLVs with narrow (six-bit) metric fields.
metric-style transition� Use to specify that the router generates and accepts both old-style and
new-style TLV tuples.� Old style refers to TLVs having metrics with a narrow (six-bit) field that range in
value from 0� 63. New style refers to TLVs having metrics with a wider field, as provided for in current extensions to IS-IS traffic engineering.
� Specify whether the command applies to level 1, level 2, or both.� Example
host1(config-router)#metric-style transition level-1
� Issuing this command results in more resource usage than issuing the metric-style narrow or metric-style wide commands.
� Use the no version to restore the default, which is to generate and accept only old-style TLVs with narrow (six-bit) metric fields.
metric-style wide� Use to specify that the router generates and accepts only new-style TLV tuples.� Old style refers to TLVs having metrics with a narrow (six-bit) field that range in
value from 0� 63. New style refers to TLVs having metrics with a wider field, as provided for in current extensions to IS-IS traffic engineering.
CHAPTER 10Configuring IS-IS
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� Use the transition option to accept old-style and new-style metrics; only new-style metrics are generated.
� Specify whether the command applies to level 1, level 2, or both.� Example
host1(config-router)#metric-style wide level-1-2
� Use the no version to restore the default, which is to generate and accept only old-style TLVs with narrow (six-bit) metric fields.
Setting the Administrative DistanceYou can indicate the dependability of a routing information source by configuring the administrative distance for learned routes.
distance ip� Use to configure the administrative distance for IS-IS learned routes.� The distance indicates the dependability of a routing information source. A
higher relative value indicates lower dependability. Preference is always given to the routes with smaller values.
� Select a value between 1 and 255. A value of 255 means discard the route.� Example
host1(config-router)#distance ip 50
� Use the no version to restore the default value, 115.
Configuring Default RoutesYou can specify a default route within IS-IS routing domains. You can also suppress the installation of a default route to level 1-2 routers bylevel 1 routers.
default-information originate� Use to generate a default route into an IS-IS routing domain.� When you specify a route map with this command and the router has a route to
0.0.0.0 in the routing table, IS-IS originates an advertisement for 0.0.0.0 in its LSPs.
� When you do not specify a route map, the default route is advertised only in level 2 LSPs.
� For level 1 routing, look for the closest level 1-2 router to find the default route. The closest level 1-2 router is found by looking at the attach bit (ATT) in level 1 LSPs.
� The default is disabled.� Example
host1(config-router)#default-information originate
� Use the no version to disable the command.
Configuring Global IS-IS ParametersE-Series Routers
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suppress-default� Use to prevent level 1 routers from automatically installing a default route to a
level 1-2 router in order to reach destinations outside the area. � Suppresses level 1-2 router from indicating to level 1 routers that it can reach
other areas. Consequently, the level 1 routers do not consider the level 1-2 router to be the nearest attached level 2 router and do not install default routes to it.
� This command is useful, for example, if you issue the distribute-domain-wide command, which causes the level 2 routes to be leaked into the level 1 area. The level 1 routers then have knowledge of the routes outside the area and will not need to rely on the nearest attached level 2 router for any unknown destination.
� Examplehost1(config-router)#suppress-default
� Use the no version to disable suppression of default routes.
Setting Router TypeYou can specify whether the router behaves as an IS-IS station router, area router, or both.
is-type� Use to configure the router to act as either a station router (level 1), an area
router (level 2), or as both a station router and an area router (level 1-2).� You should always configure the type of IS-IS router.� Level 1-2 is the default.� Example
host1(config-router)#is-type level-2-only
� Use the no version to restore the default value, level-1-2.
Summarizing RoutesYou can summarize routes redistributed into IS-IS or within IS-IS by creating aggregate addresses for the routes.
summary-address� Use to create aggregate addresses of routes that are redistributed from other
protocols in the routing table or distributed between level 1 and level 2 by a summary address. This process is called route summarization.
� A single summary address includes groups of addresses for a given level.� The metric value is used when the router advertises the summary address.
When the metric value is not used, the value of the lowest cost route (the default) is used.
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� This command reduces the size of the neighbor�s routing table and improves stability because a summary advertisement depends on many more specific routes.
� A disadvantage of summary addresses is that other routes might have less information to calculate the optimal routing table for all individual destinations.
� Examplehost1(config-router)#summary-address 10.2.0.82 255.255.0.0 level-1-2
� Use the no version to restore the default, the value of the lowest cost route.
Configuring the Router to Be IgnoredIf you have a router through which you do not want IS-IS traffic to pass, you can set the overload bit, causing other IS-IS routers to ignore the router.
set-overload-bit� Use to configure the router to set the overload bit in its nonpseudonode LSPs.
When set, other routers ignore the unreliable router in their SPF calculations until the router problems are corrected.
� You would normally set the overload bit only when a router runs into problems such as memory shortage that may result in routing table inaccuracies.
� When set, no paths through this router can be seen by other routers in the IS-IS area. IP prefixes directly connected to this router are still reachable.
� Set this command when you want to connect a router to an IS-IS network but you do not want real traffic flowing through it. For example, you could set the overload bit if a test router were connected to a production network.
� Example host1(config-router)#set-overload-bit
� Use the on-startup keyword to specify a period in seconds after router reboot during which the overload bit is set. Other systems cannot route through the router until the bit clears, by which time all interfaces and protocols are up and the router is fully operational.
� Examplehost1(config-router)#set-overload-bit on-startup 900
� There is no default value; the overload bit is not set.� Use the no version to disable the setting.
Configuring Global IS-IS ParametersE-Series Routers
10-29
Ignoring LSP ErrorsYou can configure the router to ignore rather than purge LSPs received with errors.
ignore-lsp-errors� Use to enable your router to ignore rather than purge IS-IS LSPs that are
received with internal checksum errors.� Under normal conditions, the IS-IS protocol definition requires that received
LSPs with incorrect data link checksums are to be purged by the receiver. This causes the LSP initiator to regenerate LSPs. If a network link causes data corruption while still delivering LSPs with correct data link checksums, a continuous cycle of regenerating and purging LSPs may result. This can render the network nonfunctional. Enabling this command prevents this continuous cycle from occurring because LSPs are ignored rather than purged.
� Example host1(config-router)#ignore-lsp-errors
� Use the no version to disable the function.
Logging Adjacency State ChangesYou can configure the router to log messages that track when adjacencies change state between up and down.
log-adjacency-changes� Use to generate log messages that track IS-IS adjacency state changes (up or
down).� The default is not to log adjacency state changes.� Recommended for monitoring large networks.� The system logs messages by using the router error message facility.� Specify the minimum severity (0�7) or verbosity (low, medium, high) of this log
category's messages.� Example
host1(config-router)#log-adjacency-changes severity 3 verbosity low
� Alternatively, you can use the system log command to generate the desired log messages.
� Use the no version to disable the function.
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Configuring LSP ParametersYou can specify the following parameters for LSPs:
• Maximum transmission unit (MTU)
• Transmission rate
• Generation rate
• Maximum lifetime
lsp-mtu� Use to specify the MTU LSP size in bytes. The size must be less than or equal
to the smallest MTU of any link in the area.� Use this command to limit the size of LSPs generated by this router only. The
router can receive LSPs of any size up to the maximum.� You can set the value in the range 128�9180.� The default LSP MTU value is 1497.� When a very large amount of information is generated by a single router, we
recommend that you increase the LSP MTU. However, the default MTU is usually sufficient.
� If the MTU of a link is lowered to less than 1500 bytes, the LSP MTU must be lowered accordingly on each router in the network. If this is not done, routing may become unpredictable.
� Example host1(config-router)#lsp-mtu 1500
� Use the no version to restore the default value, 1497.
lsp-gen-interval� Use to set the minimum interval rate that LSPs are generated on a per-LSP
basis. � You can set an interval value in the range 0�120 seconds. � The default interval value is 5 seconds. When a link is changing state at a high
rate, the default value limits the signalling of the changing state to once every 5 seconds. Because the generation of an LSP may cause all routers in the area to perform the shortest path first (SPF) calculation, controlling this interval can have an areawide effect.
� When you raise this interval, you reduce the load on the network imposed by a rapidly changing link.
� Example host1(config-router)#lsp-gen-interval level-2 30
� Use the no version to restore the default value, 5.
Configuring Global IS-IS ParametersE-Series Routers
10-31
lsp-refresh-interval� Use to set the LSP rate at which locally generated LSPs are periodically
transmitted.� The refresh interval determines the rate at which the router software
periodically transmits the route topology information that it originates. These transmissions prevent the information from becoming obsolete.
� You can set the interval rate in the range 1�65535 seconds; the default is 900 seconds.
� LSPs must be periodically refreshed before their lifetimes expire. The refresh interval must be less than the LSP lifetime specified by max-lsp-lifetime.
� In the unlikely event that link stage database corruption is undetected, reducing the refresh interval reduces the amount of time that the corruption can persist.
� Increasing the interval reduces the link utilization caused by the flooding of refreshed packets.
� Example host1(config-router)#lsp-refresh-interval 1000
� Use the no version to restore the default value, 900.
max-lsp-lifetime� Use to set the maximum time that LSPs persist without being refreshed.� You can select a maximum time in the range 1�65535 seconds.� The default value is 1200 seconds (20 minutes).� You might need to adjust the maximum LSP lifetime if you change the LSP
refresh interval with the lsp-refresh-interval command. The maximum LSP lifetime must be greater than the LSP refresh interval.
� Example host1(config-router)#max-lsp-lifetime 1500
� Use the no version to restore the default value, 1200.
Specifying the SPF IntervalYou can configure how often the router performs the shortest path first (SPF) calculation.
spf-interval� Use to control the minimum interval between the SPF calculations.� You can select an interval value in the range 0�120 seconds.� The default value is 5 seconds.� If you do not specify level1 or level2, the interval applies to both level 1 and
level 2.� SPF calculations are performed only when the topology of the area changes.
They are not performed when external routes change.� Controls how often the router software can perform the SPF calculation. The
SPF calculation is processor-intensive. Therefore, it may be useful to limit how
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often calculation is done, especially when the area is large and the topology changes often. Increasing the SPF interval reduces the processor load of the router, but potentially slows down the rate of convergence.
� Example host1(config-router)#spf-interval level-2 30
� Use the no version to restore the default value, 5.
Defining the SPF Route Calculation LevelThe IS-IS protocol uses the Dijkstra algorithm to compute IP node metrics when a change occurs within the IS-IS network. This calculation results in the IS-IS router containing a shortest path tree (SPT) that maps the shortest path to each node in the IS-IS network.
By default, the router uses a partial route calculation (PRC) SPF to determine the next hop (when required). This partial computation occurs when the router receives link-state PDUs (LSPs) with only changes relating to IP prefixes (for example, the addition of a new IP prefix, change in attributes of an existing IP prefix, or the removal of an existing IP prefix).
Because changes in IP prefixes happen more frequently than other events, using the PRC SPF results in faster IS-IS convergence and saves router resources. However, you can also specify that the router always use full SPF, recalculating the entire SPT, when resolving any IS-IS state changes.
full-spf-always� Use to enable and disable full SPF calculations for ISIS network changes.� Example
host1(config-router)#full-spf-always
� Use the no version to restore partial route calculation (PRC) mode for SPF calculations.
Configuring Global IS-IS ParametersE-Series Routers
10-33
Setting CLNS ParametersYou can specify transmission rates for ES and IS hello packets, the period for which the router considers ES and IS hello packets to be valid, and name-to-network service access point mappings.
clns configuration-time� Use to specify the rate (in seconds) at which ES hello and IS hello packets are
sent.� The hello packet recipient creates an adjacency entry for the router that sent it.
If the next hello packet is not received within the specified interval, the adjacency times out, and the adjacent node is determined to be unreachable.
� In most cases, these parameters should be left at their default value, which is 10 seconds.
� Example host1(config)#clns configuration 240
� Use the no version to restore the default value, 10.
clns holding-time� Use to enable sender of an ES hello or IS hello packet to specify the length of
time you consider the information in these packets to be valid.� In most cases, these parameters should be left at their default value, which is
30 seconds.� Example
host1(config)#clns holding-time 900
� Use the no version to restore the default value, 30.
clns host� Use to define a name-to-NSAP mapping that can then be used with commands
requiring NSAPs.� The default is that no mapping is defined.� The assigned NSAP name is displayed, where applicable, in show commands. � The first character can be either a letter or a number.� This command is generated after all other CLNS commands when the
configuration file is parsed. As a result, the NVRAM version of the configuration cannot be edited to specifically change the address defined in the original clns host command. You must specifically change any commands that refer to the original address. This affects commands that accept names, such as the net command.
� Enables dynamic resolution of hostnames to system IDs (within the NSAP address). The hostname mapping is sent in the LSPs within the Dynamic Hostname type-length-value (TLV type 137). Display the TLV by issuing the show isis database detail command.
� Use the show hosts command to display the mapping.
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� Examplehost1(config)#clns host
� Use the no version to restore the default state of no mapping defined.
Setting the Maximum Parallel RoutesYou can configure how many parallel routes IS-IS supports to a destination.
maximum-paths� Use to control the maximum number of parallel routes IS-IS can support.� You can select a number of routes (or paths) in the range 1�16.� The default number for IS-IS is 4 paths.� Example
host1(config-router)#maximum-paths 12
� Use the no version to restore the default value, 4.
Configuring a Virtual Multiaccess NetworkYou can specify that interfaces within a given mesh group will act as a virtual multiaccess network.
isis mesh-group� Use when you want interfaces in the same mesh group to act as a virtual
multiaccess network.� LSPs seen on one interface in a mesh group will not be flooded to another
interface in the same mesh group.� Example
host1(config-if)#isis mesh-group blocked
� Use the no version to disable the feature.
Summary Examplehost1(config)#router isis floor12
host1(config-router)#net 47.0010.0000.0000.0000.0001.0001.1111.1111.1111.00
host1(config-router)#exit
host1(config)#interface atm 0/1
host1(config-if)#ip router isis floor12
host1(config-if)#isis mesh-group blocked
host1(config-if)#exit
host1(config)#interface atm 1/0
host1(config-if)#ip router isis floor12
host1(config-router)#distribute-domain-wide
Configuring IS-IS for MPLSE-Series Routers
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host1(config-router)#distance 100 ip
host1(config-router)#default-information originate route-map 9
host1(config-router)#is-type level-1-2
host1(config-router)#summary-address 10.2.0.82 255.255.0.0 level-1-2
host1(config-router)#set-overload-bit
host1(config-router)#ignore-lsp-errors
host1(config-router)#log-adjacency-changes
host1(config-router)#lsp-mtu 1500
host1(config-router)#lsp-refresh-interval 1000
host1(config-router)#lsp-gen-interval level-2 30
host1(config-router)#max-lsp-lifetime 1500
host1(config-router)#spf-interval level-2 30
host1(config-router)#maximum-paths 32
host1(config-router)#redistribute static ip
host1(config-router)#exit
host1(config)#clns configuration-time 120
host1(config)#clns holding-time 600
Configuring IS-IS for MPLSIS-IS has several new commands to provide support for MPLS. See E-Series Routing Protocols Configuration Guide, Vol. 2, Chapter 2, Configuring MPLS, for a detailed discussion of MPLS. If you configure your tunnel with the tunnel mpls autoroute announce isis command, MPLS attempts to register the tunnel endpoint with IS-IS. You must enable this registration with IS-IS by issuing the mpls traffic-eng command.
When you configure a node as the downstream endpoint of an LSP, you must provide a stable interface as the router ID for the endpoint. Typically you select a loopback interface because of its inherent stability. Use the mpls traffic-eng router-id command to specify the router ID.
By default, IS-IS always uses the MPLS tunnel to reach the MPLS endpoint. Best paths determined by IS-IS SPF calculations are not considered. You can enable the consideration of best paths by issuing the mpls spf-use-any-best-path command. As a result, IS-IS considers metrics for IGP paths and the tunnel metric, and might forward traffic along a best path, through the MPLS tunnel, or both.
Several show commands enable monitoring of MPLS information. See Monitoring IS-IS in this chapter for more information.
MPLS traffic engineering requires that IS-IS generate the new-style TLVs that enable wider metrics. Use the metric-style wide command to
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generate the new-style TLVs. If you are using some IS-IS routers that still do not understand the new-style TLVs, use the metric-style transition command. See Extensions for Traffic Engineering (page 10-8) and Configuring Global IS-IS Parameters for detailed information about using the metric-style commands.
mpls spf-use-any-best-path� Use to enable SPF calculations to consider the IGP (IS-IS) best paths as well
as the MPLS tunnel for forwarding traffic to the MPLS endpoint. � By default, the MPLS tunnel is always selected for traffic to the tunnel endpoint;
IGP paths are not considered. For traffic beyond the endpoint, the tunnel is considered equally with any other path.
� Example host1(config-router)#mpls spf-use-any-best-path
� Use the no version to disable the use of IGP best paths.
mpls traffic-eng� Use to enable flooding of MPLS traffic engineering link information into the
specified IS-IS level. Flooding is disabled by default.� Example
host1(config-router)#mpls traffic-eng level-1
� Use the no version to disable flooding.
mpls traffic-eng router-id� Use to specify a very stable interface to be used as a router ID for MPLS traffic
engineering. Typically you specify a loopback interface to provide the greatest stability, because this is flooded to all nodes. The interface acts as the destination node for tunnels originating at other nodes.
� Example host1(config-router)#mpls traffic-eng router-id loopback 0
� Use the no version to remove the interface as a router ID.
Using IS-IS Routes for Multicast RPF ChecksYou can use the ip route-type command to specify whether IS-IS routes are available for only unicast forwarding protocols or only multicast reverse-path forwarding (RPF) checks. Routes available for unicast forwarding appear in the unicast view of the routing table, whereas routes available for multicast RPF checks appear in the multicast view of the routing table.
Monitoring IS-ISE-Series Routers
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ip route-type� Use to specify whether IS-IS routes are available only for unicast forwarding,
only for multicast reverse-path forwarding checks, or for both.� Use the show ip route command to view the routes available for unicast
forwarding.� Use the show ip rpf-routes command to view the routes available for multicast
reverse path forwarding checks.� By default, IS-IS routes are available for both unicast forwarding and multicast
reverse path forwarding checks.� Example
host1(config)#router isis
host1(config-router)#ip route-type unicast
� Use the no version to restore the default value, both.
Monitoring IS-ISThe CLI has commands available for monitoring IS-IS parameters and CLNS parameters.
Monitoring IS-IS ParametersYou can monitor the IS-IS link-state database and IS-IS debug information. Use the commands in this section to:
• Display router information.
• Display information about SPF calculations.
• Monitor IS-IS summary address information.
• Display debug information.
• Display host.
• Display information about MPLS tunnels.
• Clear adjacencies.
• Display paths to intermediate systems.
You can use the output filtering feature of the show command to include or exclude lines of output based on a text string you specify. Refer to E-Series System Basics Configuration Guide, Chapter 2, Command Line Interface, for details.
CHAPTER 10Configuring IS-IS
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clear isis adjacency� Use to remove entries from the adjacency database.� Specify a hostname or the system ID of a neighbor to clear only adjacencies
with that neighbor. � Specify no options to remove all adjacencies from the database.� Example
host1#clear isis adjacency
� There is no no version.
debug isis� Use to obtain debug-related information about certain parameters.� This command manipulates the same log as the Global Configuration log
commands.� You can select from these parameters:
� adj-packets � IS-IS adjacency-related packets� mpls traffic-eng advertisements � MPLS traffic-engineering agent
advertisements� mpls traffic-eng agents � MPLS traffic-engineering agents� snp-packets � IS-IS CSNP/PSNP packets� spf-events � IS-IS Shortest Path First events� spf-statistics � IS-IS SPF timing and statistic data� spf-triggers � IS-IS SPF triggering events� update-packets � IS-IS update-related packets
� Examplehost1#debug isis adj-packets
� Use the no version to disable debugging display.
show hosts� Use to display the name-to-NSAP mappings defined with the clns host
command. � Field descriptions
� Static Host Table� name � name assigned to the host� ip address � host IP address� type � type of host� username � username ncecessary to access the host� password � password necessary to access the host
� Clns Host Alias Table� name � name of the host alias� area address � area address of the host alias
Monitoring IS-ISE-Series Routers
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� system ID � six-byte value of the host alias� type � type of host alias
� Examplehost1:abc#show hosts
Static Host Table
-----------------
name ip address type username password
---- ---------- ---- --------- --------
jkk 10.10.0.73 ftp anonymous null
Clns Host Alias Table
---------------------
name area address system ID type
----- -------------------------------- ----------------- ------
fred 47.0005.80FF.F800.0000.0001.0001 0000.0000.0011.00 static
karen 47.0005.80FF.F800.0000.0001.0001 0000.0000.0012.00 static
show isis database� Use to display IS-IS link-state database information.� Each option (described below) can be entered in an arbitrary string within a
single command entry.� Request specific show isis database statistics by selecting from these options:
� lspid � link-state protocol ID in form xxxx.xxxx.xxxx.yy-zz� detail � detailed link-state database information; if this option is not
specified, a summary display is provided� l1 � level 1 routing link-state database� l2 � level 2 routing link-state database� level-1 � level 1 routing link-state database� level-2 � level 2 routing link-state database
� Field descriptions� LSPID � LSP identifier� LSP Seq Num � sequence number for the LSP. Enables other routers to
determine if they have received the latest information from source.� LSP Checksum � checksum of the LSP packet� LSP Holdtime � number of seconds that the LSP remains valid� ATT � attach bit; indicates that the router is a level 2 router and can reach
other areas� P � P bit; detects whether intermediate system is capable of area partition
repair� OL � overload bit; determines whether intermediate system is congested� Area Address � area addresses that can be reached from the router� NLPID � ISO network layer protocol identifier� IP Address � IP address of the interface� Hostname � hostname of the router
CHAPTER 10Configuring IS-IS
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� Router ID � ID configured on the router� Metric � metric that indicates either of the following costs:
� cost of adjacency between the originating router and the advertised neighbor
� cost between the advertising router and the advertised destination� IPv4 Interface Address � address of the interface� IPv4 Neighbor Address � address of a neighbor
� Example 1host1#show isis database
IS-IS Level-1 Link State Database
LSPID LSP Seq Num LSP Checksum LSP Holdtime ATT/P/OL
0000.0000.004E.00-00 0x000013F5 0x8BAA 1198 0/0/0
0000.0000.3333.00-00* 0x0000020F 0xEA1E 1199 0/0/0
0000.0000.3333.02-00 0x00000007 0x8C30 1199 0/0/0
0000.0000.7500.00-00 0x0000308D 0x5EDF 1198 0/0/0
0090.1A00.B000.00-00 0x00000011 0xB082 1195 1/0/0
0090.1A00.C000.00-00 0x0000005F 0x9860 1196 0/0/0
IS-IS Level-2 Link State Database
LSPID LSP Seq Num LSP Checksum LSP Holdtime ATT/P/OL
0000.0000.004E.00-00 0x00001355 0x0DA7 1198 0/0/0
0000.0000.3333.00-00* 0x00000257 0x566B 1199 0/0/0
0000.0000.3333.02-00 0x00000007 0x8C30 1199 0/0/0
0000.0000.7500.00-00 0x00003315 0x3627 1198 0/0/0
0010.7B36.5FF7.00-00 0x00000BAF 0x187A 1183 0/0/0
0090.1A00.B000.00-00 0x00000016 0xD624 1195 1/0/0
0090.1A00.C000.00-00 0x00000071 0x9358 1196 0/0/0
� Example 2host1#show isis database detail
LSPID LSP Seq Num LSP Checksum LSP Holdtime ATT/P/OL
boston.00-00*0x000001160x4760 6551/0/0
Area Address: 47.0005.80FF.F800.0000.0000.0004
NLPID: 0x81 0xcc
IP Address: 10.1.1.1
Hostname: boston
Router ID: 10.1.1.1
Metric: 10 IS newyork.00
IPv4 Interface Address: 10.1.1.1
IPv4 Neighbor Address: 10.1.1.2
Metric: 10 IS washington.00
IPv4 Interface Address: 10.1.3.1
IPv4 Neighbor Address: 10.1.3.3
Metric: 10 IP 192.168.1.0/24
Metric: 10 IP 10.1.1.0/24
Monitoring IS-ISE-Series Routers
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Metric: 10 IP 10.1.3.0/24
Metric: 20 IP 10.1.2.0/24
� Example 3host1#show isis database verbose
IS-IS Level-1 Link State Database
LSPID LSP Seq Num LSP Checksum LSP Holdtime ATT/P/OL
zion.00-00* 0x00000011 0xBFAD 487 0/0/0
Area Address: 47.0005.80FF.F800.0000.0000.0003
NLPID: 0x81 0xcc
IP Address: 222.9.1.1
Hostname: zion
Router ID: 222.9.1.1
Metric: 0 ES 2220.0900.1001
Metric: 10 IS london.00
Administrative group: 0
IPv4 Interface Address: 221.1.1.1
IPv4 Neighbor Address: 221.1.1.2
Maximum link bandwidth: 50000
Reservable link bandwidth: 50000
Unreserved bandwidth:
Priority 0: 50000
Priority 1: 50000
Priority 2: 50000
Priority 3: 50000
Priority 4: 30000
Priority 5: 30000
Priority 6: 30000
Priority 7: 30000
TE default metric: 0
Metric: 10 IS london.00
Administrative group: 0
IPv4 Interface Address: 221.1.6.1
IPv4 Neighbor Address: 221.1.6.2
Maximum link bandwidth: 50000
Reservable link bandwidth: 50000
Unreserved bandwidth:
Priority 0: 50000
Priority 1: 50000
Priority 2: 50000
Priority 3: 50000
Priority 4: 30000
Priority 5: 30000
Priority 6: 30000
Priority 7: 30000
TE default metric: 0
CHAPTER 10Configuring IS-IS
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Metric: 10 IS paris.00
Administrative group: 0
IPv4 Interface Address: 221.1.4.1
IPv4 Neighbor Address: 221.1.4.4
Maximum link bandwidth: 0
Reservable link bandwidth: 0
Unreserved bandwidth:
Priority 0: 0
Priority 1: 0
Priority 2: 0
Priority 3: 0
Priority 4: 0
Priority 5: 0
Priority 6: 0
Priority 7: 0
TE default metric: 0
Metric: 10 IP 221.1.1.0/24
Metric: 10 IP 221.1.6.0/24
Metric: 10 IP 221.1.4.0/24
Metric: 0 IP 222.9.1.1/32
show isis mpls adjacency-log� Use to display a log of the last 20 IS-IS adjacency changes. � Field descriptions
� When � amount of time since recording the log entry� Neighbor ID � identifier for the neighbor� IP Address � IP address of the neighbor� Interface � interface from which neighbor was learned� Status � adjacency status, Up or Down� Level � IS-IS routing level
� Examplehost1#show isis mpls adjacency-log
IS-IS MPLS TE log
When Neighbor ID IP Address Interface Status Level
02:25:47 2220.0900.2002.00 221.1.1.2 at2/0.1 Up L1
02:25:47 2220.0900.2002.00 221.1.6.2 at2/0.6 Up L1
02:25:47 2220.0900.4004.00 221.1.4.4 at2/1.5 Up L1
Monitoring IS-ISE-Series Routers
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show isis mpls advertisements� Use to display the last record flooded from MPLS. � Field descriptions
� System ID � name or system ID of the MPLS tail-end (destination) router� Router ID � router ID for the router � Link Count � number of links that MPLS advertises� Neighbor System ID � identifier of the remote system in an area� Administrative group � TLV administrative group or color assigned to the link� Interface IP address � IP address of the interface� Neighbor IP Address � IP address of the neighbor� Maximum link bandwidth � bandwidth capacity of the link in bits per second� Reservable link bandwidth � amount of bandwidth reservable on the link
(whether reserved or not)� Unreserved bandwidth � amount of bandwidth available for reservation on
the link� Affinity Bits � attributes flooded for the link
� Examplehost1#show isis mpls advertisements
System ID: zion.00
Router ID: 222.9.1.1
Link[1]
Neighbor System ID: london.00
Administrative group: 0
IPv4 Interface Address: 221.1.1.1
IPv4 Neighbor Address: 221.1.1.2
Maximum link bandwidth: 50000
Reservable link bandwidth: 50000
Unreserved bandwidth:
Priority 0: 50000
Priority 1: 50000
Priority 2: 50000
Priority 3: 50000
Priority 4: 30000
Priority 5: 30000
Priority 6: 30000
Priority 7: 30000
TE default metric: 0
Link[2]
Neighbor System ID: london.00
Administrative group: 0
IPv4 Interface Address: 221.1.6.1
IPv4 Neighbor Address: 221.1.6.2
Maximum link bandwidth: 50000
Reservable link bandwidth: 50000
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Unreserved bandwidth:
Priority 0: 50000
Priority 1: 50000
Priority 2: 50000
Priority 3: 50000
Priority 4: 30000
Priority 5: 30000
Priority 6: 30000
Priority 7: 30000
TE default metric: 0
Link[3]
Neighbor System ID: paris.00
Administrative group: 0
IPv4 Interface Address: 221.1.4.1
IPv4 Neighbor Address: 221.1.4.4
Maximum link bandwidth: 0
Reservable link bandwidth: 0
Unreserved bandwidth:
Priority 0: 0
Priority 1: 0
Priority 2: 0
Priority 3: 0
Priority 4: 0
Priority 5: 0
Priority 6: 0
Priority 7: 0
TE default metric: 0
show isis mpls tunnel� Use to display information about tunnels used in the calculation of IS-IS next
hops. � Field descriptions
� System Id � name or system ID of the MPLS tail-end (destination) router� Tunnel Name � name of the MPLS tunnel interface� Nexthop � destination IP address of the MPLS tunnel� Metric � metric of the MPLS tunnel� Mode � metric mode, either absolute or relative
� Example host1#show isis mpls tunnel
System Id Tunnel Name Nexthop Metric Mode
dakota-router1.00 Tunnel1 2.2.2.2 -3 Relative
Tunnel2 2.2.2.2 11 Absolute
jersey-router2.00 Tunnel3 3.3.3.3 -1 Relative
Tunnel4 3.3.3.3
Monitoring IS-ISE-Series Routers
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show isis spf-log� Use to display how often and why the router has run a full SPF calculation.� Field descriptions
� When � amount of time since a full SPF calculation took place, given in hours:minutes:seconds. The previous 20 calculations are logged.
