cisco a beginner’s guide, third...

Cisco®

:A Beginner’s Guide,

Third Edition

ProLib8 / Cisco: A Beginner's Guide, Third Ed/ Velte/225635-4/ Front MatterBlind Folio FM:i

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ProLib8 / Cisco: A Beginner's Guide, Third Ed/ Velte/225635-4/ Front MatterBlind Folio FM:ii



Cisco®

:A Beginner’s Guide,

Third EditionANTHONY T. VELTE, CISSP

TOBY J. VELTE, PH.D.

McGraw-Hill/OsborneNew York Chicago San Francisco

Lisbon London Madrid Mexico City MilanNew Delhi San Juan Seoul Singapore Sydney Toronto

ProLib8 / Cisco: A Beginner's Guide, Third Ed/ Velte/225635-4/ Front MatterBlind Folio FM:iii



ProLib8 / Cisco: A Beginner's Guide, Third Ed/ Velte/225635-4/ Front MatterBlind Folio FM:iv

McGraw-Hill/Osborne2100 Powell Street, 10th FloorEmeryville, California 94608U.S.A.

To arrange bulk purchase discounts for sales promotions, premiums, or fund-raisers,please contact McGraw-Hill/Osborne at the above address. For information ontranslations or book distributors outside the U.S.A., please see the International ContactInformation page immediately following the index of this book.

Cisco®: A Beginner’s Guide, Third Edition

Copyright © 2004 by The McGraw-Hill Companies. All rights reserved. Printed in theUnited States of America. Except as permitted under the Copyright Act of 1976, no part ofthis publication may be reproduced or distributed in any form or by any means, or storedin a database or retrieval system, without the prior written permission of the publisher,with the exception that the program listings may be entered, stored, and executed in acomputer system, but they may not be reproduced for publication.

1234567890 CUS CUS 01987654

ISBN 0-07-225635-4

PublisherBrandon A. Nordin

Vice President & Associate PublisherScott Rogers

Editorial DirectorTracy Dunkelberger

Project ManagerJanet Walden

Project EditorsClaire SplanEmily Rader

Acquisitions CoordinatorJessica Wilson

Technical EditorTony Martin

Copy EditorMike McGee

ProofreadersJudy WilsonPaul Medoff

IndexerClaire Splan

CompositionInternational Typesettingand Composition

IllustratorInternational Typesettingand Composition

Series DesignPeter F. Hancik

This book was composed with Corel VENTURA™ Publisher.

This material is not sponsored by, endorsed by, or affiliated with Cisco Systems, Inc. Cisco®, Cisco Systems®, CCDA™,CCNA™, CCDP™, CCNP™, CCIE™, CCSI™, the Cisco Systems logo, and the CCIE logo are trademarks or registeredtrademarks of Cisco Systems, Inc., in the United States and in certain other countries. All other trademarks are trademarks oftheir respective owners.

Information has been obtained by McGraw-Hill/Osborne from sources believed to be reliable. However, because of thepossibility of human or mechanical error by our sources, McGraw-Hill/Osborne, or others, McGraw-Hill/Osborne does notguarantee the accuracy, adequacy, or completeness of any information and is not responsible for any errors or omissions orthe results obtained from the use of such information.



This book is dedicated toLuke, Jack, Joey, Olivia, and their mothers,

Anne Marie and Sandra.We’d also like to dedicate this book to

Robert Elsenpeter, his wife Janet, and their son Henry.To the wives, we say thank you for

holding down the fort… again. We love you.

ProLib8 / Cisco: A Beginner's Guide, Third Ed/ Velte/225635-4/ Front MatterBlind Folio FM:v



ProLib8 / Cisco: A Beginner's Guide, Third Ed/ Velte/225635-4/ Front MatterBlind Folio FM:vi

ABOUT THE AUTHORSAnthony Velte, CISSP, MCSE+I, CCDA, is cofounder of Velte Publishing, Inc. In additionto writing and publishing a variety of technology books, Mr. Velte finds joy in spendingtime with his sons Luke, Jack, and Joey. He has founded several companies and has morerecently led several large-scale network, security, and disaster recovery projects. He canbe reached at [email protected].

Toby Velte, Ph.D., MCSE+I, CCNA, CCDA, is cofounder of Velte Publishing, Inc. Dr. Velteis an international, best-selling author of technology articles and books. He is a self-proclaimed techno-geek and has started several high-tech companies in the Minneapolisarea. He can be reached at [email protected].

ABOUT THE TECHNICAL EDITORTony Martin is a Sales Systems Engineer for Level 3 Communications, Inc. His networkcertifications and licenses include the CCNA and Civil Engineering License. Tony has de-livered simultaneous large-scale, mission-critical merger and acquisition integrations.His experience includes designing, implementing and optimizing SONET, MPLS, IP,VPN, and VOIP solutions for Fortune 500 clients. He formerly worked as a Naval Engi-neering Systems School Instructor and served over nine years in the United States Navy.He completed a Bachelor of Science degree in Corporate Education, Training, and Devel-opment. He has published white papers and was a speaker at SuperComm 2003 onCALEA in Next-Generation Carrier Networks. Mr. Martin also was an editor for the titleJuniper and Cisco Routing: Policy and Protocols for Multivendor IP Networks by Walter J.Goralski (Wiley & Sons, 2002).



