CCNA® Routing and Switching

Study Guide

Todd Lammle

CCNA ® Routing and Switching

Study Guide

Senior Acquisitions Editor: Jeff Kellum Development Editor: Pete Gaughan Technical Editors: John Swartz and Dax Mickelson Production Editor: Christine O’Connor Copy Editor: Judy Flynn Editorial Manager: Pete Gaughan Production Manager: Tim Tate Vice President and Executive Group Publisher: Richard Swadley Associate Publisher, Sybex: Chris Webb Media Project Manager I: Laura Moss-Hollister Media Associate Producer: Marilyn Hummel Media Quality Assurance: Doug Kuhn Book Designers: Judy Flynn and Bill Gibson Compositor: Craig Woods, Happenstance Type-O-Rama Proofreader: Sarah Kaikini, Word One New York Indexer: Robert Swanson Project Coordinator, Cover: Katherine Crocker Cover Designer: Ryan Sneed Copyright © 2013 by John Wiley & Sons, Inc., Indianapolis, Indiana Published by John Wiley & Sons, Inc. Indianapolis, Indiana Published simultaneously in Canada ISBN: 978-1-118-74961-6 ISBN: 978-1-118-74973-9 (ebk.) ISBN: 978-1-118-74970-8 (ebk.) No part of this publication may be reproduced, stored in a retrieval system or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, scanning or otherwise, except as permitted under Sections 107 or 108 of the 1976 United States Copyright Act, without either the prior written permission of the Publisher, or authorization through payment of the appropriate per-copy fee to the Copyright Clearance Center, 222 Rosewood Drive, Danvers, MA 01923, (978) 750-8400, fax (978) 646-8600. Requests to the Publisher for permission should be addressed to the Permissions Department, John Wiley & Sons, Inc., 111 River Street, Hoboken, NJ 07030, (201) 748-6011, fax (201) 748-6008, or online at http://www.wiley.com/go/permissions . Limit of Liability/Disclaimer of Warranty: The publisher and the author make no representations or war-ranties with respect to the accuracy or completeness of the contents of this work and specifically disclaim all warranties, including without limitation warranties of fitness for a particular purpose. No warranty may be created or extended by sales or promotional materials. The advice and strategies contained herein may not be suitable for every situation. This work is sold with the understanding that the publisher is not engaged in rendering legal, accounting, or other professional services. If professional assistance is required, the services of a competent professional person should be sought. Neither the publisher nor the author shall be liable for damages arising herefrom. The fact that an organization or Web site is referred to in this work as a citation and/or a potential source of further information does not mean that the author or the publisher endorses the information the organization or Web site may provide or recommendations it may make. Fur-ther, readers should be aware that Internet Web sites listed in this work may have changed or disappeared between when this work was written and when it is read. For general information on our other products and services or to obtain technical support, please contact our Customer Care Department within the U.S. at (877) 762-2974, outside the U.S. at (317) 572-3993 or fax (317) 572-4002. Wiley publishes in a variety of print and electronic formats and by print-on-demand. Some material included with standard print versions of this book may not be included in e-books or in print-on-demand. If this book refers to media such as a CD or DVD that is not included in the version you purchased, you may download this material at http://booksupport.wiley.com . For more information about Wiley products, visit www.wiley.com . Library of Congress Control Number: 2013948006 TRADEMARKS: Wiley, the Wiley logo, and the Sybex logo are trademarks or registered trademarks of John Wiley & Sons, Inc. and/or its affiliates, in the United States and other countries, and may not be used without written permission. CCNA is a registered trademark of Cisco Technology, Inc. All other trademarks are the property of their respective owners. John Wiley & Sons, Inc. is not associated with any product or vendor mentioned in this book. 10 9 8 7 6 5 4 3 2 1

Dear Reader,

Thank you for choosing CCNA Routing and Switching Study Guide. This book is part of a family of premium-quality Sybex books, all of which are written by outstanding authors who combine practical experience with a gift for teaching.

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Acknowledgments

There are many people that work to put a book together, and as an author, I dedicated an enormous amount of time to write this book, but it would have never been published with-out the dedicated, hard work of many other people.

Monica Worthy Lammle was crucial to the fi nished product this book became, going over every word of every chapter with me to fi ne-tune the language and grammar. Without Monica’s support in all areas of my life, I’d never have fi nished writing this book.