� Duration � number of seconds to complete this SPF run. The elapsed time is in actual clock time, not CPU time.
� First Trigger LSP � whenever a full SPF calculation is triggered by a new LSP, the LSP ID is stored in the router
� SpfType � type of SPF run� Triggers � list of causes that triggered the SPF calculation
� Example 1ERX-40-20-33:2#sho isis spf-log
Level 1 SPF log
When Duration First Trigger LSP SpfType Triggers
00:01:45 0.000 0000.0000.0000.00-00 Full LSP Add
00:01:36 0.000 0000.0000.0000.00-00 Full LSP Add
00:01:31 0.000 0000.0101.0101.00-00 Full LSP Add
00:00:08 0.000 0000.0101.0101.00-00 PRC LSP Sequence Update
� Example 2ERX-40-20-33:2#sho isis spf-log detail
Level 1 SPF log
When Duration First Trigger LSP SpfType Triggers
00:01:53 0.000 0000.0000.0000.00-00 Full LSP Add
RTupdt 0.000
RtLeak 0.000
00:01:44 0.000 0000.0000.0000.00-00 Full LSP Add
RTupdt 0.000
RtLeak 0.000
00:01:39 0.000 0000.0101.0101.00-00 Full LSP Add
RTupdt 0.000
RtLeak 0.000
00:00:16 0.000 0000.0101.0101.00-00 PRC LSP Sequence Update
RTupdt 0.000
RtLeak 0.000
CHAPTER 10Configuring IS-IS
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show isis summary-addresses� Use to display the status of IS-IS aggregate addresses.� Field descriptions
� Address � aggregate addresses advertised by summarization process� Mask � IP subnet masks used for the summary routes� Level � level for which multiple groups of addresses can be summarized� Metric � metric used to advertise the summary� State � state of the summary address
� Examplehost1#show isis summary-addresses
Address Mask Level Metric State
-------- ---------- --------- ------ -------
3.0.0.0 255.0.0.0 LEVEL-1 0 ENABLED
4.0.0.0 255.0.0.0 LEVEL-1-2 5 ENABLED
show isis topology� Use to display the paths to all intermediate systems or specific types of
intermediate systems. � Field descriptions
� System ID � name or system ID of the intermediate system� Metric � metric of the path to the intermediate system� Next Hop � destination IP address of the intermediate system� Interface � interface from which neighbor was learned� SNPA � subnetwork point of attachment; for a LAN circuit, it is the MAC
address; not meaningful for a point-to-point circuit.� Example
host1#show isis topology level-1
IS-IS paths for level-1 routers
-------------------------------
System-ID Metric Next Hop Intf SNPA
------------- ------ ------------- -------- ----
barcelona:vr2 10 barcelona:vr2 at2/0.12
undebug isis� Use to cancel the display of information about a selected event.� The same IS-IS variables can be designated as in the debug isis command.� Example
host1#undebug isis adj-packets
� There is no no version.
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Displaying CLNSYou can display the following information related to the CLNS protocol:
• CLNS information about interfaces
• Information about router adjacencies
• Information about ES and IS neighbors
• Protocol-specific information for each routing process
• Information about CLNS packets
• Global CLNS configurations
You can set a statistics baseline for CLNS using the baseline clns command.
baseline clns� Use to set a statistics baseline for CLNS. � The router implements the baseline by reading and storing the statistics at the
time the baseline is set and then subtracting this baseline whenever baseline-relative statistics are retrieved.
� Use the optional interface-specifier parameter to specify an interface; otherwise the command sets a baseline for all interfaces.
� You cannot set a baseline for groups of interfaces.� When baselining is requested, the time since the last baseline was set is
displayed in days, hours, minutes, and seconds.� Use the optional delta keyword with the show clns traffic command to specify
that baselined statistics are to be shown.� There is no no version. � Example
host1#show clns traffic detail
IS-IS: Baseline last set 0 days, 0 hours, 1 minutes, 41 seconds
IS-IS: Corrupted LSPs: 0
IS-IS: L1 LSP Database Overloads: 0
IS-IS: L2 LSP Database Overloads: 0
IS-IS: Area Addresses Dropped: 0
IS-IS: Attempts to Exceed Max Sequence: 0
IS-IS: Sequence Numbers Skipped: 6
IS-IS: Own LSPs Purged: 1
IS-IS: System ID Length Mismatches: 0
IS-IS: Maximum Area Mismatches: 0
Interface: atm2/1.3
IS-IS: Baseline last set 0 days, 0 hours, 1 minutes, 43 seconds
IS-IS: Protocol PDUs (in/out): 32/36
IS-IS: Init Failures: 0
CHAPTER 10Configuring IS-IS
10-48
IS-IS: Adjacencies Changes: 1
IS-IS: Adjacencies Rejected: 0
IS-IS: Bad LSPs: 0
IS-IS: Level-1 Designated IS Changes: 0
IS-IS: Level-2 Designated IS Changes: 0
IS-IS: Invalid 9542s: 0
host1#baseline clns atm 2/1.3
host1#show clns traffic detail delta
IS-IS: Baseline last set 0 days, 0 hours, 2 minutes, 27 seconds
IS-IS: Corrupted LSPs: 0
IS-IS: L1 LSP Database Overloads: 0
IS-IS: L2 LSP Database Overloads: 0
IS-IS: Area Addresses Dropped: 0
IS-IS: Attempts to Exceed Max Sequence: 0
IS-IS: Sequence Numbers Skipped: 6
IS-IS: Own LSPs Purged: 1
IS-IS: System ID Length Mismatches: 0
IS-IS: Maximum Area Mismatches: 0
Interface: atm2/1.3
IS-IS: Baseline last set 0 days, 0 hours, 0 minutes, 8 seconds
IS-IS: Protocol PDUs (in/out): 2/1
IS-IS: Init Failures: 0
IS-IS: Adjacencies Changes: 0
IS-IS: Adjacencies Rejected: 0
IS-IS: Bad LSPs: 0
IS-IS: Level-1 Designated IS Changes: 0
IS-IS: Level-2 Designated IS Changes: 0
IS-IS: Invalid 9542s: 0
clear isis database� Use to delete all entries from the IS-IS link-state database, or only the entries
associated with the specified neighbor.� Field descriptions
� LSPID � LSP identifier� LSP Seq Num � sequence number for the LSP. Enables other routers to
determine if they have received the latest information from source.� LSP Checksum � checksum of the LSP packet� LSP Holdtime � number of seconds that the LSP remains valid� ATT � attach bit; indicates that the router is a level 2 router and can reach
other areas� P � P bit; detects whether intermediate system is capable of area partition
repair� OL � overload bit; determines whether intermediate system is congested
� There is no no version.
Monitoring IS-ISE-Series Routers
10-49
� Examplehost1#show isis database
IS-IS Level-1 Link State Database
LSPID LSP Seq Num LSP Checksum LSP Holdtime ATT/P/OL
rtr1.00-00* 0x00000009 0x568F 1188 0/0/0
rtrtwo.00-00 0x00000005 0xEC9B 444 0/0/0
IS-IS Level-2 Link State Database
LSPID LSP Seq Num LSP Checksum LSP Holdtime ATT/P/OL
rtr1.00-00* 0x00000010 0xF630 1193 0/0/0
rtrtwo.00-00 0x0000000C 0xF8DA 1188 0/0/0
host1#clear isis database
host1#show isis database
IS-IS Level-1 Link State Database
LSPID LSP Seq Num LSP Checksum LSP Holdtime ATT/P/OL
IS-IS Level-2 Link State Database
LSPID LSP Seq Num LSP Checksum LSP Holdtime ATT/P/OL
show clns� Use to display global CLNS information about the router.� Field descriptions
� Interfaces Enabled for CLNS � number of interfaces that have the CLNS routing protocol enabled
� Configuration Timer � interval (in seconds) after which the router sends out IS hello packets
� Default Holding Timer � length of time (in seconds) that hello packets are remembered
� Packet Lifetime � default value used in packets sourced by this router � Intermediate system operation enabled (forwarding allowed) � indicates
whether this router is configured to be an ES or an IS� IS-IS Level-1-2 Router � shows whether IS-IS is running in this router, gives
tag information, and shows whether it is running level 1 or level 1-2� Routing for Area � ISO (NSAP) address for the network� Distribute domain wide enabled � indicates whether distribute-domain-wide
is enabled� Area Authentication � if area authentication is enabled, lists key-id, type of
authentication, start and stop accept times, and start and stop generate times for the key. An asterisk after the type indicates that the key is active.
� Domain Authentication � if domain authentication is enabled, lists key-id, type of authentication, start and stop accept times, and start and stop generate times for the key. An asterisk after the type indicates that the key is active.
� Use the es-neighbors keyword to display information for IS-IS end-system adjacencies or the is-neighbors keyword to display information for IS-IS
CHAPTER 10Configuring IS-IS
10-50
intermediate-system adjacencies. Neighbor entries are sorted according to the area in which they are located. The following fields are displayed when any of these keywords is used:� System Id � six-byte value of router� Interface � interface on which the router was discovered� State � adjacency state, either Up or Init
� Up � believes that the ES or IS is reachable� Init � router is an IS and is waiting for an IS-IS hello message. IS-IS
regards the neighbor as not adjacent. � Type � level 1, level 2, and level 1-2 type adjacencies
� L1 � router adjacency for level 1 routing only� L1L2 � router adjacency for level 1 and level 2 routing� L2 � router adjacency for level 2 only
� Priority � IS-IS priority that the respective neighbor is advertising. The highest-priority neighbor becomes the designated IS-IS router for the interface.
� Circuit Id � neighbor�s idea of what the designated IS-IS router is for the interface
� Add the detail keyword to display area addresses and IP addresses.� Example 1
host1#show clns
Global CLNS Information:
3 Interfaces Enabled for CLNS
NET: 47.0005.80FF.F800.0000.0001.0001.0000.0000.3333.00
Configuration Timer: 10, Default Holding Timer: 30, Packet Lifetime: 1200
Intermediate system operation enabled
IS-IS level-1-2 Router: testnet
Routing for Area: 47.0005.80FF.F800.0000.0001.0001
Distribution domain wide enabled
Area Authentication:
Key-id: 1 Type: hmac-md5
Start Accept: FRI JAN 14 09:57:41 2000
Start Generate: FRI JAN 14 09:59:41 2000
Stop Accept: 0
Stop Generate: 0
Domain Authentication:
Key-id: 1 Type: hmac-md5*
Start Accept: WED JAN 12 19:01:52 2000
Start Generate: WED JAN 12 19:03:52 2000
Stop Accept: 0
Stop Generate: 0
Monitoring IS-ISE-Series Routers
10-51
� Example 2host1#show clns is-neighbors
System Id Interface State Type Priority Circuit Id
0000.0000.7500 atm2/0.111 up L1L2 127 0000.0000.0000.00
host1#show clns is-neighbors detail
System Id Interface State Type Priority Circuit Id
0000.0000.7500 atm2/0.111 up L1L2 127 0000.0000.0000.00
Area Address(es): 47.0005.80FF.F800.0000.0001.0001
Ip Address(es): 172.30.245.33
show clns interface� Use to display CLNS-specific information about each interface.� Field descriptions
� interface � shows status of interface� Checksums � can be either enabled or disabled � MTU � shows the maximum transmission size for a packet on this interface � Encapsulation � describes encapsulation used by CLNP packets on this
interface� Next ESH/ISH � shows when the next ES hello or IS hello is sent on this
interface � Routing Protocol � lists the area(s) that this interface is in. In most cases, an
interface will be in only one area. � Circuit type � indicates whether the interface has been configured for local
routing (level 1), area routing (level 2), or local and area routing (level 1-2) � Authentication Level-1 � if area authentication is enabled, lists key-id, type of
authentication, start and stop accept times, and start and stop generate times for the key. An asterisk after the type indicates the key is active.
� Authentication Level-2 � if domain authentication is enabled, lists key-id, type of authentication, start and stop accept times, and start and stop generate times for the key. An asterisk after the type indicates the key is active.
� Remaining fields � display information about ISO CLNS routing protocols enabled on the interface. For IS-IS, specifies the level 1 and level 2 metrics, priorities, interface IDs, next IS-IS hello interval, mesh group status, and number of active level 1 and level 2 adjacencies.
� Examplehost1#show clns interface
fastEthernet0/0 is up, line protocol is down
Checksums Enabled, MTU 1500, Encapsulation SNAP
Next ESH/ISH is 1 seconds
Routing Protocol: IS-IS
Circuit Type: level-1-2
Interface number 0x1, local circuit ID 0x1
Level-1 Metric: 10, Priority: 0, Circuit ID: 0000.0000.0000.01
Number of active level-1 adjacencies: 0
Level-2 Metric: 10, Priority: 0, Circuit ID: 0000.0000.0000.01
CHAPTER 10Configuring IS-IS
10-52
Number of active level-2 adjacencies: 0
Next IS-IS LAN Level-1 Hello in 0 seconds
Next IS-IS LAN Level-2 Hello in 0 seconds
Mesh Group Inactive
serial3/1:1/1.111 is up, line protocol is up
Checksums Enabled, MTU 1600, Encapsulation Frame Relay
Next ESH/ISH is 8 seconds
Routing Protocol: IS-IS
Circuit Type: level-1-2
Interface number 0x2, local circuit ID 0x2
Level-1 Metric: 10, Priority: 0, Circuit ID: 0000.0000.0000.02
Number of active level-1 adjacencies: 0
Level-2 Metric: 10, Priority: 0, Circuit ID: 0000.0000.0000.02
Number of active level-2 adjacencies: 0
Next IS-IS PTPT Hello in 3 seconds
Mesh Group Inactive
Authentication Level-1:
Key-id: 1 Type: hmac-md5*
Start Accept: WED JAN 12 18:56:20 2000
Start Generate: WED JAN 12 18:58:20 2000
Stop Accept: 0
Stop Generate: 0
Authentication Level-2:
Key-id: 1 Type: hmac-md5
Start Accept: FRI JAN 14 09:58:27 2000
Start Generate: FRI JAN 14 10:00:27 2000
Stop Accept: 0
Stop Generate: 0
host1#show clns interface
atm2/0.111 is up, line protocol is up
Checksums Enabled, MTU 4470, Encapsulation ATM
Next ESH/ISH is 2 seconds
Routing Protocol: IS-IS
Circuit Type: level-1-2
Interface number 0x1, local circuit ID 0x1
Level-1 Metric: 10, Priority: 0, Circuit ID:0000.0000.7500.07
Number of active level-1 adjacencies: 1
Level-2 Metric: 10, Priority: 0, Circuit ID:0000.0000.0000.01
Number of active level-2 adjacencies: 1
Next IS-IS PTPT Hello in 7 seconds
Mesh Group Inactive
ethernet6/0 is up, line protocol is up
Checksums Enabled, MTU 1500, Encapsulation SNAP
Next ESH/ISH is 8 seconds
Routing Protocol: IS-IS
Circuit Type: level-1-2
Monitoring IS-ISE-Series Routers
10-53
Interface number 0x2, local circuit ID 0x2
Level-1 Metric: 10, Priority: 0, Circuit ID:0000.0000.3333.02
Number of active level-1 adjacencies: 1
Level-2 Metric: 10, Priority: 0, Circuit ID:0000.0000.3333.02
Number of active level-2 adjacencies: 1
Next IS-IS LAN Level-1 Hello in 1 seconds
Next IS-IS LAN Level-2 Hello in 3 seconds
Mesh Group Inactive
show clns neighbors� Use to display information about ES and IS neighbors.� Field descriptions
� System Id � six-byte value of router� SNPA � subnetwork point of attachment; the data link address� Interface � interface the router was learned from� State � state of the ES or IS
� Init � router is an IS and is waiting for an IS-IS hello message. IS-IS regards the neighbor as not adjacent.
� Up � believes the ES or IS is reachable � Holdtime � number of seconds before this adjacency entry times out � Type � adjacency type. Possible values are as follows:
� ES � end-system adjacency either discovered via the ES-IS protocol or statically configured
� IS � router adjacency either discovered via the ES-IS protocol or statically configured
� L1 � router adjacency for level 1 routing only � L1L2 � router adjacency for level 1 and level 2 routing � L2 � router adjacency for level 2 only
� Protocol � protocol through which the adjacency was learned. Valid protocol sources include ES-IS, IS-IS, and Static.
� Add keyword detail to display area addresses and IP addresses.� Example
host1#show clns neighbors detail
System Id SNPA Interface State Holdtime Type Protocol
0000.0000.7500 atm2/0.111 up 30 L1L2 IS-IS
Area Address(es): 47.0005.80FF.F800.0000.0001.0001
Ip Address(es): 172.30.245.33
CHAPTER 10Configuring IS-IS
10-54
show clns protocol� Use to display protocol-specific information about a routing process.� Field descriptions
� IS-IS Router � IS-IS router name� System ID � six-byte value of router� IS-Type � indicates the routing level (level 1, level 2, or both) that is enabled
on the router � Manual area addresses � configured area addresses� Routing for area address(es) � identified for level 1 routing processes. For
level 2 routing processes, lists the domain address.� Interfaces supported by IS-IS � lists interfaces and type� Distance � configured distance value� Redistributing � protocols being redistributed into IS-IS
� Examplehost1#show clns protocol
IS-IS Router:testnet
System Id: 0000.0000.3333.00 IS-Type: level-1-2
Manual area address(es):47.0005.80FF.F800.0000.0001.0001
Routing for area address(es):47.0005.80FF.F800.0000.0001.0001
Interfaces supported by IS-IS:atm2/0.111 - IP
Distance: 115
Redistributing:
show clns traffic� Use to display all CLNS packets the router sees.� Use the optional delta keyword to specify that baselined statistics are to be
shown.� Field descriptions
� IS-IS: Baseline last set � time since the baseline was set� IS-IS: Corrupted LSPs � number of LSPs received with errors� IS-IS: L1 LSP Database Overloads � number of overloads in level 1� IS-IS: L2 LSP Database Overloads � number of overloads in level 2� IS-IS: Area Addresses Dropped � number of area addresses that the router
dropped� IS-IS: Attempts to Exceed Max Sequence � number of sequence wraps over
maximum� IS-IS: Sequence Numbers Skipped � number of LSPs received out of order� IS-IS: Own LSPs Purged � number of LSPs deleted� IS-IS: System ID Length Mismatches � number of unmatched system ID
lengths� IS-IS: Maximum Area Mismatches � number of rejected hellos due to area
mismatches� IS-IS: Area/Domain Authentication Failures � number of authentication
failures on received level 1 and level 2 LSP/SNPs
Monitoring IS-ISE-Series Routers
10-55
� When you specify an interface, reports include the following additional field descriptions:� IS-IS: Protocol PDUs (in/out) � number of packets in/out on interface� IS-IS: Init Failures � number of rejected hellos on interface� IS-IS: Adjacencies Changes � number of times adjacencies have
transitioned from down to up� IS-IS: Adjacencies Rejected � number of times hellos are rejected because
of an incompatibility� IS-IS: Bad LSPs � number of LSPs received with errors� IS-IS: Level-1 Designated IS Changes � number of times the level 1
designated router has changed� IS-IS: Level-2 Designated IS Changes � number of times the level 2
designated router has changed� IS-IS: Invalid 9542s � number of rejected ES hello packets� IS-IS: Authentication Failures � number of authentication failures on
received level 1 and level 2 hello packets� IS-IS: Interface � IS-IS interface for which details are displayed
� Add the detail keyword to show data for all interfaces.� Example
host1#show clns traffic
IS-IS: Baseline last set 0 days, 21 hours, 12 minutes, 15 seconds
IS-IS: Corrupted LSPs: 0
IS-IS: L1 LSP Database Overloads: 0
IS-IS: L2 LSP Database Overloads: 0
IS-IS: Area Addresses Dropped: 0
IS-IS: Attempts to Exceed Max Sequence: 0
IS-IS: Sequence Numbers Skipped: 5
IS-IS: Own LSPs Purged: 0
IS-IS: System ID Length Mismatches: 0
IS-IS: Maximum Area Mismatches: 0
IS-IS: Area/Domain Authentication Failures: 0
host1#show clns traffic detail
IS-IS: Baseline last set 0 days, 21 hours, 12 minutes, 40 seconds
IS-IS: Corrupted LSPs: 0
IS-IS: L1 LSP Database Overloads: 0
IS-IS: L2 LSP Database Overloads: 0
IS-IS: Area Addresses Dropped: 0
IS-IS: Attempts to Exceed Max Sequence: 0
IS-IS: Sequence Numbers Skipped: 5
IS-IS: Own LSPs Purged: 0
IS-IS: System ID Length Mismatches: 0
IS-IS: Maximum Area Mismatches: 0
IS-IS: Area/Domain Authentication Failures: 0
Interface: fastEthernet0/0
IS-IS: Baseline last set 0 days, 21 hours, 12 minutes, 40 seconds
CHAPTER 10Configuring IS-IS
10-56
IS-IS: Protocol PDUs (in/out): 62005/66617
IS-IS: Init Failures: 0
IS-IS: Adjacencies Changes: 2
IS-IS: Adjacencies Rejected: 0
IS-IS: Bad LSPs: 0
IS-IS: Level-1 Designated IS Changes: 2
IS-IS: Level-2 Designated IS Changes: 2
IS-IS: Invalid 9542s: 0
IS-IS: Authentication Failures: 0
Interface: serial3/2:1/1.222
IS-IS: Baseline last set 0 days, 21 hours, 12 minutes, 40 seconds
IS-IS: Protocol PDUs (in/out): 10422/9522
IS-IS: Init Failures: 0
IS-IS: Adjacencies Changes: 1
IS-IS: Adjacencies Rejected: 0
IS-IS: Bad LSPs: 0
IS-IS: Level-1 Designated IS Changes: 0
IS-IS: Level-2 Designated IS Changes: 0
IS-IS: Invalid 9542s: 0
IS-IS: Authentication Failures: 0
11
Configuring VRRPThis chapter describes how to configure the Virtual Router Redundancy Protocol (VRRP) on your E-series router.
OverviewVRRP can prevent loss of network connectivity to end hosts if the static default IP gateway fails. By implementing VRRP, you can designate a number of routers as “backup” routers in the event that the default “master” router fails.
Note: It is important to understand that the term �virtual router� as defined in the E-Series System Basics Configuration Guide, Chapter 11, Configuring Virtual Routers, is different from what is implied by VRRP. In this chapter, the term �virtual router� always refers to a VRRP router; that is, a router that has enabled VRRP.
In case of a failure, VRRP dynamically shifts the packet-forwarding responsibility to a backup router. A redundancy scheme is created by VRRP, which allows hosts to keep a single IP address for the default gateway, but maps the IP address to a well-known virtual MAC address. VRRP provides this redundancy without user intervention or additional configuration at the end hosts.
Topic Page
Overview 11-1
References 11-2
How VRRP Works 11-3
How VRRP Is Implemented in the E-Series Router 11-7
Configuring VRRP 11-8
Monitoring VRRP 11-12
CHAPTER 11Configuring VRRP
11-2
VRRP is supported on the FE-2 line module and the GE/FE line module. VLANs and S-VLANs are fully supported.
TerminologyTable 11-1 provides definitions for the basic VRRP terms used in this chapter.
ReferencesFor more information about VRRP, see:
• RFC 2338 – Virtual Router Redundancy Protocol (April 1998)
• RFC 2787 – Definitions of Managed Objects for the Virtual Router Redundancy Protocol (March 2000)
Note: It is important to have some background understanding of the Address Resolution Protocol (ARP) before configuring VRRP. See the section, Address Resolution Protocol (ARP), in Chapter 2, Configuring IP.
Table 11-1 VRRP definitions
Term Definition
VRRP router A router that is running VRRP. It may participate in one or more virtual router IDs (VRIDs). An IP redundancy instance can:� Act as a master with associated addresses it owns at an IP
interface� Act simultaneously as a backup for other routers with
additional VRID mappings and priorities for those routers
Master router The VRRP router that assumes the responsibility of forwarding packets sent to the IP address(es) associated with the virtual router, and that answers ARP requests for these IP addresses. If the IP address owner is available, then it always becomes the master.
Backup router The VRRP router available to assume forwarding responsibility if the current master router fails.
IP address owner The IP interface�VRID pair instance that has the associated IP address(es) as real interface address(es). This router, when up, responds to packets addressed to one of these IP addresses for ICMP pings or TCP connections. The IP address owner is the primary router.
Primary IP address
An IP address configured as primary from the set of real interface addresses. VRRP advertisements are always sent (by the master router) using the primary IP address as the source of the IP packet.
How VRRP WorksE-Series Routers
11-3
How VRRP WorksThe advantage of using VRRP is that you gain a higher availability for the default path without requiring configuration of dynamic routing or router discovery protocols on every end host.
VRRP routers viewed as a “redundancy group” share the responsibility for forwarding packets as if they “owned” the IP address corresponding to the default gateway configured on the hosts. At any time, one of the VRRP routers acts as the master, and other VRRP routers act as backups. If the master router fails, a backup router becomes the new master. In this way, router redundancy is always provided, allowing traffic on the LAN to be routed without relying on a single router.
There is always a master for the shared IP address. If the master goes down, an elected VRRP router forwards packets on behalf of the owner by taking over the virtual MAC address used by the owner.
When implemented in your network, VRRP assumes that if any link to a subnet is active, the router has access to the entire subnet. VRRP leverages the broadcast capabilities of Ethernet. Provided that one of the routers in a VRRP configuration is running, ARP requests for the IP addresses assigned to the default gateway always receive replies. Additionally, end hosts can send packets outside their subnet without interruption.
Configuration ExamplesThree VRRP configuration examples are described and illustrated in this section. They include:
• Basic VRRP configuration
• Common VRRP configuration
• VRRP configuration without the real address owner
Basic VRRP Configuration As shown in Figure 11-1, the basic VRRP configuration uses a single VRID (VRID 1). Because R1 is the address owner, it serves as the master. Router R2 is the backup. The four end hosts on subnet 1 are configured to use 10.0.0.1/8 as the default router. IP address 10.0.0.1 is associated with VRID 1.
In this example, if R1 becomes unavailable, R2 takes over VRID 1 and its associated IP addresses. Packets sent to IP destinations outside the 10.x.x.x subnet using 10.0.0.1 as the router are then forwarded by R2. Even though R2 assumes R1’s forwarding responsibilities, it never
CHAPTER 11Configuring VRRP
11-4
processes any packet with destination address (DA) 10.0.0.1. When R1 becomes active again, it takes over as the master and R2 reverts to backup.
The VRRP MAC address is always: 00-00-5e-00-01-vrid. The valid VRID range is 0x01–0xFF.
Figure 11-1 Basic VRRP configuration
Commonly Used VRRP ConfigurationFigure 11-2 shows two physical routers backing each other up through VRRP. Routers R1 and R2 are both configured with VRID 1 and VRID 2. In this configuration, under normal circumstances the routing load is distributed between the two routers.
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How VRRP WorksE-Series Routers
11-5
Figure 11-2 Commonly used VRRP configuration
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CHAPTER 11Configuring VRRP
11-6
VRRP Configuration Without the Real Address OwnerFigure 11-3 is noticeably similar to Figure 11-2 except that there is no real owner for the addresses configured by the VRIDs. Consequently, both routers R1 and R2 are configured as backup routers for VRID 1, VRID 2, VRID 3, and VRID 4.
Figure 11-3 VRRP configuration without the real address owner
Assuming that preemption is enabled, the router that is configured with the highest priority for each VRID becomes the master. If priorities are the same, the router that has the highest primary address becomes the master.
This configuration shows how the address owner does not necessarily need to exist under VRRP. The configuration seems somewhat mysterious, since the PCs are never able to “ping” their gateway; however, they can talk to destinations outside their own subnet.
IP multicast packets are used by the election protocol specified in VRRP to provide the router with redundancy. Therefore, VRRP can operate over a variety of multiaccess LAN technologies supporting IP multicast. It is important to remember that there is always one master for an IP address shared by the redundancy group.
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How VRRP Is Implemented in the E-Series RouterE-Series Routers
11-7
How VRRP Is Implemented in the E-Series RouterVRRP is implemented in the E-series router meet two goals. The first goal is to avoid the single point of failure inherent to hosts that have a single default gateway configured. The second goal is to keep the complexity of redundancy away from the hosts themselves. These goals are in compliance with RFC 2338 and RFC 2787.
The association between VRIDs and IP addresses is coordinated among all participating VRRP routers. A scenario is provided to help you understand how VRRP is implemented in the router.
1 The E-series router assigns common VRIDs to the group of routers that are going to share IP addresses.
2 The E-series router sends VRRP advertisements to well-known multicast addresses. The router that owns the addresses automatically becomes the master and sends periodic VRRP advertisement messages. A VRRP advertisement consists of the IP addresses that the master controls and the VRID.
3 If the master stops advertising for a predetermined period of time, the remaining routers using the same VRID enter an election process to determine which router takes over the master responsibilities.
4 If the master does not own the IP addresses for which it is responsible, it drops all packets that have DAs to these IP addresses.
5 If the elected master fails, backup routers start the election process again.
6 When the original master becomes operational again, it restarts broadcasting advertisements as long as preemption is enabled or the master is the address owner. Packet forwarding responsibility then shifts back to the original master router.