ProLib8 / Cisco: A Beginner's Guide, Third Ed/ Velte/225635-4/ Front Matter

AT A GLANCE

Part I Cisco Overview

▼ 1 Cisco and the Internet . . . . . . . . . . . . . . 3▼ 2 Networking Primer . . . . . . . . . . . . . . . 37▼ 3 Cisco Certifications . . . . . . . . . . . . . . . 103

Part II Cisco Internetworking Tools

▼ 4 Router Overview . . . . . . . . . . . . . . . . . 131▼ 5 Configuring Routers . . . . . . . . . . . . . . . 167▼ 6 Switches . . . . . . . . . . . . . . . . . . . . . . 217▼ 7 Quality of Service . . . . . . . . . . . . . . . . 275▼ 8 Security Overview . . . . . . . . . . . . . . . . 307▼ 9 Security Building Blocks . . . . . . . . . . . . 345▼ 10 Cisco Wireless . . . . . . . . . . . . . . . . . . 391

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viii Cisco: A Beginner's Guide, Third Edit ion


Part III Cisco Business Solutions

▼ 11 Cisco IP Contact Center . . . . . . . . . . . . . 437▼ 12 Storage Tools . . . . . . . . . . . . . . . . . . . 473▼ 13 Cisco Content Networking . . . . . . . . . . . 497

Part IV Designing Cisco Networks

▼ 14 Routing Protocols . . . . . . . . . . . . . . . . 527▼ 15 Network Management . . . . . . . . . . . . . 573▼ 16 Network Design Process . . . . . . . . . . . . 631▼ 17 Troubleshooting Cisco Networks . . . . . . . 679

▼ Index . . . . . . . . . . . . . . . . . . . . . . . 723



CONTENTS

Foreword . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xviiAcknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . xixIntroduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xxi

Part I

Cisco Overview

▼ 1 Cisco and the Internet . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3Internetworking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Cisco’s Position in the Computer Industry . . . . . . . . . . 6The Internet Landscape . . . . . . . . . . . . . . . . . . . . . 8

Cisco’s Offerings . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19Competition . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20Cisco Hardware Devices . . . . . . . . . . . . . . . . . . . . . 28Cisco Solutions . . . . . . . . . . . . . . . . . . . . . . . . . . 35

▼ 2 Networking Primer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37Bits and Bytes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

How Computers Understand Data . . . . . . . . . . . . . . . 38OSI Reference Model . . . . . . . . . . . . . . . . . . . . . . . . . . 42

ix




The Seven-Layer Stack . . . . . . . . . . . . . . . . . . . . . . 42OSI Implementation by Layer . . . . . . . . . . . . . . . . . . 45

Network Technologies . . . . . . . . . . . . . . . . . . . . . . . . . 47Ethernet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48Token Ring . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50ATM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52Gigabit and 10 Gigabit Ethernet . . . . . . . . . . . . . . . . . 58FDDI . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58

WAN Technologies . . . . . . . . . . . . . . . . . . . . . . . . . . . 60Dial-in Technologies . . . . . . . . . . . . . . . . . . . . . . . 61WAN Trunk Technologies . . . . . . . . . . . . . . . . . . . . 65

TCP/IP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68TCP/IP Messaging . . . . . . . . . . . . . . . . . . . . . . . . 69The Transport Layer . . . . . . . . . . . . . . . . . . . . . . . 73

IP Addressing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79The IP Address Format . . . . . . . . . . . . . . . . . . . . . . 79IP Address Classes . . . . . . . . . . . . . . . . . . . . . . . . 82Private Addressing . . . . . . . . . . . . . . . . . . . . . . . . 83Subnetting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84IP Version 6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90

Putting It All Together . . . . . . . . . . . . . . . . . . . . . . . . . 101

▼ 3 Cisco Certifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103Certifications Overview . . . . . . . . . . . . . . . . . . . . . . . . 105

Cisco Career Paths Overview . . . . . . . . . . . . . . . . . . 105The CCIE Pathway . . . . . . . . . . . . . . . . . . . . . . . . . . . 106

CCIE Overview . . . . . . . . . . . . . . . . . . . . . . . . . . 106CCIE Tracks . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107

Associate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108CCDA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108CCNA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108

Professional . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110CCDP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110CCIP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111CCNP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111CCSP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112

Cisco Qualified Specialist . . . . . . . . . . . . . . . . . . . . . . . 115Access Routing and LAN Switching Certification . . . . . . 115Cable Communications Certification . . . . . . . . . . . . . . 115Content Networking Certification . . . . . . . . . . . . . . . 116IP Telephony Certification . . . . . . . . . . . . . . . . . . . . 117Multiservice Switching Certification . . . . . . . . . . . . . . 119Network Management Certification . . . . . . . . . . . . . . 119

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Optical Certification . . . . . . . . . . . . . . . . . . . . . . . 120Public Access Certification . . . . . . . . . . . . . . . . . . . . 121VPN and Security Certification . . . . . . . . . . . . . . . . . 123Wireless LAN Certification . . . . . . . . . . . . . . . . . . . 124

Where to Get Help . . . . . . . . . . . . . . . . . . . . . . . . . . . 125Web Sites . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125Classes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126

Part II

Cisco Internetworking Tools

▼ 4 Router Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131How Routers Work . . . . . . . . . . . . . . . . . . . . . . . . . . . 133

Routing for Efficiency . . . . . . . . . . . . . . . . . . . . . . 134Routers and the Internet . . . . . . . . . . . . . . . . . . . . . 135Optical Routers . . . . . . . . . . . . . . . . . . . . . . . . . . 137

Communicating with a Router . . . . . . . . . . . . . . . . . . . . 140The Console Port . . . . . . . . . . . . . . . . . . . . . . . . . 141The Auxiliary Port . . . . . . . . . . . . . . . . . . . . . . . . 143Telnet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143The HTTP Server User Interface . . . . . . . . . . . . . . . . 145

Router Security . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146Router Passwords . . . . . . . . . . . . . . . . . . . . . . . . . 147

Router Hardware . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150Router Memory . . . . . . . . . . . . . . . . . . . . . . . . . . 151Router Ports and Modules . . . . . . . . . . . . . . . . . . . . 153

Essential Files . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157IOS: The Internetwork Operating System . . . . . . . . . . . 157The Configuration File . . . . . . . . . . . . . . . . . . . . . . 164

▼ 5 Configuring Routers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 167The Configuration File’s Central Role . . . . . . . . . . . . . . . . 168

Three Types of Cisco Router Files . . . . . . . . . . . . . . . 169Getting Started with Cisco Routers . . . . . . . . . . . . . . . . . . 172

