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800 East 96th Street Indianapolis, IN 46240 USA Cisco Press CCNA ICND2 Official Exam Certification Guide Second Edition Wendell Odom, CCIE No. 1624 ii CCNA ICND2 Official Exam Certification Guide, Second Edition Wendell Odom Copyright © 2008 Cisco Systems, Inc. Published by: Cisco Press 800 East 96th Street Indianapolis, IN 46240 USA All rights reserved. No part of this book may be reproduced or transmitted in any form or by any means, electronic or mechanical, including photocopying, 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 First Printing August 2007 Library of Congress Cataloging-in-Publication Data: Odom, Wendell. CCNA ICND2 official exam certification guide / Wendell Odom. -- 2nd ed. p. cm. ISBN 978-1-58720-181-3 (hbk : CD-ROM) 1. Electronic data processing personnel--Certification. 2. Computer network protocols--Study guides. 3. Internetworking (Telecommunication)--Study guides. I. Title. QA76.3.O3618 2004 004.6--dc22 2007029471 ISBN-13: 978-1-58720-181-3 ISBN-10: 1-58720-181-x Warning and Disclaimer This book is designed to provide information about the Cisco ICND1 (640-822), ICND2 (640-816), and CCNA (640- 802) exams. Every effort has been made to make this book as complete and as accurate as possible, but no warranty or fitness is implied. The information is provided on an “as is” basis. The authors, 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. Trademark Acknowledgments All terms mentioned in this book that are known to be trademarks or service marks have been appropriately capital- ized. 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. iii Corporate and Government Sales The publisher offers excellent discounts on this book when ordered in quantity for bulk purchases or special sales, which may include electronic versions and/or custom covers and content particular to your business, training goals, marketing focus, and branding interests. For more information, please contact: U.S. Corporate and Government Sales 1-800-382-3419 corpsales@pearsontechgroup.com For sales outside the United States please contact: International Sales international@pearsoned.com Feedback Information At Cisco Press, our goal is to create in-depth technical books of the highest quality and value. Each book is crafted with care and precision, undergoing rigorous development that involves the unique expertise of members from the pro- fessional technical community. Readers’ feedback is a natural continuation of this process. If you have any comments regarding how we could improve the quality of this book, or otherwise alter it to better suit your needs, you can contact us through email at feedback@ciscopress.com. Please make sure to include the book title and ISBN in your message. We greatly appreciate your assistance. Publisher: Paul Boger Cisco Representative: Anthony Wolfenden Associate Publisher: David Dusthimer Cisco Press Program Manager: Jeff Brady Executive Editor: Brett Bartow Copy Editors: Written Elegance and Gayle Johnson Managing Editor: Patrick Kanouse Technical Editors: Teri Cook and Steve Kalman Development Editor: Andrew Cupp Proofreader: Susan Eldridge Senior Project Editor: Meg Shaw and Tonya Simpson Editorial Assistant: Vanessa Evans Designer: Louisa Adair Composition: Mark Shirar Indexer: Ken Johnson iv About the Author Wendell Odom , CCIE No. 1624, has been in the networking industry since 1981. He currently teaches QoS, MPLS, and CCNA courses for Skyline Advanced Technology Services (http://www.skyline-ats.com). Wendell also has worked as a network engineer, consultant, and systems engineer, and as an instructor and course developer. He is the author of all prior editions of CCNA Exam Certification Guide , as well as the Cisco QoS Exam Certification Guide , Second Edition, Computer Networking First-Step , CCIE Routing and Switching Official Exam Certification Guide , Second Edition, and CCNA Video Mentor , all from Cisco Press. v About the Technical Reviewers Teri Cook (CCSI, CCDP, CCNP, CCDA, CCNA, MCT, and MCSE 2000/2003: Security) has more than 10 years of experience in the IT industry. She has worked with different types of organizations within the private business and DoD sectors, providing senior-level network and security technical skills in the design and implementation of complex computing environments. Since obtaining her certifications, Teri has been committed to bringing quality IT training to IT professionals as an instructor. She is an outstanding instructor that utilizes real-world experience to present complex networking technologies. As an IT instructor, Teri has been teaching Cisco classes for more than five years. Stephen Kalman is a data security trainer and the author or tech editor of more than 20 books, courses, and CBT titles. His most recent book is Web Security Field Guide , published by Cisco Press. In