Ccna Student Guide

No part of this book may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying and recording, or by any information storage and retrieval system, without written permission from the publisher, except for the inclusion of brief quotations in a review. Printed in the United States of America 1 2 3 4 5 6 7 8 9 0 First Printing July 2003 Library of Congress Cataloging-in-Publication Number: 2002116060 ISBN: 1-58720-083-x Warning and Disclaimer

This book is designed to provide information about selected topics for the ICND Exam for the CCNA certi? ation. Every effort has been made to make this book as complete and accurate as possible, but no warranty or ? tness is implied. The information is provided on an “as is” basis. The author, Cisco Press, and Cisco Systems, Inc. shall have neither liability nor responsibility to any person or entity with respect to any loss or damages arising from the information contained in this book or from the use of the discs or programs that may accompany it. The opinions expressed in this book belong to the author and are not necessarily those of Cisco Systems, Inc. Feedback Information

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Trademark Acknowledgments All terms mentioned in this book that are known to be trademarks or service marks have been appropriately capitalized. Cisco Press or Cisco Systems, Inc. cannot attest to the accuracy of this information. Use of a term in this book should not be regarded as affecting the validity of any trademark or service mark. 083x_FMi. book Page iii Thursday, July 3, 2003 12:49 PM iii Publisher: John Wait Cisco Representative: Anthony Wolfenden Editor-In-Chief: John Kane Cisco Press Program Manager: Sonia Torres Chavez Executive Editor: Brett Bartow Cisco Marketing Communications Manager: Scott Miller

Managing Editor: Patrick Kanouse Cisco Marketing Program Manager: Edie Quiroz Development Editor: Christopher Cleveland Technical Editors: Elan Beer, Lynn Maynes, Martin Walshaw Project Editor: Marc Fowler Copy Editor: Gayle Johnson Team Coordinator: Tammi Barnett Book Designer: Louisa Adair Cover Designer: Louisa Adair Compositor: Mark Shirar Indexer: Tim Wright 083x_FMi.

book Page iv Thursday, July 3, 2003 12:49 PM iv About the Author Wendell Odom, CCIE No. 1624, is a senior instructor with Skyline Computer (www. skylinecomputer. com), where he teaches courses on QoS, CCNA, and CCIE lab preparation.

He has worked in the networking arena for 20 years, with jobs in pre- and postsales technical consulting, teaching, and course development. He has written portions of more than 12 courses, covering topics such as IP routing, MPLS, Cisco WAN switches, SNA protocols, and LAN troubleshooting.

He is the author of three prior editions of CCNA Exam Certi? cation Guide and DQOS Exam Certi? cation Guide. About the Technical Reviewers Elan Beer, CCIE No. 1837, CCSI No. 94008, is a senior consultant and Certi? ed Cisco Instructor. His internetworking expertise is recognized internationally through his global consulting and training engagements.

As one of the industry’s top internetworking consultants and Cisco instructors, Beer has used his expertise to design, implement, and deploy multi-protocol networks for a wide international clientele. As a senior instructor and course developer, Beer has designed and presented public and implementation-speci? c technical courses spanning many of today’s top technologies. He can be reached at elan@CiscoConsultants. com. Lynn Maynes, CCIE No. 6569, is a senior network engineer with Sprint Managed Network Services specializing in network design, architecture, and security for large-scale networks worldwide.

He has more than 9 years of experience in computer networking and is a coauthor of the Cisco Press book, CCNA Practical Studies. He holds a bachelor’s degree in international business from Westminster College. Martin Walshaw, CCIE No. 5629, CISSP, CCNP, CCDP, is a systems engineer working for Cisco Systems in the Enterprise line of business in South Africa. His areas of specialty include convergence, security, and content delivery networking.

Over the last 15 years, Walshaw has dabbled in many aspects of the IT industry, ranging from programming in RPG III and COBOL to PC sales.

When Walshaw isn’t working, he likes to spend all his available time with his patient wife, Val, and his sons, Joshua and Callum. Without their patience, understanding, and support, projects such as this would not be possible. Dedication The nature of the book-writing process requires some long and odd work hours. My darling wife, Kris, never complains about it, picks up my slack, and makes our lives run smoothly— all so I can write. Kris, the ? rst time you read this dedication, you’re entitled to a whole week of “Honey do” tasks from me at home.

Thanks for making it all possible! 083x_FMi. book Page v Thursday, July 3, 2003 12:49 PM Acknowledgments The technical editing team for this book and its companion volume were fantastic. Not only did they ? nd where I had written wrong technical facts, they also helped me ? nd new, more interesting, and clearer ways to convey certain facts about networking.

Lynn was particularly helpful with comments that helped keep small sections in line with the overall theme of the chapter—a skill I’m sure he developed as a result of having written books himself. Martin helped a lot with technical details and perspectives from what customers see every day. And Elan excelled at noticing both small, nitpicky errors and signi? ant technical problems.

(And that’s not an insult—every technical author loves help in ? nding the small problems! ) Together, these three gentlemen formed a great team with complementary skills. Thanks so much, guys! The production team, headed by Patrick Kanouse, did their usual excellent job. Like the “behind-the-scenes” people in many businesses, their speci? c efforts might not be obvious to the public, but they are no less appreciated by me. In particular, Marc Fowler, the project editor, did an incredible job working through these two books on a very tight schedule, with his usual excellent work.

You folks make me look good on paper. If only you could be in charge of my wardrobe too, I’d look good all the time! Brett Bartow, Executive Editor, did his usual New-York-Yankees-like job of helping steer these two projects toward completion.