Communicating with IOS . . . . . . . . . . . . . . . . . . . . 172Meet IOS 12.3 . . . . . . . . . . . . . . . . . . . . . . . . . . . 173Using IOS Commands . . . . . . . . . . . . . . . . . . . . . . 176Overview of Router Modes . . . . . . . . . . . . . . . . . . . 183

Essential Router Commands . . . . . . . . . . . . . . . . . . . . . . 185Step-by-Step Router Configuration . . . . . . . . . . . . . . . . . . 187

Setup Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188Giving a Router an Identity . . . . . . . . . . . . . . . . . . . 192

Contents xi




Examining Device Status . . . . . . . . . . . . . . . . . . . . . 193Cisco Discovery Protocol . . . . . . . . . . . . . . . . . . . . 194

Password Recovery . . . . . . . . . . . . . . . . . . . . . . . . . . . 197Recovering Enable Passwords . . . . . . . . . . . . . . . . . . 198Recovering Passwords from Older Cisco Routers . . . . . . 203

Using Applications to Help Configure Routers . . . . . . . . . . . 204ConfigMaker . . . . . . . . . . . . . . . . . . . . . . . . . . . 204Fast Step . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 209

▼ 6 Switches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 217Network Topologies . . . . . . . . . . . . . . . . . . . . . . . . . . 219

The Importance of Network Domains . . . . . . . . . . . . . 222Cabling Defines Network Speed and Distance . . . . . . . . 226

Cisco Switches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 233How an Individual Switch Works . . . . . . . . . . . . . . . 234Switched Networking Basics . . . . . . . . . . . . . . . . . . 236Designing Switched Internetworks . . . . . . . . . . . . . . . 237VLANs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 242Cisco’s Switched Network Products . . . . . . . . . . . . . . 244Configuring and Managing Cisco Switches . . . . . . . . . . 245

Visual Switch Manager . . . . . . . . . . . . . . . . . . . . . . . . . 245Visual Switch Manager Software . . . . . . . . . . . . . . . . 249The Visual Switch Manager Home Page . . . . . . . . . . . . 250The Interactive Device Graphic in Visual Switch Manager . . . 251Network View . . . . . . . . . . . . . . . . . . . . . . . . . . . 253Switch Port Configuration . . . . . . . . . . . . . . . . . . . . 253Port Grouping . . . . . . . . . . . . . . . . . . . . . . . . . . . 255Port Monitoring (SPAN) . . . . . . . . . . . . . . . . . . . . . 256Flooding Controls/Network Port . . . . . . . . . . . . . . . . 257System Configuration . . . . . . . . . . . . . . . . . . . . . . 259IP Management . . . . . . . . . . . . . . . . . . . . . . . . . . 259SNMP Configuration . . . . . . . . . . . . . . . . . . . . . . . 261ARP Table . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 262Address Management . . . . . . . . . . . . . . . . . . . . . . 262Port Security . . . . . . . . . . . . . . . . . . . . . . . . . . . . 263Cisco Discovery Protocol . . . . . . . . . . . . . . . . . . . . 264Cisco Group Multicast Protocol . . . . . . . . . . . . . . . . . 265Spanning-Tree Protocol . . . . . . . . . . . . . . . . . . . . . 266VLAN Membership . . . . . . . . . . . . . . . . . . . . . . . 267VTP Management . . . . . . . . . . . . . . . . . . . . . . . . . 268VMPS Configuration . . . . . . . . . . . . . . . . . . . . . . . 270VTP/VQP Statistics . . . . . . . . . . . . . . . . . . . . . . . . 271Logging Configuration . . . . . . . . . . . . . . . . . . . . . . 272

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Contents xiii


▼ 7 Quality of Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 275What Is QoS? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 276

Why Your Organization Needs QoS . . . . . . . . . . . . . . 277Key QoS Concepts . . . . . . . . . . . . . . . . . . . . . . . . 279

Ensuring QoS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 282Bandwidth Provisioning . . . . . . . . . . . . . . . . . . . . . 283Bandwidth Prioritization . . . . . . . . . . . . . . . . . . . . 286Congestion Avoidance . . . . . . . . . . . . . . . . . . . . . . 289Congestion Management . . . . . . . . . . . . . . . . . . . . 292Packet Shapers . . . . . . . . . . . . . . . . . . . . . . . . . . 295Networking Scenarios . . . . . . . . . . . . . . . . . . . . . . 297

Cisco’s Solution . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 299Services . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 299Products . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 301

▼ 8 Security Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 307Overview of Network Security . . . . . . . . . . . . . . . . . . . . 310

Traffic-Based Security . . . . . . . . . . . . . . . . . . . . . . 310User-Based Security . . . . . . . . . . . . . . . . . . . . . . . 312

Authentication, Authorization, and Accounting . . . . . . . . . . 315Overview of the AAA Model . . . . . . . . . . . . . . . . . . 316How AAA Works . . . . . . . . . . . . . . . . . . . . . . . . . 323

Dynamic Access Lists . . . . . . . . . . . . . . . . . . . . . . . . . . 341Lock-and-Key Using a Local User Database . . . . . . . . . . 343

▼ 9 Security Building Blocks . . . . . . . . . . . . . . . . . . . . . . . . . . . 345Firewalls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 347

Firewall Basics . . . . . . . . . . . . . . . . . . . . . . . . . . 347How Firewalls Work . . . . . . . . . . . . . . . . . . . . . . . 351The IOS Firewall Feature Set . . . . . . . . . . . . . . . . . . 360Cisco Secure PIX Firewall . . . . . . . . . . . . . . . . . . . . 370

Virtual Private Networks . . . . . . . . . . . . . . . . . . . . . . . . 377What Composes a VPN . . . . . . . . . . . . . . . . . . . . . 379Cisco’s Solution . . . . . . . . . . . . . . . . . . . . . . . . . . 382

Access Routers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 386Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 386Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 388