Next in line to thank is my new technical editor, John Swartz, who also coauthored the CCNA Data Center study guides with me. His expertise in the Cisco technical fi eld, and his history of networking in general, is second to none. His detailed analysis of my work helped make this my best CCNA study guide ever. Thank you, John, for working hard under pressure, with tight deadlines, and for staying the course of delivering high-quality work in a short time frame.

Jeff Kellum, my acquisitions editor, is instrumental to my success in the world of Cisco certifi cation. Jeff, I look forward to our continued progress together.

Christine O’Connor, my production editor, and Judy Flynn, my copyeditor, were my rock and foundation for formatting an intense editing of every page in this book. This amazing team gives me the confi dence to help keep me moving during the diffi cult and very long days, we– after we– . How Christine stays so organized with all my changes, as well as making sure every fi gure is in the right place in the book is still a mystery to me! You’re amazing, Christine! Thank you! Judy understands my writing style so well now, after doing at least a dozen books with me, that she even sometimes fi nds a technical error that may have slipped through as I was going through the material. Thank you Judy for doing such a great job! I truly thank you both.

Troy McMillian really helped me on this book (on all books actually!) by working on the review and bonus questions, fl ash cards, as well as a 3rd technical edit on the last stage of editing. He did a high-quality job in a short time! Thanks, Troy! Jim Frey and Paul Sutton really helped me put together this book’s amazing fi gures, and an all-around second-look technical edit. Thank you both!

Also, thanks to Dax Mickelson and Dennis Frye for performing the technical proofread of the book.

Finally, a big thanks to Craig Woods at Happenstance-Type-O-Rama and to the Sybex media-development team.

About the Author

Todd Lammle is the authority on Cisco certifi cation and internetworking and is Cisco certi-fi ed in most Cisco certifi cation categories. He is a world-renowned author, speaker, trainer, and consultant. Todd has three decades of experience working with LANs, WANs, and large enterprise licensed and unlicensed wireless networks, and lately he’s been implementing large Cisco data centers worldwide. His years of real-world experience is evident in his writing; he is not just an author but an experienced networking engineer with very practical experience working on the largest networks in the world, at such companies as Xerox, Hughes Aircraft, Texaco, AAA, Cisco, and Toshiba, among many others. Todd has published over 60 books, including the very popular CCNA: Cisco Certifi ed Network Associate Study Guide , CCNA Wireless Study Guide , and CCNA Data Center Study Guide , all from Sybex. He runs an international consulting and training company based in Colorado, Texas, and San Francisco.

You can reach Todd through his forum and blog at www.lammle.com .

Contents at a Glance

Introduction xxvii

ICND1 (100-101) Exam Objectives xxxviii

ICND2 (200-101) Exam Objectives xliv

CCNA Composite (200-120) Exam Objectives xlvii

Assessment Test lviii

Part I ICND1 1 Chapter 1 Internetworking 3

Chapter 2 Ethernet Networking and Data Encapsulation 41

Chapter 3 Introduction to TCP/IP 87

Chapter 4 Easy Subnetting 139

Chapter 5 VLSMs, Summarization, and Troubleshooting TCP/IP 181

Chapter 6 Cisco’s Internetworking Operating System (IOS) 213

Chapter 7 Managing a Cisco Internetwork 283

Chapter 8 IP Routing 331

Chapter 9 Open Shortest Path First (OSPF) 385

Chapter 10 Layer 2 Switching 425

Chapter 11 VLANs and InterVLAN Routing 459

Chapter 12 Security 501

Chapter 13 Network Address Translation (NAT) 541

Chapter 14 Internet Protocol Version 6 (IPv6) 569

Part II ICND2 613 Chapter 15 Enhanced Switched Technologies 615

Chapter 16 Managing Cisco Devices 661

Chapter 17 IP Services 699

Chapter 18 Troubleshooting IP, IPv6, and VLANs 741

Chapter 19 Enhanced IGRP 783

Chapter 20 Multi-Area OSPF 847

Chapter 21 Wide Area Networks 897

Appendix A Answers to Written Labs 967

Appendix B Answers to Review Questions 987

Appendix C Disabling and Configuring Network Services 1029

Appendix D About the Additional Study Tools 1041

Index 1045

Contents

Introduction xxvii

ICND1 (100-101) Exam Objectives xxxviii

ICND2 (200-101) Exam Objectives xliv

CCNA Composite (200-120) Exam Objectives xlvii

Assessment Test lviii

Part I ICND1 1

Chapter 1 Internetworking 3

Internetworking Basics 4 Internetworking Models 12

The Layered Approach 13 Advantages of Reference Models 14

The OSI Reference Model 14 The Application Layer 16 The Presentation Layer 17 The Session Layer 17 The Transport Layer 18 The Network Layer 23 The Data Link Layer 25 The Physical Layer 28