In between talking about sports, Brett worked through the many changes in direction with this book and helped guide us to the right product. And yes, so the whole world knows, he did pick an Atlanta Braves player, John Smoltz, for his fantasy league baseball team—again proving he’s a really smart guy. Chris Cleveland developed this book and the CCNA INTRO Exam Certi? ation Guide. He’s simply the best. He also works way harder than I do to get these books to market.

You da man, Chris C! 083x_FMi. book Page vi Thursday, July 3, 2003 12:49 PM vi Contents at a Glance Introduction xvi Part I LAN Switching 3 Chapter 1 LAN Switching Review and Con? guring Cisco 2950 LAN Switches Chapter 2 Spanning Tree Protocol Chapter 3 Virtual LANs and Trunking Part II TCP/IP 95 Chapter 4 IP Addressing and Subnetting Chapter 5 RIP, IGRP, and Static Route Concepts and Con? guration Chapter 6 OSPF and EIGRP Concepts and Con? guration Chapter 7 Advanced Routing Protocol Topics Chapter 8

Advanced TCP/IP Topics Part III Wide-Area Networks 299 Chapter 9 Point-to-Point Leased Line Implementation Chapter 10 ISDN and Dial-on-Demand Routing Chapter 11 Frame Relay Part IV Network Security 421 Chapter 12 IP Access Control List Security Part V Final Preparation 457 Chapter 13 Final Preparation Part VI Appendixes 493 5 31 67 97 141 185 219 251 301 321 371 423 459 Appendix A Answers to the “Do I Know This Already? ” Quizzes and Q;A Questions Appendix B Decimal to Binary Conversion Chart 555 Appendix C Using the Simulation Software for Hands-on Exercises Appendix D Comparisons of Dynamic Routing Protocols

Appendix E Glossary Index Configuring Cisco 1900 Switches 599 610 577 567 561 495 083x_FMi. book Page vii Thursday, July 3, 2003 12:49 PM vii Contents Introduction xvi Part I LAN Switching 3 Chapter 1 LAN Switching Review and Configuring Cisco 2950 LAN Switches 5 “Do I Know This Already? ” Quiz 5 Foundation Topics 10 Brief Review of LAN Switching 10 The Forward-Versus-Filter Decision 11 How Switches Learn MAC Addresses 12 Forwarding Unknown Unicasts and Broadcasts 13 LAN Switch Logic Summary 14 Basic Configuration and Operation Commands for the Cisco 2950 Switch Basic Switch Operation 16

Typical Basic Administrative Configuration 20 Port Security Configuration 25 Foundation Summary 28 Q;A 29 Chapter 2 14 Spanning Tree Protocol 31 “Do I Know This Already? ” Quiz 31 Foundation Topics 36 Spanning Tree Protocol 36 What IEEE 802. 1d Spanning Tree Does 36 How Spanning Tree Works 38 Electing the Root and Discovering Root Ports and Designated Ports Reacting to Changes in the Network 42 Spanning Tree Protocol Summary 45 Optional STP Features 46 EtherChannel 47 PortFast 48 Rapid Spanning Tree (IEEE 802. 1w) 48 RSTP Link and Edge Types 49 RSTP Port States 50 RSTP Port Roles 50 RSTP Convergence 52

Edge-Type Behavior and PortFast 52 Link-Type Shared 52 Link-Type Point-to-Point 52 An Example of Speedy RSTP Convergence 53 Spanning Tree Protocol Configuration 56 Basic STP show Commands 57 Changing STP Port Costs and Bridge Priority 58 EtherChannel Configuration 60 39 083x_FMi. book Page viii Thursday, July 3, 2003 12:49 PM viii Foundation Summary Foundation Summary Q;A 65 Chapter 3 62 64 Virtual LANs and Trunking 67 “Do I Know This Already? ” Quiz 67 Foundation Topics 71 Review of Virtual LAN Concepts 71 Trunking with ISL and 802.

1Q 72 ISL 73 802. 1Q 73 ISL and 802. 1Q Compared 74 VLAN Trunking Protocol (VTP) 76

How VTP Works 76 VTP Pruning 78 VLAN and Trunking Configuration 79 VLAN Configuration for a Single Switch VLAN Trunking Configuration 84 Foundation Summary 89 Q;A 91 Part II TCP/IP 95 Chapter 4 80 IP Addressing and Subnetting 97 “Do I Know This Already? ” Quiz 97 Foundation Topics 102 IP Addressing Review 102 IP Subnetting 104 Analyzing and Interpreting IP Addresses and Subnets 106 Math Operations Used to Answer Subnetting Questions 107 Converting IP Addresses from Decimal to Binary and Back Again 107 The Boolean AND Operation 109 Prefix Notation 111 How Many Hosts and How Many Subnets? 111

What Is the Subnet Number, and What Are the IP Addresses in the Subnet? Finding the Subnet Number 116 Finding the Subnet Broadcast Address 118 Finding the Range of Valid IP Addresses in a Subnet 119 Finding the Answers Without Using Binary 121 Which Subnet Masks Meet the Stated Design Requirements? 127 What Are the Other Subnet Numbers? 130 Foundation Summary 135 Q;A 137 116 083x_FMi. book Page ix Thursday, July 3, 2003 12:49 PM ix Chapter 5 RIP, IGRP, and Static Route Concepts and Configuration 141 “Do I Know This Already? ” Quiz 142 Foundation Topics 145 Configuring and Testing Static Routes 145