Intrusion Detection System . . . . . . . . . . . . . . . . . . . . . . 388Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . 388Monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . 390



xiv Cisco: A Beginner's Guide, Third Edit ion


▼ 10 Cisco Wireless . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 391Introduction to Wireless Networking . . . . . . . . . . . . . . . . . 392

The Roots of Wireless Networking . . . . . . . . . . . . . . . 392Benefits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 393

WLANs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 395How They Work . . . . . . . . . . . . . . . . . . . . . . . . . 395Architecture . . . . . . . . . . . . . . . . . . . . . . . . . . . . 397Technologies . . . . . . . . . . . . . . . . . . . . . . . . . . . 400

Cisco Wireless Networking . . . . . . . . . . . . . . . . . . . . . . 412Acquisitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 412Wireless Products . . . . . . . . . . . . . . . . . . . . . . . . . 413

Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 419Access Points . . . . . . . . . . . . . . . . . . . . . . . . . . . 419Clients . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 422Security . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 427

Part III

Cisco Business Solutions

▼ 11 Cisco IP Contact Center . . . . . . . . . . . . . . . . . . . . . . . . . . . 437VoIP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 438

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . 439Building VoIP Networks . . . . . . . . . . . . . . . . . . . . . 441H.323 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 449Implementation . . . . . . . . . . . . . . . . . . . . . . . . . . 455Cisco VoIP Products . . . . . . . . . . . . . . . . . . . . . . . 457

Cisco Intelligent Contact Management . . . . . . . . . . . . . . . . 461Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 461Call Flow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 465Callbacks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 467Web Collaboration . . . . . . . . . . . . . . . . . . . . . . . . 468Switching and Routing . . . . . . . . . . . . . . . . . . . . . . 469ICM Security Best Practices . . . . . . . . . . . . . . . . . . . 469

▼ 12 Storage Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 473Storage Area Networks . . . . . . . . . . . . . . . . . . . . . . . . . 474

Storage Needs . . . . . . . . . . . . . . . . . . . . . . . . . . . 474Fibre Channel . . . . . . . . . . . . . . . . . . . . . . . . . . . 476Other SAN Protocols . . . . . . . . . . . . . . . . . . . . . . . 478Designing and Building a SAN . . . . . . . . . . . . . . . . . 479

Cisco MDS Switches . . . . . . . . . . . . . . . . . . . . . . . . . . 484Technologies . . . . . . . . . . . . . . . . . . . . . . . . . . . 485Hardware . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 490Software . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 494



▼ 13 Cisco Content Networking . . . . . . . . . . . . . . . . . . . . . . . . . . 497Content Delivery Networks . . . . . . . . . . . . . . . . . . . . . . 498

Meet the CDN . . . . . . . . . . . . . . . . . . . . . . . . . . . 498Cisco’s Solution . . . . . . . . . . . . . . . . . . . . . . . . . . 500

Cisco Products . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 508Content Distribution Managers . . . . . . . . . . . . . . . . . 508Content Routers . . . . . . . . . . . . . . . . . . . . . . . . . . 509Content Engines . . . . . . . . . . . . . . . . . . . . . . . . . 509Content Switches . . . . . . . . . . . . . . . . . . . . . . . . . 511Cisco IP/TV . . . . . . . . . . . . . . . . . . . . . . . . . . . . 511Global Site Selector Platform . . . . . . . . . . . . . . . . . . 512CDN Software . . . . . . . . . . . . . . . . . . . . . . . . . . . 512

Caching . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 514Web Cache Communication Protocol . . . . . . . . . . . . . 514Freshness . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 515Content Engine Caching . . . . . . . . . . . . . . . . . . . . . 517

Part IV

Designing Cisco Networks

▼ 14 Routing Protocols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 527Overview of Routing Protocols . . . . . . . . . . . . . . . . . . . . 528

Routing Protocol Basics . . . . . . . . . . . . . . . . . . . . . 529Routing Protocol Architectures . . . . . . . . . . . . . . . . . 546How Routing Protocols Are Implemented . . . . . . . . . . . 551

Overview of Cisco Routing Protocols . . . . . . . . . . . . . . . . . 557Cisco’s Interior Gateway Routing Protocol . . . . . . . . . . 558Configuring RIP 2 . . . . . . . . . . . . . . . . . . . . . . . . 563Configuring Open Shortest Path First . . . . . . . . . . . . . 564Border Gateway Protocol . . . . . . . . . . . . . . . . . . . . 567Mulitprotocol Label Switching . . . . . . . . . . . . . . . . . 568Cisco’s Routing Protocol Strategy . . . . . . . . . . . . . . . 571

▼ 15 Network Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . 573Overview of Network Management . . . . . . . . . . . . . . . . . 574

The Evolution of Management Tools . . . . . . . . . . . . . . 576Network Management Tools Today . . . . . . . . . . . . . . 578Trends in Enterprise System Management . . . . . . . . . . 581

SNMP Is IP’s Common Management Platform . . . . . . . . . . . 583What Is SNMP? . . . . . . . . . . . . . . . . . . . . . . . . . . 583SNMP Polling and Managed Objects . . . . . . . . . . . . . . 585The MIB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 585

Contents xv




Polling Groups and Data Aggregation . . . . . . . . . . . . . 592SNMP Commands . . . . . . . . . . . . . . . . . . . . . . . . 595Thresholds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 595Events and Traps . . . . . . . . . . . . . . . . . . . . . . . . . 596RMON: Hardware Probes for Switched Networks . . . . . . 598Trends in Network Management Technology . . . . . . . . . 601Cisco’s SNMP and RMON Implementations . . . . . . . . . 605

CiscoWorks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 609CiscoWorks Overview . . . . . . . . . . . . . . . . . . . . . . 610CiscoWorks Resource Manager Essentials . . . . . . . . . . . 611CiscoView: The Tool for Managing Individual Devices . . . 616Threshold Manager . . . . . . . . . . . . . . . . . . . . . . . . 618Resource Manager Essentials Applications . . . . . . . . . . 619CiscoWorks for Switched Internetworks . . . . . . . . . . . . 625