addition to those responsibilities he runs a consulting company, Esquire Micro Consultants, which specializes in network security assessments and forensics. Mr. Kalman holds SSCP, CISSP, ISSMP, CEH, CHFI, CCNA, CCSA (Checkpoint), A+, Network+, and Security+ certifications and is a member of the New York State Bar. vi Dedications For my wonderful, lovely, giving wife. Thanks so much for all your support, encouragement, love, and respect. vii Acknowledgments The team that helped produce this book has simply been awesome. Everyone who has touched the book has made it better, and the team has been particularly great at helping catch the errors that always creep into the manuscript. Both Teri and Steve did great jobs as technical editors. Teri’s ability to see each phrase in the context of an entire chapter, or whole book, was awesome, helping to catch things that no one would otherwise catch. Steve did his usual great job—something like 5–6 books of mine that he’s done now—and as always, I get to learn a lot just by reading Steve’s input. The depth of the reviews for this book was better than any of my other books because of Teri and Steve; thanks very much! Drew Cupp got the “opportunity” to develop one of my books for the first time in a long time. Drew’s insights and edits worked wonders, and a fresh set of eyes on the materials copied from the previous edition strengthened those parts a lot. All while juggling things in the middle of a whirlwind schedule—thanks, Drew, for doing a great job! The wonderful and mostly hidden production folks did their usual great job. When I saw how they reworded something, and thought “Wow, why didn’t I write that?” it made me appreciate the kind of team we have at Cisco Press. The final copy edit, figure review, and pages review process required a fair amount of juggling and effort as well—especially for the extra quality initiatives we’ve implemented. Thanks to you all! Brett Bartow again was the executive editor on the book, as has been the case for almost all the books I’ve helped write. Brett did his usual great and patient job, being my advocate in so many ways. Brett, thanks for doing so many things on so many levels to help us be successful together. Additionally, there are several folks who don’t have any direct stake in the book who also helped it along. Thanks to Frank Knox for the discussions on the exams, why they’re so difficult, and how to handle troubleshooting. Thanks to Rus Healy for the help with wireless. Thanks to the Mikes at Skyline for making my schedule work to get this book (and the ICND1 book) out the door. And thanks to the course and exam teams at Cisco for the great early communications and interactions about the changes to the courses and exams. And as always, a special thanks to my Lord and Savior Jesus Christ—thanks for helping me rejoice in you even while doing the final reviews of 1400 pages of manuscript in just a few weeks! viii This Book Is Safari Enabled The Safari ® Enabled icon on the cover of your favorite technology book means the book is available through Safari Bookshelf. When you buy this book, you get free access to the online edition for 45 days. Safari Bookshelf is an electronic reference library that lets you easily search thousands of technical books, find code samples, download chapters, and access technical information whenever and wherever you need it. To gain 45-day Safari Enabled access to this book: • Go to http://www.ciscopress.com/safarienabled • Complete the brief registration form • Enter the coupon code 37R6-7E1Q-6HAX-5YQZ-G6KW If you have difficulty registering on Safari Bookshelf or accessing the online edition, please e-mail customer-service@safaribooksonline.com. ix Contents at a Glance Foreword xxvi Introduction xxvii Part I: LAN Switching 3 Chapter 1 Virtual LANs 5 Chapter 2 Spanning Tree Protocol 57 Chapter 3 Troubleshooting LAN Switching 109 Part II: IP Routing 157 Chapter 4 IP Routing: Static and Connected Routes 159 Chapter 5 VLSM and Route Summarization 199 Chapter 6 IP Access Control Lists 227 Chapter 7 Troubleshooting IP Routing 269 Part III: Routing Protocols Configuration and Troubleshooting 303 Chapter 8 Routing Protocol Theory 305 Chapter 9 OSPF 343 Chapter 10 EIGRP 377 Chapter 11 Troubleshooting Routing Protocols 407 Part IV: Wide-Area Networks 431 Chapter 12 Point-to-Point WANs 433 Chapter 13 Frame Relay Concepts 457 Chapter 14 Frame Relay Configuration and Troubleshooting 483 Chapter 15 Virtual Private Networks 525 Part V: Scaling the IP Address Space 543 Chapter 16 Network Address Translation 545 Chapter 17 IP Version 6 577 Part VI: Final Preparation 617 Chapter 18 Final Preparation 619 Part VII: Appendixes 631 Appendix A Answers to the “Do I Know This Already?” Quizzes 633 Appendix B Decimal to Binary Conversion Table 645 Appendix C ICND2 Exam Updates: Version 1.0 649 Glossary 653 Index 674 x Part VIII: CD-Only Appendix D Subnetting Practice Appendix E Subnetting Reference Pages Appendix F Additional Scenarios Appendix G Video Scenario Reference Appendix H ICND1 Chapter 12: IP Addressing and Subnetting Appendix I ICND1 Chapter 17: WAN Configuration Appendix J Memory Tables Appendix K Memory Tables Answer Key Appendix L ICND2 Open-Ended Questions [...]