Summary 29 Exam Essentials 30 Written Labs 32

Written Lab 1.1: OSI Questions 32 Written Lab 1.2: Defining the OSI Layers and Devices 33 Written Lab 1.3: Identifying Collision and

Broadcast Domains 34 Review Questions 35

Chapter 2 Ethernet Networking and Data Encapsulation 41

Ethernet Networks in Review 42 Collision Domain 43 Broadcast Domain 44 CSMA/CD 45 Half- and Full-Duplex Ethernet 47 Ethernet at the Data Link Layer 49 Ethernet at the Physical Layer 55

xii Contents

Ethernet Cabling 59 Straight-through Cable 60 Crossover Cable 60 Rolled Cable 62 Fiber Optic 64

Data Encapsulation 66 The Cisco three-layer Hierarchical Model 70

The Core Layer 70 The Distribution Layer 72 The Access Layer 72

Summary 73 Exam Essentials 73 Written Labs 74

Written Lab 2.1: Binary/Decimal/Hexadecimal Conversion 75 Written Lab 2.2: CSMA/CD Operations 79 Written Lab 2.3: Cabling 79 Written Lab 2.4: Encapsulation 80

Review Questions 81

Chapter 3 Introduction to TCP/IP 87

Introducing TCP/IP 88 A Brief History of TCP/IP 89

TCP/IP and the DoD Model 89 The Process/Application Layer Protocols 91 The Host-to-host Layer Protocols 101 The Internet Layer Protocols 110

IP Addressing 118 IP Terminology 118 The Hierarchical IP Addressing Scheme 119 Private IP Addresses (RFC 1918) 124

IPv4 Address Types 126 Layer 2 Broadcasts 126 Layer 3 Broadcasts 126 Unicast Address 127 Multicast Address 128

Summary 129 Exam Essentials 130 Written Labs 132

Written Lab 3.1: TCP/IP 132 Written Lab 3.2: Mapping Applications to the DoD Model 132

Review Questions 134

Chapter 4 Easy Subnetting 139

Subnetting Basics 140 How to Create Subnets 142 Subnet Masks 142

Contents xiii

Classless Inter-Domain Routing (CIDR) 144 IP Subnet-Zero 146 Subnetting Class C Addresses 146 Subnetting Class B Addresses 158 Subnetting Class A Addresses 167

Summary 170 Exam Essentials 170 Written Labs 171

Written Lab 4.1: Written Subnet Practice #1 171 Written Lab 4.2: Written Subnet Practice #2 172 Written Lab 4.3: Written Subnet Practice #3 173

Review Questions 174

Chapter 5 VLSMs, Summarization, and Troubleshooting TCP/IP 181

Variable Length Subnet Masks (VLSMs) 182 VLSM Design 184 Implementing VLSM Networks 184

Summarization 193 Troubleshooting IP Addressing 196

Determining IP Address Problems 198 Summary 203 Exam Essentials 204 Written Lab 5 205 Review Questions 206

Chapter 6 Cisco’s Internetworking Operating System (IOS) 213

The IOS User Interface 215 Cisco IOS 216 Connecting to a Cisco IOS Device 216 Bringing Up a Switch 218

Command-line Interface (CLI) 219 Entering the CLI 219 Overview of Router Modes 219 CLI Prompts 220 Editing and Help Features 223

Administrative Configurations 228 Hostnames 228 Banners 229 Setting Passwords 231 Encrypting Your Passwords 237 Descriptions 239

Router and Switch Interfaces 241 Bringing Up an Interface 244

xiv Contents

Viewing, Saving, and Erasing Configurations 250 Deleting the Configuration and Reloading the Device 252 Verifying Your Configuration 253

Summary 264 Exam Essentials 265 Written Lab 6 268 Hands-on Labs 268

Hands-on Lab 6.1: Erasing an Existing Configuration 269 Hands-on Lab 6.2: Exploring User, Privileged,

and Configuration Modes 269 Hands-on Lab 6.3: Using the Help and Editing Features 270 Hands-on Lab 6.4: Saving a Configuration 271 Hands-on Lab 6.5: Setting Passwords 272 Hands-on Lab 6.6: Setting the Hostname, Descriptions,

IP Address, and Clock Rate 274 Review Questions 277

Chapter 7 Managing a Cisco Internetwork 283

The Internal Components of a Cisco Router and Switch 284 The Router and Switch Boot Sequence 285