▼ 16 Network Design Process . . . . . . . . . . . . . . . . . . . . . . . . . . . 631Internetwork Design Basics . . . . . . . . . . . . . . . . . . . . . . 632

Internetworking Basics Reviewed . . . . . . . . . . . . . . . 632The Three-Layer Hierarchical Design Model . . . . . . . . . 639Design Methods . . . . . . . . . . . . . . . . . . . . . . . . . . 644

Designing to Fit Needs . . . . . . . . . . . . . . . . . . . . . . . . . 649Understanding Existing Internetworks . . . . . . . . . . . . 651Characterizing Networks . . . . . . . . . . . . . . . . . . . . 652

Cisco Network Designs . . . . . . . . . . . . . . . . . . . . . . . . . 657Logical Network Design . . . . . . . . . . . . . . . . . . . . . 657Campus Network Designs . . . . . . . . . . . . . . . . . . . . 662

▼ 17 Troubleshooting Cisco Networks . . . . . . . . . . . . . . . . . . . . . . . 679The Mechanics of Network Troubleshooting . . . . . . . . . . . . 680

Network Troubleshooting Methods . . . . . . . . . . . . . . 681Troubleshooting Host IP Configuration . . . . . . . . . . . . 683Isolating Connectivity Problems . . . . . . . . . . . . . . . . 687Troubleshooting WAN Links . . . . . . . . . . . . . . . . . . 703Client-Server VPNs . . . . . . . . . . . . . . . . . . . . . . . . 707

Troubleshooting Cisco Hardware . . . . . . . . . . . . . . . . . . . 710Inspecting Devices . . . . . . . . . . . . . . . . . . . . . . . . 711The Reboot Test . . . . . . . . . . . . . . . . . . . . . . . . . . 712

Troubleshooting Network Configurations . . . . . . . . . . . . . . 713Wireless Networks . . . . . . . . . . . . . . . . . . . . . . . . 713

Troubleshooting Network Performance . . . . . . . . . . . . . . . 719

▼ Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 723

xvi Cisco: A Beginner's Guide, Third Edit ion




FOREWORD

When it comes to networking, Cisco® rules the roost. Internet infra-structure, corporate networks—they all involve those green boxes.Knowing how they work, what they can do, and how to implement

things is key to working on today’s computing infrastructure.

Choosing a network career path means learning about certifications, security,and network design issues. Fortunately, you can gain the critical knowledge you’llneed without spending countless hours trying to figure things out all by yourself—an impractical move at best.

I still remember setting up my first screening routers in front of my firstfirewall. Even now, many, many networks and routers later, there’s somethingabout building a new network that fills me with a sense of purpose. Putting accesslists on a live, running router to help secure a network is still a skill that comes inhandy, many years after I first learned how. Confidently assuring an executive thathis network won’t go down because of the change is about the only real differencetime has added.

When I connected usatoday.com to the Internet, I’d already learned enoughabout Cisco routers to proclaim confidently that the site would be ready for demon-strating during the Windows 95 launch day, even though we had less than 48 hoursto perform the entire operation, from ordering a circuit to having visitors access thesite. Knowing how to set up the routers gave me that confidence.

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Building and understanding networks is the key to keeping a modern company run-ning. Like laying the train tracks of yesteryear, these are the connections that keep theeconomy flowing. Network design and operations are a rewarding career. Learning theins and outs and the fundamentals can be a challenge. Fortunately, you’ve picked the bestway to start—a comprehensive book that’s easy to understand and easy to reference.

Computer networks are amazing things. The ability to communicate with peopleyou’ve never met, order products from companies around the globe instantly, keep in in-stant touch with friends on another continent—all of these things are taken for granted bypeople all over the world. A relative few understand the technology that allows them tosit at their desks and do these things. Web sites, e-mail, instant messaging, and voice andvideo communications all require a network.

It used to be said “You can’t go wrong buying IBM.” In today’s corporate world, thesame is said of Cisco. Knowing how Cisco gear works is the only real way to get a goodnetworking job. Knowing how networks work is fundamental to today’s corporate andInternet infrastructure. Here, you’ll learn both at once.

This book is your first step in learning how to work with the equipment that powersmost of those networks, and in understanding how it all works. Like any good journey,this one promises to be a grand adventure.

Paul D. RobertsonDirector of Risk Assessment, TruSecure® CorporationModerator, Firewall-Wizards® Security Mailing List

Paul Robertson has been in information technology and security for over 20 years; high-lights include being stationed at the White House while in the United States Army andputting USA Today’s Web site on the Internet. Paul currently helps manage risk for hun-dreds of corporate clients at TruSecure®, and he participates in computer forensics, advo-cating www.personalfirewallday.org and moderating the Firewall-Wizards mailing list.


xviii Cisco: A Beginner's Guide, Third Edit ion



ACKNOWLEDGMENTS

The first edition of this book would never have taken off without theenormous contributions of author Tom Shaughnessy. To him we owe awonderful basis from which to build. For both the second and third

editions, we called upon the talents of author Robert Elesenpeter. He cor-rected typos, edited and reworked text and art so that it was clear and cur-rent, and contributed some original work to flesh out both editions. We alsoextend our appreciation to technical editor Tony Martin. His careful reviewhas helped ensure a high level of technical accuracy in this edition.

It was yet again a pleasure working with the team at Osborne/McGraw Hill. Tothis edition’s acquisitions editor, Tracy Dunkleberger, and acquisitions coordina-tors, Jessica Wilson and Athena Honore, we say thank you very much. To theOsborne illustration team, we say thank you for your patience. And to this edition’sproject editors, Claire Splan and Emily Rader, and copy editor Mike McGee, we saythank you so very much for your light but incisive touch with the wordsmith’s evernecessary scalpel.

