Cisco Confidential 1© 2010 Cisco and/or its affiliates. All rights reserved.

Configure and Troubleshoot IP Routing Protocols - EIGRP & OSPF

Manas R MoothedathSumit Kothiyal

Process

Technology

CiscoSupport Community

IP Routing Protocols – Part 2

Manas Moothedath and Sumit Kothiyal

Cisco Systems (India) Pvt Limited

26th Mar 2014

EIGRP

EIGRP

Cisco Confidential 4© 2013-2014 Cisco and/or its affiliates. All rights reserved.

EIGRP packets – a quick recap 

Basic troubleshooting of EIGRP issues. 

A closer look at typical EIGRP error messages

Practical view of EIGRP failure scenarios

Best practices in EIGRP 

AGENDA

Cisco Confidential 5© 2013-2014 Cisco and/or its affiliates. All rights reserved.

EIGRP Packets – A Quick Recap

- The Hello

R1 R2

Hello

Hello

Network command ENABLES EIGRP.

Cisco Confidential 6© 2013-2014 Cisco and/or its affiliates. All rights reserved.

EIGRP Packets – A Quick Recap

- The Update

R1 R2

Update

Cisco Confidential 7© 2013-2014 Cisco and/or its affiliates. All rights reserved.

EIGRP Packets – A Quick Recap

- The Query

- The ReplyR1 R2

R3

X

Query

Reply

Cisco Confidential 8© 2013-2014 Cisco and/or its affiliates. All rights reserved.

Troubleshooting EIGRP – Effect to cause…

Typical EIGRP error messages – neighborship flapping continuously: a) EIGRP Hold time expired

b) Retry Limit Exceeded

c) Peer restarted

Cisco Confidential 9© 2013-2014 Cisco and/or its affiliates. All rights reserved.

The EIGRP – STUCK IN ACTIVE

Revisiting the EIGRP Query

“show ip eigrp topology active”

Cisco Confidential 10© 2013-2014 Cisco and/or its affiliates. All rights reserved.

Understanding the ‘EIGRP Topology’

router B# show ip eigrp topology 170.16.0.0 255.255.0.0

IP-EIGRP topology entry for 172.16.0.0/16State is Passive, Query origin flag is 1, 1 Successor(s), FD is 3757056Routing Descriptor Blocks:12.1.2.2 (Serial1), from 12.1.2.2, Send flag is 0x0Composite metric is (3757056/3245056), Route is External Vector metric: Minimum bandwidth is 1544 Kbit Total delay is 82000 microseconds Reliability is 255/255 Load is 1/255 Minimum MTU is 1500 Hop count is 7 External data: Originating router is 192.168.1.1 AS number of routes is 0 External protocol is OSPF, external metric is 64 Administrator tag is 0

Cisco Confidential 11© 2013-2014 Cisco and/or its affiliates. All rights reserved.

Typical EIGRP Failures scenarios:

1. One way link

2. Mismatched Parameters

3. Query boundary too large

4. Duplicate router-idHello

ping 224.0.0.10

Cisco Confidential 12© 2013-2014 Cisco and/or its affiliates. All rights reserved.

EIGRP Caveats:

1. auto-summary • Enabled/Disabled?

2. Redistribution metric into EIGRP• MUST be specified

3. Routes advertised to a neighbor1. Only if EIGRP in Routing Table2. Only the best routes

172.16.1.0/24

172.16.2.0/24

192.168.1.0/24

172.16.3.0/24

Discontiguous

Classful Boundary

OSPF

Cisco Confidential 14© 2013-2014 Cisco and/or its affiliates. All rights reserved.

OSPF Hello

OSPF Neighborship States

Troubleshooting Neighborship Issues

Common Misconceptions

Common Issues.

AGENDA

Cisco Confidential 15© 2013-2014 Cisco and/or its affiliates. All rights reserved.

OSPF Hello

• Hello Interval

• Dead Interval

• Subnet Mask

• Area ID

• Authentication

• Optional Capabilities - eg. Stub

Cisco Confidential 16© 2013-2014 Cisco and/or its affiliates. All rights reserved.

Neighborship states

• Down

• INIT - Initiated (Multicast)

• 2-WAY - See ourself in the neighbor Hello (Multicast)

• Exstart - Master/Slave (Unicast)

• Exchange - Exchanging DBD (Unicast)

• Loading - LSR - LSU - Exchange LSA’s (Unicast)

• Full

Cisco Confidential 17© 2013-2014 Cisco and/or its affiliates. All rights reserved.

Lab Topology:

R1R2

R3

R4

R5

R6 R7

Cisco Confidential 18© 2013-2014 Cisco and/or its affiliates. All rights reserved.

Neighborship Issue

Neighbor not seen –• Hello Parameters mismatch.• Multicast Issues.

Neighbor stuck in Exstart –• MTU mismatch.• Unicast Issue.

Cisco Confidential 19© 2013-2014 Cisco and/or its affiliates. All rights reserved.

Common Caveats:

• Summary LSA is not summarisation.

• Distribute-list out doesn’t work.

• Checking the LSA in the wrong database (checking intra-area route in show ip ospf database)

Cisco Confidential 20© 2013-2014 Cisco and/or its affiliates. All rights reserved.

Other issues:

• 2-way with all the neighbors (no DR)

• Not full will all the neighbors• expected, DR-BDR are full with all the neighbors. • DROthers are only full with DR-BDR

• Advertising router is not reachable (not pingable)could be expected if RID is not advertised.

- RID is just a name.

Thank you.