Backing Up and Restoring the Cisco Configuration 286 Backing Up the Cisco Configuration 286 Restoring the Cisco Configuration 288 Erasing the Configuration 289

Configuring DHCP 290 DHCP Relay 291 Verifying DHCP on Cisco IOS 292

Network Time Protocol (NTP) 293 Using Cisco Discovery Protocol (CDP) 295

Getting CDP Timers and Holdtime Information 295 Gathering Neighbor Information 296 Documenting a Network Topology Using CDP 300

Using Telnet 303 Telnetting into Multiple Devices Simultaneously 305 Checking Telnet Connections 306 Checking Telnet Users 306 Closing Telnet Sessions 306

Resolving Hostnames 307 Building a Host Table 307 Using DNS to Resolve Names 309

Checking Network Connectivity and Troubleshooting 311 Using the ping Command 312 Using the traceroute Command 312

Contents xv

Debugging 314 Using the show processes Command 316

Summary 317 Exam Essentials 317 Written Lab 7 319

Written Lab 7.1: IOS Management 319 Written Lab 7.2: Router Memory 319

Hands-on Labs 320 Hands-on Lab 7.1: Backing Up the Router Configuration 320 Hands-on Lab 7.2: Using the Cisco Discovery

Protocol (CDP) 321 Hands-on Lab 7.3: Using Telnet 322 Hands-on Lab 7.4: Resolving Hostnames 323

Review Questions 325

Chapter 8 IP Routing 331

Routing Basics 333 The IP Routing Process 335

The Cisco Router Internal Process 341 Testing Your IP Routing Understanding 342

Configuring IP Routing 346 Configuring IP Routing in Our Network 356

Static Routing 357 Default Routing 362

Dynamic Routing 365 Routing Protocol Basics 365

Routing Information Protocol (RIP) 367 Configuring RIP Routing 367 Holding Down RIP Propagations 371

Summary 373 Exam Essentials 374 Written Lab 8 376 Hands-on Labs 376

Hands-on Lab 8.1: Creating Static Routes 377 Hands-on Lab 8.2: Configuring RIP Routing 378

Review Questions 380

Chapter 9 Open Shortest Path First (OSPF) 385

Open Shortest Path First (OSPF) Basics 386 OSPF Terminology 389 OSPF Operation 391

Configuring OSPF 393 Enabling OSPF 393 Configuring OSPF Areas 394 Configuring Our Network with OSPF 397

xvi Contents

OSPF and Loopback Interfaces 402 Configuring Loopback Interfaces 403

Verifying OSPF Configuration 405 The show ip ospf Command 406 The show ip ospf database Command 407 The show ip ospf interface Command 408 The show ip ospf neighbor Command 409 The show ip protocols Command 411

Summary 411 Exam Essentials 412 Written Lab 9 413 Hands-on Labs 413

Hands-on Lab 9.1: Enabling the OSPF Process 414 Hands-on Lab 9.2: Configuring OSPF Interfaces 415 Hands-on Lab 9.3: Verifying OSPF Operation 416

Review Questions 417

Chapter 10 Layer 2 Switching 425

Switching Services 426 Three Switch Functions at Layer 2 427 Port Security 431

Configuring Catalyst Switches 436 Catalyst Switch Configuration 436 Verifying Cisco Catalyst Switches 444

Summary 447 Exam Essentials 447 Written Lab 10 448 Hands-on Labs 448

Lab 10.1: Configuring Layer 2 Switches 449 Lab 10.2: Verifying Layer 2 Switches 450 Lab 10.3: Configuring Port Security 450

Review Questions 452

Chapter 11 VLANs and InterVLAN Routing 459

VLAN Basics 460 Broadcast Control 463 Security 464 Flexibility and Scalability 464

Identifying VLANs 465 Frame Tagging 467 VLAN Identification Methods 468

Routing between VLANs 469

Contents xvii

Configuring VLANs 472 Assigning Switch Ports to VLANs 475 Configuring Trunk Ports 476 Configuring Inter-VLAN Routing 480

Summary 487 Exam Essentials 488 Written Lab 11 489 Hands-on Labs 489

Hands-on Lab 11.1: Configuring and Verifying VLANs 490 Hands-on Lab 11.2: Configuring and Verifying