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ProLib8 / Cisco: A Beginner's Guide, Third Ed/ Velte/225635-4/ Front MatterBlind Folio FM:xx



INTRODUCTION

The volume in your hands is the third edition of the worldwide,best-selling introduction to Cisco networking. Since its introduction,this book has sold over 60 thousand copies, has been translated into

numerous languages, and is distributed all over the world. This level of in-terest confirms what you already know—Cisco is, and continues to be, ahuge player in the communications industry, and people want to better un-derstand how this behemoth works.

Although three years have passed since writing the second edition, the bookhas remained quite popular, and we felt that another refresh was in order. As withthe second edition, we took the book apart and reexamined each chapter. If youplace this book next to the first edition and second editions, the first thing you’llprobably notice is that it is getting progressively thicker. Although we werehard-pressed to find material we thought was no longer pertinent, we certainlyfound new subjects that just had to be discussed. For instance, we have again fol-lowed Cisco’s changes to its certification program and updated our coverage ofwhich Cisco certifications are current and how to get them. In the second edition,we added a new chapter that focused on Cisco business solutions, including Voiceover IP (VoIP), storage area networks (SANs), and content distribution networks(CDNs). In this edition, we expanded the content in all three areas, making eachinto its own chapter. Because security has become ever more important, we also

xxi




beefed up the security content, which is now covered in two chapters. Of course, all chap-ters were updated to cover the latest hardware and software offerings from Cisco.

So what’s the reason for all of this work and revision? We continue to think that thereis an enormous need by networking professionals for a clear, concise introduction toCisco and its technology. In offices and conference rooms throughout the world, scenar-ios like the one described next are enacted—with abysmal outcomes. What is trulyneeded is a simple understanding of networking and Cisco’s role in networking to makesense of many IT issues. So the story begins…

Almost two million dollars spent so far, thought the VP, yet the board was forced toseriously contemplate pulling the plug on the project. He’d been sent to identify the prob-lem and to identify how to fix it. “OK,” he said, as he took a seat at the head of the table,“I’m throwing open the agenda. I want to know what the project’s major problems are,what is causing them, and how long and how much it’ll take to fix them.” Turning towardthe CIO and his network manager, the VP went on, “We all know that this project is cen-tral to our corporate strategy; nothing else has had a higher priority or consumed moreresources during the last year. Yet our two primary competitors have already success-fully expanded their Web site capacity, implemented load balancing, and upgraded theirbusiness-to-business environments. But we can’t see the light at the end of the tunnel. Letme remind you that this isn’t just another little departmental application; the board wantsthe Internet to become our primary place of business. Our competition has already cuttheir cost of sales by 15 percent or more, and we’ve lost 5 percent market share in the lastquarter alone. We aren’t thrilled with having a half-finished network that runs like a dog,not to mention being over budget, but this weekend’s security breach may have been thelast straw. What’s wrong with this project?”

The CIO spoke up, saying the contractors weren’t adhering to the three-level hierar-chical design he’d requested, complaining that back doors and chains were choking per-formance. The consultant shot back that if the company had retained the contractors forproject management, things would be under better control using their rigorous manage-ment methodology. A person from the Web programming team snidely noted that thecontext-based access control algorithm was “puking back hosed code every time the im-plicit deny rule hit bottom.” Another complained that the so-called strong cryptographychosen for the VPN was using an overwrought DES key. The consultants disputed thatstatement, noting that RMONs were probably chewing up too many CPU clicks with MIBcollection and that the NMS was overpolling SNMP anyway.

The Network Manager then took exception, pointing out that the originalEtherChannel wire-speed benchmark could be attained only if “major upgrades” weremade to the blades jacked into the backplanes of the various LAN switches, especially theones feeding the ATM LANE adapters, because they were blocking broadcasts withinVLANs. Sure, now they all agreed that the route switch processor modules on the “bighonker” Cisco 7500 were grossly underconfigured, but that wasn’t the story during thebig “to route or to switch” debate during the design phase. Fact is, if the backbone routershad PIM sparse mode implemented, everything would be cool, but now multicasts werebringing the network to its knees because there were too many unknown groups, especially

xxii Cisco: A Beginner's Guide, Third Edit ion




going through the IGX switch fabric. Without that humming, QoS—especially for trafficshaping and CAR—didn’t have a snowball’s chance in summer, at least not without a seriouscommitment being made to multilayer switching, as had been recommended. This wasthe case given all the subnet masks, DHCP, and DNS to handle at the access layer.

The consultants begged to disagree, pointing out that propagation delays werespawning loops, especially in the RIP domains, something they had specifically recom-mended against. IGRP was the superior choice or, better yet, EIGRP. However, once therouting metrics were properly tuned, the RIP versus IGRP thing would fall to the way-side. Then traps could at long last be set to alarm for out-of-band operations, freeing theteam to tweak the CBAC and ASA algorithms to assure that last weekend’s security debacledidn’t repeat itself.

The VP felt trapped and alarmed. Sensing the VP’s growing discomfort, the head con-sultant blurted out an offer to reduce the billing rate for the nine people engaged full-timeon the project from $160 to $150 an hour. At the end of his rope, the VP said, “I must tellyou that I’ve never heard so much bull in my entire life. I’ve been in data processing forover twenty years, and I haven’t understood a thing said in this meeting. It really bothersme that you network people can’t speak plain English. This project is caught in a loop,and I’ve gotta get a grip on things here. Let’s adjourn for now and get together afterlunch.”

At the back of the room sat two young staffers who were in the meeting just in case thenetwork performance statistics they’d gathered needed explanation. They hadn’t under-stood much of what was said, either. But without saying a word, they looked at one an-other and raised their eyebrows at the same thought: $160 per hour?

WHO SHOULD READ THIS BOOKThis book is designed for anybody new to internetworking. It covers what one might referto as the Internet’s technical infrastructure. The software on your desktop—the Webbrowser, FTP software, or ICQ messenger—is only the tip of the iceberg. Over the past 30years, an ever-growing group of dedicated computer scientists, telecommunications en-gineers, and programmers have been busy designing and building a global infrastructurethat is revolutionizing commerce and culture alike. As you saw in the earlier meeting sce-nario, internetworking has taken on a language all its own—separate even from that usedby the computer industry at large.