Router Election RulesIf the master router becomes unavailable, there are rules that govern election of the master router:
• The backup router assigned the highest priority for each VRID becomes the master.
• If two backup routers were assigned the same priority, the router that has the highest primary address becomes the master. For example, if several routers were all assigned the default priority of 100, then the IP addresses must be compared.
CHAPTER 11Configuring VRRP
11-8
• Router election on a VRRP router can also be determined by whether or not the preemption option is enabled.
When a backup router detects a master router with a lower priority than the backup has, the backup router may either choose to leave the current master alone or take over the current master and become the master itself.
When preemption is enabled, a backup router always preempts or takes over the responsibility of the master router. When preemption is disabled, the lower-priority backup is left in the master state.
Note: It is possible that ICMP redirect�s source address may be overridden when VRRP is in use. When a backup VRID acts as a master on a given IP interface, its ICMP redirects must �fake� the source IP address of the IP address owner. The IP address must be faked because hosts accept only an ICMP redirect that was sent by the host�s current gateway.
Configuring VRRPYou must perform certain steps to configure VRRP; others are optional.
Configuring the IP InterfaceBefore you configure VRRP, you must configure an IP interface and assign a primary IP address and subnet mask. When the IP address belongs to the owner of the VRID, it must be associated with the VRID you create.
To configure an IP interface and IP address:
1 Configure an IP interface.
host1(config)#interface fastEthernet 4/0
2 Assign an IP address and a subnet mask.
host1(config-if)#ip address 194.50.1.42 255.255.255.0
Note: It is recommended that you complete all IP address configurations before you configure VRRP. If for any reason the IP address information is changed after you configure VRRP, you must revise the associated IP addresses configured on the related VRRP entries. If auto addresses are specified in the ip vrrp virtual-address command and they are used in conjunction with priority 255, you must disable and reenable the VRRP entry for the association list to be updated.
Configuring VRRPE-Series Routers
11-9
Creating VRIDsA master or backup router running the VRRP protocol may participate in one or more VRID instances. There are several ways to create a VRID instance:
• It is recommended that you create and/or configure a VRID instance first, and enable it last. For example:
host1(config-if)#ip vrrp 198
host1(config-if)#ip vrrp 198 priority 255
• You can create and enable a VRID instance by using the ip vrrp vrid enable command, as shown below.
host1(config-if)#ip vrrp 25 enable
• You continue to configure the VRID by identifying the VRID each time a VRRP command is used. For example:
host1(config-if)#ip vrrp 175 authentication-type none
• Alternatively, you can create a new VRID when configuring any VRRP command, providing it is the first time the VRID instance is used. For example, if you execute the command ip vrrp vrid preempt and it is the first time that VRID is used, a new VRID is created.
host1(config-if)#ip vrrp 16 preempt
• Use the ip vrrp vrid enable command last. The new VRID is not enabled until you execute this command.
host1(config-if)#ip vrrp 198 enable
host1(config-if)#ip vrrp 16 enable
host1(config-if)#ip vrrp 175 enable
Configuration StepsBefore configuring VRRP, you may find it helpful to review the configuration examples in the earlier section How VRRP Works.
To configure VRRP parameters:
1 (Optional) Create a VRID instance.
host1(config-if)#ip vrrp 25
2 (Optional) Set a VRRP advertisement interval for the same VRID.
host1(config-if)#ip vrrp 25 advertise-interval 50
CHAPTER 11Configuring VRRP
11-10
3 Set the VRRP router priority for owner and/or backup router(s).
This step is mandatory to configure priority for the owner VRID (255). This step is optional to configure priority for a backup VRID (1–254). The default is 100.
host1(config-if)#ip vrrp 25 priority 255
host1(config-if)#ip vrrp 22 priority 254
4 (Optional) Set the preemption option. In this example a new VRID is created.
host1(config-if)#ip vrrp 10 preempt
5 Associate an IP address with a VRID.
host1(config-if)#ip vrrp 25 virtual-address 194.2.1.63 255.255.255.0
6 (Optional) Set the VRRP authentication type to either text or none.
host1(config-if)#ip vrrp 25 authentication-type none
7 (Optional) Configure the VRRP authentication key.
host1(config-if)#ip vrrp 25 authentication-key dublin
8 Enable the VRID instance.
host1(config-if)#ip vrrp 25 enable
ip vrrp� Use to create a VRID instance. � The VRID range is between 1�255.� Example
host1(config-if)#ip vrrp 25
� Use the no version to remove a VRID instance.
ip vrrp advertise-interval� Use to configure the advertisement interval time.� The interval time can be configured for seconds or milliseconds.� Use seconds to be in compliance with RFC 2338.� If your VRID environment consists of only E-series routers, you can optionally
use milliseconds.� Example
host1(config-if)#ip vrrp 25 advertise-interval 50
� Use the no version to restore the default, 1 second.
Configuring VRRPE-Series Routers
11-11
ip vrrp authentication-key� Use to specify the authentication key.� Use the key keyword only when the authentication type is text. See ip vrrp
authentication-type.� Example
host1(config-if)#ip vrrp 25 authentication-key dublin
� Use no ip vrrp authentication-key to set the authentication key to its default, empty string.
ip vrrp authentication-type� Use to specify the authentication type of either text or none.� Example
host1(config-if)#ip vrrp 175 authentication-type none
� Use no ip vrrp authentication-type to set the authentication type to its default, none.
ip vrrp enable� Use to enable an existing VRID instance.� The VRID range is between 1�255.� The default is disable.� Example
host1(config-if)#ip vrrp 175 enable
� Use the no version to disable an existing VRID instance.
ip vrrp preempt� Use to enable preemption. � When preemption is enabled, a backup router always takes over the
responsibility of the master router. When preemption is disabled, the lower- priority backup is left in the master state.
� Examplehost1(config-if)#ip vrrp 10 preempt
� The default is enabled.� Use the no version to disable preemption.
ip vrrp priority� Use to configure the priority of VRRP routers.� A value of 255 implies �master router� priority.� A value of 1�254 implies �backup router� priority.� Example
host1(config-if)#ip vrrp 25 priority 255
� Use the no version to set the priority to the default value, 100.
CHAPTER 11Configuring VRRP
11-12
ip vrrp virtual-address� Use to associate an IP address with a VRID.� If the auto keyword is used, associated addresses are automatically learned or
configured, depending on the priority attribute.� There is no default.� Example
host1(config-if)#ip vrrp 25 virtual-address 194.2.1.63 255.255.255.0
� Use no ip vrrp virtual-address to remove an IP address association with a VRID. If auto addresses are used, the no version clears the auto flag.
Monitoring VRRPYou can use several VRRP show commands to monitor the details of your VRRP configuration.
baseline ip vrrp� Sets the baseline on all VRRP statistics as the current value.� Example
host1#baseline ip vrrp
show ip vrrp� Use to display a detailed summary of all VRIDs configured.� Use the interface keyword to specify a specific Fast Ethernet or Gigabit
Ethernet interface.� Field descriptions
� Interface � Fast Ethernet or Gigabit Ethernet interface specifier and VRID� primary address � IP address used while in master state; not necessarily an
associated address� operational state � state of the VRRP router: master, backup, or init; when
the operational state is backup, the current master�s ip address is given� admin state � administrative status: enabled or disabled� up time � number of seconds that the VRID has been enabled in non-init
state� interval � VRRP advertisement interval: seconds/milliseconds� last error status � help text used to debug any error detected� priority � priority of VRRP router� auth type � the VRRP authentication type: none or text� preemption � VRRP router preemption status: enabled or disabled� auto assoc address(es) � IP addresses associated with VRID
Monitoring VRRPE-Series Routers
11-13
� ExampleInterface: fastEthernet5/0.0 vrrpVrid: 1
primary address: 10.0.0.2
operational state: backup (current master: 130.0.0.1)
admin state: enabled
up time: 145 seconds
interval: 1 second
last error status: no error
priority: 101
auth type: none
preemption: enabled
auto assoc address(es): 10.0.0.1, 100.0.0.1, 101.0.0.1
show ip vrrp brief� Use to display a brief summary of all VRIDs configured.� Use the interface keyword to specify a specific Fast Ethernet or Gigabit
Ethernet interface. � Field descriptions
� Interface � Fast Ethernet or Gigabit Ethernet specifier� VRID � VRRP router instance configured on this interface� Primary Address � IP address used while in master state; not necessarily an
associated address� State � operational state of VRRP router: master, backup, or init� Adv � advertisement interval in seconds� Pri � priority assigned to this router� Admin � administrative state of the VRID: enabled or disabled
� ExampleInterface VRID Primary Address State Adv Pri Admin
----------------------- ---- --------------- ------ --- --- --------
fastEthernet12/8.1.1 255 123.123.123.123 init 1 100 disabled
gigabitEthernet12/8.1.1 1 1.1.1.1 master 1 254 enabled
show ip vrrp neighbor� Use to display neighbors known to the VRRP routers.� Use the interface keyword to specify a specific Fast Ethernet or Gigabit
Ethernet interface. � Field descriptions
� Interface � Fast Ethernet or Gigabit Ethernet interface specifier and VRID of neighbors known to VRRP router
� time discovered � date and time neighbor was detected� primary address � primary IP address of neighbor� adv interval (sec) � VRRP advertisement interval in seconds� priority � priority status of VRRP router (255 = owner)
CHAPTER 11Configuring VRRP
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� auth type � VRRP authentication type: none or text� assoc address(es) � IP addresses associated with VRID that are advertised
by neighbor� Example
Interface: fastEthernet5/0.0 vrrpVrid: 1
time discovered: 08/09/2001 07:44
primary address: 10.0.0.1
adv interval (sec): 1
priority: 255 (owner)
auth type: none
assoc address(es): 10.0.0.1, 100.0.0.1, 101.0.0.1
Interface: fastEthernet5/0.1 vrrpVrid: 11
time discovered: 08/09/2001 07:44
primary address: 11.0.0.1
adv interval (sec): 1
priority: 255 (owner)
auth type: none
assoc address(es): 11.0.0.1, 110.0.0.1, 111.0.0.1
show ip vrrp statistics� Use to display statistics of configured VRRP routers and each individual VRID.� Use the delta keyword with the show ip vrrp statistics command to view the
baseline statistics.� Use the interface keyword with the show ip vrrp statistics command to
specify a specific Fast Ethernet or Gigabit Ethernet interface.� Field descriptions
� checksumErrors � total number of VRRP packets received with an invalid VRRP checksum value
� versionErrors � total number of VRRP packets received with an unknown or unsupported version number
� vrIdErrors � total number of VRRP packets received with an invalid VRID for this virtual router
� iccErrors � count of line module notifications that did not make it to the controller
� txErrors � count of advertisements that did not get sent due to resource limitations
� rxErrors � count of advertisements received that could not be parsed by VRRP applications
� Interface � Fast Ethernet or Gigabit Ethernet interface specifier and VRID� becomeMaster � total number of times that this VRID state has transitioned
to master� advertiseRcvd � total number of VRRP advertisements received� advertiseIntervalErrors � total number of VRRP advertisement packets
received for which the advertisement interval is different from the one configured for the VRID
Monitoring VRRPE-Series Routers
11-15
� authFailures � total number of VRRP packets received that do not pass the authentication check
� ipTtlErrors � total number of VRRP packets received with IP TTL (time-to-live) not equal to 255
� priorityZeroPktsRcvd � total number of VRRP packets received with a priority of 0
� priorityZeroPktsSent � total number of VRRP packets sent with a priority of 0� invalidTypePktsRcvd � total number of VRRP packets received with an
invalid value in the Type field� addressListErrors � total number of VRRP packets received for which the
address list does not match the locally configured list for the VRID� invalidAuthType � total number of VRRP packets received with an unknown
authentication type� authTypeMismatch � total number of VRRP packets received with an
authentication type not equal to the locally configured authentication method� packetLengthErrors � total number of VRRP packets received with a packet
length less than the length of the VRRP header� Example of statistics per interface
host1#show ip vrrp statistics interface fastEthernet 4/0
Globals:
checksumErrors: 0
versionErrors: 0
vrIdErrors: 1
iccErrors: 0
txErrors: 0
rxErrors: 0
Interface: fastEthernet4/0 vrrpVrid: 1
becomeMaster: 10
advertiseRcvd: 0
advertiseIntervalErrors: 0
authFailures: 0
ipTtlErrors: 0
priorityZeroPktsRcvd: 0
priorityZeroPktsSent: 9
invalidTypePktsRcvd: 0
addressListErrors: 0
invalidAuthType: 0
authTypeMismatch: 0
packetLengthErrors: 0
Interface: fastEthernet4/0 vrrpVrid: 50
becomeMaster: 0
advertiseRcvd: 1000
advertiseIntervalErrors: 0
authFailures: 0
ipTtlErrors: 0
CHAPTER 11Configuring VRRP
11-16
priorityZeroPktsRcvd: 0
priorityZeroPktsSent: 0
invalidTypePktsRcvd: 0
addressListErrors: 0
invalidAuthType: 0
authTypeMismatch: 0
packetLengthErrors: 0
� Example of statistics per interface and VRIDhost1#show ip vrrp statistics interface fastEthernet 4/0 1
Interface: fastEthernet4/0 vrrpVrid: 1
becomeMaster: 0
advertiseRcvd: 0
advertiseIntervalErrors: 0
authFailures: 0
ipTtlErrors: 0
priorityZeroPktsRcvd: 0
priorityZeroPktsSent: 0
invalidTypePktsRcvd: 0
addressListErrors: 0
invalidAuthType: 0
authTypeMismatch: 0
packetLengthErrors: 0
show ip vrrp statistics global� Use to display the statistics of configured VRRP routers and each individual
VRID.� Use the delta keyword with the show ip vrrp statistics commands to view the
baseline statistics.� Field descriptions
� checksumErrors � total number of VRRP packets received with an invalid VRRP checksum value
� versionErrors � total number of VRRP packets received with an unknown or unsupported version number
� vrIdErrors � total number of VRRP packets received with an invalid VRID for this virtual router
� iccErrors � count of line module notifications that did not make it to the controller
� txErrors � count of advertisements that did not get sent due to resource limitations
� rxErrors � count of advertisements received that could not be parsed by VRRP applications
Monitoring VRRPE-Series Routers
11-17
� Examplehost1#show ip vrrp statistics global
Globals:
checksumErrors: 0
versionErrors: 0
vrIdErrors: 0
iccErrors: 0
txErrors: 0
rxErrors: 0
show ip vrrp summary� Use to display a summary count on all VRIDs configured.� Field descriptions
� ip interfaces with vrrp � total number of VRIDs configured on ip interfaces� entries � total number of entries in all states� entries enabled � number of entries that were enabled� entries with owner priority � number of entries with owner priority� entries in init state � number of entries in the init state� entries in backup state � number of entries in backup state� entries in master state � number of entries in master state
� Examplehost1#show ip vrrp summary
ip interfaces with vrrp: 1
entries: 10
entries enabled: 10
entries with owner priority: 1
entries in init state: 0
entries in backup state: 9
entries in master state: 1
CHAPTER 11Configuring VRRP
11-18
Part 4Internet Protocol Security
12
Configuring IPSecThis chapter describes IPSec capabilities of the E-series router.
Overview The IP security functionality covered in this chapter includes the following major areas:
• Encapsulating protocols, including AH and ESP, to provide security on specified packets
• The ISAKMP/IKE protocol suite to provide automatic negotiation of security associations including session keys
Topic Page
Overview 12-1
References 12-3
IPSec Concepts 12-4
IKE Overview 12-15
Configuration Tasks 12-20
Configuration Examples 12-31
Monitoring IPSec 12-42
CHAPTER 12Configuring IPSec
12-2
TermsTable 12-1 defines terms and abbreviations that are used in this discussion of IPSec.
Table 12-1 IPSec terms and abbreviations
Term Definition
3DES Triple DES encryption/decryption algorithm
AH Authentication Header. Provides authentication of the sender and of data integrity.
CA certificate authority
DES Data Encryption Standard encryption algorithm
DSS Digital Signature Standard authentication algorithm
ESP Encapsulating Security Payload, provides data integrity, data confidentiality and, optionally, sender�s authentication
HMAC Hashed Message Authentication Code
IKE Internet Key Exchange
IKE endpoint IP address of the entity that is one of two endpoints in an IKE/ISAKMP SA.
Inbound traffic In the context of a secure interface, inbound traffic refers to already secured traffic arriving on that interface (identified based on its SPI). This traffic is cleared and checked against the security parameters set for that interface.
IPSec IP security
IPSec endpoint
IP address of the entity that is one of two endpoints in an IPSec SA
ISAKMP Internet Security Association and Key Management Protocol
ISAKMP SA Security associations used to secure control channels between security gateways. These are negotiated via IKE phase I.
MDx Message Digest x hash algorithm
Nonce A random value used to detect and protect against replay attacks
Outbound traffic
In the context of a secure interface, outbound traffic is the clear traffic forwarded to the interface (either by policy or by routing) that should be secured according to security parameters set for that interface.
PFS Perfect forward secrecy
RSA Rivest-Shamir-Adleman encryption algorithm
SA Security association. The set of security parameters that dictate how IPSec processes a packet, including encapsulation protocol and session keys. A single secure tunnel uses multiple SAs.
Secure tunnel A virtual connection between two security gateways used to exchange data packets in a secure way. A secure tunnel is made up of a local SA and a remote SA, where both are negotiated in the context of an ISAKMP SA.
ReferencesE-Series Routers
12-3
ReferencesThis IPSec implementation supports the following RFCs:
• RFC 2401 – Security Architecture for the Internet Protocol (November 1998)
• RFC 2402 – IP Authentication Header (November 1998)
• RFC 2403 – The Use of HMAC-MD5-96 within ESP and AH (November 1998)
• RFC 2404 – The Use of HMAC-SHA-1-96 within ESP and AH (November 1998)
• RFC 2405 – The ESP DES-CBC Cipher Algorithm With Explicit IV (November 1998)
• RFC 2406 – IP Encapsulating Security Payload (ESP) (November 1998)
• RFC 2407 – The Internet IP Security Domain of Interpretation for ISAKMP (November 1998)
• RFC 2408 – Internet Security Association and Key Management Protocol (ISAKMP) (November 1998)
• RFC 2409 – The Internet Key Exchange (IKE) (November 1998)
• RFC 2410 – The NULL Encryption Algorithm and Its Use With IPSec (November 1998)
• RFC 768 – User Datagram Protocol (August 1980)
For information on using digital certificates, see Chapter 13, Configuring Digital Certificates.
SHA Secure Hash Algorithm
SPI Security parameter index
VPN Virtual private network
Table 12-1 IPSec terms and abbreviations (continued)
Term Definition
CHAPTER 12Configuring IPSec
12-4
IPSec Concepts This section provides an overview of IPSec concepts.
IPSec provides security to IP flows through the use of authentication and encryption.
• Authentication verifies that data is not altered during transmission and ensures that users are communicating with the individual or organization that they believe they are communicating with.
• Encryption makes data confidential by making it unreadable to everyone except the sender and intended recipient.
IPSec comprises two encapsulating protocols:
• Encapsulating Security Payload (ESP) provides confidentiality and authentication functions to every data packet.
• Authentication Header (AH) provides authentication to every data packet.
Secure IP InterfacesSecure IP interfaces are virtual IP interfaces that can be configured to provide confidentiality and authentication services for the data flowing through such interfaces. The software provides these services using mechanisms created by the suite of IPSec standards established by the IETF.
Secure IP interfaces connect the router to any other endpoint through the routed network and allow much of the same functionality as other IP interfaces. Traffic can reach a secure IP interface via routing and/or policy routing.
• A secure tunnel is a layer 2 entity. It is a point-to-point connection that is mapped on top of other IP interfaces. Secure tunnels carry only IP traffic.
• A secure IP interface is a layer 3 entity; that is, an IP interface mapped on top of a secure tunnel that inherits all security associated with it.
Secure IP interfaces are a logical representation of a secure connection between two security endpoints, one of which is the local system. The remote endpoint can be another security gateway or a host.
RFC 2401 ComplianceRFC 2401 states that a security policy database (SPD) must exist for each physical interface in the router, and an administrator must configure
IPSec ConceptsE-Series Routers
12-5
these SPDs to determine which traffic must be IPSec-protected, not IPSec-protected, or denied. The E-series router does not support a system-wide SPD. Instead, the router takes advantage of routing policies that are applied to physical interfaces to describe which traffic should be forwarded to a single IPSec tunnel, which traffic should be discarded, and so on. The router also applies IPSec selectors to traffic going into or coming out of a secure tunnel so that no unwanted traffic is allowed inside the tunnel. Supported selectors include IP addresses, subnets, and IP address ranges. Note that an implementation that strictly follows RFC 2401 requires a separate IPSec tunnel for each SPD entry.
IPSec Protocol Stack Figure 12-1 shows the protocol stack on a client, an IPSec gateway, and a server. In the figure, HTTP and TCP are examples of higher-level protocols involved in the end-to-end communication; other end-to-end communication protocols are also supported. The layers where the data can be encrypted are shown in gray.
Figure 12-1 IPSec tunneling stack
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CHAPTER 12Configuring IPSec
12-6
Figure 12-2 shows the packet encapsulation for IPSec tunneling.
Figure 12-2 IPSec tunneling packet encapsulation
Security ParametersSecure IP interfaces allow tunneled traffic to be secured in many ways. For that, secure interfaces are associated with security parameters that are enforced for traffic that goes through these interfaces. Table 12-2 gives a brief description of all parameters used for a secure IP interface.
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Table 12-2 Security parameters used on secure IP interfaces
Security Parameter Description
Manual or signalled A secure IP interface can be either manual or signalled. � Manual interfaces are configured manually on both local and
remote security gateways. � Signalled interfaces are able to dynamically set up
connections between security gateways using ISAKMP/IKE.
Operational VR Operational parameters for the secure IP interface, including the virtual router context to which this interface belongs and the network prefix reachable through the interface.
Transport VR Transport network characteristics for the tunnel, including its virtual router context and source and destination IP addresses.
Perfect forward secrecy
A key generation approach that guarantees that every newly generated session key is not in any way related to the previous keys. PFS ensures that a compromised session key will not compromise previous and subsequent keys.
Lifetime A limit on time and traffic volume allowed over the interface before an SA needs to be renegotiated.
Inbound and outbound SAs
The actual session-related parameters used by both security gateways to secure the traffic between them. The SA can be manually defined for manual secure IP tunnels or dynamically negotiated for signalled tunnels.Two sets of SA parameters exist. One for inbound traffic and another for outbound traffic.
Transform set The set of security parameters, including protocols and algorithms, that is considered adequate to provide a required security level to the traffic flowing through an interface.
IPSec ConceptsE-Series Routers
12-7
Figure 12-3 shows the relationships of the various security parameters to the IPSec security interface. Each parameter is covered in detail in the following sections.
Figure 12-3 IPSec security parameters in relation to secure IP interface
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CHAPTER 12Configuring IPSec
12-8
Manual Versus Signalled Interfaces The router supports both manual and signalled interfaces:
• Manual interfaces use a preconfigured set of SA parameters to secure traffic f lowing through a secure IP interface. If SA parameters are not preconfigured for a manual secure interface, all traffic reaching the interface is dropped. Statistics are kept for dropped traffic. A manual secure IP tunnel must be manually provisioned in both peer security gateways.
• Signalled interfaces negotiate an SA on demand with the remote security gateway. The remote security gateway must also support SA negotiation; otherwise traffic is dropped. Again, statistics are kept for dropped traffic.
The router supports SA negotiation within an IKE SA by means of the ISAKMP and IKE protocols. Only one IKE SA is maintained between a set of local and remote IKE endpoints. That means that if an IKE SA already exists between the two endpoints, it is reused.
Secure IP interface parameters can be required, optional, or not applicable, depending on whether the interface is manual or signalled. Table 12-3 shows how the other security parameters fit with manual and signalled interfaces.
Operational Virtual Router The operational VR for a secure IP tunnel is the VR in which a secure IP tunnel exists.
The IP address and mask associated with a secure IP interface exist only within the operational VR under which the interface is declared. The VR defines the network prefix, which is reachable through the logical IP interface.
Table 12-3 Security parameters per IPSec policy type
Security Parameter Manual Signalled
Transport VR Required Required
Operational VR Required Required
Perfect forward secrecy Optional Optional
Lifetime Optional Optional
Inbound and outbound SAs Required Not Applicable
Transform set Required Required
IPSec ConceptsE-Series Routers
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A secure IP tunnel is always a member of one and only one operational VR. Therefore, the operational VR attributes are mandatory for any secure tunnel. These attributes include:
• IP address and mask
• Virtual router where the secure IP interface exists
Transport Virtual Router The transport VR for a secure IP tunnel is the VR in which both of the secure tunnel endpoints, the source and destination, are routable addresses. Normally, the transport VR is the default ISP routing infrastructure on top of which VPNs are provisioned.
The IPSec service line module is a security gateway and, as such, is one of the endpoints for secure tunnels. The tunnel endpoints are the tunnel source and the tunnel destination IP addresses.
• The tunnel source IP address must be one of the local IP addresses configured on the router.
• The tunnel destination address must be a routable IP address within the transport VR routing tables.
The transport VR information is required, although its explicit configuration is not. If omitted, the transport VR is assumed to be the same as the operational VR. However, the tunnel source and destination are mandatory elements.
Transport VR Definition The transport VR definition includes:
• Transport virtual router name – If not explicitly configured, the operational VR is assumed.
• Tunnel source endpoint – IP address used as the tunnel source endpoint on this end of the tunnel. In the case of signalled tunnels, the router monitors and transmits on port 500 of this address for IKE negotiations. The tunnel source endpoint must be a configured IP address on the transport VR, or the router indicates an error.
• Tunnel destination endpoint – IP address associated with the termination or initiation point of the secure IP tunnel. This address must be routable within the context of the transport VR. Each secure IP tunnel can have a different remote IP address.
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Perfect Forward Secrecy PFS is an optional feature that causes every newly refreshed key to be completely unrelated to the previous key. PFS provides added security, but requires extra processing for a new Diffie-Hellmann key exchange on every key refresh.
If PFS is enabled, the router mandates PFS during SA negotiation. The remote security gateway must accept PFS if the SA is to be successfully negotiated.
On the other hand, if PFS is disabled, PFS may still be negotiated if the remote security gateway requests PFS.
PFS supports three Diffie-Hellmann prime modulus groups:
• Group 1 – A 768-bit Diffie-Hellmann prime modulus group
• Group 2 – A 1024-bit Diffie-Hellmann prime modulus group
• Group 5 – A 1536-bit Diffie-Hellmann prime modulus group
SA negotiation favors the highest request. For example, if group 2 is requested locally, the remote security gateway must support group 2 for the SA negotiation to be successful. If group 1 is requested locally, then either groups 1 or 2 can be accepted, depending on requests from the remote security gateway.
Lifetime You can set a lifetime for user SAs and IKE SAs. For information on setting the IKE SA lifetime, see Lifetime in the IKE Policies section later in this chapter.
For signalled IPSec interfaces, both the inbound and outbound SA must be assigned a lifetime. The lifetime parameter controls the duration for which the SA is valid. When a user SA is established, both a timer and a traffic volume counter are set. When either counter reaches the limit specified by the SA’s lifetime, a new SA is negotiated and the expired SA is deleted. The renegotiations refresh several SA parameters, including keys.
Note the following about how the lifetime parameters work:
• To avoid delays in the data flow, a new user SA is actually renegotiated before the expiration. If the SA expires in the middle of processing a packet, the router finishes processing that packet.
• The actual user SA lifetime may not equal the value configured in the router.
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• There are both global and tunnel-specific lifetime parameters. If there is no tunnel-specific lifetime configured, the router uses the global lifetime. The global lifetime parameters have the following default settings:
> 8 hours for the time-based lifetime
> 100 MB for the traffic-based lifetime
• Lifetime parameters are valid only for user SAs established via IKE. Manually configured user SAs ignore this parameter.
You can set a lifetime for all SAs on a specific tunnel, and you can set a global lifetime.
• To set the tunnel lifetime, use the tunnel lifetime command.
• To set the global (default) lifetime, use the ipsec lifetime command.
Inbound and Outbound SAs SA parameters are the actual session parameters used to secure a specific data f low associated with a specific secure IP interface.
• For manual secure IP interfaces, the system administrator sets SA parameters. Manually setting SA parameters allows provisioning of IP security to destinations that do not support SA negotiation via IKE.
• For signalled secure IP interfaces, the two security gateway peers negotiate SA parameters; the system administrator is not allowed to set any of the parameters. In fact, for some of these parameters, such as session keys, the system administrator is not granted even read-access.
Similarly to IPSec SA, SA parameters are unidirectional. Therefore, for a two-way data f low, two SAs need to be established—one for inbound traffic and another for outbound traffic. For each direction, SA parameters must be set for each transform associated with a secure IP interface. Therefore, two sets of SA parameters exist for each secure IP interface, one being the inbound SA parameters and the other the outbound SA parameters.
The following parameters form each set of SA parameters:
• SPI – A unique identifier for the SA used when securing this flow. An SPI is unique for a given destination IP address and protocol tuple. The destination IP address is either the remote secure IP interface endpoint for the outbound direction or the local secure IP interface endpoint for the inbound direction.
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• Encapsulation – The encapsulation options include both an encapsulating protocol and an encapsulating mode. The protocol can be either ESP or AH. The mode is tunnel mode.
• Transforms – The allowed transforms for given SA parameters depend on its encapsulation protocol. See Transform Sets for more information.
• Keys – The session key used for the respective SA transform. The key length depends on the SA transform to which it applies, and is as follows:
> DES – 8 bytes
> 3DES – 24 bytes
> MD5 – 16 bytes
> SHA – 20 bytes
Transform Sets Transform sets are composed of security parameters that provide a required security level to a particular data f low. Transform sets are used during user SA negotiation to find common agreement between the local and the remote security gateway on how to protect that specific data f low.