Trunk Links 491 Hands-on Lab 11.3: Configuring Router on a

Stick Routing 492 Hands-on Lab 11.4: Configuring IVR with a

Layer 3 Switch 492 Review Questions 494

Chapter 12 Security 501

Perimeter, Firewall, and Internal Routers 502 Introduction to Access Lists 503

Mitigating Security Issues with ACLs 506 Standard Access Lists 507

Wildcard Masking 508 Standard Access List Example 510 Controlling VTY (Telnet/SSH) Access 514

Extended Access Lists 515 Extended Access List Example 1 519 Extended Access List Example 2 521 Extended Access List Example 3 522 Named ACLs 523 Remarks 525

Monitoring Access Lists 526 Summary 528 Exam Essentials 529 Written Lab 12 530 Hands-on Labs 530

Hands-on Lab 12.1: Standard IP Access Lists 531 Hands-on Lab 12.2: Extended IP Access Lists 532

Review Questions 535

Chapter 13 Network Address Translation (NAT) 541

When Do We Use NAT? 542 Types of Network Address Translation 544 NAT Names 544

xviii Contents

How NAT Works 545 Static NAT Configuration 547 Dynamic NAT Configuration 548 PAT (Overloading) Configuration 548 Simple Verification of NAT 549

Testing and Troubleshooting NAT 550 Summary 555 Exam Essentials 556 Written Lab 13 557 Hands-on Labs 557

Lab 13.1: Preparing for NAT 558 Lab 13.2: Configuring Dynamic NAT 560 Lab 13.3: Configuring PAT 561

Review Questions 564

Chapter 14 Internet Protocol Version 6 (IPv6) 569

Why Do We Need IPv6? 571 The Benefits and Uses of IPv6 571 IPv6 Addressing and Expressions 573

Shortened Expression 574 Address Types 575 Special Addresses 576

How IPv6 Works in an Internetwork 577 Manual Address Assignment 578 Stateless Autoconfiguration (eui-64) 578 DHCPv6 (Stateful) 581 IPv6 Header 582 ICMPv6 583

IPv6 Routing Protocols 586 Static Routing with IPv6 586 OSPFv3 587

Configuring IPv6 on Our Internetwork 588 Configuring Routing on Our Internetwork 591

Verifying OSPFv3 594 Summary 599 Exam Essentials 599 Written Labs 601

Written Lab 14.1 601 Written Lab 14.2 601

Hands-on Labs 602 Hands-on Lab 14.1: Manual and

Stateful Autoconfiguration 602 Hands-on Lab 14.2: Static and Default Routing 604 Hands-on Lab 14.3: OSPFv3 605

Review Questions 607

Contents xix

Part II ICND2 613

Chapter 15 Enhanced Switched Technologies 615

Spanning Tree Protocol (STP) 616 Spanning-tree Terms 617 Spanning-tree Operations 621

Types of Spanning-tree Protocols 623 Common Spanning Tree 624 Per-VLAN Spanning Tree+ 625

Modifying and Verifying the Bridge ID 631 Spanning-tree Failure Consequences 636 PortFast and BPDU Guard 638

BPDU Guard 640 EtherChannel 642

Configuring and Verifying Port Channels 643 Summary 646 Exam Essentials 647 Written Lab 5 648 Hands-on Labs 648

Hands-on Lab 15.1: Verifying STP and Finding Your Root Bridge 649

Hands-on Lab 15.2: Configuring and Verifying Your Root Bridge 651

Hands-on Lab 15.3: Configuring PortFast and BPDU Guard 652

Hands-on Lab 15.4: Configuring and Verifying EtherChannel 653

Review Questions 656

Chapter 16 Managing Cisco Devices 661

The Internal Components of a Cisco Router 662

The Router Boot Sequence 663 Managing Configuration Register 664

Understanding the Configuration Register Bits 665 Checking the Current Configuration Register Value 666 Boot System Commands 667 Recovering Passwords 669

Backing Up and Restoring the Cisco IOS 671 Verifying Flash Memory 673 Backing Up the Cisco IOS 674 Restoring or Upgrading the Cisco Router IOS 675 Using the Cisco IOS File System (Cisco IFS) 677

xx Contents

Licensing 682 Right-To-Use Licenses (Evaluation Licenses) 684 Backing Up and Uninstalling the License 687

Summary 688 Exam Essentials 689 Written Labs 691

Written Lab 16.1: IOS Management 691 Written Lab 16.2: Router Memory 691

Hands-on Labs 692 Hands-on Lab 16.1: Backing Up Your Router IOS 692 Hands-on Lab 16.2: Upgrading or Restoring