This book is for aspiring professionals interested in learning about the networking gi-ant, managers in the computing industry whose knowledge of internetworking is weak,computer platform and software pros, and even individuals in the general public with ataste for technology.

This book is for those interested in the Internet and internetworking, not just in Cisco.Technology basics are covered generically before delving into Cisco particulars. Cisco isused for all examples in this book because it has the biggest and most comprehensiveproduct line in the industry and is still the most important player in the field.

Introduction xxiii




For those of you interested in pursuing Cisco certification, read this book to be intro-duced to industry background, concepts, terms, and technology. Then go on to a testpreparation book to nail down your CCNA test. Indeed, the publisher of this book alsopublishes the best CCNA test prep book, CCNA Cisco Certified Network Associate StudyGuide, Second Edition, by Syngress Media, Inc. (McGraw-Hill/Osborne, 2000).

WHAT THIS BOOK COVERSThe following is a chapter-by-chapter breakdown of the subject matter covered in thisbook.

Part I, “Cisco Overview”Chapter 1, “Cisco and the Internet”—The Internet represents the biggest and fastest eco-nomic change in history, and sooner or later all our lives will be profoundly affected by it(if they haven’t been already). This chapter surveys the Internet as a phenomenon, with aparticular eye toward Cisco Systems and how its IOS operating software has vaulted thecompany to a position among the computer industry elite, alongside Microsoft, Intel, andIBM. The internetworking industry is outlined, and how Cisco’s product line matches upto industry niches is explained.

Chapter 2, “Networking Primer”—Modern internetworking is the culmination ofdozens of sophisticated technologies. This chapter explains things from the wire up,starting first with electrons passing over cables, up through binary bits and bytes. Themajor LAN technologies such as Ethernet and Token Ring are explained, right down tohow they differ and which are rising or fading from use, including high-speed backbonetechnologies such as ATM and Gigabit Ethernet. The seven-layer Open Systems Intercon-nection (OSI) reference model is explained, including the inner workings of the TCP/IPprotocol suite—the software used to run the Internet. You’ll learn the difference betweenconnection-oriented and connectionless networking, and how domain names are trans-lated to numerical IP addresses. The important networking fundamentals of IP address-ing and subnet masks are explained in detail. Dial-in technologies such as DSL and ISDNare covered, as are WAN trunk technologies like T1 and T3, Frame Relay, and ATM.

Chapter 3, “Cisco Certifications”—Like Microsoft and Novell, Cisco has a full-fledged certification program for technicians working on their products. This chapterdetails the three paths—Cisco Certified Network Associate (CCNA), Cisco Certified Net-work Professional (CCNP), and Cisco Certified Internetworking Engineer (CCIE)—alongwith the sundry other areas in which Cisco certifies network professionals. Complete ex-planations are given of exam objectives for each certification. We also highlight a numberof ways you can find help preparing for the Cisco exams. A must-read for anyone inter-ested in pursuing a career in internetworking or anyone faced with recruiting and man-aging Cisco-certified personnel.

xxiv Cisco: A Beginner's Guide, Third Edit ion




Part II, “Cisco Internetworking Tools”Chapter 4, “Router Overview”—This chapter focuses on Cisco router basics. We coverrouter hardware components from the printed circuit board up through the CPU, and ex-plain how network administrators can log into Cisco routers to work on them, evenrebooting to perform such basic tasks as password recovery. The major software compo-nents in Cisco routers are also surveyed, including the Cisco IOS command interface andfeature sets. Cisco’s router product line is reviewed here, including some tips on how toselect the best router to solve a particular internetworking problem.

Chapter 5, “Configuring Routers”—Now it’s time to delve into the heavier stuff,especially the configuration file. This chapter goes into the Cisco IOS operating mode,command hierarchy, utilities, and how to use the IOS help subsystem. But most of the fo-cus is on the all-important configuration file, and how it’s used to set up Cisco routers andconfigure networks. Reading this chapter introduces you to essential Cisco router com-mands, command syntax, how to read device status, and how to configure key router pa-rameters. Cisco’s ConfigMaker and FastStep configuration software tools are reviewed.

Chapter 6, “Switches”—The so-called access layer is where host devices such as PCsand servers plug into internetworks. This chapter explains internetwork topology basics,cabling specifications, what bandwidth is, what distinguishes collision and broadcast do-mains, and how hubs and access switches differ. High-end LAN backbone switches arealso covered, from the perspective of one of the most important subjects in the industrytoday—whether to design routed or switched networks. The more technical dimensionsof switched networking are introduced, including switching protocols, virtual LANs(VLANs), and multilayered switching. Cisco’s switch product lines are reviewed.

Chapter 7, “Quality of Service”—As more and more applications become band-width hogs, mission critical data can find itself mired down in the ether. Providing fast,reliable service is essential for any internetwork. Throwing more bandwidth at the prob-lem isn’t the solution. Rather, organizations need good Quality of Service (QoS) technolo-gies and policies in place. This chapter discusses the issue of QoS and tells you how youcan implement a good QoS solution using Cisco tools. We cover the philosophy behinddifferent QoS techniques and introduce you to Cisco’s QoS hardware and software offerings.

Chapter 8, “Security Overview”—Network security that exists beyond firewalls isuser-based security, used to set and enforce passwords to access networks and authoriza-tions to use network resources. This chapter first covers the underlying industry stan-dards for security, especially the AAA (Authentication, Authorization, and Accounting)standard. AAA is covered at the command level, and then the CiscoSecure ACS productsuite is reviewed. Cisco offers two user-based security products: RADIUS, an industrystandard, and its proprietary TACACS+. Both are reviewed in detail.