A transform set includes encapsulation protocols and transforms; for example, encryption/decryption/authentication algorithms. These parameters are grouped to specify the acceptable protection for a given data f low. Many transform sets are supported, since different traffic requires distinct security levels.
A secure IP tunnel is associated with one transform set. Multiple secure IP tunnels can refer to the same transform set.
Changing existing transform sets affects only future user SA negotiations. User SAs that are already established remain valid and do not use the changed transform set until they are renegotiated.
For manually configured secure IP tunnels, the associated transform set must contain a single transform option.
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Encapsulation Protocols Both the AH and ESP protocols are supported. See supported transforms in Table 12-4.
• AH provides authentication.
• ESP provides data confidentiality and antireplay functions. ESP can also provide data authentication, although, in this implementation, ESP does not cover the outer IP header.
Encapsulation Modes IPSec supports two encapsulation modes—tunnel mode and transport mode. Currently the E-series router supports only tunnel mode. Tunnel mode creates a second IP header in the packet and uses both the local and remote security gateway addresses as source and destination IP addresses.
Supported Transforms Table 12-4 describes the supported transforms.
Table 12-4 Supported transforms
Transform Description
AH-MD5 IPSec performs AH protocol encapsulation using the MD5 hash function with HMAC message authentication.
AH-SHA IPSec performs AH protocol encapsulation using the SHA-1 hash function with HMAC message authentication. SHA-1 is considered stronger than MD5.
ESP-MD5 IPSec performs ESP protocol encapsulation using the MD5 hash function with HMAC message authentication.
ESP-SHA IPSec performs ESP protocol encapsulation using the SHA-1 hash function with HMAC message authentication. SHA-1 is considered stronger than MD5.
ESP-DES IPSec performs ESP protocol encapsulation using the DES encryption algorithm. DES uses a 56-bit symmetric key and is considered a weak (breakable) encryption algorithm.
ESP-3DES IPSec performs ESP protocol encapsulation using the 3DES encryption algorithm. 3DES uses a 168-bit symmetric encryption key and is widely accepted as a strong encryption algorithm. Export control issues apply to products that ship from the USA with 3DES.
ESP-DES-MD5 Combination of ESP-MD5 and ESP-DES transforms.
ESP-DES-SHA Combination of ESP-SHA and ESP-DES transforms.
ESP-3DES-MD5 Combination of ESP-MD5 and ESP-3DES transforms.
ESP-3DES-SHA Combination of ESP-SHA and ESP-3DES transforms.
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Table 12-5 shows the security functions achieved with the supported transforms, and provides a view of which combinations can be used, depending on security requirements.
Note that the IPSec service line module does not support both the ESP and AH encapsulation modes concurrently on the same secure tunnel.
Negotiating Transforms Inside a transform set, IPSec transforms are numbered in a priority sequence.
• During negotiation as an initiator of the user SA, the router uses transform number one first. If the remote system does not agree on the transform, the router then tries number two, and so on. If both end systems do not agree on a transform, the user SA fails and the secure IP tunnel is not established.
• During negotiation as a responder, the router compares the proposed transform from the remote end against each transform in the transform set. If there is no match, the router provides a negative answer to the remote end, which can either try another transform or give up. If no match is found, the secure IP tunnel is not established.
Other Security Features
IP Security Policies The E-series router does not support a system-wide security policy database (SPD). Instead, the router takes advantage of routing to forward traffic to and from a secure tunnel. The router still applies IPSec selectors to traffic going into or coming out of a secure tunnel so that no unwanted
Table 12-5 Combinations of supported security transforms
Security Type Supported Transform Combinations
Data authentication only AH-HMAC-MD5AH-HMAC-SHAESP-HMAC-MD5ESP-HMAC-SHA
Data confidentiality only ESP-DESESP-3DES
Data authentication and confidentiality ESP-DES-MD5ESP-DES-SHAESP-3DES-MD5ESP-3DES-SHA
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traffic is allowed inside the tunnel. Supported selectors include IP addresses, subnets, and IP address ranges.
ESP Processing The router supports both the encryption and authentication functions of ESP encapsulation as defined in RFC 2406. Specifically, the router supports:
• DES and 3DES encryption algorithms
• The HMAC-SHA and HMAC-MD5 authentication algorithms
• ESP security options on a per-tunnel (per-SA) basis
• Tunnel mode
AH Processing The router supports AH encapsulation as defined in RFC 2402. Specifically, the router supports:
• HMAC-SHA and HMAC-MD5 authentication algorithms
• AH authentication options on a per-tunnel (per-SA) basis
• Tunnel mode
IPSec Maximums SupportedRefer to the E-Series Release Notes, Appendix A, System Maximums corresponding to your software release for information on maximum values.
IKE Overview The IKE suite of protocols allows a pair of security gateways to:
• Dynamically establish a secure tunnel over which the security gateways can exchange tunnel and key information.
• Set up user-level tunnels or SAs, including tunnel attribute negotiations and key management. These tunnels can also be refreshed and terminated on top of the same secure channel.
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IKE is based on the Oakley and Skeme key determination protocols and the ISAKMP framework for key exchange and security association establishment. IKE provides:
• Automatic key refreshing on configurable timeout.
• Support for public key infrastructure (PKI) authentication systems.
• Antireplay defense.
IKE is layered on UDP and uses UDP port 500 to exchange IKE information between the security gateways. Therefore, UDP port 500 packets must be permitted on any IP interface involved in connecting a security gateway peer.
The following sections expand on the IKE functionality available for the router.
Main Mode and Aggressive ModeIKE phase 1 negotiations are used to establish IKE SAs. These SAs protect the IKE phase 2 negotiations. IKE uses one of two modes for phase 1 negotiations: main mode or aggressive mode. The choice of main or aggressive mode is a matter of tradeoffs. Some of the characteristics of the two modes are:
• Main mode
> Protects the identities of the peers during negotiations and is therefore more secure.
> Allows greater proposal flexibility than aggressive mode.
> Is more time consuming than aggressive mode because more messages are exchanged between peers. (Six messages are exchanged in main mode.)
• Aggressive mode
> Exposes identities of the peers to eavesdropping, making it less secure than main mode.
> Is faster than main mode because fewer messages are exchanged between peers. (Three messages are exchanged in aggressive mode.)
The next section describes aggressive mode in more detail.
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Aggressive Mode Negotiations During aggressive mode phase 1 negotiations, the E-series router behaves as follows:
• When the router is the initiator, the router searches all policy rules to find those that allow aggressive mode. The router then selects the rule with highest priority and uses the rule to initiate phase 1 negotiation. If there are no policy rules with aggressive mode allowed, the router selects the highest-priority rule that allows main mode.
• When the router is the responder, the negotiation depends on what the initiator proposes, as well as what is configured in the policy rules.
Table 12-6 outlines the possible combinations of initiator proposals and policy rules. As shown, allowing aggressive mode in a policy rule allows negotiation to take place no matter what the initiator requests.
The router responds to phase 1 negotiations with the highest priority policy rule that matches the initiator. A match means that all parameters, including the exchange type, match.
IKE PoliciesAn IKE policy defines a combination of security parameters to be used during the IKE SA negotiation. IKE policies are configured on both security gateway peers, and there must be at least one policy on the local peer that matches a policy on the remote peer. Failing that, the two peers will not be able to successfully negotiate the IKE SA, and no data flow will be possible.
IKE policies are global to the router. Every IPSec service line module on a router uses the same set of policies when negotiating IKE SAs. The agreed-on IKE SA between the local system and a remote security gateway may vary, because it depends on the IKE policies used by each remote peer. However, the initial set of IKE policies the router uses is always the same and independent of which peer the router is negotiating with.
Table 12-6 Initiator proposals and policy rules
Initiator Requests Responder Policy Rule Match
Aggressive mode Aggressive allowed Yes
Aggressive mode Aggressive not allowed No
Main mode Aggressive allowed Yes
Main mode Aggressive not allowed Yes
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During negotiation, the router may skip IKE policies that require parameters that are not configured for the remote security gateway with which the IKE SA is being negotiated.
You can define up to ten IKE policies, with each policy having a different combination of security parameters. A default IKE policy that contains default values for every policy parameter is available. This policy is used only when IKE policies are not configured and IKE is required.
The following sections describe each of the parameters contained in an IKE policy.
Priority Priority allows better (more secure) policies to be given preference during the negotiation process. The fact still remains that every IKE policy is considered secure enough to secure the IKE SA flow.
During IKE negotiation all policies are scanned, one at a time, starting from the highest-priority policy and ending with the lowest-priority policy. The first policy that the peer security gateway accepts is used for that IKE session. This procedure is repeated for every IKE session that needs to be established.
Encryption A specific encryption transform can be applied to an IKE policy. The supported encryption algorithms are:
• DES
• 3DES
Hash FunctionA specific hash function can be specified to an IKE policy. The supported ones are:
• MD5
• SHA-1
IKE also uses an authentication algorithm during IKE exchanges. This authentication algorithm is automatically set to the HMAC version of the specified hash algorithm. Therefore, you cannot have the hash function set to MD5 and authentication algorithm set to HMAC-SHA.
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Authentication Mode As part of the IKE protocol, one security gateway needs to authenticate the other security gateway to make sure that the IKE SA is established with the intended party. The E-series router supports two authentication methods:
• Digital certificates (using RSA algorithms)
For digital certificate authentication, an initiator signs message interchange data using his private key, and a responder uses the initiator’s public key to verify the signature. Typically, the public key is exchanged via messages containing an X.509v3 certificate. This certificate provides a level of assurance that a peer’s identity (as represented in the certificate) is associated with a particular public key.
For more information, see Chapter 13, Configuring Digital Certificates.
• Preshared keys
With preshared key authentication mode, the same secret string (similar to a password) must be configured on both security gateways before the gateways can authenticate each other. It is not advisable to share a preshared key among multiple pairs of security gateways, because it reduces the key’s security level.
The router allows preshared keys to be up to 256 characters composed of any ASCII alphanumeric character.
Diffie-Hellman Group An IKE policy must specify which Diffie-Hellmann group is used during the symmetrical key generation phase of IKE. The following Diffie-Hellmann groups are supported:
• Group 1 (768-bit)
• Group 2 (1024-bit)
• Group 5 (1536-bit)
Lifetime Like a user SA, an IKE SA should not last indefinitely. Therefore, the router allows you to specify a lifetime parameter for an IKE policy. The timer for the lifetime parameter begins when the IKE SA is established using IKE.
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IKE SA NegotiationAs the initiator of an IKE SA, the router sends its IKE policies to the remote peer. If the peer has an IKE policy that matches the encryption, hash, authentication method, and Diffie-Hellmann group settings, the peer returns the matching policy. The peers use the lesser lifetime setting as the IKE SA lifetime. If no match is found, the IKE SA fails, and a log alarm is generated.
As the responder of an IKE negotiation, the router receives all IKE policies from a remote security gateway. The router then scans its own list of IKE policies to check whether a match exists, starting from the highest priority. If it finds a match, that policy is successfully negotiated. Again, the lifetime is negotiated to the lesser of the two lifetimes, and failures are logged.
Configuration Tasks This section shows the steps to configure an IPSec license and IPSec parameters, create an IPSec tunnel, and define an ISAKMP/IKE policy. The next section contains configuration examples.
Configuring an IPSec License You can purchase IPSec licenses, which allow additional IPSec tunnels in the E-series router. The number of additional tunnels depends on the number of IPSec Service line modules (ISMs) installed in the router and the type of license that you purchase. Table 12-7 shows how many tunnels are allowed in the router depending on how many ISMs are installed and the type of license configured on the router.
If you have two ISMs in one chassis and have not purchased an IPSec license, you can configure 5,000 tunnels on the router. If you remove one of the ISMs, the router allows all 5,000 tunnels to migrate to the remaining ISM. However, on reload, the router brings up only 2,500 tunnels.
Table 12-7 Number of IPSec tunnels allowed in E-series routers
Number of ISMs in Chassis
Number of IPSec Tunnels Allowed in System
Without a License Level 1 License Level 2 License
One 2,500 5,000 5,000
Two 5,000 7,500 10,000
Three (for redundancy) 5,000 7,500 10,000
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license ipsec-tunnels� Use to specify an IPSec tunnel license.
Note: Acquire the license from Juniper Networks Customer Service or your Juniper Networks sales representative.
� Examplehost1(config)#license ipsec-tunnels g1k23b23eb2j
� Use the no version to disable the license.
Configuring IPSec Parameters To configure IPSec:
1 For each endpoint, create a transform set that provides the desired encryption and authentication.
host1(config)#ipsec transform-set customerAprotection esp-3des-hmac-sha
host1(config)#ipsec transform-set customerBprotection ah-hmac-md5
2 Add a preshared key that the routers use to authenticate each other.
host1(config)#ipsec key manual pre-share 5.2.0.1
host1(config-manual-key)#key customerASecret
Once you enter a preshared key, the router encrypts the key and displays it in masked form to increase the security of the key. If you need to reenter the key, you can enter it in its masked form using this command.
To see the masked form of the key:
host1#show config
!
ipsec key manual pre-share 10.10.1.1
masked-key “AAAAGAAAAAcAAAACfd+SAsaVQ6Qeopt2rJOP6LDg+0hX5cMO”
!
To enter the masked key:
host1(config-manual-key)#masked-key AAAAGAAAAAcAAAACfd+SAsaVQ6Qeopt2rJOP6LDg+0hX5cMO
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3 Define the local endpoint used for ISAKMP/IKE negotiations for all IPSec tunnels in the router.
host1(config)#ipsec local-endpoint 10.10.1.1 transport-virtual-router vr#8
4 (Optional) Set the global (default) lifetime for all SAs on the router.
host1(config)#ipsec lifetime kilobytes 42000000
ipsec key manual� Use to specify that a peer use a manual key for authentication during the tunnel
establishment phase, and display the prompt that lets you enter the manual key. To enter a key, use the key command.
� Specify the peer using its IP address.� You must enter this command in the virtual router context where the IP address
of the peer is defined. � Example
host1(config)#ipsec key manual pre-share 10.10.1.1
host1(config-manual-key)#
� Use the no version to delete a manually configured key from the router.
ipsec lifetime� Use to set the global (default) lifetime in seconds and/or volume of traffic. The
IPSec lifetime applies to tunnels that do not have a tunnel lifetime defined. When either limit is reached, the SA is renegotiated.
� To set a lifetime for all SAs on a tunnel, use the tunnel lifetime command.� To set a lifetime for a specific SA, use the lifetime command.� Example 1
host1(config)#ipsec lifetime kilobytes 42000000
� Example 2host1(config)#ipsec lifetime seconds 8600
� Use the no version to restore the default values of 4294967295 kilobytes and 28800 seconds (8 hours).
ipsec local-endpoint� Use to define a default local endpoint for ISAKMP/IKE negotiations and all
IPSec tunnels for a transport virtual router. � You must specify the IP address used as the local endpoint and the transport
virtual router on which the IP address is defined.
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� Examplehost1(config)#ipsec local-endpoint 10.10.1.1 transport-virtual-router VR#8
� Use the no version to delete a local endpoint. You cannot remove an endpoint if a tunnel is referencing the endpoint.
ipsec transform-set� Use to create a transform set. Each transform in a set provides a different
combination of data authentication and confidentiality. � Transform sets used for manually configured tunnels can have one transform.� Transform sets used for signalled tunnels can have up to six transforms. The
actual transform used on the tunnel is negotiated with the peer. Transforms are numbered in a priority sequence in the order in which you enter them.
� Examplehost1(config)#ipsec transform-set espSet esp-3des-hmac-md5 esp-3des-null-auth
� Use the no version to delete a transform set. You cannot remove a transform set if a tunnel is referencing the transform set.
key� Use to enter a manual preshared key. � Preshared keys can have up to 256 characters composed of any ASCII
alphanumeric character. To include spaces in the key, enclose the key in quotation marks.
� Examplehost1(config-manual-key)#key dj5fe23owi8er49fdsa
� Examplehost1(config-manual-key)#key “my key with spaces”
� There is no no version. To delete a key, use the no version of the ipsec key manual command.
masked-key� Use to enter the preshared key in masked form. � For security purposes, the router displays the key only in masked form. If you
delete the key or reboot the router to factory defaults, you can use this command to reenter the key in its masked form so that the key is not visible while you enter it.
� To see the masked key, use the show config command.
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� Examplehost1#show config
!
ipsec key manual pre-share 10.10.1.1
masked-key “AAAAGAAAAAcAAAACfd+SAsaVQ6Qeopt2rJOP6LDg+0hX5cMO”
!
host1#configure terminal
host1(config)#ipsec key manual pre-share 10.10.1.1
host1(config-manual-key)#masked-key AAAAGAAAAAcAAAACfd+SAsaVQ6Qeopt2rJOP6LDg+0hX5cMO
� There is no no version. To delete a key, use the no version of the ipsec key manual command.
Creating an IPSec TunnelTo create an IPSec tunnel:
1 Enter virtual router mode. Specify the VR that contains the source and destination addresses assigned to the tunnel interface.
host1(config)#virtual-router vrA
host1:vrA(config)#
2 Create an IPSec tunnel, and specify the transport VR.
host1:vrA(config)#interface tunnel ipsec:Aottawa2boston transport-virtual-router default
host1:vrA(config-if)#
3 Specify the IP address of this tunnel interface.
host1:vrA(config-if)#ip address 10.3.0.0 255.255.0.0
4 Specify the transform set that ISAKMP uses for SA negotiations.
host1:vrA(config-if)#tunnel transform-set customerAprotection
5 Configure the local endpoint of the tunnel.
host1:vrA(config-if)#tunnel local-identity subnet 10.1.0.0 255.255.0.0
6 Configure the peer endpoint of the tunnel.
host1:vrA(config-if)#tunnel peer-identity subnet 10.3.0.0 255.255.0.0
7 Specify an existing interface address that the tunnel uses as its source address.
host1:vrA(config-if)#tunnel source 5.1.0.1
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8 Set the address of the remote tunnel endpoint.
host1:vrA(config-if)#tunnel destination 5.3.0.1
host1:vrA(config-if)#exit
9 For manual tunnels, specify the algorithm sets and the session key used for inbound SAs and for outbound SAs.
host1:vrA(config-if)#tunnel session-key-inbound esp-3des-hmac-md5 xj82k14OWaRqy dj3EwxNQ98z3bPw9
host1:vrA(config-if)#tunnel session-key-outbound esp-3des-hmac-md5 421 tM967dq3KvZ3j52r HeI38pkRn963wEg4
10 (Optional) Configure PFS on this tunnel.
host1:vrA(config-if)#tunnel pfs group 5
11 (Optional) Set the tunnel type to signalled or manual. The default is signalled.
host1:vrA(config-if)#tunnel signaling manual
12 (Optional) Set the renegotiation time of the SAs in use by this tunnel.
host1(config-if)#tunnel lifetime seconds 48000 kilobytes 249000
13 (Optional) Set the MTU size for the tunnel.
host1(config-if)#tunnel mtu 2240
interface tunnel� Use to create or configure an IPSec tunnel interface. � To establish the tunnel on a virtual router other than the current virtual router
context, use the transport-virtual-router keyword. � Example
host1(config)#interface tunnel ipsec:jak transport-virtual-router tvr041
host1(config-if)#
� Use the no version to remove the tunnel.
tunnel destination� Use to set the address of the remote tunnel endpoint.� Example
host1(config-if)#tunnel destination 10.10.11.12
� Use the no version to remove the address.
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tunnel lifetime� Use to set the renegotiation time of the SAs in use by this tunnel. � To configure the lifetime in amount of data, use the kilobytes keyword.� To configure the lifetime in number of seconds, use the seconds keyword.� If you include the seconds keyword as the first keyword on the command line,
you can also include the kilobytes keyword on the same line. � Before either the volume of traffic or number of seconds limit is reached, the SA
is renegotiated, which ensures that the tunnel does not go down during renegotiation. host1(config-if)#tunnel lifetime seconds 48000 kilobytes 249000
� Use the no version to set the lifetime to the default lifetime, which you define using the ipsec lifetime command.
tunnel local-identity� Use to configure the local identity (selector) of the tunnel. Specify the identity
using one of the following keywords: � address � specifies an IP address as the local identity � subnet � specifies a subnet as the local identity � range � specifies a range of IP addresses as the local identity
� Example 1host1(config-if)#tunnel local-identity range 10.10.1.1 10.10.2.1
� Example 2host1(config-if)#tunnel local-identity subnet 10.10.1.1 255.255.255.0
� Use the no version to set the default identity, which is subnet 0.0.0.00.0.0.0
tunnel mtu� Use to set the MTU size for the tunnel. � Example
host1(config-if)#tunnel mtu 2240
� Use the no version to set the MTU to the default of 1440.
tunnel peer-identity� Use to configure the peer identity (selector) that ISAKMP uses. Specify the
identity using one of the following keywords: � address � specifies an IP address as the peer identity � subnet � specifies a subnet as the peer identity � range � specifies a range of IP addresses as the peer identity
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� Example 1host1(config-if)#tunnel peer-identity range 10.10.1.1 10.10.2.2
� Example 2host1(config-if)#tunnel peer-identity subnet 130.10.1.1 255.255.255.0
� Use the no version to remove the peer identity.
tunnel pfs group� Use to configure perfect forward secrecy on this tunnel. � Assign a Diffie-Hellman prime modulus group using one of the following
keywords:� 1 � 768-bit group� 2 � 1024-bit group� 5 � 1536-bit group
� Example host1(config-if)#tunnel pfs group 5
� Use the no version to remove PFS from this tunnel.
tunnel session-key-inbound� Use to manually configure the authentication and/or encryption algorithm sets
and session keys for inbound SAs on a tunnel. You can enter this command only on tunnels that have tunnel signalling set to manual.
� To see a list of available algorithm sets, use the online Help.� Keys are an arbitrary hexadecimal string. If the algorithm set includes:
� DES, create an 8-byte key � 3DES, create a 24-byte key � MD5, create a 16-byte key � SHA, create a 20-byte key
� Examplehost1(config-if)#tunnel session-key-inbound esp-3des-hmac-md5 xj82kl40WaQp03i7 5bv0k4hm23z6uPn9
� Use the no version to remove inbound session keys from a tunnel.
tunnel session-key-outbound� Use to manually configure the authentication and/or encryption algorithm sets,
SPI, and session keys for outbound SAs on a tunnel. You can enter this command only on tunnels that have tunnel signalling set to manual.
� To see a list of available algorithm sets, use the online Help. � The SPI is a number from 256 to 4294967295 that identifies an SA.
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� Keys are an arbitrary hexadecimal string. If the algorithm set includes: � DES, create an 8-byte key � 3DES, create a 24-byte key � MD5, create a 16-byte key � SHA, create a 20-byte key
� Examplehost1(config-if)#tunnel session-key-outbound esp-3des-hmac-md5 421 tM967dq3KvZ3j52r HeI38pkRn963wEg4
� Use the no version to remove outbound session keys from a tunnel.
tunnel signaling� Use to set the tunnel type to signalled (ISAKMP) or manual. Specify a keyword:
� isakmp � uses ISAKMP/IKE to negotiate SAs and to establish keys� manual � specifies that security parameters and keys are configured
manually � Example
host1(config-if)#tunnel signaling manual
� Use the no version to restore the default, isakmp.
tunnel source� Use to specify an existing interface address that will serve as the tunnel�s
source address. � Example
host1(config-if)#tunnel source 10.10.2.8
� Use the no version to remove the tunnel source.
tunnel transform-set� Use to specify the transform set that ISAKMP uses during SA negotiations on
this tunnel. You create transform sets using the ipsec transform-set command.
� Examplehost1(config-if)#tunnel transform-set espSet
� Use the no version to remove the transform set from a tunnel.
Defining an ISAKMP/IKE PolicyISAKMP/IKE policies define parameters that the router uses during ISAKMP/IKE phase 1 negotiation.
To create an ISAKMP/IKE policy:
host1(config)#ipsec isakmp-policy-rule 3
host1(config-isakmp-policy)#
Configuration TasksE-Series Routers
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You can then set the following parameters, or use the default settings:
• Allow aggressive mode negotiation.
host1(config-isakmp-policy)#aggressive-mode
• Specify the authentication method.
host1(config-isakmp-policy)#authentication pre-share
• Specify the encryption algorithm.
host1(config-isakmp-policy)#encryption 3des
• Assign a Diffie-Hellman group.
host1(config-isakmp-policy)#group 5
• Set the hash algorithm.
host1(config-isakmp-policy)#hash md5
• Specify the lifetime of IKE SAs created using this policy.
host1(config-isakmp-policy)#lifetime 360
aggressive-mode� Use to allow aggressive mode negotiation for the tunnel. � If you allow aggressive mode negotiation, the tunnel proposes aggressive
mode to the peer in connections that the policy initiates. � If the peer initiates a negotiation, the tunnel accepts the negotiation if the mode
matches this policy. � Example
host1(config-isakmp-policy)#aggressive-mode
� Use the no version to set the negotiation mode to main mode.
authentication� Use to specify the authentication method the router uses in the IKE policy,
preshared keys or RSA signature. � Example
host1(config-isakmp-policy)#authentication pre-share
� Use the no version to restore the default, preshared keys.
encryption� Use to specify one of the following encryption algorithms to use in the IKE
policy: � 3des � 168-bit 3DES-CBC � des � 56-bit DES-CBC
CHAPTER 12Configuring IPSec
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� Example host1(config-isakmp-policy)#encryption 3des
� Use the no version to restore the default encryption algorithm, 3DES.
group� Use to assign a Diffie-Hellman group to the IKE policy. Specify:
� 1 � 768-bit group� 2 � 1024-bit group� 5 � 1536-bit group
� Examplehost1(config-isakmp-policy)#group 5
� Use the no version to restore the default, 1024-bit group.
hash� Use to set the hash algorithm for the IKE policy:
� md5 � MD5 (HMAC variant)� sha � SHA-1 (HMAC variant)
� Examplehost1(config-isakmp-policy)#hash md5
� Use the no version to restore the default, sha.
ipsec isakmp-policy-rule� Use to define an ISAKMP/IKE policy. � When you enter the command, you include a number that identifies the policy
and assigns a priority to the policy. You can number policies from 1 to 10000, with 1 having the highest priority.
� You can add up to 10 ISAKMP/IKE policies per router.� Example
host1(config)#ipsec isakmp-policy-rule 3
host1(config-isakmp-policy)#
� Use the no version to remove policies. If you do not include a priority number with the no version, all policies are removed.
lifetime� Use to specify the lifetime of IKE SAs. � The range is 60 to 86400 seconds.
host1(config-isakmp-policy)#lifetime 360
� Use the no version to reset the SA lifetime to the default, 28800 seconds.
Configuration ExamplesE-Series Routers
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Refreshing SAsTo refresh ISAKMP/IKE or IPSec SAs:
host1(config)#ipsec clear sa tunnel ipsec:Aottawa2boca phase 2
ipsec clear sa� Use to refresh ISAKMP/IKE or IPSec SAs. � To reinitialize all SAs, use the all keyword.� To reinitialize SAs on a specific tunnel, use the tunnel keyword.� To reinitialize SAs on tunnels that are in a specific state, use the state keyword.� To specify the type of SA to be reinitialized, ISAKMP/IKE or IPSEC, use the
phase keyword. � Example
host1(config)#ipsec clear sa all phase 2
� There is no no version.
Configuration Examples This section contains examples of two IPSec applications. The first example shows a customer who replaces a leased line network with an IPSec network that allows the company to connect its corporate locations over the Internet. The second example provides leased line replacement to two customers who use address schemes in the same range.
Configuration NotesBoth the local and remote identities shown in these examples serve two purposes:
• They identify multiple IPSec tunnels between the same endpoints.
• They filter traffic going into and coming out of the tunnels so that it is within the specified range. If the configuration requires that only one IPSec tunnel exists between two endpoints and no traffic filtering is required, you can omit the tunnel local-identity and tunnel peer-identity commands.
Example 1In Figure 12-4 customer A is using Frame Relay to connect its corporate offices in three cities: Boston, Ottawa, and Boca.
CHAPTER 12Configuring IPSec
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Figure 12-4 Customer A�s corporate Frame Relay network
Customer A hires ISP-X to provide a leased line replacement over an IP infrastructure using IPSec. ISP-X can offer a replacement for long-haul Frame Relay links by creating IPSec tunnels to carry customer A’s traffic securely between the sites over the public or ISP-provided IP network. This alternative will cost only a fraction of the price of the Frame Relay links. Figure 12-5 shows the connectivity scheme.