Your Router IOS 692 Review Questions 694

Chapter 17 IP Services 699

Client Redundancy Issues 700 Introducing First Hop Redundancy Protocol (FHRP) 702 Hot Standby Router Protocol (HSRP) 704

Virtual MAC Address 705 HSRP Timers 706 Group Roles 708 Configuring and Verifying HSRP 709

Virtual Router Redundancy Protocol 715 Comparing VRRP and HSRP 715 VRRP Redundancy Characteristics 715

Gateway Load Balancing Protocol 716 GLBP Functions 717 GLBP Features 717 GLBP Per-host Traffic Balancing 718 Configuring GLBP 718

Syslog 721 Configuring and Verifying Syslog 723

SNMP 726 Management Information Base (MIB) 727 Configuring SNMP 728

NetFlow 730 NetFlow Overview and Flows 731 Configuring NetFlow 732

Summary 734 Exam Essentials 734 Written Lab 17 735 Review Questions 736

Contents xxi

Chapter 18 Troubleshooting IP, IPv6, and VLANs 741

Troubleshooting IP Network Connectivity 742 Troubleshooting IPv6 Network Connectivity 754

ICMPv6 755 Troubleshooting VLAN Connectivity 763

VLAN Troubleshooting 763 Trunk Troubleshooting 768

Summary 776 Exam Essentials 777 Written Lab 18 778 Review Questions 779

Chapter 19 Enhanced IGRP 783

EIGRP Features and Operations 784 Neighbor Discovery 785 Reliable Transport Protocol (RTP) 790 Diffusing Update Algorithm (DUAL) 791 Route Discovery and Maintenance 792

Configuring EIGRP 792 VLSM Support and Summarization 795 Controlling EIGRP Traffic 798 Split Horizon 809

Verifying and Troubleshooting EIGRP 811 Troubleshooting Example with EIGRP 818

EIGRPv6 828 Summary 833 Exam Essentials 834 Written Lab 19 835 Hands-on Labs 835

Hands-on Lab 19.1: Configuring and Verifying EIGRP 835 Hands-on Lab 19.2: Configuring and Verifying EIGRPv6 837

Review Questions 838

Chapter 20 Multi-Area OSPF 847

OSPF Scalability 848 Categories of Multi-area Components 850

Adjacency Requirements 850 OSPF Router Roles 851 Link-state Advertisements 852 OSPF Hello Protocol 854 Neighbor States 855

Basic Multi-area Configuration 857

xxii Contents

Verifying and Troubleshooting Multi-area OSPF Networks 859

The show ip ospf Command 861 The show ip ospf interface Command 862 The show ip protocols Command 864 The show ip route Command 865 The show ip ospf database Command 866

Troubleshooting OSPF Scenario 868 OSPFv3 876

Verifying OSPFv3 879 Summary 881 Exam Essentials 881 Written Lab 20 883 Hands-on Labs 883

Hands-on Lab 20.1: Configuring and Verifying OSPF Multi-Area 884

Hands-on Lab 20.2: Configuring and Verifying OSPFv3 887 Review Questions 890

Chapter 21 Wide Area Networks 897

Introduction to Wide Area Networks 898 Defining WAN Terms 899 WAN Connection Bandwidth 900 WAN Connection Types 900 WAN Support 902

Cable and DSL 905 Cable 906 Digital Subscriber Line (DSL) 907

Cabling the Serial Wide Area Network 910 Serial Transmission 910 Data Terminal Equipment and Data

Communication Equipment 911 High-Level Data-Link Control (HDLC) Protocol 912 Point-to-Point Protocol (PPP) 914

Link Control Protocol (LCP) Configuration Options 915 PPP Session Establishment 916 PPP Authentication Methods 917 Configuring PPP on Cisco Routers 917 Configuring PPP Authentication 917 Verifying and Troubleshooting Serial Links 918

Frame Relay 923 Introduction to Frame Relay Technology 924 Frame Relay Implementation and Monitoring 931

Contents xxiii

Virtual Private Networks 942 Benefits of VPNs 943 Introduction to Cisco IOS IPsec 944 IPsec Transforms 945

GRE Tunnels 946 Configuring GRE Tunnels 947 Verifying GRP Tunnels 949

Summary 951 Exam Essentials 951 Written Lab 21 953 Hands-on Labs 953

Hands-on Lab 21.1: Configuring PPP Encapsulation and Authentication 953

Hands-on Lab 21.2: Configuring and Monitoring HDLC 955 Hands-on Lab 21.3: Configuring Frame Relay

and Subinterfaces 956 Hands-on Lab 21.4: Configuring a GRE Tunnel 958

Review Questions 961

Appendix A Answers to Written Labs 967

Chapter 1: Internetworking 968 Written Lab 1.1: OSI Questions 968 Written Lab 1.2: Defining the OSI Layers and Devices 969 Written Lab 1.3: Identifying Collision and