Chapter 9, “Security Building Blocks”—There are three types of technologiesthrough which internetworks can be accessed: firewalls, access servers, and virtual pri-vate networks (VPNs). This chapter explains each of the three, with a particular focus onfirewalls. The access list is explained, as are adaptive firewall security algorithms, thetechnology at the heart of internetwork security at the packet level. Cisco sells twofirewall products: the Cisco PIX Firewall hardware/software combination and the IOS

Introduction xxv




Firewall software feature set, and both are explained in detail. The VPN—the wide areanetwork (WAN) of the future—is covered. How access servers work, and the role theyplay is also surveyed. Further, Cisco’s access server product line is reviewed.

Chapter 10, “Cisco Wireless”—Until recently, the only way to connect to aninternetwork was via a thin piece of cable snaking into the back of your PC. As efficient asthis has been, it was only a matter of time until someone figured out how to cut the cordand let devices communicate with each other in a wireless medium. In this chapter, wecover the fundamentals of wireless networking, and then delve into Cisco’s solution.Wireless networking is not just a “gee-whiz” technology. Wireless networking brings thepower of computing and network connectivity to a range of useful applications and isbeneficial to such fields as health care and education. Cisco offers solutions for both wire-less LANs and wireless WANs with its Aironet series that we discuss and then show youhow to configure.

Part III, “Cisco Business Solutions”Chapter 11, “Cisco IP Contact Center”—Networks and internetworks are great ways tomove data from place to place. However, it isn’t just text files and the fourth-quarter earn-ings statement that can traverse a Cisco-based network infrastructure. Thanks to Voiceover IP (VoIP), your organization can use its internetwork as the backbone of your tele-communications system. Additionally, customers who need to get in contact with yourorganization will benefit from Cisco Intelligent Contact Management, a system allowingcustomers to contact an organization through its Web site and request telephone or textchats.

Chapter 12, “Storage Tools”—With benefits of the Information Age comes a heftyissue—where do we keep all that information? In this chapter, we examine storage areanetworks (SANs), which are akin to LANs but are built with the goal of storing informa-tion. We’ll talk about SAN designs and construction and then look at the products Ciscooffers for its SAN solutions, including its Multilayer Datacenter Switches (MDS) line.

Chapter 13, “Cisco Content Networking”—Organizations are offering more andmore information on their Web sites. However, as more people request that data fromvarious locations, the need arises to direct the client to the closest, fastest repository ofthat information. Content delivery networks (CDNs) help resolve congested networksbecause clients are given the data they need from the ideal location. This chapter coversCDN basics, along with Cisco’s product line for this technology. Additionally, we coverthe topic of caching, a way in which service providers and large organizations can main-tain frequently accessed Web information so that it can be delivered without having to re-peatedly go to the Internet to access it.

Part IV, “Designing Cisco Networks”Chapter 14, “Routing Protocols”—Large internetworks, or for that matter the Internet,wouldn’t be possible without routing protocols. This chapter covers fundamental prob-lems confronting any internetwork, as well as how routing protocols are used to adapt toshifting traffic patterns, emerging problems, and topology changes. Basic routing protocol

xxvi Cisco: A Beginner's Guide, Third Edit ion




technology is covered here, as are the various major routing protocols in use today—bothopen standard protocols (RIP, OSPF, BGP) and Cisco-proprietary protocols (IGRP andEIGRP). Cisco’s routing protocols are overviewed, down to the command level whererouting metrics are set to modify network behavior to meet enterprise requirements.

Chapter 15, “Network Management”—Network management has become a majorissue as internetworks have grown in size and complexity. This chapter covers the stan-dards and technologies that underlie network management systems: the Simple NetworkManagement Protocol (SNMP), remote monitor instrumentation (RMON), and the man-agement information base (MIB). Issues surrounding network management standardsare covered, as is Cisco’s approach to implementing them. SNMP configuration is intro-duced at the command level. Cisco’s suite of network management software products—Resource Management Essentials and CWSI Campus—are also reviewed.

Chapter 16, “Network Design Process”—There are basics that must be coveredwhen considering any network design decision, whether for a whole new internetworkor a modest expansion of an existing one. The classic three-layer hierarchical designmodel is reviewed in terms of what to look for in the access, distribution, and backbonelayers. Key design subjects such as topology meshing and load balancing are reviewed.How to perform a comprehensive network needs analysis and how to translate it into de-sign solutions using Cisco products is explained, covering such design factors as routingprotocols, address design, routing versus switching, WAN services, and traffic load bal-ancing.

Chapter 17, “Troubleshooting Cisco Networks”—You’ve arrived as a network prowhen you can troubleshoot an internetwork. This chapter surveys typical internetworkproblems and the proper methodology for diagnosing and fixing them. Key Cisco IOStroubleshooting commands are reviewed in terms of how to handle connectivity prob-lems, performance bottlenecks, and other problems. Particular attention is paid to how totrack down and isolate configuration problems, how to tune routing protocol metrics,and how to troubleshoot WAN services such as serial line links. Additionally, we covercommon wireless network problems, along with how to troubleshoot network perfor-mance issues.

HOW TO READ THIS BOOKThis book can be picked up and read from the beginning of any chapter. Chapters cover-ing technology start out with the basics and give explanations from the standpoint of thetechnology’s historical background, how it developed, and what the issues and trendssurrounding it are. Only then is Cisco specifically covered in terms of IOS commands,Cisco software tools, and Cisco hardware and software products.

This book doesn’t try to reinvent the wheel by publishing yet another glossary oninternetworking terms and acronyms. Every term introduced in this book is defined andexplained in context. But the book should be read with the reader’s browser pointed toCisco’s Web site at www.cisco.com. While this book stands on its own, it never hurts tobrowse around to help reinforce newly learned subject matter. Cisco’s Web site contains a

Introduction xxvii




wealth of product illustrations, white papers, and other materials. In particular, readers ofthis book should use the Universal Resource Locator (URL) for two excellent online glos-saries that complement this book:

▼ Cisco Systems Terms and Acronymswww.cisco.com/univercd/cc/td/doc/cisintwk/ita/cisco12.htm

▲ Internetworking Terms and Acronymswww.cisco.com/univercd/cc/td/doc/cisintwk/ita/index.htm

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cisco a beginner’s guide, third...

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