Figure 12-5 ISP-X uses E-series routers to connect corporate offices over the Internet
To configure the connections as shown in Figure 12-5:
1 On each E-series router, create a protection suite that provides 3DES encryption with SHA-1 authentication on every packet.
erx1(config)#ipsec transform-set customerAprotection esp-3des-hmac-sha
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erx2(config)#ipsec transform-set customerAprotection esp-3des-hmac-sha
erx3(config)#ipsec transform-set customerAprotection esp-3des-hmac-sha
2 On each E-series router, create preshared keys that the three routers will use to authenticate each other:
erx1(config)#ipsec key manual pre-share 100.2.0.1
erx1(config-manual-key)#key customerASecret
erx1(config-manual-key)#exit
erx1(config)#ipsec key manual pre-share 100.3.0.1
erx1(config-manual-key)#key customerASecret
erx1(config-manual-key)#exit
erx2(config)#ipsec key manual pre-share 100.1.0.1
erx2(config-manual-key)#key customerASecret
erx2(config-manual-key)#exit
erx2(config)#ipsec key manual pre-share 100.3.0.1
erx2(config-manual-key)#key customerASecret
erx2(config-manual-key)#exit
erx3(config)#ipsec key manual pre-share 100.1.0.1
erx3(config-manual-key)#exit
erx3(config-manual-key)#key customerASecret
erx3(config)#ipsec key manual pre-share 100.2.0.1
erx3(config-manual-key)#key customerASecret
erx3(config-manual-key)#exit
3 On erx1 create two IPSec tunnels, one to carry customer A’s traffic between Ottawa and Boston and another to carry the traffic between Ottawa and Boca:
Tunnel 1:
erx1(config)#interface tunnel ipsec:Aottawa2boston
erx1(config-if)#tunnel transform-set customerAprotection
erx1(config-if)#tunnel local-identity subnet 200.1.0.0 255.255.0.0
erx1(config-if)#tunnel peer-identity subnet 200.3.0.0 255.255.0.0
erx1(config-if)#tunnel source 100.1.0.1
erx1(config-if)#tunnel destination 100.3.0.1
erx1(config-if)#ip address 200.3.0.0 255.255.0.0
erx1(config-if)#exit
Tunnel 2:
erx1(config)#interface tunnel ipsec:Aottawa2boca
erx1(config-if)#tunnel transform-set customerAprotection
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erx1(config-if)#tunnel local-identity subnet 200.1.0.0 255.255.0.0
erx1(config-if)#tunnel peer-identity subnet 200.2.0.0 255.255.0.0
erx1(config-if)#tunnel source 100.1.0.1
erx1(config-if)#tunnel destination 100.2.0.1
erx1(config-if)#ip address 200.2.0.0 255.255.0.0
erx1(config-if)#exit
4 On erx2 create two IPSec tunnels, one to carry customer A’s traffic between Boca and Ottawa and another to carry the traffic between Boca and Boston:
Tunnel 1:
erx2(config)#interface tunnel ipsec:Aboca2ottawa
erx2(config-if)#tunnel transform-set customerAprotection
erx2(config-if)#tunnel local-identity subnet 200.2.0.0 255.255.0.0
erx2(config-if)#tunnel peer-identity subnet 200.1.0.0 255.255.0.0
erx2(config-if)#tunnel source 100.2.0.1
erx2(config-if)#tunnel destination 100.1.0.1
erx2(config-if)#ip address 200.1.0.0 255.255.0.0
erx2(config-if)#exit
Tunnel 2:
erx2(config)#interface tunnel ipsec:Aboca2boston
erx2(config-if)#tunnel transform-set customerAprotection
erx2(config-if)#tunnel local-identity subnet 200.2.0.0 255.255.0.0
erx2(config-if)#tunnel peer-identity subnet 200.3.0.0 255.255.0.0
erx2(config-if)#tunnel source 100.2.0.1
erx2(config-if)#tunnel destination 100.3.0.1
erx2(config-if)#ip address 200.3.0.0 255.255.0.0
erx2(config-if)#exit
Configuration ExamplesE-Series Routers
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5 Finally, on erx3 create two IPSec tunnels, one to carry customer A’s traffic between Boston and Ottawa and another to carry the traffic between Boston and Boca:
Tunnel 1:
erx3(config)#interface tunnel ipsec:Aboston2ottawa
erx3(config-if)#tunnel transform-set customerAprotectionerx3(config-if)#tunnel local-identity subnet 200.3.0.0 255.255.0.0
erx3(config-if)#tunnel peer-identity subnet 200.1.0.0 255.255.0.0
erx3(config-if)#tunnel source 100.3.0.1
erx3(config-if)#tunnel destination 100.1.0.1
erx3(config-if)#ip address 200.1.0.0 255.255.0.0
erx3(config-if)#exit
Tunnel 2:
erx3(config)#interface tunnel ipsec:Aboston2boca
erx3(config-if)#tunnel transform-set customerAprotection
erx3(config-if)#tunnel local-identity subnet 200.3.0.0 255.255.0.0
erx3(config-if)#tunnel peer-identity subnet 200.2.0.0 255.255.0.0
erx3(config-if)#tunnel source 100.3.0.1
erx3(config-if)#tunnel destination 100.2.0.1
erx3(config-if)#ip address 200.2.0.0 255.255.0.0
erx3(config-if)#exit
The configuration is complete. Now customer A traffic between different cities flows through the public, or untrusted, IP network inside a tunnel, where each packet is encrypted and authenticated. Of course, this example shows the basic secure encapsulation of customer traffic over the untrusted IP network. You can add features such as key refreshing.
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Example 2Example 2, shown in Figure 12-6, enhances the previous example by having the same ISP-X providing leased line replacement to two customers who use address schemes in the same range. There are two ways to solve scenarios in which different customers use similar IP address schemes:
• One solution is to have different transport virtual routers—a configuration similar to example 1, except that a different VR domain is possible.
• Another solution, as described in this example, simply duplicates the endpoints for the transport VR. This example assumes that the transport VR is the default VR.
Figure 12-6 Connecting customers who use similar address schemes
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Configuration ExamplesE-Series Routers
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To configure the connections as shown in Figure 12-6:
1 On each E-series router, create a protection suite that provides customer A with 3DES encryption and SHA-1 authentication, and customer B with AH authentication using MD5.
erx1(config)#ipsec transform-set customerAprotection esp-3des-hmac-sha
erx1(config)#ipsec transform-set customerBprotection ah-hmac-md5
erx2(config)#ipsec transform-set customerAprotection esp-3des-hmac-sha
erx2(config)#ipsec transform-set customerBprotection ah-hmac-md5
erx3(config)#ipsec transform-set customerAprotection esp-3des-hmac-sha
erx3(config)#ipsec transform-set customerBprotection ah-hmac-md5
2 On each E-series router, create a protection suite that the three routers will use to authenticate each other:
erx1(config)#ipsec key manual pre-share 5.2.0.1
erx1(config-manual-key)#key customerASecret
erx1(config-manual-key)#exit
erx1(config)#ipsec key manual pre-share 5.3.0.1
erx1(config-manual-key)#key customerASecret
erx1(config-manual-key)#exit
erx1(config)#ipsec key manual pre-share 5.2.0.2
erx1(config-manual-key)#key customerBSecret
erx1(config-manual-key)#exit
erx1(config)#ipsec key manual pre-share 5.3.0.2
erx1(config-manual-key)#key customerBSecret
erx1(config-manual-key)#exit
erx2(config)#ipsec key manual pre-share 5.1.0.1
erx2(config-manual-key)#key customerASecret
erx2(config-manual-key)#exit
erx2(config)#ipsec key manual pre-share 5.3.0.1
erx2(config-manual-key)#key customerASecret
erx2(config-manual-key)#exit
erx2(config)#ipsec key manual pre-share 5.1.0.2
erx2(config-manual-key)#key customerBSecret
erx2(config-manual-key)#exit
erx2(config)#ipsec key manual pre-share 5.3.0.2
erx2(config-manual-key)#key customerBSecret
erx2(config-manual-key)#exit
CHAPTER 12Configuring IPSec
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erx3(config)#ipsec key manual pre-share 5.1.0.1
erx3(config-manual-key)#key customerASecret
erx3(config-manual-key)#exit
erx3(config)#ipsec key manual pre-share 5.2.0.1
erx3(config-manual-key)#key customerASecret
erx3(config-manual-key)#exit
erx3(config)#ipsec key manual pre-share 5.1.0.2
erx3(config-manual-key)#key customerBSecret
erx3(config-manual-key)#exit
erx3(config)#ipsec key manual pre-share 5.2.0.2
erx3(config-manual-key)#key customerBSecret
erx3(config-manual-key)#exit
3 On erx1, create two IPSec tunnels, one to carry customer A’s traffic and another to carry customer B’s traffic. You must create each pair of tunnels in the virtual routers where the IP interfaces reaching those customers are defined. The endpoints for the tunnels should be created in the ISP default virtual router.
Virtual router A:
erx1(config)#virtual-router vrA
erx1:vrA(config)#
Tunnel from Ottawa to Boston on virtual router A:
erx1:vrA(config)#interface tunnel ipsec:Aottawa2boston transport-virtual-router default
erx1:vrA(config-if)#tunnel transform-set customerAprotection
erx1:vrA(config-if)#tunnel local-identity subnet 10.1.0.0 255.255.0.0
erx1:vrA(config-if)#tunnel peer-identity subnet 10.3.0.0 255.255.0.0
erx1:vrA(config-if)#tunnel source 5.1.0.1
erx1:vrA(config-if)#tunnel destination 5.3.0.1
erx1:vrA(config-if)#ip address 10.3.0.0 255.255.0.0
erx1:vrA(config-if)#exit
Tunnel from Ottawa to Boca on virtual router A:
erx1:vrA(config)#interface tunnel ipsec:Aottawa2boca transport-virtual-router default
erx1:vrA(config-if)#tunnel transform-set customerAprotection
erx1:vrA(config-if)#tunnel local-identity subnet 10.1.0.0 255.255.0.0
erx1:vrA(config-if)#tunnel peer-identity subnet 10.2.0.0 255.255.0.0
erx1:vrA(config-if)#tunnel source 5.1.0.1
erx1:vrA(config-if)#tunnel destination 5.2.0.1
erx1:vrA(config-if)#ip address 10.2.0.0 255.255.0.0
erx1:vrA(config-if)#exit
Configuration ExamplesE-Series Routers
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Virtual router B:
erx1(config)#virtual-router vrB
erx1:vrB(config)#
Tunnel from Ottawa to Boston on virtual router B:
erx1:vrB(config)#interface tunnel ipsec:Bottawa2boston transport-virtual-router default
erx1:vrB(config-if)#tunnel transform-set customerBprotection
erx1:vrB(config-if)#tunnel local-identity subnet 10.1.0.0 255.255.0.0
erx1:vrB(config-if)#tunnel peer-identity subnet 10.3.0.0 255.255.0.0
erx1:vrB(config-if)#tunnel source 5.1.0.2
erx1:vrB(config-if)#tunnel destination 5.3.0.2
erx1:vrB(config-if)#ip address 10.3.0.0 255.255.0.0
erx1:vrB(config-if)#exit
Tunnel from Ottawa to Boca on virtual router B:
erx1:vrB(config)#interface tunnel ipsec:Bottawa2boca transport-virtual-router default
erx1:vrB(config-if)#tunnel transform-set customerBprotection
erx1:vrB(config-if)#tunnel local-identity subnet 10.1.0.0 255.255.0.0
erx1:vrB(config-if)#tunnel peer-identity subnet 10.2.0.0 255.255.0.0
erx1:vrB(config-if)#tunnel source 5.1.0.2
erx1:vrB(config-if)#tunnel destination 5.2.0.2
erx1:vrB(config-if)#ip address 10.2.0.0 255.255.0.0
erx1:vrB(config-if)#exit
4 On erx2, create two IPSec tunnels, one to carry customer A’s traffic and another to carry customer B’s traffic. You must create each pair of tunnels in the virtual routers where the IP interfaces reaching those customers are defined. The endpoints for the tunnels should be created in the ISP default virtual router.
Virtual router A:
erx2(config)#virtual-router vrA
erx2:vrA(config)#
Tunnel from Boca to Ottawa on virtual router A:
erx2:vrA(config)#interface tunnel ipsec:Aboca2ottawa transport-virtual-router default
erx2:vrA(config-if)#tunnel transform-set customerAprotection
erx2:vrA(config-if)#tunnel local-identity subnet 10.2.0.0 255.255.0.0
erx2:vrA(config-if)#tunnel peer-identity subnet 10.1.0.0 255.255.0.0
erx2:vrA(config-if)#tunnel source 5.2.0.1
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erx2:vrA(config-if)#tunnel destination 5.1.0.1
erx2:vrA(config-if)#ip address 10.1.0.0 255.255.0.0
erx2:vrA(config-if)#exit
Tunnel from Boca to Boston on virtual router A:
erx2:vrA(config)#interface tunnel ipsec:Aboca2boston transport-virtual-router default
erx2:vrA(config-if)#tunnel transform-set customerAprotection
erx2:vrA(config-if)#tunnel local-identity subnet 10.2.0.0 255.255.0.0
erx2:vrA(config-if)#tunnel peer-identity subnet 10.3.0.0 255.255.0.0
erx2:vrA(config-if)#tunnel source 5.2.0.1
erx2:vrA(config-if)#tunnel destination 5.3.0.1
erx2:vrA(config-if)#ip address 10.3.0.0 255.255.0.0
erx2:vrA(config-if)#exit
Virtual router B:
erx2(config)#virtual-router vrB
erx2:vrB(config)#
Tunnel from Boca to Ottawa on virtual router B:
erx2:vrB(config)#interface tunnel ipsec:Bboca2ottawa transport-virtual-router default
erx2:vrB(config-if)#tunnel transform-set customerBprotection
erx2:vrB(config-if)#tunnel local-identity subnet 10.2.0.0 255.255.0.0
erx2:vrB(config-if)#tunnel peer-identity subnet 10.1.0.0 255.255.0.0
erx2:vrB(config-if)#tunnel source 5.2.0.2
erx2:vrB(config-if)#tunnel destination 5.1.0.2
erx2:vrB(config-if)#ip address 10.1.0.0 255.255.0.0
erx2:vrB(config-if)#exit
Tunnel from Boca to Boston on virtual router B:
erx2:vrB(config)#interface tunnel ipsec:Bboca2boston transport-virtual-router default
erx2:vrB(config-if)#tunnel transform-set customerBprotection
erx2:vrB(config-if)#tunnel local-identity subnet 10.2.0.0 255.255.0.0
erx2:vrB(config-if)#tunnel peer-identity subnet 10.3.0.0 255.255.0.0
erx2:vrB(config-if)#tunnel source 5.2.0.2
erx2:vrB(config-if)#tunnel destination 5.3.0.2
erx2:vrB(config-if)#ip address 10.3.0.0 255.255.0.0
erx2:vrB(config-if)#exit
Configuration ExamplesE-Series Routers
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5 Last, on erx3, create two IPSec tunnels, one to carry customer A’s traffic and another to carry customer B’s traffic.
Virtual router A:
erx3(config)#virtual-router vrA
erx3:vrA(config)#
Tunnel from Boston to Ottawa on virtual router A:
erx3:vrA(config)#interface tunnel ipsec:Aboston2ottawa transport-virtual-router default
erx3:vrA(config-if)#tunnel transform-set customerAprotection
erx3:vrA(config-if)#tunnel local-identity subnet 10.3.0.0 255.255.0.0
erx3:vrA(config-if)#tunnel peer-identity subnet 10.1.0.0 255.255.0.0
erx3:vrA(config-if)#tunnel source 5.3.0.1
erx3:vrA(config-if)#tunnel destination 5.1.0.1
erx3:vrA(config-if)#ip address 10.1.0.0 255.255.0.0
erx3:vrA(config-if)#exit
Tunnel from Boston to Boca on virtual router A:
erx3:vrA(config)#interface tunnel ipsec:Aboston2boca transport-virtual-router default
erx3:vrA(config-if)#tunnel transform-set customerAprotection
erx3:vrA(config-if)#tunnel local-identity subnet 10.3.0.0 255.255.0.0
erx3:vrA(config-if)#tunnel peer-identity subnet 10.2.0.0 255.255.0.0
erx3:vrA(config-if)#tunnel source 5.3.0.1
erx3:vrA(config-if)#tunnel destination 5.2.0.1
erx3:vrA(config-if)#ip address 10.1.0.0 255.255.0.0
erx3:vrA(config-if)#exit
Virtual router B:
erx3(config)#virtual-router vrB
erx3:vrB(config)#
Tunnel from Boston to Ottawa on virtual router B:
erx3:vrB(config)#interface tunnel ipsec:Bboston2ottawa transport-virtual-router default
erx3:vrB(config-if)#tunnel transform-set customerBprotection
erx3:vrB(config-if)#tunnel local-identity subnet 10.3.0.0 255.255.0.0
erx3:vrB(config-if)#tunnel peer-identity subnet 10.1.0.0 255.255.0.0
erx3:vrB(config-if)#tunnel source 5.3.0.1
erx3:vrB(config-if)#tunnel destination 5.1.0.1
erx3:vrB(config-if)#ip address 10.1.0.0 255.255.0.0
erx3:vrB(config-if)#exit
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Tunnel from Boston to Boca on virtual router B:
erx3:vrB(config)#interface tunnel ipsec:Bboston2boca transport-virtual-router default
erx3:vrB(config-if)#tunnel transform-set customerBprotection
erx3:vrB(config-if)#tunnel local-identity subnet 10.3.0.0 255.255.0.0
erx3:vrB(config-if)#tunnel peer-identity subnet 10.2.0.0 255.255.0.0
erx3:vrB(config-if)#tunnel source 5.3.0.1
erx3:vrB(config-if)#tunnel destination 5.2.0.1
erx3:vrB(config-if)#ip address 10.2.0.0 255.255.0.0
erx3:vrB(config-if)#exit
The configuration is complete. Customer A’s traffic and customer B’s traffic can flow through the public, or untrusted, IP network inside a tunnel, where each packet is encrypted and authenticated.
Monitoring IPSec This section contains information on troubleshooting and monitoring IPSec.
System Event LogsTo troubleshoot and monitor IPSec, use the following system event logs:
> auditIpsec – Lower layers of IKE SA negotiations
> ikepki – Upper layers of IKE SA negotiations
> stTunnel – Secure tunnel interface
For more information on using event logs, see E-Series System Basics Configuration Guide, Chapter 12, Logging System Events.
show CommandsTo view your IPSec configuration and to monitor IPSec tunnels and statistics, use the following show commands.
show ike policy-rule� Use to display the configuration of IKE phase 1 policy rules. � Field descriptions
� Protection suite priority � priority number assigned to the policy rule� encryption algorithm � encryption algorithm used in the IKE policy: des, 3des� hash algorithm � hash algorithm used in the IKE policy: SHA, MD5
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� authentication method � authentication method used in the IKE policy: RSA signature, preshared keys
� Diffie-Hellman group � size of the Diffie-Hellman group: 768-bit, 1024-bit, 1536-bit
� lifetime � lifetime of SAs created with this policy: 60 to 86400 seconds� aggressive mode � allowed or not allowed
� Examplehost1#show ike policy-rule
IKE Policy Rules:
Protection suite priority: 5
encryption algorithm :3DES Triple Data Encryption Standard(168 bit keys)
hash algorithm :SHA Secure Hash Standard
authentication method:RSA Signatures
Diffie-Hellman group :5 (1536 bit)
lifetime :7200 seconds
aggressive mode :Not Allowed
Protection suite priority: 6
encryption algorithm :3DES Triple Data Encryption Standard(168 bit keys)
hash algorithm :SHA Secure Hash Standard
authentication method:Pre Shared Keys
Diffie-Hellman group :2 (1024 bit)
lifetime :28800 seconds
aggressive mode :Not Allowed
show ike sa� Use to display IKE phase 1 SAs running on the router. � Field descriptions
� Source � local IP address of phase 1 negotiation� Destination � remote IP address of phase 1 negotiation� Time(s) � time remaining in phase 1 lifetime, in seconds� State � current state of the phase 1 negotiation. Corresponds to the
messaging state in the main mode and aggressive mode negotiations. The number in brackets corresponds to the state number. Possible states are:� MM_SA_I Sent SA � initiator has sent initial main mode SA payload to the
responder� MM_SA_R Sent SA � responder has sent a response to the initial main
mode SA� MM_KE_I Sent KE � initiator has sent initial main mode key exchange to
the responder� MM_KE_R Sent KE � responder has sent a response to the key
exchange
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� MM_FINAL_I Sent final packet � initiator has sent the final packet in the main mode negotiation
� MM_FINAL_R Sent final packet � responder has finished main mode negotiation
� MM_DONE_I Done � initiator has finished main mode negotiation� AM_SA_I Sent SA, KE � initiator has sent initial aggressive mode SA
payload and key exchange to the responder� AM_SA_R Sent SA, KE � responder has sent aggressive mode SA payload
and key exchange to the initiator� AM_FINAL_I Sent final packet � initiator has finished aggressive mode
negotiation� AM_DONE_R Done � responder has finished aggressive mode
negotiation� Example
host1#show ike sa
IKE Phase 1 SA's:
Source Destination Time(s) State
10.13.0.99 10.13.0.100 12585 MM_DONE_I Done(9)
10.13.1.99 10.13.1.100 12584 MM_DONE_I Done(9)
10.13.2.99 10.13.2.100 12584 MM_DONE_I Done(9)
10.13.3.99 10.13.3.100 12591 MM_DONE_I Done(9)
10.13.4.99 10.13.4.100 12598 MM_DONE_I Done(9)
10.13.5.99 10.13.5.100 12632 MM_DONE_I Done(9)
10.13.6.99 10.13.6.100 12658 MM_DONE_I Done(9)
10.13.7.99 10.13.7.100 12690 MM_DONE_I Done(9)
10.13.8.99 10.13.8.100 12716 MM_DONE_I Done(9)
show ipsec lifetime� Use to display the configured IPSec default lifetime. � Example
host1#show ipsec lifetime
Default lifetime in seconds is '7200'.
Default lifetime in kilobytes is '4294967295'.
show ipsec local-endpoint� Use to display the address and transport virtual router of local endpoints. � To display the local endpoint of a specific transport virtual router, include the
virtual router name.� Example
host1#show ipsec local-endpoint transport-virtual-router default
Local endpoint for transport-virtual-router default is '0.0.0.0'.
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show ipsec transform-set� Use to display transform sets configured on the router. � To display a specific transform set, include the transform set name.� Field descriptions
� Transform-set � displays the transforms in the transform set� Example 1
host1#show ipsec transform-set
Transform-set: Highest security = {esp-3des-hmac-sha }.
Transform-set: transform-esp-3des-hmac-sha = {esp-3des-hmac-sha }.
� Example 2host1#show ipsec transform-set transform-esp-3des-hmac-sha
Transform-set: transform-esp-3des-hmac-sha = {esp-3des-hmac-sha}.
show ipsec tunnel detail� Use to display the running configuration and statistics for each tunnel. � Field descriptions
� IPSEC tunnel � name and state of tunnel for which information is displayed � Tunnel operational configuration � configuration running on the tunnel
� Tunnel type � manual, signaled� Tunnel mtu � MTU size of the tunnel� Tunnel localEndpoint � IP address of local tunnel endpoint � Tunnel destination address � IP address of tunnel destination� Tunnel transport virtual router � name of transport virtual router over
which tunnel runs � Tunnel transform set � tunnel transform set in use on this tunnel� Tunnel local identity � IP address of local endpoint identity that ISAKMP
uses � Tunnel peer identity � IP address of peer endpoint identity that ISAKMP
uses� Tunnel inbound spi/SA � SPI and SA in use on traffic received from the
tunnel� Tunnel outbound spi/SA � SPI and SA in use on traffic sent to the tunnel� Tunnel lifetime seconds � configured lifetime in seconds � Tunnel lifetime kilobytes � configured lifetime in kilobytes� Tunnel pfs � PFS group in use on the tunnel: 0 (PFS is not in use), 1
(768-bit group), 2 (1024-bit group), 5 (1536-bit group)� Tunnel administrative state � Up, Down
� Tunnel Statistics � displays statistics on traffic received on and sent from this tunnel� InUserPackets � number of user packets received � InUserOctets � number of octets received from user packets� InAccPackets � number of encapsulated packets received
CHAPTER 12Configuring IPSec
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� InAccOctets � number of octets received in encapsulated packets� InAuthErrors � number of authentication errors received� InReplayErrors � number of replay errors in received traffic� InPolicyErrors � number of policy errors in received traffic� InOtherRxErrors � number of packets received that have errors other
than those listed above� InDecryptErrors � number of decryption errors in received traffic� InPadErrors � number of packets received that had invalid values after
the packet was decrypted� OutUserPackets � number of user packets sent � OutUserOctets � number of octets sent in user packets� OutAccPackets � number of encapsulated packets sent� OutAccOctets � number of octets sent in encapsulated packets� OutPolicyErrors � number of packets arriving at tunnel for encapsulation
that do not meet specified tunnel identifier (selector)� OutOtherTxErrors � number of outbound packets that have errors other
than those listed above� Example
host1#show ipsec tunnel detail
IPSEC tunnel s0l1e3d0 is up
Tunnel operational configuration:
Tunnel type is signaled
Tunnel mtu is 1440
Tunnel localEndpoint is 10.255.1.13
Tunnel destination address is 10.255.1.14
Tunnel transport virtual router is vr00
Tunnel transform set is transform-esp-3des-hmac-sha
Tunnel local identity is ipAddress: 10.0.10.3
Tunnel peer identity is ipAddress: 10.0.11.3
Tunnel inbound spi is 0x13c00201, SA is esp-3des-hmac-sha.
Tunnel outbound spi is 0x12b90209, SA is esp-3des-hmac-sha.
Tunnel lifetime seconds is 7200
Tunnel lifetime kilobytes is 102400
Tunnel pfs is group 5
Tunnel administrative state is Up
Tunnel Statistics :
InUserPackets 297
InUserOcets 306232
InAccPackets 297
InAccOcets 322864
InAuthErrors 0
InReplayErrors 0
InPolicyErrors 0
InOtherRxErrors 0
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InDecryptErrors 0
InPadErrors 0
OutUserPackets 316
OutUserOctes 317424
OutAccPackets 316
OutAccOcets 335120
OutPolicyErrors 0
OutOtherTxErrors 0
show ipsec tunnel summary� Use to display a summary of all tunnels configured on the router. � Field descriptions
� Total number of ipsec interface � number of tunnels configured on the router� Administrative status � number of tunnels with an administrative status of
enabled and disabled� Operational status � number of tunnels with an operational status of up,
down, lower layer down, not present� Example
host1#show ipsec tunnel summary
Total number of ipsec interface is 40
Administrative status enabled disabled
40 0
Operational status up down lower-down not-present
40 0 0 0
show ipsec tunnel virtual-router� Use to display the status of tunnels configured on a virtual router. � To display only tunnels that are in a specific state, use the state keyword.� To display tunnels that are using a particular IP address, use the ip keyword.� Field descriptions
� For a description of fields, see the show ipsec tunnel detail command.� Example
host1#show ipsec tunnel virtual-router default ip 10.255.1.13
IPSEC tunnel s0l1e3d0 is up
IPSEC tunnel s0l1e3d1 is up
IPSEC tunnel s0l2e3d0 is up
IPSEC tunnel s0l2e3d1 is up
IPSEC tunnel s0l3e3d0 is up
IPSEC tunnel s0l4e3d0 is up
IPSEC tunnel s0l4e3d1 is up
IPSEC tunnel s0l5e3d0 is up
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show license ipsec-tunnels� Use to display the IPSec license key configured on the router and the number
of tunnels allowed on the router. � Example
host1#show license ipsec-tunnels
ipsec-tunnels license is 'g1k23b23eb2j' which allows 5000 tunnels with 1 IPsec card and 7500 tunnels with 2 or more IPsec cards.
13
Configuring Digital CertificatesThis chapter describes the digital certificates feature on your E-series router.
Overview You can use digital certificates in place of preshared keys for IKE negotiations. For more information about IKE, see IKE Overview in Chapter 12, Configuring IPSec.
Topic Page
Overview 13-1
References 13-2
IKE Authentication Using Digital Certificates 13-3
Configuration Tasks 13-7
Monitoring Digital Certificates 13-12
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TermsTable 13-1 defines terms and abbreviations that are used in this discussion of digital certificates.
ReferencesDigital certificates support:
• RFC 2986 – PKCS #10: Certification Request Syntax Specification Version 1.7 (November 2000)
• RFC 2459 – Internet X.509 Public Key Infrastructure Certificate and CRL Profile (January 1999)
For more information on IPSec and IKE, see Chapter 12, Configuring IPSec.
Table 13-1 Digital certificate terms and abbreviations
Term Definition
3DES Triple DES encryption/decryption algorithm
Base64 Method used to encode certificate requests and certificates before they are sent to or from the CA.
CA Certificate authority. An organization that creates digital certificates.
Certificate Binds a person or entity to a public key using a digital signature.
Certificate revocation list (CRL)
A list of certificates that a CA has revoked
ESP Encapsulating Security Payload; provides data integrity, data confidentiality and, optionally, sender�s authentication
IKE Internet Key Exchange
PKCS Public-Key Cryptography Standards; a series of standards established by RSA Laboratories
PKCS10 PKCS #10, which describes a syntax for certification requests
Root CA CA that signs the certificates of subordinate CAs
Root certificate Self-signed public key certificate for a root CA. Root certificates are used to verify other certificates
RSA Rivest-Shamir-Adleman encryption algorithm
SA Security association. The set of security parameters that dictate how IPSec processes a packet, including encapsulation protocol and session keys. A single secure tunnel uses multiple SAs.
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IKE Authentication Using Digital Certificates As part of the IKE protocol, one security gateway needs to authenticate another security gateway to make sure that IKE SAs are established with the intended party. The E-series router supports two authentication methods:
• Digital certificates (using RSA algorithms)
For digital certificate authentication, an initiator signs message interchange data using his private key, and a responder uses the initiator’s public key to verify the signature. Typically, the public key is exchanged via messages containing an X.509v3 certificate. This certificate provides a level of assurance that a peer’s identity—as represented in the certificate—is associated with a particular public key.
• Preshared keys
With preshared key authentication, the same secret must be configured on both security gateways before the gateways can authenticate each other.
The following sections provide information on digital certificates. For information on using preshared keys, see IKE Overview in Chapter 12, Configuring IPSec.
Signature Authentication The following are key steps for using public key cryptography to authenticate a peer. These steps are described in more detail in the following sections.
1 Generating a private/public key pair.
Before the router can place a digital signature on messages, it requires a private key to sign, and requires a public key so that message receivers can verify the signature.
2 Obtaining a public key certificate.
The router requires at least one public key certificate, which binds the router identity to its public key. The CA verifies the identity represented on the certificate and then signs the certificate. The router sends the certificate to IKE peers during negotiations to advertise the router public key.
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3 Obtaining a root CA certificate.