Broadcast Domains 970 Chapter 2: Ethernet Networking and Data Encapsulation 970

Written Lab 2.1: Binary/Decimal/Hexadecimal Conversion 970 Written Lab 2.2: CSMA/CD Operations 973 Written Lab 2.3: Cabling 973 Written Lab 2.4: Encapsulation 974

Chapter 3: Introduction to TCP/IP 974 Written Lab 3.1: TCP/IP 974 Written Lab 3.2: Mapping Applications to the DoD Model 974

Chapter 4: Easy Subnetting 975 Written Lab 4.1: Written Subnet Practice #1 975 Written Lab 4.2: Written Subnet Practice #2 976 Written Lab 4.3: Written Subnet Practice #3 977

Chapter 5: VLSMs, Summarization and Troubleshooting TCP/IP 977

Chapter 6: Cisco’s Internetworking Operating System (IOS) 978 Written Lab 6 978

Chapter 7: Managing a Cisco Internetwork 978 Written Lab 7.1: IOS Management 978 Written Lab 7.2: Router Memory 979

xxiv Contents

Chapter 8: IP Routing 979 Chapter 9: Open Shortest Path First (OSPF) 980 Chapter 10: Layer 2 Switching 980 Chapter 11: VLANs and InterVLAN Routing 980 Chapter 12: Security 981 Chapter 13: Network Address Translation (NAT) 981 Chapter 14: Internet Protocol Version 6 (IPv6) 982

Written Lab 14.1 982 Written Lab 14.2 982

Chapter 15: Enhanced Switch Technologies 982 Chapter 16: Managing Cisco Devices 983

Written Lab 16.1: IOS Management 983 Written Lab 16.2: Router Memory 983

Chapter 17: IP Services 984 Chapter 18: Troubleshooting IP, IPv6, and VLANs 984 Chapter 19: Enhanced IGRP 984 Chapter 20: Multi-Area OSPF 985 Chapter 21: Wide Area Networks 985

Appendix B Answers to Review Questions 987

Chapter 1: Internetworking 988 Chapter 2: Ethernet Networking and Data Encapsulation 990 Chapter 3: Introduction to TCP/IP 991 Chapter 4: Easy Subnetting 993 Chapter 5: VLSMs, Summarization, and

Troubleshooting TCP/IP 995 Chapter 6: Cisco’s Internetworking Operating System (IOS) 997 Chapter 7: Managing a Cisco Internetwork 999 Chapter 8: IP Routing 1001 Chapter 9: Open Shortest Path First (OSPF) 1002 Chapter 10: Layer 2 Switching 1004 Chapter 11: VLANs and InterVLAN Routing 1007 Chapter 12: Security 1008 Chapter 13: Network Address Translation (NAT) 1011 Chapter 14: Internet Protocol Version 6 (IPv6) 1012 Chapter 15: Enhanced Switch Technologies 1014 Chapter 16: Managing Cisco Devices 1016 Chapter 17: IP Services 1018 Chapter 18: Troubleshooting IP, IPv6, and VLANs 1021 Chapter 19: Enhanced IGRP 1022 Chapter 20: Multi-Area OSPF 1024 Chapter 21: Wide Area Networks 1026

Contents xxv

Appendix C Disabling and Configuring Network Services 1029

Blocking SNMP Packets 1030 Disabling Echo 1030 Turning off BootP and Auto-Config 1031 Disabling the HTTP Interface 1032 Disabling IP Source Routing 1032 Disabling Proxy ARP 1032 Disabling Redirect Messages 1032 Disabling the Generation of ICMP Unreachable Messages 1033 Disabling Multicast Route Caching 1033 Disabling the Maintenance Operation Protocol (MOP) 1033 Turning Off the X.25 PAD Service 1034 Enabling the Nagle TCP Congestion Algorithm 1034 Logging Every Event 1034 Disabling Cisco Discovery Protocol 1035 Disabling the Default Forwarded UDP Protocols 1035 Cisco’s Auto Secure 1036

Appendix D About the Additional Study Tools 1041

Additional Study Tools 1042 Test Engine 1042 Electronic Flashcards 1042 Videos 1042 Network Simulator 1043 PDF of Glossary of Terms 1043 Adobe Reader 1043

Minimum System Requirements 1043 Using the Study Tools 1044 Troubleshooting 1044

Customer Care 1044

Index 1045

Introduction

Welcome to the exciting world of Cisco certifi cation! If you’ve picked up this book because you want to improve yourself and your life with a better, more satisfying, and secure job, you’ve done the right thing. Whether you’re striving to enter the thriving, dynamic IT sector or se– ing to enhance your skill set and advance your position within it, being Cisco certifi ed can seriously stack the odds in your favor to help you attain your goals!