... Redundant Network 32 7 The Holddown Process and Holddown Timer 33 0 Distance Vector Summary 33 2 Link-State Routing Protocol Features 33 3 Building the Same LSDB on Every Router 33 3 Applying Dijkstra SPF Math to Find the Best Routes 33 5 Convergence with Link-State Protocols 33 7 Summary and Comparisons to Distance Vector Protocols 33 7 Exam Preparation Tasks 33 9 Review All the Key Topics 33 9 Complete the Tables... Dead Timers 36 7 xviii OSPF Metrics (Cost) 36 9 OSPF Authentication 37 0 OSPF Load Balancing 37 2 Exam Preparation Tasks 37 3 Review All the Key Topics 37 3 Complete the Tables and Lists from Memory 37 3 Definitions of Key Terms 37 4 Command Reference to Check Your Memory 37 4 Chapter 10 EIGRP 37 7 “Do I Know This Already?” Quiz 37 7 Foundation Topics 38 0 EIGRP Concepts and Operation 38 0 EIGRP Neighbors 38 0 Exchanging... Memory 34 0 Definitions of Key Terms 34 0 Command Reference to Check Your Memory 34 0 Chapter 9 OSPF 34 3 “Do I Know This Already?” Quiz 34 3 Foundation Topics 34 7 OSPF Protocols and Operation 34 7 OSPF Neighbors 34 7 Identifying OSPF Routers with a Router ID 34 8 Meeting Neighbors by Saying Hello 34 8 Potential Problems in Becoming a Neighbor 34 9 Neighbor States 35 0 OSPF Topology Database Exchange 35 2 Overview... Algorithms 31 3 Metrics 31 4 IGP Comparisons: Summary 31 5 Administrative Distance 31 6 Distance Vector Routing Protocol Features 31 8 The Concept of a Distance and a Vector 31 8 30 3 xvii Distance Vector Operation in a Stable Network 31 9 Distance Vector Loop Prevention 32 0 Route Poisoning 32 1 Problem: Counting to Infinity over a Single Link 32 2 Split Horizon 32 4 Poison Reverse and Triggered Updates 32 6 Problem:... Chapter 16 Chapter 17 633 634 634 635 636 637 638 639 639 640 641 642 642 6 43 Appendix B Decimal to Binary Conversion Table Appendix C ICND2 Exam Updates: Version 1.0 Glossary Index 6 53 674 622 645 649 633 xxiv Part VIII: CD-Only Appendix D Subnetting Practice Appendix E Subnetting Reference Pages Appendix F Additional Scenarios Appendix G Video Scenario Reference Appendix H ICND1 Chapter 12: IP Addressing... 35 2 Choosing a Designated Router 35 2 Database Exchange 35 4 Maintaining the LSDB While Being Fully Adjacent 35 5 Summary of Neighbor States 35 5 Building the IP Routing Table 35 6 Scaling OSPF Through Hierarchical Design 35 7 OSPF Areas 35 8 OSPF Area Design Advantages 36 0 OSPF Configuration 36 1 OSPF Single-Area Configuration 36 2 OSPF Configuration with Multiple Areas 36 4 Configuring the OSPF Router ID 36 6... Tasks 30 1 Review All the Key Topics 30 1 Complete the Tables and Lists from Memory 30 1 Definitions of Key Terms 30 1 Part III: Routing Protocols Configuration and Troubleshooting Chapter 8 Routing Protocol Theory 30 5 “Do I Know This Already?” Quiz 30 5 Foundation Topics 30 9 Dynamic Routing Protocol Overview 30 9 Routing Protocol Functions 31 0 Interior and Exterior Routing Protocols 31 1 Comparing IGPs 31 3 IGP... EIGRP Topology Information 38 1 Calculating the Best Routes for the Routing Table 38 2 Feasible Distance and Reported Distance 38 4 Caveats with Bandwidth on Serial Links 38 5 EIGRP Convergence 38 5 EIGRP Successors and Feasible Successors 38 6 The Query and Reply Process 38 7 EIGRP Summary and Comparisons with OSPF 38 8 EIGRP Configuration and Verification 38 9 Basic EIGRP Configuration 39 0 EIGRP Metrics, Successors,... Fundamentals 528 IPsec VPNs 531 IPsec Encryption 532 IPsec Key Exchange 533 IPsec Authentication and Message Integrity 534 The ESP and AH Security Protocols 536 IPsec Implementation Considerations 537 SSL VPNs 538 Exam Preparation Tasks 540 Review All the Key Topics 540 Complete the Tables and Lists from Memory 540 Definitions of Key Terms 540 Part V: Scaling the IP Address Space 5 43 Chapter 16 Network Address... Neighbor Example 1 4 23 OSPF Neighbor Example 2 425 The MTU Matching Requirement 427 Exam Preparation Tasks 428 Review All the Key Topics 428 Complete the Tables and Lists from Memory 428 Command Reference to Check Your Memory 428 Part IV: Wide-Area Networks 431 Chapter 12 Point-to-Point WANs 433 “Do I Know This Already?” Quiz 433 Foundation Topics 436 PPP Concepts 436 The PPP Protocol Field 436 PPP Link Control . Functions 31 0 Interior and Exterior Routing Protocols 31 1 Comparing IGPs 31 3 IGP Routing Protocol Algorithms 31 3 Metrics 31 4 IGP Comparisons: Summary 31 5 Administrative. Redundant Network 32 7 The Holddown Process and Holddown Timer 33 0 Distance Vector Summary 33 2 Link-State Routing Protocol Features 33 3 Building the Same