The router requires at least one root CA certificate to send to IKE peers, and also to verify that a peer’s certificate is genuine.
4 Authenticating the peer.
As part of IKE negotiations, the router receives its peer’s digital signature in a message exchange. The router must verify the digital signature using the peer’s public key. The public key is contained in the peer’s certificate, which often is received during the IKE negotiation. To ensure that the peer certificate is valid, the router verifies its digital signature using the CA public key contained in the root CA certificate. The router and its IKE peer require at least one common trusted root CA for authentication to work.
Generally, only step 4 above is required each time a Phase 1 negotiation happens. The first three steps are required only if keys are compromised or router certificates require renewal.
Generating Private/Public Key Pairs The E-series router needs at least one valid pair of public/private keys whenever it uses any of the public key methods for authenticating an IKE peer. The E-series router can generate its own public/private key pairs. The public/private key pair supports the RSA standard (1024 or 2048 bits).
The private key is used only by the E-series router. It is never exchanged with any other nodes. It is used to place a digital signature on IKE authentication messages. When generated, it is securely stored internally to the E-series router in flash memory. Access to the private key is never allowed, not even to a system administrator or a network management system. Private key storage includes protection mechanisms to prevent improper private key usage, including encryption with 3DES using a unique internally generated key. The key is also tied to SRP-specific data to prevent swapping flash disks between routers.
The public key is used in the generation of the router certificate request, which is sent to a CA. Based on the certificate request, the CA generates a public key certificate for the E-series router.
The router public/private key pair is a global system attribute. It does not matter how many IPSec service line modules exist in the router; only one set of keys is available at any given moment. The private/public key pair applies across all virtual routers and is persistent across reloads and booting to factory defaults.
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Obtaining a Public Key Certificate Once the public key is generated, the router must obtain a public key certificate from a CA, a process called certificate enrollment. The E-series router supports manual certificate enrollment, which works as follows:
1 An operator generates a certificate request by supplying identity information.
2 The E-series router creates a certificate request file and makes it available to the operator.
3 The operator supplies the certificate request file to a CA for approval, typically by copying and pasting the file to a Web page.
4 The CA approves the request and generates a certificate.
5 The operator copies the certificate file onto the E-series router so that it can be used for IKE negotiations.
The standards supported for this enrollment are PKCS #10 certificate requests and X.509v3 certificates. Certificates are encoded in base64 (MIME) so that the files are easily transferred through cut and paste operations and e-mail.
Obtaining a Root CA Certificate Downloading the root CA’s self-signed certificate is also done manually.
An operator obtains the root CA certificate, typically through a Web browser, and copies the certificate file to the E-series router so that the router can use it as part of IKE negotiations. The standards supported for obtaining root CAs are X.509v3, base64, and BER-encoded certificates.
Authenticating the Peer The E-series router validates X.509v3 certificates from the peer by confirming that the ID payload passed in IKE matches the identifiers in the peer certificate. The router also verifies that the signature is correct, based on the root CA public key.
Note: The E-series router does not support certificate chains (where a root CA signs the certificate of a subordinate CA, and a subordinate CA signs the peer certificate), so validation must be done on each stage up to the root CA that both peers trust).
The E-series router also validates the certificate based on its time window, so correct UTC time on the router is essential. In addition to the certificate checks, the E-series router confirms that message data received
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from the peer has the correct signature based on the peer’s public key as found in its certificate. Once complete, the IKE authentication is done and quick-mode negotiation of SAs can proceed.
Checking CRLs To use CRL checking, you must copy CRL files that are published by CAs to the E-series router. Using the ike crl command, you can control how the router handles CRLs during negotiation of IKE phase 1 signature authentication. The ike crl command has three settings:
• Ignored – Allows negotiations to succeed even if a CRL is invalid or the peer’s certificate appears in the CRL; this is the most lenient setting.
• Optional – If the router finds a valid CRL, it uses it.
• Required – Requires a valid CRL, and the certificates belonging to the E-series router or the peer must not appear in the CRL; this is the strictest setting.
Based on the CRL setting, you can expect that phase 1 IKE negotiations will succeed or fail depending on the following conditions:
• CRL OK – The certificate revocation list is present for the CA and valid (not expired).
• CRL expired – The CRL is present on the E-series router but is old
• Missing CRL – There is no CRL on the router for the CA.
• Peer Cert revoked – The CRL contains the peer certificate.
• ERX Cert revoked – The CRL contains the E-series router’s certificate.
Table 13-2 shows some examples of how the CRL setting affects the outcome of IKE phase 1 negotiations. It shows common problem conditions such as ERX Cert revoked.
Table 13-2 Outcome of IKE phase 1 negotiations
CRL Setting
Condition Optional Ignored Required
CRL OK Succeed Succeed Succeed
CRL expired Succeed Succeed Fail
Missing CRL Succeed Succeed Fail
Peer Cert revoked Fail Succeed Fail
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File Extensions Table 13-3 describes the file extensions that digital certificates use on the E-series router.
In addition, router IKE identity information and private keys are kept on the f lash disk in hidden areas not visible to users. (These files do not appear when you enter a dir command).
Configuration Tasks To set up digital certificates:
1 Generate RSA key pairs.
host1(config)#ipsec key generate rsa 2048
Please wait.................................................
..........................
IPsec Generate Keys complete
2 In your IKE policy, set the authentication method to RSA signatures.
host1(config)#ipsec isakmp-policy-rule 1
host1(config-isakmp-policy)#authentication rsa-sig
Note: For more information on setting up IKE policies, see Defining an ISAKMP/IKE Policy in Chapter 12, Configuring IPSec.
ERX Cert revoked Fail Succeed Fail
Table 13-2 Outcome of IKE phase 1 negotiations (continued)
CRL Setting
Condition Optional Ignored Required
Table 13-3 File extensions
File Extension Description
.crq Used for certificate request files that are generated on the E-series router and taken to CAs for obtaining a certificate.
.cer Used for public certificate files. The public certificates for root CAs and the router public certificates are copied to the E-series router. They are autorecognized as belonging to the E-series router or CA by certificate subject name and issuer name (in a CA they are the same). The E-series router supports multiple CAs.
.crl Used for certificate revocation lists that are obtained offline from CAs and copied to the E-series router. CRLs indicate which certificates from a particular CA are revoked.
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3 Enter IPSec Identity Configuration mode.
host1(config)#ipsec identity
host1(config-ipsec-identity)#
4 Specify the information that the router uses to generate a certificate request.
a Specify a country name.
host1(config-ipsec-identity)#country CA
b Specify a common name.
host1(config-ipsec-identity)#common-name Jim
c Specify a domain name.
host1(config-ipsec-identity)#domain-name myerx.kanata.junipernetworks.com
d Specify an organization.
host1(config-ipsec-identity)#organization juniperNetworks
host1(config-ipsec-identity)#exit
host1(config)#
5 Generate a certificate request using certificate parameters from the IPSec identity configuration.
host1(config)#ipsec certificate-request generate rsa myrequest.crq
6 Once the certificate request is generated, you need to copy the file from the E-series router and send it to the CA. Typically, you will copy the file and paste it to a CA’s Web page.
7 When you receive the certificate from the CA, copy the certificate to the E-series router, and then inform the router that a new certificate exists.
host1(config)#ipsec certificate-database refresh
8 (Optional) Set the sensitivity of how the router handles CRLs.
host1(config)#ike crl ignored
9 (Optional) To delete RSA key pairs, use the ipsec key zeroize command.
host1(config)#ipsec key zeroize rsa
Configuration TasksE-Series Routers
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authentication� Use to specify the authentication method that the router uses in the IKE policy
to RSA signature. � Example
host1(config-isakmp-policy)#authentication rsa-sig
� Use the no version to restore the default, preshared keys.
common-name� Use to specify a common name used to generate certificate requests. � Example
host1(config-ipsec-identity)#common-name Jim
� Use the no version to remove the common name.
country� Use to specify a country name used to generate certificate requests. � Example
host1(config-ipsec-identity)#country CA
� Use the no version to remove the country name.
domain-name� Use to specify the domain name that the router uses in IKE authentication
messages and to generate certificate requests.� The domain name is used in the SubjectAlternative DNS certicate extensions
and as an FQDN (fully qualified domain name) ID payload for IKE negotiations. � Example
host1(config-ipsec-identity)#domain-name myerx.kanata.junipernetworks.com
� Use the no version to remove the domain name.
ike crl� Use to control how the router handles certificate revocation lists (CRLs) during
negotiation of IKE phase 1 signature authentication. Specify one of the following keywords:� ignored � allows negotiations to succeed even if a CRL is invalid or the
peer�s certificate appears in the CRL; this is the most lenient setting� optional � if the router finds a valid CRL, it uses it; this is the default setting� required � requires a valid CRL; either the certificates that belong to the
E-series router or the peer must not appear in the CRL; this is the strictest setting
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� Examplehost1(config)#ike crl ignored
� Use the no version to return the CRL setting to the default, optional.
ipsec certificate-database refresh� Use to inform the E-series router that a public key certificate has been copied to
the router. The router then verifies public certificates found on its disk against its private key and prepares the certificates for use. Note: On reload, the router scans all certificate files and determines which files are router public certificates and which are root CA certificates.
� Examplehost1(config)#ipsec certificate-database refresh
� There is no no version.
ipsec certificate-request generate � Use to cause the router to generate a certificate request using certificate
parameters from the IPSec identity configuration. � Include a name for the certificate request file. The file name must have a .crq
extension.� Once the router generates the certificate, use offline methods to send the
certificate request file to the CA.� Example
host1(config)#ipsec certificate-request generate rsa myrequest.crq
� There is no no version.
ipsec identity � Use to enter IPSec Identity Configuration mode where you can specify
information that the router uses in certificate requests and during negotiations with its peers.
� Examplehost1(config)#ipsec identity
host1(config-ipsec-identity)#
� Use the no version to remove the identity configuration.
ipsec isakmp-policy-rule� Use to define an ISAKMP/IKE policy. � When you enter the command, you include a number that identifies the policy
and assigns a priority to the policy. You can number policies from 1 to 10000, with 1 having the highest priority.
Configuration TasksE-Series Routers
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� Example host1(config)#ipsec isakmp-policy-rule 3
host1(config-isakmp-policy)#
� Use the no version to remove policies. If you do not include a priority number with the no version, all policies are removed.
ipsec key generate� Use to generate RSA key pairs. Include a length of 1024 or 2048 bits. The
generated keys can be used only after the CA issues a certificate for them.� Example
host1(config)#ipsec key generate rsa 4096
Please wait.................................................
..........................
IPsec Generate Keys complete
� There is no no version. To remove a key pair, use the ipsec key zeroize command.
ipsec key zeroize� Use to delete RSA key pairs. Include one of the following keywords
� rsa � removes the RSA key pair from the router� pre-share � removes all preshared keys from the router � all � removes all keys within the VR context from the router
� Examplehost1(config)#ipsec key zeroize rsa
� There is no no version.
organization� Use to specify the organization used in the Subject Name field of certificates. � Example
host1(config-ipsec-identity)#organization juniperNetworks
� Use the no version to remove the organization name.
CHAPTER 13Configuring Digital Certificates
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Monitoring Digital Certificates Use the following show commands to display IKE certificates, CRLs, and your IKE configuration.
show ike certificates� Use to display the IKE certificates and CRLs on the E-series router. Specify the
type of certificate you want to display: � all � all certificates configured on the router � crl � certificate revocation lists� peer � peer certificates � public-certs � public certificates� root-cas � root CA certificates
� Use the hex-format keyword to display certificate data, such as serial numbers, in hexadecimal format. Doing so allows easier comparison with CAs, such as Microsoft, that display certificates in hex format.
� Examplehost1#show ike certificates public-certs
Certificate =
SerialNumber = 4882201
SubjectName = <C=CA, O=Juniper Networks, CN=Trev Larock>
IssuerName = <C=FI, O=SSH Communications Security Corp, CN=SSH Test CA 1 No
Liabilities>
Validity =
NotBefore = 2003 Feb 5th, 00:37:07 GMT
NotAfter = 2003 Mar 7th, 01:07:07 GMT
PublicKeyInfo =
PublicKey =
Algorithm name (SSH) : if-modn{sign{rsa-pkcs1-md5}}
Modulus n (1024 bits) :
13225766016639784111076637633741932992106377577699283110795188796052482
65342146764124357160800571914230195127208418504109976431218877486359782
05039116157265311149909398062120023292037934003177853958261330798885742
78483784295640530834307567681635251787413138487842020206430811996635774
6473467422163528513914011
Exponent e ( 17 bits) :
65537
Extensions =
Available = authority key identifier, subject key identifier, key
usage(critical), subject alternative names, CRL distribution points,
extended key usage
SubjectAlternativeNames =
Following names detected =
DNS (domain name server name)
Viewing specific name types =
Monitoring Digital CertificatesE-Series Routers
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DNS = treverx1.unispherenetworks.com
KeyUsage = DigitalSignature
[CRITICAL]
CRLDistributionPoints =
% Entry 1
FullName =
Following names detected =
URI (uniform resource indicator)
Viewing specific name types =
URI =
ldap://193.64.193.154:389/CN=SSH%20Test%20CA%201%20No%20Liabilities
,O=SSH%20Communications%20Security%20Corp,C=FI?certificaterevocatio
nlist
AuthorityKeyID =
KeyID =
: 3d cb be 20 64 49 16 1d 88 b7 98 67 93 f0 5d 42 81 2e bd 0c
SubjectKeyID =
KeyId =
: cb 89 0a 07 8c b1 bd a0 5a 8d 9f fb 08 6f ae bf fc 22 37 2b
ExtendedKeyUsage =
clientAuth (1.3.6.1.5.5.7.3.2)
ikeIntermediate (1.3.6.1.5.5.8.2.2)
host1#show ike certificates root-cas
Certificate =
SerialNumber = 1538512
SubjectName = <C=FI, O=SSH Communications Security Corp, CN=SSH Test CA 1 No
Liabilities>
IssuerName = <C=FI, O=SSH Communications Security Corp, CN=SSH Test CA 1 No
Liabilities>
Certificate seems to be self-signed.
* Signature verification success.
Validity =
NotBefore = 2001 Aug 1st, 07:08:32 GMT
NotAfter = 2004 Aug 1st, 07:08:32 GMT
PublicKeyInfo =
PublicKey =
Algorithm name (SSH) : if-modn{sign{rsa-pkcs1-md5}}
Modulus n (1024 bits) :
11917611287778603070080534566511562975214407448390943179928807818173885
47247666155825989542261220981799976308014604905009354671795084636946388
05807250595102357061876406491725197545378029185127138910656474019020750
57893862702272777323679505496338679231604634989591340666076231855527357
3617925277649092630861237
Exponent e ( 17 bits) :
65537
CHAPTER 13Configuring Digital Certificates
13-14
Extensions =
Available = authority key identifier, subject key identifier, key
usage(critical), subject alternative names, basic constraints(critical)
SubjectAlternativeNames =
Following names detected =
EMAIL (rfc822)
Viewing specific name types =
EMAIL = [email protected]
KeyUsage = DigitalSignature KeyCertSign CRLSign
[CRITICAL]
BasicConstraints =
PathLength = 0
cA = TRUE
[CRITICAL]
show ike configuration� Use to display a summary of the IKE configuration.� Field descriptions
� Ike identity � information from your IKE identify configuration that the router uses to generate certificate requests
� CRL Check � setting of the CRL check: optional, required, ignored� Example
host1#show ike configuration
Ike configuration:
Ike identity:
Domain Name :treverxsys2.juniper.net
Common Name :Sys2 ERX
Organization:Juniper Networks
Country :CA
CRL Check:optional
show ike identity � Use to display the IKE identity configuration. � Example
host1#show ike identity
Ike identity:
Domain Name :myerx.kanata.junipernetworks.com
Common Name :jim
Organization:junipernetworks
Country :ca
14
Configuring L2TP with IPSecThis chapter describes the L2TP with IPSec feature on your E-series router.
Overview IPSec remote access allows clients to connect to a corporate VPN over the public Internet with a secure connection. IPSec remote access works by running an L2TP tunnel on top of an IPSec transport mode connection. The secure tunnel runs from the client PC to the E-series router that terminates the secure tunnel. Using L2TP with IPSec, B-RAS clients can securely connect to a corporate or other VPN in addition to another unsecured connection to the Internet.
Topic Page
Overview 14-1
References 14-2
How Secure Remote Access Works 14-2
Configuration Tasks for Client PC 14-7
Configuration Tasks for E-Series Routers 14-7
Monitoring L2TP over IPSec 14-13
CHAPTER 14Configuring L2TP with IPSec
14-2
References This IPSec with L2TP implementation supports:
• RFC 3193 – Securing L2TP using IPSec (November 2001)
• RFC 2661 – Layer Two Tunneling Protocol “L2TP” (August 1999)
• RFC 2401 – Security Architecture for the Internet Protocol (November 1998)
For more information on related router features, see:
• Chapter 12, Configuring IPSec
• Chapter 13, Configuring Digital Certificates
• E-Series Broadband Access Configuration Guide, Chapter 5, Configuring L2TP
How Secure Remote Access WorksOn the router side of the L2TP connection, the E-series router acts as the L2TP Network Server (LNS). On the PC client side of the connection, the client acts as the L2TP Access Concentrator (LAC) and runs L2TP/IPSec software that is built into specified Microsoft Windows operating systems. Both sides of the connection run IPSec in transport mode with Encapsulating Security Payload (ESP) encryption and authentication.
In the model shown in Figure 14-1, a client PC connects to its local provider, who gives the client a public IP address. Using the public IP address, the client PC initiates an IPSec connection toward the L2TP/IPSec gateway for the private network that it wants to connect to. After establishing the IPSec connection, the client establishes an L2TP tunnel to the same L2TP/IPSec gateway, which provides the client with another IP interface to access the private network it is connecting to. The L2TP tunnel is completely protected by the IPSec connection established earlier.
How Secure Remote Access WorksE-Series Routers
14-3
Figure 14-1 L2TP with IPSec application
Setting Up the Secure ConnectionFigure 14-2 gives an overview of the process used to set up a secure connection between the client PC and the E-series router.
Figure 14-2 L2TP with IPSec model
To set up the secure connection shown in Figure 14-2:
1 Obtain an IP address from your ISP, using a normal B-RAS termination.
2 IKE signals a security association (SA) between the client PC and the E-series router.
• Two unidirectional SAs are established to secure data traffic.
• The IPSec connection secures UDP port 1701.
3 Set up an L2TP tunnel and session between the client PC (the LAC) and the E-series router (the LNS).
• The tunnel runs over the SAs that IKE established.
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CHAPTER 14Configuring L2TP with IPSec
14-4
L2TP with IPSec Control and Data Frames L2TP defines control and data messages used for L2TP/IPSec. Figure 14-3 shows an L2TP/IPSec encapsulated control frame. The gray area indicates the encrypted part of the frame.
Figure 14-3 L2TP/IPSec encapsulated control frame
Figure 14-4 is an L2TP/IPSec encapsulated data frame. The gray area shows the encrypted part of the frame.
Figure 14-4 L2TP/IPSec encapsulated data packet
Compatibility and Requirements This section covers various compatibility issues and requirements for the IPSec/L2TP traffic.
End-to-End SecurityL2TP/IPSec provides security only between tunnel endpoints. It does not provide end-to-end security. For end-to-end security, you need additional security for the connection beyond the router.
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How Secure Remote Access WorksE-Series Routers
14-5
Client Software SupportedThe L2TP/IPSec software supports the following client PC operating systems and L2TP and IPSec applications:
• Windows 2000 and Windows XP running built-in IPSec VPN software.
• Microsoft L2TP/IPSec VPN client for Windows NT, Windows 98, and Windows Me.
• SafeNet client software.
Interactions with NAT Network address translation (NAT) devices can change the IP address and/or port number of a traversing IP packet. Encrypted frames, where an ESP header follows the IP header, may or may not get through the NAT device.
You can set up the router to run in NAT passthrough mode, which causes the router to not generate or check UDP checksums. The reason is that a NAT device may change the IP address while the UDP header is encrypted. In this case, the UDP checksum cannot be recalculated. Not generating or checking UDP checksums does not compromise security, because IPSec protects UDP with an authentication algorithm far stronger than UDP checksums. To set up the router to run in NAT passthrough mode, use the application l2tp-nat-passthrough command.
For the router to accept an IP address that is changed by NAT, configure the IP address in the IPSec transport profile as the wildcard.
Tunnel Creation The E-series router can have both secured and unsecured L2TP tunnels. When you configure L2TP, you can differentiate the secured and unsecured tunnels in the L2TP destination profile with the enable ipsec transport command. Unsecured L2TP tunnels are not allowed on the IPSec service module.
Interaction Between IPSec and PPPPPP defines the ECP and CCP modes, and these modes are currently not supported in the E-series router. There will be no interaction related to encryption directives between IPSec and PPP.
CHAPTER 14Configuring L2TP with IPSec
14-6
Number of L2TP/IPSec ConnectionsThe IPSec service module allows up to 5,000 secure tunnels and L2TP/IPSec connections combined.
LNS Change of Address For L2TP applications, the LNS may change the IP address from its end when an incoming call is terminated. If this is done in an L2TP tunnel protected by IPSec, the following procedure must be followed:
1 The LNS must send a StopCCN to the LAC, with the Result and Error Code AVP present.
2 The Result Code must be set to 2 (General Error), and the Error Code should be set to 7 (Try Another).
3 The optional error message must be present, and the contents must contain only the IP address (ASCII, dotted decimal encoded) that the LNS wants to use for subsequent communications.
4 The StopCCN message must be sent with the same address and port that the LAC used to send the SCCRQ.
In the above scenario, the LAC—that is, the client PC—needs to establish a new IPSec tunnel toward the new LNS address before a new SCCRQ can be sent to the new destination.
LNS Change of Port In the L2TP world, the LNS is allowed to change its port number; this functionality is currently not supported in the E-series router. IPSec allows only port 1701 to be used for L2TP/IPSec tunnels. However, the LAC is allowed to use any source port it desires.
Group Preshared Key Group preshared keys allow the provisioning of secure remote access via L2TP/IPSec to networks that do not use a certificate authority (CA) to issue certificates. A group preshared key is associated with a local IP address in the E-series router and is used to authenticate L2TP/IPSec clients that target this IP address as their VPN server address.
Caution: Group preshared keys are not fully secure, and we recommend that you use digital certificates in place of group preshared keys. Group preshared keys are open to man-in-the-middle attacks. To reduce this risk, the E-series router accepts only IPSec connections that specify L2TP traffic selectors for security associations (SAs) that are negotiated over IKE connections authenticated with group preshared keys.
Configuration Tasks for Client PCE-Series Routers
14-7
Configuration Tasks for Client PCTo set up client PCs, you need to:
• Create an IPSec security policy to secure L2TP traffic to the E-series router.
• Get a certificate for the client or set up preshared keys.
• Create a VPN connection to the router.
• Log the client on to the E-series router.
Configuration Tasks for E-Series Routers The main configuration tasks for setting up IPSec over L2TP are:
• Set up IP connectivity to L2TP clients; for example, PPPoE, DHCP, or static IP.
• Set up digital certificates on the router, or configure preshared keys for IKE authentication.
To set up digital certificates, see Chapter 13, Configuring Digital Certificates.
To set up preshared keys, see Configuring IPSec Parameters in Chapter 12, Configuring IPSec.
• Create IPSec policies. See Defining an ISAKMP/IKE Policy in Chapter 12, Configuring IPSec.
• Configure RADIUS authentication and accounting. See E-Series Broadband Access Configuration Guide, Chapter 1, Configuring Remote Access.
• Configure L2TP destination profiles. See next section.
• Configure IPSec transport profiles. See section later in this chapter.
Configuring L2TP Destination Profiles To configure an L2TP destination profile:
1 Create a destination profile that defines the location of the LAC, and access L2TP Destination Profile Configuration mode.
host1(config)#l2tp destination profile boston4 ip address 192.168.76.20
host1(config-l2tp-dest-profile)#
CHAPTER 14Configuring L2TP with IPSec
14-8
2 Specify that for L2TP tunnels associated with this destination profile, the router accepts only tunnels protected by IPSec.
host1(config-l2tp-dest-profile-host)#enable ipsec-transport
3 Define the L2TP host profile, and enter L2TP Destination Profile Host Configuration mode.
host1(config-l2tp-dest-profile)#remote host default
host1(config-l2tp-dest-profile-host)#
4 (Optional) Assign a profile name for a remote host.
host1(config-l2tp-dest-profile-host)#profile georgeProfile1
5 Specify the local IP address to be used in any packets sent to the LAC.
host1(config-l2tp-dest-profile-host)#local ip address 10.0.0.1
For information on other L2TP destination profile commands, see Configuring the LNS in E-Series Broadband Access Configuration Guide, Chapter 5, Configuring L2TP.
enable ipsec-transport� Use to specify that the router accepts only L2TP tunnels protected by an IPSec
transport connection.� Example
host1(config-l2tp-dest-profile-host)#enable ipsec-transport
� Use the no version to disable IPSec transport mode.
Configuring IPSec Transport Profiles To create an IPSec transport profile:
Boston(config)#ipsec transport profile secureL2tp virtual-router default ip address 0.0.0.0
Boston(config-ipsec-transport-profile)#
You can then set any of the following parameters for the profile.
• Specify the type of application that the profile secures.
Boston(config-ipsec-transport-profile)#application l2tp-nat-passthrough
• Set a lifetime range for the IPSec connection in volume of traffic and/or seconds.
Boston(config-ipsec-transport-profile)#lifetime seconds 3600 28800 kilobytes 102400 4294967295
Configuration Tasks for E-Series RoutersE-Series Routers
14-9
• Configure perfect forward secrecy for connections created with this IPSec transport profile.
host1(config-ipsec-transport-profile)#pfs group 5
• Specify the transform set(s) that an IPSec transport connection uses to negotiate a transform algorithm.
Boston(config-ipsec-transport-profile)#transform-set esp-3des-hmac-sha esp-3des-hmac-md5
• Specify the local endpoint (for L2TP, the LNS address) of the IPSec transport connection, and enter Local IPSec Transport Profile mode.
Boston(config-ipsec-transport-profile)#local ip address 10.10.1.1
Boston(config-ipsec-transport-profile-local)#
• Configure a key for IKE negotiations.
a Enter the unencrypted key.
host1(config-ipsec-transport-profile-local)#pre-share secretforL2tp
The router encrypts the key and stores it in encrypted form. You can no longer retrieve the unencrypted.
b Display the encrypted key.
Note: The show config command displays the key in its encrypted (masked) format.
host1#show config
!
ipsec transport profile secureL2tp virtual-router default ip address 10.0.0.0
local ip address 0.0.0.0
pre-share-masked AAAAGAAAAAIAAAACmQGsvejwZkiSLTFOWvjianwzRyr41KgE
!
c Enter the encrypted key in the local transport profile.
host1(config-ipsec-transport-profile-local)#pre-share-masked AAAAGAAAAAIAAAACmQGsvejwZkiSLTFOWvjianwzRyr41KgE
If you must reenter the key (for example, on a system reload using the show config output command to configure the router), you can use the masked-key. If you know the unencrypted key, you can enter it using the pre-share command.
CHAPTER 14Configuring L2TP with IPSec
14-10
application� Use to specify the type of application that is secured by connections created
with this IPSec transport profile. To specify the application, use one of the following keywords: � l2tp � secures L2TP traffic � l2tp-nat-passthrough � secures L2TP traffic and also allows clients to
connect from behind NAT devices that support IPSec passthrough. To allow these clients to connect, the router: � Does not generate or verify UDP checksums. This does not compromise
security, because IPSec protects UDP packets with an authentication algorithm far stronger than UDP checksums.
� Provides IPSec filtering based on the received IP address (the NAT public IP address), rather than filtering based on the negotiated IKE identities.
� ExampleBoston(config-ipsec-transport-profile)#application l2tp-nat-passthrough
� Use the no version to return to the default application, L2TP.
ipsec transport profile� Use to create a transport profile for IPSec and access the IPSec transport
profile configuration prompt. To create a new profile, you must include the following keywords: � virtual-router � name of the virtual router on which you want to create the
profile� ip address � remote endpoint for the IPSec transport connection. You can
enter a fixed IP address or the wildcard address, 0.0.0.0. If you use the wildcard address, the profile accepts any remote client connection, which is a typical scenario for secure remote access.
� ExampleBoston(config)#ipsec transport profile secureL2tp virtual-router default ip address 0.0.0.0
Boston(config-ipsec-transport-profile)#
� Use the no version to delete the profile.
lifetime� Use to set a lifetime range for the IPSec connection in volume of traffic and/or
in seconds. � If the PC client offers a lifetime within this range, the router accepts the offer. If
the PC client offers a lifetime outside of this range, the router rejects the connection.
� ExampleBoston(config-ipsec-transport-profile)#lifetime seconds 900 86400 kilobytes 100000 4294967295
� Use the no version to restore the default values, 100000�4294967295 KB and 900�86400 seconds (1�24 hours).
Configuration Tasks for E-Series RoutersE-Series Routers
14-11
local ip address� Use to specify the local endpoint (for L2TP, the LNS address) of the IPSec
transport connection and to enter Local IPSec Transport Profile Configuration mode.
� You can enter this command multiple times in an IPSec transport profile. � You can enter a fixed IP address or the wildcard address, 0.0.0.0. The wildcard
address has a lower precedence than a fixed IP address.Caution: We do not recommend that you use address 0.0.0.0 because it allows any address to accept IKE calls, and it creates a group preshared key, which is not fully secure.