Cisco certifi cations are powerful instruments of success that also markedly improve your grasp of all things internetworking. As you progress through this book, you’ll gain a complete understanding of networking that reaches far beyond Cisco devices. By the end of this book, you’ll compr› ensively know how disparate network topologies and technologies work together to form the fully operational networks that are vital to today’s very way of life in the developed world. The knowledge and expertise you’ll gain here is essential for and relevant to every networking job and is why Cisco certifi cations are in such high demand—even at companies with few Cisco devices!

Although it’s now common knowledge that Cisco rules routing and switching, the fact that it also rocks the voice, data center, and service provider worlds is also well recognized. And Cisco certifi cations reach way beyond the popular but less extensive certifi cations like those offered by CompTIA and Microsoft to equip you with indispensable insight into today’s vastly complex networking realm. Essentially, by deciding to become Cisco certifi ed, you’re proudly announcing that you want to become an unrivaled networking expert—a goal that this book will get you well on your way to achieving. Congratulations in advance on the beginning of your brilliant future!

For up-to-the-minute updates covering additions or modifications to the Cisco certification exams, as well as additional study tools, review questions, and bonus materials, be sure to visit the Todd Lammle websites and forum at www.lammle.com , www.lammlesim.com , and www.lammle.com/forum .

Cisco’s Network Certifications

It used to be that to secure the holy grail of Cisco certifi cations—the CCIE—you passed only one written test before being faced with a grueling, formidable hands-on lab. This intensely daunting, all-or-nothing approach made it nearly impossible to succeed and predictably didn’t work out too well for most people. Cisco responded to this issue by creating a series of new certifi cations, which not only made it easier to eventually win the highly coveted CCIE prize, it gave employers a way to accurately rate and measure the skill levels of prospective and current employees. This exciting paradigm shift in Cisco’s certifi cation path truly opened doors that few were allowed through before!

xxviii Introduction

Beginning in 1998, obtaining the Cisco Certifi ed Network Associate (CCNA) certifi cation was the fi rst milestone in the Cisco certifi cation climb, as well as the offi cial prerequisite to each of the more advanced levels. But that changed in 2007, when Cisco announced the Cisco Certifi ed Entry Network Technician (CCENT) certifi cation. And then in March 2013, Cisco once again proclaimed updates to the CCENT and CCNA Routing and Switching (R/S) tests. Now the Cisco certifi cation process looks like Figure I.1.

F I GU R E I .1 The Cisco certification path

Routing/Switching

CCIE

CCNP

CCNA

CCENT

Data Center

CCIE

CCNP

CCNA

No Pre-req

Voice

Cisco 2013 Certification Path Announcements

CCIE

CCNP

CCNA

CCENT

Security

CCIE

CCNP

CCNA

CCENT

Wireless

CCIE

CCNP

CCNA

CCENT

I have included only the most popular tracks in Figure I.1. In addition to the ones in this image, there are also tracks for Design, Service Provider, Service Provider Operations, and Video. Also note that the CCIE Voice certification retirement will be announced shortly.

The Cisco R/S path is by far the most popular and could very well remain so, but soon you’ll see the Data Center path become more and more of a focus as companies migrate to data center technologies. The Voice track also actually does provide a good job opportunity. Still, understanding the foundation of R/S before attempting any other certifi cation track is something I highly recommend.

Even so, and as the fi gure shows, you only need your CCENT certifi cation to get under-way for most of the tracks. Also, note that there are a few other certifi cation tracks you can go down that are not shown in the fi gure, although they’re not as popular as the ones shown. You can fi nd information on all Cisco certifi cation tracks at: www.cisco.com .

Cisco Certified Entry Network Technician (CCENT) Don’t be fooled by the oh-so-misleading name of this fi rst certifi cation because it absolutely isn’t entry level! Okay—maybe entry level for Cisco’s certifi cation path, but defi nitely not for someone without experience trying to break into the highly lucrative yet challenging IT