� ExampleBoston(config-ipsec-transport-profile)#local ip address 192.168.1.2
host1(config-ipsec-transport-profile-local)#
� Use the no version to delete the IP address.
pfs group� Use to configure perfect forward secrecy for connections created with this
IPSec transport profile. � Assign a Diffie-Hellman prime modulus group using one of the following
keywords:� 1 � 768-bit group� 2 � 1024-bit group� 5 � 1536-bit group
� Example host1(config-ipsec-transport-profile)#pfs group 5
� Use the no version to remove PFS from this profile, which is the default setting.
pre-share� Use to configure an unencrypted (red) preshared key to authenticate IKE
negotiations that arrive from any remote IP address specified for this transport profile and that are destined for the local IP address. If the remote endpoint address is a wildcard address, this preshared key is a group preshared key. Caution: Group preshared keys are not fully secure, and we do not recommend using them. They are provided for trials and testing purposes where the missed security does not pose a risk to the provider.
� After you enter the preshared key, use the show config command to see the encrypted form of the key. You then enter the encrypted key with the pre-share-masked command.
� To have preshared key authentication take place, you must also specify the IKE policy rule as preshared by entering authentication pre-share in ISAKMP Policy Configuration mode.
CHAPTER 14Configuring L2TP with IPSec
14-12
� Examplehost1(config-ipsec-transport-profile-local)#pre-share secretforL2tp
� Use the no version to remove the key.
pre-share-masked� Use to specify an encrypted preshared key. To obtain this key, you enter an
unencrypted key using the pre-share command. You then run the show config command, and the router displays the preshared key in encrypted form. You enter the encrypted key using this command.
� The router uses the preshared key to authenticate IKE negotiations that arrive from any remote IP address specified for this transport profile and that are destined for any local IP address specified for this transport profile. If the remote endpoint address is a wildcard address, this preshared key is a group preshared key. Caution: Group preshared keys are not fully secure, and we do not recommend using them. They are provided for trials and testing purposes, where the missed security does not pose a risk to the provider.
� To have preshared key authentication take place, you must also specify the IKE policy rule as preshared by entering authentication pre-share in ISAKMP Policy Configuration mode.
� Examplehost1(config-ipsec-transport-profile-local)#pre-share-masked AAAAGAAAAAcAAAACZquq4ABieTUBuNBELSY8b/L3CX/RcPX7
� There is no no version. To remove a key, use the no pre-share command.
transform-set� Use to specify the transform set(s) that an IPSec transport connection can use
to negotiate a transform algorithm. Each transform in the set provides a different combination of data authentication and confidentiality.
� ExampleBoston(config-ipsec-transport-profile)#transform-set esp-3des-hmac-sha
� Use the no version to reset the transform to the default, esp-edes-hmac-sha.
Monitoring L2TP over IPSecE-Series Routers
14-13
Monitoring L2TP over IPSecThis section contains information on troubleshooting and monitoring L2TP over IPSec.
System Event LogsTo troubleshoot and monitor L2TP over IPSec, use the following system event log:
> itm – IPSec transport mode
For more information on using event logs, see E-Series System Basics Configuration Guide, Chapter 12, Logging System Events.
show CommandsTo display information on L2TP over IPSec profiles and connections, use the following show commands.
show ipsec transport interface� Use to display information on transport connections. � Field descriptions
� Connection � number of the IPSec transport connection� Operational Status � status of the connection: up, down� Transport virtual-router � name of the transport virtual router for which
configuration and statistics are displayed� Virtual router � virtual router on which this profile is configured� Local ip address � local endpoint address� Peer ip address � remote endpoint address� Local identity � shows the subnet, protocol, and port � Remote identity � shows the subnet, protocol, and port � Transported-application � type of application the connection is protecting� Inbound SA � algorithm and SPI � Outbound SA � algorithm and SPI � Pfs group � PFS group being used for the connection� Lifetime � configured lifetime in seconds and kilobytes
� Statistics� InUserPackets � number of user packets received � InUserOctets � number of octets received from user packets� InAccPackets � number of encapsulated packets received� InAccOctets � number of octets received in encapsulated packets� InAuthErrors � number of authentication errors received� InReplyErrors � number of reply errors in received traffic
CHAPTER 14Configuring L2TP with IPSec
14-14
� InPolicyErrors � number of policy errors in received traffic� InOtherRxErrors � number of packets received that have errors other
than those listed above� InDecryptErrors � number of decryption errors in received traffic� InPadErrors � number of packets received that had invalid values after
the packet was decrypted� OutUserPackets � number of user packets sent � OutUserOctets � number of octets sent in user packets� OutAccPackets � number of encapsulated packets sent� OutAccOctets � number of octets sent in encapsulated packets� OutPolicyErrors � number of packets arriving at the transport connection
for encapsulation that do not meet the specified identifier (selector)� OutOtherTxErrors � number of outbound packets that have errors other
than those listed above� Example
boston#show ipsec transport interface
Connection 1 Up
Connection 2 Up
There are 2 connections found.
� Exampleboston#show ipsec transport interface 1
Connection 1
Operational Status Up
Configuration Attributes
Transport virtual-router default
Local ip address 1.2.3.4
Peer ip address 5.6.7.8
Local identity is subnet 1.2.3.4 255.255.255.255, proto 17, port 1701
Remote identity is subnet 5.6.7.8 255.255.255.255, proto 17, port 1701
Transported-application l2tp
Inbound SA esp-3des-hmac-md5 Spi 0x1abcd0101
Outbound SA esp-3des-hmac-md5 Spi 0x1abcd0101
Pfs group 5
Lifetime seconds 3600 kilobytes 102400
� Exampleboston#show ipsec transport interface detail 1
Connection 1
Operational Status Up
Configuration Attributes
Transport virtual-router default
Local ip address 1.2.3.4
Peer ip address 5.6.7.8
Local identity is subnet 1.2.3.4 255.255.255.255, proto 17, port 1701
Remote identity is subnet 5.6.7.8 255.255.255.255, proto 17, port 1701
Transported-application l2tp
Monitoring L2TP over IPSecE-Series Routers
14-15
Inbound SA esp-3des-hmac-md5 Spi 0x1abcd0101
Outbound SA esp-3des-hmac-md5 Spi 0x1abcd0101
Pfs group 5
Lifetime seconds 3600 kilobytes 102400
Statistics
InUserPackets 0
InUserOctets 0
InAccPackets 0
InAccOctets 0
InAuthErrors 0
InReplyErrors 0
InPolicyErrors 0
InOtherRxErrors 0
InDecryptErrors 0
InPadErrors 0
OutUserPackets 0
OutUserOctets 0
OutAccPackets 0
OutAccOctets 0
OutPolicyErrors 0
OutOtherRxErrors 0
InDecryptErrors 0
InPadErrors 0
show ipsec transport interface summary� Use to display a summary of existing IPSec transport connections by
application and state. � Field descriptions
� ipsec transport interfaces � interfaces by type of application� total � total number of IPSec transport interfaces for each application� up � number of IPSec transport interfaces that are currently up� down � number of IPSec transport interfaces that are currently down
� Exampleboston#show ipsec transport interface summary
ipsec transport interfaces total up down
l2tp 1234 1001 233
l2tp-nat-passthrough 7044 43 7001
------------------------------------------------------
total 8278 1044 7234
show ipsec transport profile� Use to display the configuration of an IPSec transport profile. � Field descriptions
� IPSec transport profile � name of the profile
CHAPTER 14Configuring L2TP with IPSec
14-16
� Virtual router � virtual router on which this profile is configured� Peer address � remote endpoint address� Application � type of application that this profile is protecting� Lifetime range in seconds � lifetime range in seconds configured for the
profile� Lifetime range in kilobytes � lifetime range in kilobytes configured for the
profile� TransformSet � transform set(s) configured for the profile� Pfs group � PFS group configured for the profile; 0 (zero) means that PFS
is not configured for the profile � Local ip address � local endpoint address
� Examplehost1#show ipsec transport profile
IPSEC transport profile secureL2tp
1 Ipsec transport profile found
� Examplehost1#show ipsec transport profile secureL2tp
IPSEC transport profile secureL2tp
Virtual router default
Peer address 0.0.0.0
Application l2tp
Lifetime range in seconds 3600 86400
Lifetime range in kilobytes 102400 4294967295
TransformSet transport-esp-3des-md5
Pfs group 0
Local ip address : 0.0.0.0
Index
AABRs (area border routers), OSPF
configuring area range 9-12defined 9-2
access-list command 1-17, 1-23, 4-11IS-IS 10-21OSPF 9-27
access lists, BGP 1-16 to 1-24access lists, IP
monitoring 1-44, 2-57redirecting traffic with null interface
instead 1-26redistributing access routes 1-7redistributing static routes 1-18specifying multicast groups 5-22
address commands, OSPFaddress area 9-14address authentication key 9-23address authentication message-digest 9-23address authentication-none 9-24address cost 9-14address dead-interval 9-14address hello-interval 9-14address message-digest-key 9-24address network 9-34address passive-interface 9-15address priority 9-15address retransmit-interval 9-15address transmit-delay 9-15
address commands, RIPaddress 8-9address authentication key 8-9address authentication mode 8-10address receive version 8-10address send version 8-10
address ranges, IS-IS 10-27Address Resolution Protocol. See ARPadjacencies, clearing IS-IS 10-38adjacency, OPSF 9-2adjacency levels, IS-IS 10-15
displaying information on 10-49logging changes between 10-29
administrative distanceIP, setting 2-23
IS-IS 10-26OSPF 9-30RIP 8-12
advertising DVMRP routes 5-60, 5-66aggregate addresses
IS-IS 10-27OSPF routing 9-12
application layer, TCP/IP 2-4area-authentication-key command 10-20area border routers, OSPF. See ABRsarea commands
area 9-20area default-cost 9-20area nssa 9-20area range 9-12area stub 9-20
area IDs (OSPF packets) 9-2area-message-digest-key command 10-6, 10-20areas, IS-IS 10-2areas, OSPF 9-2
configuring 9-19 to 9-22defining 9-5, 9-9stub areas 9-3, 9-20
area virtual-link commandsarea virtual-link 9-21area virtual-link authentication-key 9-24area virtual-link authentication
message-digest 9-24area virtual-link authentication-none 9-25area virtual-link dead-interval 9-21area virtual-link hello-interval 9-21area virtual-link message-digest-key md5 9-25area virtual-link retransmit-interval 9-22area virtual-link transmit-delay 9-22
ARP (Address Resolution Protocol)hosts 2-14monitoring 2-57physical and logical addresses 2-6
arp commandsarp 2-17arp timeout 2-17
AS (autonomous system) 9-3ASBR (autonomous system boundary router)
default route and 9-30
Index2
OSPF 9-3AS-path, BGP
access lists, modifying 1-12filtering 1-19 to 1-21
AS-path attribute 1-19assert messages 5-37assigning multicast groups 5-21audience for documentation xxauthentication
IS-IS, halting 10-8IS-IS HMAC MD5 10-5, 10-16, 10-20IS-IS key commands 10-6IS-IS MD5 packet timing 10-7IS-IS MD5 start and stop timing 10-7managing and replacing IS-IS keys 10-8OSPF 9-3, 9-6, 9-25OSPF, configuring 9-22 to 9-26RIP 8-3type 9-3
authentication commandsauthentication key 8-19authentication message-digest 9-38authentication mode 8-19
authentication-key command 9-38authentication-none command 9-38autocost, OSPF routing 9-31automatic virtual link, OSPF 9-22automatic virtual-link command 9-22autonomous system boundary router. See ASBRauto-RP router
PIM S-DM 5-45PIM SM 5-44
Bbackbone area, OSPF 9-19backup router 11-7
defined 11-2election process and 11-7VRRP 11-1
bandwidth, OSPF interface cost by 9-31baseline commands
baseline clns 10-47baseline ip 2-55baseline ip dvmrp 5-69baseline ip igmp 5-25baseline ip igmp-proxy interface 5-32baseline ip ospf 9-28baseline ip rip 8-23baseline ip tcp 2-55baseline ip udp 2-56
baseline ipv6 3-20baseline ipv6 interface 3-21baseline ip vrrp 11-12
BGP (Border Gateway Protocol), OSPF routing with 9-7
BGP/MPLS VPNs, interaction with OSPF 9-37BGP/MPLS VPNs, multicast services over
configuring 5-47overview 5-39
BGP multicasting 5-74BGP protocol
clearing IP routing table 1-43communities 1-8, 1-13, 1-35community lists 2-60reinstalling routes in IP routing table 1-43well-known communities 1-32
border routers, OSPF 9-45B-RAS applications, creating an IP profile 2-11B-RAS applications, creating an IPv6 profile 3-11broadcast addressing 2-19 to 2-20broadcast storms 2-20
CCDs
E-series routers documentation CD xxiJUNOSe software CD xxiii
certificate revocation list. See CRLchecksum computation 6-4CIDR (Classless Interdomain Routing) 2-8, 9-3Class D IPv4 addresses 5-15classes of IP addresses 2-6Classless Interdomain Routing. See CIDRclear arp command 2-17clear ip commands
clear ip dvmrp route 5-68clear ip interface 2-28clear ip isis redistribution 10-22clear ip mroute 5-4clear ip ospf redistribution 9-29clear ip pim auto-rp 5-50clear ip pim interface count 5-50clear ip pim remote-neighbor count 5-50clear ip prefix-list 1-27, 1-28clear ip prefix-tree 1-30clear ip routes 1-43, 2-28
clear ipv6 interface command 3-14clear isis commands
clear isis adjacency 10-38clear isis database 10-48
E-Series Routers3
CLNP (Connectionless-mode Network Protocol) 10-2
CLNS (Connectionless Network Service Protocol)defined 10-2displaying 10-47 to 10-48
clns commandsclns configuration-time 10-33clns holding-time 10-33clns host 10-5, 10-33See also show clns commands 10-33
communities, BGP 1-8, 1-13, 1-31, 1-35community lists, BGP 1-32, 2-60complete sequence number PDU. See CSNPconfiguring 5-6
DVMRP 5-62IGMP 5-18IGMP proxy 5-30IP tunnels 6-3PIM 5-44routing policy 1-1VRRP 11-8 to 11-12
Connectionless-mode Network Protocol. See CLNP
Connectionless Network Service Protocol. See CLNS
connectionless protocols 2-2, 3-2connection-oriented protocols 2-2conventions defined
icons xxsyntax xxtext xx
cost, IS-IS interface 10-17cost, OSPF routing 9-16
autocost 9-31default cost 9-20equal-cost multipath 9-7
cost command 9-39creating an IP profile
access-routes 2-12address 2-12directed-broadcast 2-12mtu (maximum transmission unit) 2-12redirects 2-12unnumbered 2-12virtual-router 2-12
creating an IPv6 profileaddress 3-11ipv6-virtual-router 3-11mtu (maximum transmission unit) 3-11unnumbered 3-11
creating OSPF interfaces 9-8CRL (certificate revocation list) 13-2CRL (certificate revocation lists)
checking 13-6file extension 13-7viewing on E-series router 13-12
cryptographic authentication, OSPF 9-6CSNP (complete sequence number PDU) 10-2CSNP interval, IS-IS interface 10-15customer support xxiv
Ddatabase, OSPF 9-45datagrams, IP 2-2
fragmenting and reassembling 2-3, 2-20dead interval, OSPF 9-17, 9-21dead-interval command 9-39debounce-time command 8-10debug commands 8-22, 9-42
debug ip ospf 9-43debug ip pim 5-51debug ip rip 8-22debug isis 10-38
debug-related information, IS-IS 10-38, 10-46default-information originate command 1-24
IS-IS 10-26OSPF 9-30RIP 8-11
default-metric command 8-11default routes
cost, OSPF 9-20IP routing 2-26IS-IS routing 10-26OSPF routing 9-30suppressing IS-IS 10-27
deletingDVMRP routes 5-68IP multicast routes 5-4IS-IS redistribution information 10-22OSPF interfaces 9-8OSPF redistribution information 9-29
dense mode multicasting protocols 5-5description, adding to IP interfaces 2-30, 3-16designated routers. See DRsdestination, tunnel 6-2destination address (DA), VRRP 11-4digital certificates
authenticating the peer 13-5base64 13-2checking CRLs 13-6
Index4
configuring 13-7file extensions 13-7generating private/public key pairs 13-4monitoring 13-12obtaining a public key certificate 13-5obtaining a root CA certificate 13-5overview 13-1signature authentication 13-3viewing on E-series routers 13-12X.509v3 13-3
directed broadcast packets 2-19directly connected networks 8-1disable command 5-67, 8-11disable-dynamic-redistribute command
DVMRP 5-66IS-IS 10-22OSPF 9-30RIP 8-11
disable-incremental-external-spf command 9-41disabling
DVMRP 5-67IGMP 5-25
disabling dynamic route redistributionDVMRP 5-66ISIS 10-22OSPF 9-30RIP 8-11
distance, RIP administrative 8-12distance commands 8-12
distance 2-24distance ip 2-24, 10-26distance ospf 9-30
Distance Vector Multicast Routing Protocol. See DVMRP
distribute-domain-wide command 10-24distribute-list command 8-12, 8-20documentation set, E-series xxii
CD xxicomments on xxiii
domain, OSPF 9-3domain-authentication-key command 10-20domain-message-digest-key command 10-6, 10-21domain-wide prefix distribution 10-24downstream interface 5-30dropped packets, troubleshooting 2-65DRs (designated routers)
IS-IS routing 10-17OSPF routing 9-3PIM routing 5-34
DVMRP 5-59 to 5-74advertising routes 5-60, 5-66configuring
limits 5-62summary addresses 5-63
default router, configuring 5-61deleting routes 5-68disabling 5-67enabling
on an interface 5-61on a virtual router 5-61
exchanging unicast routes 5-66filtering reports 5-62metric 5-64monitoring 5-69 to 5-74neighbors 5-59pruning 5-59reassembly of tunnel packets 7-2removing 5-67summary addresses 5-63tunnels 5-68, 6-2using with IGMP 5-62using with PIM 5-43, 5-62
dynamic hostname resolution, IS-IS 10-5, 10-33dynamic route redistribution, disabling
in DVMRP 5-66in IS-IS 10-22in OSPF 9-30in RIP 8-11
EECMP (equal-cost multipath)
IP 2-32IS-IS 10-9, 10-34OSPF 9-7, 9-31RIP 8-6, 8-14
enablingdirected broadcasts 2-20DVMRP 5-61ICMP Router Discovery Protocol 2-39IGMP 5-18, 5-19IGMP proxy 5-31IP multicasting 5-4IP redirects 2-39IS-IS 10-12 to 10-14MD5 authentication 9-26OSPF 9-9 to 9-13PIM 5-42, 5-43PIM SSM 5-49unreachable messages (ICMP) 2-39
E-Series Routers5
endpoints, tunnel 6-2end system. See ES (end system)entry, routing table 2-22equal-cost multipath. See ECMPERX-14xx models xixERX-7xx models xixES (end system)
hello packet rate 10-33neighbor information 10-53
E-series documentation set xxiicomments on xxiii
E-series models xixE-series router
IP features of 2-5IPv6 features of 3-2IS-IS features 10-11routing policy 1-1 to 1-54
E-series routers documentation setCD xxi
Ethernet controllers 2-6exchanging DVMRP unicast routes 5-66exit-remote-neighbor command 8-20extended communities, BGP 1-35external routes, OSPF 9-5
Ffabric congestion 2-65Fast Ethernet (FE) modules 11-2filtering
AS paths 1-19DVMRP reports 5-62network prefixes 1-16undesirable traffic 1-26
filter lists, BGP 1-19 to 1-21flooded broadcast packets 2-19flooding 9-3forwarding table 2-22fragmenting IP datagrams 2-3, 2-20full spf, IS-IS 10-32full-spf-always command 10-32
Ggateways 2-3Gigabit Ethernet (GE) modules 11-2global IP routing table 2-22GRE, reassembly of tunnel packets 7-2GRE tunnels 6-2group (multicast) addressing 2-7
group membershipqueries 5-15reports 5-16
Hhashcheck process 9-23hash functions 9-22hello interval 5-41
IS-IS interface 10-16, 10-33OSPF interface 9-17, 9-21PIM 5-43, 5-47, 5-53, 5-55
hello-interval command 9-39hello multiplier, IS-IS interface 10-16hello packet validity rate, IS-IS 10-33Hello protocol 9-3HMAC MD5
authentication, IS-IS 10-5IS-IS area-wide password 10-20IS-IS domain-wide password 10-21IS-IS password on the interface 10-16
hold timeIS-IS 10-16IS-IS SPF 10-31PIM SM 5-41SPF 9-33
hop count 5-64, 8-2host access routes on PPP interface 2-26hosts 2-3
IICMP (Internet Control Message
Protocol) 2-38 to 2-39echo request packets
IP 2-40IPv6 3-14
icmp update-source command 2-39icons defined, notice xxidentifying
DVMRP neighbors 5-59IP multicast groups 5-16
IGMP 5-39IGMP (Internet Group Management
Protocol) 5-15 to 5-34configuring 5-19disabling 5-25enabling 5-18, 5-19limiting groups on interfaces 5-22monitoring 5-14, 5-25 to 5-29performing host functions 5-30
Index6
querier 5-19removing 5-25specifying version 5-19
igmp commandsigmp disable 5-25igmp promiscuous 5-24
IGMP proxy 5-29configuring 5-30enabling 5-31monitoring 5-32 to 5-34version 5-29
IGMP reports, accepting 5-24ignore-lsp-errors command 10-29IGP (interior gateway protocol) 5-59, 9-3IKE (Internet Key Exchange)
aggressive mode characteristics 12-16aggressive mode negotiations 12-17initiator proposals and policy rules 12-17main mode characteristics 12-16overview 12-15SA negotiation 12-20using digital certificates 13-3
IKE policies 12-17authentication mode 12-19Diffie-Hellman group 12-19encryption algorithms
3DES 12-18DES 12-18
hash functionMD5 12-18SHA-1 12-18
lifetime 12-19priority 12-18
importing routes. See redistributing routesincremental SPF 9-40installing the system software xixinstance, route map 1-3Integrated IS-IS routing 10-9interarea routes, OSPF 9-5interface commands
interface ip 2-35interface tunnel 6-4, 12-25
interface-event-disable command 8-12interfaces
IPv6, enabling and disabling 3-14NAT, marking 4-8
interior gateway protocol. See IGPintermediate system. See IS (intermediate system)Intermediate System-to-Intermediate System. See
IS-IS
Internet addresses 2-6internet community, BGP 1-32Internet Control Message Protocol. See ICMPInternet Group Management Protocol. See IGMPInternet Key Exchange. See IKEInternet Layer, TCP/IP 2-4interval rate, LSP (IS-IS) 10-30intra-area routes, OSPF 9-5investigating IP multicast routes 5-74IP 2-1 to 2-81
ARP protocol 2-6, 2-14, 2-57assigning router IDs 2-25broadcast addressing 2-19 to 2-20ECMP 2-32E-series router features 2-5functions of 2-2ICMP and 2-38 to 2-39layers of 2-3 to 2-4managing the routing table 1-43monitoring 2-56 to 2-81profile 2-11 to 2-14reachability commands 2-40routing 2-21 to 2-33source address verification 2-27
ip access-route table-map command 1-26IP addresses 2-6 to 2-9
class D 5-15classes of 2-6for multicasting 5-15interfaces without (unnumbered) 2-26IP address owner, VRRP 11-2matching route’s destination 1-9multinetting 2-10OSPF routing costs and 9-16prefix lists 1-27prefix trees 1-30primary
adding 2-10deleting 2-10
primary IP address, VRRP 11-2router IDs and 2-25secondary
adding 2-10deleting 2-10
VRRP 11-7, 11-8ip commands
ip access-routes 2-12, 2-26ip address 2-10, 2-12ip alwaysup 2-30ip as-path access-list 1-19
E-Series Routers7
ip bgp-community new-format 1-34ip broadcast-address 2-20ip community-list 1-34ip debounce-time 2-30ip description 2-30ip directed-address 2-20ip directed-broadcast 2-12ip disable-forwarding 2-29ip extcommunity-list 1-36ip icmp update-source 2-40ip ignore-df-bit 2-21ip irdp 2-39ip mask-reply 2-39ip mtu 2-13, 2-21ip multicast-routing 5-4ip multicast-routing disable-rpf-check 5-8ip multipath round-robin 2-32ip prefix-list 1-17, 1-27ip prefix-tree 1-17, 1-30, 8-12ip proxy-arp 2-18ip redirects 2-13, 2-39ip refresh-route 1-43, 2-28ip route 1-27, 2-25ip router-id 2-25ip router isis 10-12ip route-type 5-8, 8-18, 9-37, 10-37ip rpf-route 5-6ip sa-validate 2-27ip share-interface 2-36ip share-nexthop 2-36ip shutdown 2-27ip source-route 2-29ip speed 2-31ip split-horizon 8-13ip tunnel reassembly 7-2ip unnumbered 2-13ip unnumbered loopback 2-26ip unreachables 2-39ip vrrp 11-10ip vrrp advertise-interval 11-10ip vrrp authentication-key 11-11ip vrrp authentication-type 11-11ip vrrp enable 11-9, 11-11ip vrrp preempt 11-11ip vrrp priority 11-9, 11-11ip vrrp virtual-address 11-8, 11-12no ip interface 2-27See also show ip commands 2-12
ip dvmrp commandsip dvmrp 5-61, 5-68
ip dvmrp accept-filter 5-63ip dvmrp announce-list 5-66ip dvmrp auto-summary 5-64ip dvmrp disable 5-67ip dvmrp metric-offset 5-64ip dvmrp routehog-notification 5-62ip dvmrp route-limit 5-62ip dvmrp summary-address 5-64ip dvmrp unicast-routing 5-67See also show ip dvmrp commands 5-61, 5-68
IP fragmentation, reassembling for tunnel packets 7-1
ip igmp commandsip igmp 5-19ip igmp access-group 5-22ip igmp group limit 5-22ip igmp immediate-leave 5-20ip igmp last-member query-interval 5-20ip igmp promiscuous 5-24ip igmp-proxy 5-31ip igmp-proxy unsolicited-report-interval 5-31ip igmp-proxy V1-router-present-time 5-31ip igmp querier 5-19ip igmp querier-timeout 5-20ip igmp query-interval 5-21ip igmp query-max-response-time 5-21ip igmp robustness 5-21ip igmp static-exclude 5-23ip igmp static-group 5-21ip igmp static-include 5-23ip igmp version 5-19See also show ip igmp commands 5-19
IP in IP tunnels 6-2IP interface, creating 2-35IP interfaces
adding a description 2-30, 3-16clearing 2-28moving 2-37primary 2-33removing IP configuration 2-27setting a baseline 2-28shared 2-33sharing 2-33shutting down 2-27unnumbered 2-26
IP multicast groupsassigning to an interface 5-21identifying 5-16leaving 5-16maintaining membership of 5-16
Index8
reporting 5-15specifying 5-22
IP multicastingbenefits of 5-2deleting routes 5-4dense mode protocols 5-5enabling 5-4M-BONE 5-59monitoring 5-8sparse mode protocols 5-5
IP multicast interfaces, monitoring 5-14IP multicast routes 5-74ip nat commands
address 4-12ip nat 4-8ip nat inside source list 4-13ip nat inside source static 4-9ip nat outside source list 4-14ip nat outside source static 4-10ip nat pool 4-12ip nat translation 4-15ip nat translation max-entries 4-8
ip ospf commandsip ospf authentication-key 9-25ip ospf authentication message-digest 9-25ip ospf authentication-none 9-26ip ospf cost 9-16ip ospf dead-interval 9-17ip ospf hello-interval 9-17ip ospf message-digest-key 9-26ip ospf network 9-35ip ospf priority 9-17ip ospf retransmit-interval 9-17ip ospf shutdown 9-30ip ospf transmit-delay 9-18
ip pim commandsip pim 5-43ip pim query-interval 5-43ip pim rp-address 5-45ip pim send-rp-announce 5-45ip pim send-rp-discovery scope 5-46ip pim spt-threshold 5-46See also show ip pim commands 5-43
IP profile, B-RAS 2-11IP reassembly of tunnel packets 7-1
configuring 7-2monitoring 7-3
ip rip commandsip rip 8-12ip rip authentication key 8-13
ip rip authentication mode 8-13ip rip receive version 8-13ip rip send version 8-13See also show ip rip commands
IPSecAH 12-4AH processing 12-15concepts 12-4configuration
examples 12-31tasks 12-20
configuringIPSec parameters 12-21ISAKMP/IKE policy 12-28tunnels 12-24
digital certificates 13-1encapsulation modes 12-13encapsulation protocols 12-13ESP 12-4ESP processing 12-15L2TP with IPSec 14-1license 12-20monitoring 12-42overview 12-1packet encapsulation 12-6protocol stack 12-5reassembly of tunnel packets 7-2remote access 14-1secure IP interfaces 12-4security parameters 12-6security parameters per policy type 12-8tunnel destination endpoint 12-9tunnel source endpoint 12-9See also L2TP with IPSec 14-1
ipsec certificate commandsipsec certificate-database refresh 13-10ipsec certificate-request generate 13-10
ipsec commandsipsec clear 12-31ipsec identity 13-10ipsec isakmp-policy-rule 12-30, 13-10ipsec key generate 13-11ipsec key manual 12-22ipsec key zeroize 13-11ipsec lifetime 12-22ipsec local-endpoint 12-22ipsec transform-set 12-23key 12-23masked-key 12-23
E-Series Routers9
IPSec identity commandscommon-name 13-9country 13-9domain-name 13-9ipsec identity 13-10organization 13-11
IPSec security parametersinbound SAs 12-6, 12-11in relation to IPSec interface 12-7lifetime 12-6lifetime for user SAs 12-10manual versus signalled 12-6, 12-8negotiating transforms 12-14operational VR 12-6, 12-8outbound SAs 12-6, 12-11perfect forward secrecy (PFS) 12-6, 12-10per IPSec policy type 12-8transform combinations supported 12-14transform sets 12-6, 12-12transforms supported 12-13transport VR 12-6, 12-9
IPSec transport local profile commandspre-share 14-11pre-share-masked 14-12
IPSec transport profile commandsapplication 14-10ipsec transport profile 14-10lifetime 14-10local ip address 14-11pfs group 14-11transform-set 14-12
IP security policies 12-14IP tunnels 6-1 to 6-12
configuring 6-3monitoring 5-14, 6-8
IPv6address, defining 3-12addressing
compression and 3-6prefix 3-6scope 3-7structure 3-8types of 3-6understanding 3-5
configuring neighbor discovery 3-17enabling and disabling 3-14E-series router features 3-2headers
extensions 3-5standard 3-4
ICMP and 3-8instance, creating an 3-16interface, unnumbered 3-12interfaces
clearing 3-14managing 3-14
license 3-11monitoring 3-21 to 3-35neighbor discovery, defining 3-18neighbors, creating 3-17, 3-20overview 3-2packet headers 3-3ping and 3-8profile 3-11 to 3-13references 3-3static routes and 3-13traceroute and 3-8
ipv6 commandsipv6 3-16ipv6 address 3-12ipv6 description 3-16ipv6 enable 3-14ipv6 mtu 3-12ipv6 nd 3-18ipv6 nd dad attempts 3-19ipv6 nd ns-interval 3-18ipv6 nd reachable-time 3-18, 3-19ipv6 neighbor 3-17, 3-20ipv6 neighbor proxy 3-19ipv6 route 3-13ipv6 routes 3-17ipv6 unnumbered 3-12ipv6 virtual-router 3-12
ipv6 nd commandsipv6 nd 3-18ipv6 nd dad attempts 3-19ipv6 nd ns-interval 3-18ipv6 nd reachable-time 3-18
IPv6 profile, B-RAS 3-11IRDP (ICMP Router Discover Protocol) 2-39IS (intermediate system) 10-2
hello packet rate 10-33neighbor information 10-53
ISAKMP policy commandsaggressive-mode 12-29authentication 12-29, 13-9encryption 12-29group 12-30hash 12-30lifetime 12-30
Index10
IS-IS (Intermediate System-to-Intermediate System) 10-1 to 10-56
adjacencies, clearing 10-38configuring 10-11 to 10-35
default routes 10-26for MPLS 10-35global parameters 10-20 to 10-35interface-specific
parameters 10-14 to 10-19redistribution 10-21
displaying CLNS 10-47 to 10-48dynamic hostname resolution 10-33ECMP 10-9enabling 10-12 to 10-14hello packet validity rate 10-33HMAC MD5 authentication
for level 1 packets 10-21for level 2 packets 10-20on the interface 10-16
Integrated IS-IS 10-9level 1 routing 10-4level 2 routing 10-5LSPs. See LSPs (link state packets), IS-ISmonitoring 10-37 to 10-46MPLS and 10-35redistributing routes between levels 10-23route leaking 10-23router type 10-27routes
summarizing 10-27using for multicast RPF checks 10-36
routing levels/layers 10-2, 10-3, 10-4, 10-17, 10-27
starting and stopping MD5 packets 10-7suboptimal paths, correcting 10-23summarizing routes 10-27suppressing default routes 10-27system identifier 10-3topology elements 10-4traffic engineering 10-35troubleshooting 10-38
isis commandsisis authentication-key 10-15isis circuit-type 10-15isis csnp-interval 10-15isis hello-interval 10-16isis hello-multiplier 10-16isis lsp-interval 10-16isis mesh-group 10-34isis message-digest-key 10-6, 10-16
isis metric 10-17isis priority 10-17isis retransmit-interval 10-18isis retransmit-throttle-interval 10-18See also show isis commands 10-6
IS-IS protocol, OSPF routing with 9-7ISO 10589. See IS-ISISO address 10-3is-type command 10-27
Jjoin messages 5-39
LL2F, reassembly of tunnel packets 7-2L2TP, reassembly of tunnel packets 7-2l2tp ignore-receive-data-sequencing command 7-3L2TP with IPSec 14-1
client software supported 14-5compatibility 14-4configuring
client PC 14-7E-series router 14-7IPSec transport profiles 14-8L2TP destination profiles 14-7
control and data frames 14-4group preshared key 14-6how it works 14-2LNS change
of address 14-6of port 14-6
overview 14-1references 14-2requirements 14-4setting up secure connection 14-3tunnel creation 14-5with NAT 14-5with PPP 14-5
leakage, OSPF route 9-6leave group membership messages 5-16leaving an IP multicast group 5-16level 1 routing, IS-IS 10-2, 10-4level 2 routing, IS-IS 10-3, 10-5levels of IS-IS routing 10-2, 10-3, 10-4, 10-17,
10-27license ipsec-tunnels command 12-21license ipv6 command 3-11lifetime, IPSec 12-10, 12-19limited broadcast packets 2-19
E-Series Routers11
limiting IGMP groups on interfaces 5-22limiting translation entries 4-8line modules, forwarding table on 2-22link state advertisements. See LSAslink state metrics, IS-IS 10-17link state packets. See LSPslocal-as community, BGP 1-32local routing table 2-21log-adjacency-changes command 10-29logical addresses 2-6loopback interfaces 6-3LSAs (link state advertisements) 9-3
opaque LSAs 9-6retransmit interval and transmit delay 9-17,
9-22LSDB (link state database) 9-5lsp-gen-interval command 10-30lsp-mtu command 10-30lsp-refresh-interval command 10-31LSPs (link state packets), IS-IS
ignoring errors 10-29interval rate 10-30MTU 10-30overload bit 10-28refresh interval 10-31retransmission interval 10-18retransmission throttle interval 10-18transmission interval 10-16
MMAC addresses
and ARP 2-14defined 2-6
manual IPSec interfaces 12-8manuals, E-series xxii
comments on xxiiion CD xxi
map tag, route map 1-3master router 11-1 to 11-11match commands 1-8 to 1-11
and route maps 1-2match as-path 1-8match community 1-8match distance 1-8match extcommunity 1-8, 1-36match ip address 1-9, 1-27, 1-30, 1-31match ip next-hop 1-9, 1-10, 1-27, 1-29, 1-30,
1-31match level 1-10match metric 1-10
match metric-type 1-10match route-type 1-10match-set summary prefix-tree 1-31, 8-14match tag 1-11match-set summary prefix-tree 1-30
maximum-paths commandIP 2-32IS-IS 10-34OSPF 9-31RIP 8-14
maximum transmission unit. See MTUmax-lsp-lifetime command 10-31M-BONE (multicast backbone of the
Internet) 5-59MD5 authentication
IS-IS 10-5OSPF 9-22, 9-25, 9-26
mesh group, setting (IS-IS) 10-34message-digest-key md5 command 9-39message digests 9-22metric, DVMRP 5-64metric, setting 2-25metrics, OSPF default 9-33metric-style commands
metric-style narrow 10-25metric-style transition 10-25metric-style wide 10-25
MIB, OSPF 9-7MIBs xxiiimodels
ERX-14xx xixERX-7xx xixE-series xix
monitoringARP 2-57DVMRP 5-69 to 5-74IGMP 5-14, 5-25 to 5-29IGMP proxy 5-32 to 5-34IP 2-56 to 2-81IP multicast interfaces 5-14IP multicast settings 5-8IP tunnels 5-14, 6-8IPv6 3-21 to 3-35IS-IS 10-37 to 10-46mrinfo requests 5-14NAT 4-23OSPF 9-42 to 9-53PIM 5-14, 5-51 to 5-59routing policy 1-43 to 1-54RPF routes 5-6
Index12
mpls commandsmpls spf-use-any-best-path (IS-IS) 10-36mpls spf-use-any-best-path (OSPF) 9-36mpls traffic-eng (IS-IS) 10-36mpls traffic-eng area 9-36mpls traffic-eng router-id 9-36mpls traffic-eng router-id (IS-IS) 10-36
mrinfo requests, support for 5-14mtrace command 5-74MTU (maximum transmission unit)
IP 2-3, 2-21IP tunnels 6-4IPv6 3-12IS-IS 10-30OSPF 9-13
multicast, addressing 2-7multicast group port limit command 5-23multicasting, IP. See IP multicastingmulticast services over BGP/MPLS VPNs
configuring 5-47overview 5-39
multihomed hosts 2-3multinetting 2-9
N NAT (Network Address Translation)
configuration examples 4-15 to 4-22NAT (Network Address Translation)
access list rules, creating 4-10address pools, defining 4-11address translation
dynamic 4-6inside source 4-5outside source 4-6static 4-6
bidirectional 4-3configuration types 4-2configuring 4-1dynamic address translation, defining 4-10dynamic inside source translation,
creating 4-13dynamic outside source translation,
creating 4-14interfaces, specifying inside and outside 4-8monitoring 4-23order of operations 4-7overview 4-2references 4-7static address translation, defining 4-9terms 4-4
inside global address 4-5inside local address 4-5outside global address 4-5outside local address 4-5
timeouts, defining 4-14traditional 4-2
basic 4-3NAPT (Network Address Port
Translation) 4-3translation entries, limiting 4-8translation rules, defining 4-12translations, clearing 4-15twice 4-4
ND (neighbor discovery)configuring 3-17understanding 3-9
neighbor commandsneighbor 8-15, 9-35neighbor distribute-list 1-17, 1-25neighbor filter-list 1-19, 1-25neighbor prefix-list 1-17, 1-25neighbor prefix-tree 1-17, 1-25neighbor send-community 1-35
neighboring routers, OSPF 9-3, 9-51neighbors, DVMRP 5-59NET (network entity title) 10-3, 10-12, 10-13net command 10-13network area command 9-9network command 8-15network entity title. See NETnetwork interface layer (TCP/IP) 2-3Network Layer addresses 10-4network masks 2-7 to 2-8network prefixes, filtering 1-16network service access point. See NSAPnext-hop routers, setting/redistributing routes 1-9,
1-10, 1-14, 1-29no-advertise community, BGP 1-32no area command 9-20no-export community, BGP 1-32no-export-subconfed community, BGP 1-32no ipv6 command 3-16nonbroadcast networks 9-3notice icons defined xxnot-so-stubby area, OSPF. See NSSANSAP (network service access point) 10-3, 10-5,
10-33NSSA (not-so-stubby area), OSPF 9-3, 9-20null authentication, OSPF 9-6null interface 1-26
E-Series Routers13
Oopaque LSAs, OSPF 9-6Open Shortest Path First. See OSPFOSPF (Open Shortest Path First) 9-1 to 9-53
ABRs 9-2adjacency 9-2areas, defining 9-5ASBR 9-3authentication
MD5 9-25simple password 9-6, 9-25
autocost 9-31automatic virtual links 9-22backbone area 9-19BGP/MPLS VPNs and 9-37BGP and 9-7clearing IP routing table 1-43configuring
areas 9-19 to 9-22authentication 9-22 to 9-26incremental SPF 9-40interfaces 9-13 to 9-18NBMA networks 9-34remote neighbors 9-37traps 9-41
creating interfaces 9-8database 9-45dead interval 9-17default cost 9-20deleting interfaces 9-8domain 9-3ECMP 9-7enabling 9-9interaction with BGP/MPLS VPNs 9-37MD5 authentication 9-25metrics, default 9-33MIB 9-7monitoring 9-42 to 9-53password authentication, simple 9-6, 9-25reinstalling routes in IP routing table 1-43route leakage 9-6routes, using for multicast RPF checks 9-37routing costs 9-16routing priority 9-5SPF hold time interval 9-33stub area 9-3topology elements 9-4traffic engineering 9-35transmit delay 9-18, 9-22troubleshooting 9-42
virtual links 9-6ospf commands
ospf auto-cost reference-bandwidth 9-31ospf enable 9-10, 9-11ospf log-adjacency-changes 9-31, 9-43ospf shutdown 9-31See also show ospf commands
overload bit, IS-IS 10-28
Ppackets, IP 2-2
broadcast packets 2-19echo request and trace packets 2-42ICMP messages and 2-38
packets, IPv6 echo request and trace 3-15packet switching networks 2-2parallel routes, maximum number of 2-32, 8-14,
9-31, 10-34passive-interface command 8-15, 9-32, 10-19passwords
IS-IS area authentication 10-20IS-IS authentication 10-16IS-IS domain authentication 10-21OSPF MD5 authentication 9-25OSPF simple password authentication 9-6,
9-25PDU (protocol data unit) 10-3perfect forward secrecy 12-10physical addresses 2-6PIM (Protocol Independent
Multicast) 5-34 to 5-59displaying events 5-51enabling
on an interface 5-43on a virtual router 5-42
monitoring 5-14, 5-51 to 5-59removing 5-49resetting counters and mappings 5-50using with DVMRP 5-43, 5-62using with IGMP 5-43See also PIM DM, PIM SM, and PIM S-DM
PIM dense mode. See PIM DMpim disable command 5-43PIM DM (PIM dense mode) 5-35
See also PIMPIM S-DM (PIM sparse-dense mode) 5-42
configuring auto-RP router 5-45PIM SM (PIM sparse mode) 5-38
configuring auto-RP router 5-44hold time 5-41
Index14
joining groups 5-39multicast services over BGP/MPLS VPNs
configuring 5-47overview 5-39
pruning 5-39remote neighbors
configuring 5-47creating 5-39
setting a threshold 5-46timers 5-41
PIM sparse modeSee also PIM SM
PIM sparse-dense modeSee PIM S-DM
PIM SSM (PIM source-specific multicast)enabling 5-49requirements for IGMPv3 5-49
ping command 2-40, 3-8Point-to-Point Protocol. See PPPPPP (Point-to-Point Protocol), host access
routes 2-26prefixes, filtering network 1-16prefix lists 1-27prefix trees 1-30preventing recursive tunnels 6-7primary IP
addresses 2-10interface 2-33
priorityIS-IS designated router 10-17OSPF routing 9-5, 9-17
profile, creating 2-11, 3-11profile command 2-12, 2-13, 2-14, 3-11, 3-13protocol data unit. See PDUProtocol Independent Multicast. See PIMprotocol number 2-2protocols (IP), monitoring 1-47prune messages 5-5, 5-36, 5-39
Qquery-interval command 5-47
Rreachability commands
IP 2-40IP multicast 5-74
reassembling IP datagrams 2-3receive version command 8-20recursive tunnels, preventing 6-7
redirects, IP 2-39redistribute command 1-25
DVMRP 5-65IS-IS 10-22OSPF 9-6, 9-32RIP 8-15
redistribute isis ip command 10-24redistributing routes, DVMRP 5-65redistributing routes between IS-IS levels 10-23redistribution policy (IP), monitoring 1-48, 2-69,
2-72, 3-30redistribution routes
clearing all (IS-IS) 10-22clearing all (OSPF) 9-29disabling dynamic (DVMRP) 5-66disabling dynamic (IS-IS) 10-22disabling dynamic (OSPF) 9-30disabling dynamic (RIP) 8-11setting 8-15, 9-32, 10-22
redundancy, tunnel server 6-3refresh interval, LSP (IS-IS) 10-31regular expressions and routing policy 1-37
AS-path lists 1-37community lists 1-38community number format 1-38examples 1-40metacharacters
defined 1-38specifying as literals 1-39
release notes xxiiireliable protocols 2-38, 3-8remote-neighbor command 5-47, 8-20, 9-39remote neighbors
OSPF 9-37PIM SM 5-39PIM SM, configuring 5-47RIP 8-19
removingDVMRP 5-67PIM 5-49See also deleting
rendezvous point router. See RP routersreporting IP multicast groups 5-15request messages, RIP 8-2resetting PIM counters and mappings 5-50response messages, RIP 8-2Response Time Reporter. See RTRretransmission interval, IS-IS 10-18retransmission throttle interval, IS-IS 10-18
E-Series Routers15
retransmit intervaland transmit delay 9-17, 9-22OSPF 9-17, 9-22
retransmit-interval command 9-40reverse-path forwarding. See RPFRIP (Routing Information Protocol) 8-1 to 8-28
authentication 8-3clearing IP routing table 1-43configuring 8-7 to 8-15debounce interval 8-10disabling dynamic route distribution 8-11ECMP 8-6maximum number of parallel routes 8-14message types 8-2monitoring 8-22 to 8-28purging the routing table 8-12reinstalling routes in IP routing table 1-43remote neighbors 8-19request messages 8-2response messages 8-2route specificity 8-16route tags 8-3split horizon mechanism 8-6subnet masks 8-4summarizing routes 8-5triggered updates, disabling 8-18troubleshooting 8-22using routes for multicast RPF checks 8-18
route leakage, OSPF 9-6route leaking between IS-IS levels 10-23route-map command 1-11, 5-65, 8-16, 9-27, 10-21route maps
and routing policy 1-2 to 1-16deny keyword 1-3filtering incoming/outgoing routes with access
lists 1-22 to 1-24instance 1-3map tag 1-3match clause 1-2monitoring 1-54permit keyword 1-3sequence number 1-3set clause 1-2
route maps, IP, monitoring 2-80router commands
router dvmrp 5-66, 5-68router igmp 5-25router isis 10-13router ospf 9-10, 9-11router pim 5-43, 5-49
router rip 8-16, 8-18router IDs 2-25, 9-3router type, IS-IS 10-27routes
summarizing IS-IS 10-27summarizing RIP 8-5using for other protocols 5-8using IS-IS 10-36using OSPF 9-37using RIP 8-18
route tags, RIP 8-3routing, IP 2-21 to 2-33
adding host route to peer on PPP interface 2-26
default routes 2-26disabling forwarding of packets 2-29identifying a router 2-25maximum number of parallel routes 2-32monitoring 1-49, 1-50, 2-61, 2-72, 2-74routing operations 2-25routing tables 2-21 to 2-27source address validation 2-27static routes 2-25See also IP
routing, IPv6See also IPv6hop limit 3-13monitoring 3-28, 3-31static routes 3-13
routing, IS-ISclearing redistribution information 10-22default route and routing domain 10-26designated routers 10-17integrated 10-9layers/levels of 10-2, 10-3, 10-4, 10-17maximum number of parallel routes 10-34OSPF routing with 9-7route summarization 10-27routing domains 10-3setting redistribution routes 10-22specifying type (level) 10-27See also IS-IS
routing, OSPFclearing redistribution information 9-29cost 9-16
autocost 9-31default routing cost 9-20equal-cost multipath 9-7
default route and routing domain 9-30displaying information about 9-44
Index16
intra-area, interarea, external routes 9-5leakage 9-6maximum number of parallel routes 9-31priority 9-5, 9-17See also OSPF
routing, RIPdebounce interval 8-10maximum number of parallel routes 8-14purging the routing table 8-12route specificity 8-16triggered updates, disabling 8-18
routing information base (RIB) 2-21Routing Information Protocol. See RIProuting policy
community 1-31community list 1-32configuring 1-1managing the routing table 1-43monitoring 1-43overview 1-1prefix lists 1-27prefix trees 1-30route maps 1-2troubleshooting 1-43
routing policy, BGPaccess lists 1-16 to 1-24monitoring 1-43 to 1-54route maps 1-2 to 1-16
routing tableentry 2-22global IP 2-22local 2-21
routing table, managing the IP 1-43RP (rendez-vous point) routers 5-44
configuring, automatic 5-45configuring, static 5-44
RP (rendezvous point) routersassigning automatically 5-45configuring, automatic 5-44
RPF (reverse-path forwarding) 5-5RPF routes, monitoring 5-6RTR (Response Time Reporter) 2-42
collecting history 2-46collecting statistics 2-46configuring 2-43monitoring 2-50options 2-44probe
configuring 2-43scheduling 2-48
shutting down 2-49reaction conditions 2-47
Ssecondary IP addresses 2-10secure IP interfaces 12-4security parameters 12-6send-more-specific-routes-disable command 8-16send version command 8-21sequence number, route map 1-3set commands 1-12 to 1-16
and route maps 1-2set as-path prepend 1-12set automatic-tag 1-12set comm-list delete 1-12set community 1-13, 1-35set dampening 1-13set distance 1-13set extcommunity 1-14, 1-36set ip next-hop 1-14set level 1-14set local-preference 1-14set metric 1-15set metric-type 1-15set origin 1-16set route-type 1-16set tag 1-16set weight 1-16
set-overload-bit command 10-28setting
administrative distance, IP 2-23baseline
DVMRP 5-69IGMP 5-25IGMP Proxy 5-32
DVMRP hop-count 5-64metric 2-25threshold, PIM SM 5-46
shared IP interfacesconfiguring 2-34moving 2-37primary interface 2-33shared interface 2-33
shared trees 5-38, 5-39, 5-46shortest path trees. See SRTsshow access-list command 1-44, 2-57show arp command 2-57show clns commands
show clns 10-49show clns interface 10-51
E-Series Routers17
show clns neighbors 10-53show clns protocol 10-54show clns traffic 10-54
show dvmrp commandsshow dvmrp tunnel 6-8show dvmrp tunnel summary 6-9
show gre commandsshow gre tunnel 6-10show gre tunnel summary 6-12
show host command 10-38show ike commands
show ike certificates 13-12show ike configuration 13-14show ike identity 13-14show ike policy-rule 12-42show ike sa 12-43
show ip commandsshow ip 2-58show ip address 2-58show ip as-path-access-list 1-45, 2-60show ip community-list 1-45, 2-60show ip dynamic-interface-prefix 2-61show ip extcommunity-list 1-37show ip forwarding-table 2-61show ip interface 2-61show ip interface shares 2-65show ip mroute 5-8show ip mroute count 5-10, 5-11show ip mroute summary 5-12show ip prefix-list 1-46show ip prefix-list detail 1-46show ip prefix-list summary 1-46show ip prefix-tree 1-47show ip prefix-tree detail 1-47show ip prefix-tree summary 1-47show ip protocols 1-47, 2-69show ip redistribute 1-48, 2-72, 3-30show ip route 1-49, 2-72show ip route slot 1-50, 2-74show ip rpf-route 5-6show ip static 1-51, 2-74show ip tcp statistics 2-75show ip traffic 1-51show ip tunnel reassembly statistics 7-3show ip udp statistics 2-80show ip vrrp 11-12show ip vrrp brief 11-13show ip vrrp neighbors 11-13show ip vrrp statistics 11-14show ip vrrp statistics global 11-16
show ip dvmrp commandsshow ip dvmrp 5-69show ip dvmrp interface 5-70show ip dvmrp mroute 5-71show ip dvmrp neighbor 5-71show ip dvmrp route 5-73show ip dvmrp routeNextHop 5-74
show ip igmp commandsshow ip igmp 5-25show ip igmp groups 5-26show ip igmp interface 5-27show ip igmp interface brief 5-28show ip igmp-proxy 5-32show ip igmp-proxy groups 5-32show ip igmp-proxy interface 5-33
show ip multicast commandsshow ip multicast protocols 5-12show ip multicast protocols brief 5-13show ip multicast routing 5-14
show ip nat commandsshow ip nat statistics 4-23show ip nat translations 4-24
show ip ospf commandsshow ip ospf 9-44show ip ospf border-routers 9-45show ip ospf database 9-45show ip ospf database opaque-area 9-47show ip ospf interface 9-49show ip ospf internal-statistics 9-49show ip ospf neighbors 9-51show ip ospf remote-neighbor interface 9-51show ip ospf spf-log 9-51show ip ospf virtual-links 9-53
show ip pim commandsshow ip pim auto-rp 5-51show ip pim dense-mode sg-state 5-52show ip pim interface 5-53show ip pim neighbor 5-54show ip pim remote-neighbor 5-55show ip pim rp 5-55show ip pim rp-hash 5-56show ip pim sparse-mode sg-state 5-56show ip pim sparse-mode unicast-route 5-58show ip pim spt-threshold 5-58
show ip rip commands 8-23 to 8-26show ip rip 8-23show ip rip brief 8-25show ip rip database 8-26show ip rip network 8-27show ip rip stats 8-28
Index18
show ip rip summary-address 8-28show ipsec commands
show ipsec lifetime 12-44show ipsec local-endpoint 12-44show ipsec transform-set 12-45show ipsec tunnel detail 12-45show ipsec tunnel summary 12-47show ipsec tunnel virtual-router 12-47show license ipsec-tunnels 12-48
show IPSec transport profile commandsshow ipsec transport interface 14-13show ipsec transport interface summary 14-15show ipsec transport profile 14-15
show ipv6 commandsshow ipv6 3-22show ipv6 address 3-22show ipv6 neighbors 3-28show ipv6 protocols 3-29show ipv6 route 3-31show ipv6 static 3-32show ipv6 traffic 3-32show ipv6 udp statistics 3-34show license ipv6 3-35
show isis commandsshow isis database 10-39show isis mpls adjacency-log 10-42show isis mpls advertisements 10-43show isis mpls tunnel 10-44show isis spf-log 10-45show isis summary-addresses 10-46show isis topology 10-46
show multicast group limit command 5-29show profile commands
show profile 2-68, 3-28show profile brief 2-81
show route-map command 1-54, 2-81signalled IPSec interfaces 12-8simple password authentication, OSPF 9-6, 9-25snmp trap ip link-status command 2-31software, installing xixsource, tunnel 6-2source address verification 2-27source-rooted trees. See SRTssparse mode multicast protocols 5-5specifying IP multicast groups 5-22SPF, incremental 9-40SPF calculations, information on 9-51, 10-45SPF hold time
interval 9-33IS-IS 10-31
spf-interval command 10-31split-horizon command 8-21split horizon mechanism 8-6SPTs (shortest path trees). See SRTsSRP module, global IP routing table on 2-22SRTs (source-rooted trees) 5-35, 5-39, 5-46, 5-59starting IS-IS MD5 packets 10-7static routes 1-51, 2-25, 2-74, 3-13, 3-32, 5-6, 6-7static tunnels 6-1 to 6-12stopping IS-IS MD5 packets 10-7stub areas, OSPF 9-3, 9-20subnet addressing 2-7subnet masks, RIP 8-4summarizing RIP routes 8-5summary-address command 10-27, 9-12summary addresses
DVMRP routing 5-63IS-IS routing 10-27OSPF routing 9-12
supernets 2-9suppress-default command 10-27suppressing IS-IS default routes 10-27syntax conventions defined xxsystem identifier, IS-IS 10-3
Ttable
forwarding 2-22global IP routing 2-22local routing 2-21
table-map command (RIP) 8-17, 9-32table-map command, IP 1-26TCP/IP protocol suite
defined 2-2layers of 2-3 to 2-4
text conventions defined xxtimers
PIM SM 5-41RIP 8-17
timers commandstimers 8-17timers spf 9-33
time-to-live command 8-21TLV for resolution of IS-IS dynamic
hostname 10-5, 10-33topology
IS-IS 10-4OSPF 9-4
trace packets 2-42, 3-15, 5-74traceroute command 2-40, 2-42, 3-8, 3-15
E-Series Routers19
traffic, IP 1-51, 2-11 to 2-80traffic engineering
and IS-IS 10-35and OSPF 9-35
transform sets, IPSec 12-12transmit delay, OSPF 9-18, 9-22transmit-delay command 9-40transport layer (TCP/IP) 2-4transport network 6-7traps, OSPF 9-41traps command 9-42triggered-update-disable command 8-18troubleshooting
dropped packets 2-65IS-IS 10-38OSPF 9-42RIP 8-22routing policy 1-43
TSM (Tunnel Service line module)installing 6-2monitoring parameters 6-8redundancy 6-3
ttl command 9-40tunnel commands, IP
tunnel checksum 6-4tunnel destination 6-4tunnel mtu 6-4tunnel source 6-5
tunnel commands, IPSectunnel destination 12-25tunnel lifetime 12-26tunnel local-identity 12-26tunnel mtu 12-26tunnel peer-identity 12-26tunnel pfs group 12-27tunnel session-key-inbound 12-27tunnel session-key-outbound 12-27tunnel signaling 12-28tunnel source 12-28tunnel transform set 12-28
tunnels, IP 6-1 to 6-12DVMRP (IP in IP) 6-2endpoints 6-2GRE 6-2
tunnels, reassembling tunnel packets 7-1Tunnel Service line module. See TSMtype-length-value for resolution of IS-IS dynamic
hostname 10-5, 10-33
UUDP (User Datagram Protocol) 8-2undebug commands
undebug ip ospf 9-43undebug ip pim 5-51undebug ip rip 8-22undebug isis 10-46
unicast routes, DVMRP 5-66unnumbered interface
IP 2-26IPv6 3-12
unreachable messages (ICMP) 2-39unreliable protocols 2-2, 2-38, 3-8updates, BGP
AS-path filters for 1-19 to 1-21update-source command 5-48, 8-21, 9-40updating the system software xixupstream interface 5-29User Datagram Protocol. See UDP
Vvalidating source addresses 2-27virtual links, OSPF 9-3, 9-6, 9-22virtual MAC address 11-1virtual-router command 2-13Virtual Router Redundancy Protocol (VRRP). See
VRRPVRID (virtual router ID)
configuration 11-9creating 11-8, 11-9router election rules 11-7
VRRP (Virtual Router Redundancy Protocol)advertisement interval 11-9advertisement messages 11-7authentication key 11-10authentication type 11-10backup router 11-1, 11-7configuration examples 11-3 to 11-6configuring 11-8 to 11-12Fast Ethernet (FE) modules 11-2Gigabit Ethernet (GE) modules 11-2how it works 11-3implementation 11-7, 11-8MAC address 11-1master router 11-1 to 11-11monitoring 11-12overview 11-1preemption 11-8, 11-11router election rules 11-7
Index20
router priority 11-10VLAN support 11-2VRRP router defined 11-2
vrrp commandsip vrrp 11-10ip vrrp advertise-interval 11-10ip vrrp authentication-key 11-11ip vrrp authentication-type 11-11ip vrrp enable 11-9, 11-11ip vrrp preempt 11-9, 11-11ip vrrp priority 11-11ip vrrp virtual-address 11-12
Wwell-known communities, BGP 1-32
XX.509v3 certificates 13-3
