1102.book Page i Tuesday, May 20, 2003 2:53 PM Cisco Networking Academy Program CCNA 1 and 2 Companion Guide Third Edition Cisco Systems, Inc. Cisco Networking Academy Program Cisco Press rd 201 West 103 Street Indianapolis, Indiana 46290 USA www.ciscopress.com fmatter.fm Page ii Wednesday, May 21, 2003 11:31 AM ii Cisco Networking Academy Program CCNA 1 and 2 Companion Guide Third Edition Cisco Systems, Inc. Cisco Networking Academy Program Copyright © 2003 Cisco Systems, Inc. Published by: Cisco Press 201 West 103rd Street Indianapolis, IN 46290 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 inclu- sion of brief quotations in a review. Printed in the United States of America 1 2 3 4 5 6 7 8 9 0 Library of Congress Cataloging-in-Publication Number: 2002116787 ISBN: 1-58713-110-2 First Printing June 2003 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. Warning and Disclaimer This book is designed to provide information about CCNA 1: Networking Basics and CCNA 2: Routers and Routing Basics of the Cisco Networking Academy Program CCNA course. Every effort has been made to make this book as complete and as accurate as possible, but no war- ranty or fitness 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. This book is part of the Cisco Networking Academy ® Program series from Cisco Press. The products in this series support and complement the Cisco Networking Academy Program curriculum. If you are using this book outside the Networking Academy program, then you are not preparing with a Cisco trained and authorized Networking Academy provider. For information on the Cisco Networking Academy Program or to locate a Networking Academy, please visit www.cisco.com/edu. 1102.book Page iii Tuesday, May 20, 2003 2:53 PM iii 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 develop- ment that involves the unique expertise of members from the professional 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 e-mail at 1102.book Page iv Tuesday, May 20, 2003 2:53 PM iv Publisher John Wait Editor-in-Chief John Kane Executive Editor Carl Lindholm Cisco Representative Anthony Wolfenden Cisco Press Program Manager Sonia Torres Chavez Manager, Marketing Communications, Scott Miller Cisco Systems Cisco Marketing Program Manager Edie Quiroz Production Manager Patrick Kanouse Senior Development Editor Chris Cleveland Senior Editor Sheri Cain Copy Editors Krista Hansing, Kevin A. Kent, Gayle Johnson Technical Editors Jhun DeLeon, Ralph Duffy, Jim Lorenz, Arthur Tucker Assistant Editor Sarah Kimberly Designer Louisa Adair Composition Octal Publishing, Inc. Indexer Tim Wright 1102.book Page v Tuesday, May 20, 2003 2:53 PM v Overview Foreword. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .xxv Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .xxvii Part I CCNA 1: Networking Basics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3 Chapter 1 Introduction to Networking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5 Chapter 2 Networking Fundamentals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43 Chapter 3 Networking Media . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .115 Chapter 4 Cable Testing and Cabling LANs and WANs . . . . . . . . . . . . . . .183 Chapter 5 Ethernet Fundamentals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .251 Chapter 6 Ethernet Technologies and Ethernet Switching. . . . . . . . . . . . .315 Chapter 7 TCP/IP Protocol Suite and IP Addressing . . . . . . . . . . . . . . . . . .375 Chapter 8 Routing Fundamentals and Subnets . . . . . . . . . . . . . . . . . . . . .427 Chapter 9 TCP/IP Transport and Application Layer. . . . . . . . . . . . . . . . . . .477 Part II CCNA 2: Routers and Routing Basics. . . . . . . . . . . . . . . . . . . . .509 Chapter 10 WANs and Routers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .511 Chapter 11 Router Fundamentals. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .553 Chapter 12 Router Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .587 Chapter 13 Learning About Neighboring and Remote Devices. . . . . . . . . .621 Chapter 14 Managing Cisco IOS Software . . . . . . . . . . . . . . . . . . . . . . . . . .645 Chapter 15 Routing and Routing Protocols . . . . . . . . . . . . . . . . . . . . . . . . . .675 Chapter 16 Distance Vector Routing Protocols . . . . . . . . . . . . . . . . . . . . . . .711 Chapter 17 TCP/IP Error and Control Messages . . . . . . . . . . . . . . . . . . . . . .761 1102.book Page vi Tuesday, May 20, 2003 2:53 PM vi Chapter 18 Basic Router Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . .787 Chapter 19 Intermediate TCP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .815 Chapter 20 Access Control Lists . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .841 Part III Appendixes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .877 Appendix A Structured Cabling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .879 Appendix B Glossary of Key Terms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .979 Appendix C Check Your Understanding Answer Key. . . . . . . . . . . . . . . . . .1009 Index 1047 1102.book Page vii Tuesday, May 20, 2003 2:53 PM vii Table of Contents Foreword xxv Introduction xxvii Part I CCNA 1: Networking Basics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3 Chapter 1 Introduction to Networking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5 The Fundamentals of Internet Connectivity . . . . . . . . . . . . . . . . .5 PC Basics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6 Electronic Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7 PC Components. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7 Motherboard Components . . . . . . . . . . . . . . . . . . . . . . . . . . .10 Desktop Versus Laptop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11 Network Interface Cards . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12 NIC and Modem Installation. . . . . . . . . . . . . . . . . . . . . . . . . .13 Overview of High-Speed and Dialup Connectivity . . . . . . . . . . .14 TCP/IP Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15 Testing Connectivity with Ping . . . . . . . . . . . . . . . . . . . . . . . . . .15 Web Browsers and Plug-Ins . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16 Other Common Computer Applications . . . . . . . . . . . . . . . . . . .18 Binary Numbers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18 Binary Representation of Data. . . . . . . . . . . . . . . . . . . . . . . . .19 Bits, Bytes, and Measurement Terms . . . . . . . . . . . . . . . . . . . . . .19 Base 10 Number System . . . . . . . . . . . . . . . . . . . . . . . . . . . . .21 Base 2 Number System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .22 Base 16 Number System . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23 Decimal-to-Binary Conversion. . . . . . . . . . . . . . . . . . . . . . . . .24 Binary-to-Decimal Conversion. . . . . . . . . . . . . . . . . . . . . . . . .26 Hexadecimal and Binary Conversion . . . . . . . . . . . . . . . . . . . .28 Four-Octet Dotted-Decimal Representation of a 32-Bit Binary Number . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30 Boolean Logic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30 IP Addresses and Subnet Masks . . . . . . . . . . . . . . . . . . . . . . . .32 Summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33 Key Terms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35 Check Your Understanding . . . . . . . . . . . . . . . . . . . . . . . . . . . . .39 1102.book Page viii Tuesday, May 20, 2003 2:53 PM viii Chapter 2 Networking Fundamentals. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43 Networking Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43 Data Networks. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .44 Computer Networking History . . . . . . . . . . . . . . . . . . . . . . . .47 Network Protocols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .49 Local-Area Networks (LANs) . . . . . . . . . . . . . . . . . . . . . . . . .49 Wide-Area Networks (WANs) . . . . . . . . . . . . . . . . . . . . . . . . .50 Metropolitan-Area Networks (MANs). . . . . . . . . . . . . . . . . . .52 Specialized Networks Located Within the LAN . . . . . . . . . . . .53 Virtual Private Networks . . . . . . . . . . . . . . . . . . . . . . . . . . . . .56 Digital Bandwidth . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .58 The Importance of Bandwidth . . . . . . . . . . . . . . . . . . . . . . . . .58 Analogies That Describe Digital Bandwidth . . . . . . . . . . . . . . . .59 Digital Bandwidth Measurements . . . . . . . . . . . . . . . . . . . . . .61 Bandwidth Limitations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .61 Data Throughput . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .63 Data Transfer Calculation . . . . . . . . . . . . . . . . . . . . . . . . . . . .64 Digital Bandwidth Versus Analog Bandwidth. . . . . . . . . . . . . .66 Networking Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .67 Using Layers to Analyze Problems in a Flow of Materials . . . .67 Using Layers to Describe Data Communication . . . . . . . . . . . .68 The OSI Reference Model . . . . . . . . . . . . . . . . . . . . . . . . . . . .69 OSI Layers and Functions . . . . . . . . . . . . . . . . . . . . . . . . . . . .71 Peer-to-Peer Communications . . . . . . . . . . . . . . . . . . . . . . . . .72 DoD (TCP/IP) Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .74 Detailed Encapsulation Process . . . . . . . . . . . . . . . . . . . . . . . .75 Networking Devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .78 Repeaters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .79 Hubs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .79 Network Interface Cards . . . . . . . . . . . . . . . . . . . . . . . . . . . . .81 Bridges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .82 Layer 2 Switches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .83 Routers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .84 Voice, DSL, Cable Modem, and Optical Devices . . . . . . . . . . .86 Security Devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .89 Wireless Devices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .91 Network Topologies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .93 Bus Topology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .95 Star and Extended-Star Topologies. . . . . . . . . . . . . . . . . . . . . .95 Ring Topology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .97 1102.book Page ix Tuesday, May 20, 2003 2:53 PM ix Hierarchical Topology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .98 Full-Mesh and Partial-Mesh Topologies. . . . . . . . . . . . . . . . . .98 Logical Topology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .99 Summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .100 Key Terms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .103 Check Your Understanding . . . . . . . . . . . . . . . . . . . . . . . . . . . .106 Chapter 3 Networking Media . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .115 Electricity Basics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .115 Atoms and Molecules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .115 Electrical Properties of Matter . . . . . . . . . . . . . . . . . . . . . . . .117 Measuring Electricity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .118 Voltage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .119 Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .120 Wattage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .120 Resistance and Impedance . . . . . . . . . . . . . . . . . . . . . . . . . . .120 Circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .121 Copper Media. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .123 American Wire Gauge System . . . . . . . . . . . . . . . . . . . . . . . .123 Twisted-Pair Cable. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .124 Shielded Twisted-Pair Cable. . . . . . . . . . . . . . . . . . . . . . . . . .124 Unshielded Twisted-Pair Cable. . . . . . . . . . . . . . . . . . . . . . . .125 Coaxial Cable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .128 Cable Specification and Termination . . . . . . . . . . . . . . . . . . .130 Optical Media. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .133 The Electromagnetic Spectrum. . . . . . . . . . . . . . . . . . . . . . . .134 The Ray Model of Light . . . . . . . . . . . . . . . . . . . . . . . . . . . .135 The Law of Reflection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .137 The Law of Refraction (Snell’s Law) . . . . . . . . . . . . . . . . . . .138 Total Internal Reflection . . . . . . . . . . . . . . . . . . . . . . . . . . . .139 Fiber-Optic Cables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .141 Multimode Fiber . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .144 Single-Mode Fiber . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .145 Cable Designs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .146 Other Optical Networking Components . . . . . . . . . . . . . . . .147 Signals and Noise in Optical Fiber . . . . . . . . . . . . . . . . . . . . .149 Installation, Care, and Testing of Optical Fiber . . . . . . . . . . .151 Wireless Communications . . . . . . . . . . . . . . . . . . . . . . . . . . . . .154 Wireless Data Communications . . . . . . . . . . . . . . . . . . . . . . .154 1102.book Page x Tuesday, May 20, 2003 2:53 PM x Wireless Signal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .155 Radio Frequency Bands . . . . . . . . . . . . . . . . . . . . . . . . . . . . .157 Spread-Spectrum Technology . . . . . . . . . . . . . . . . . . . . . . . . .159 FHSS Versus DSSS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .159 Wireless Networking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .161 Wireless LAN Organization and Standards . . . . . . . . . . . . . .161 Wireless Devices and Topologies . . . . . . . . . . . . . . . . . . . . . .162 How Wireless LANs Communicate . . . . . . . . . . . . . . . . . . . .165 Authentication and Association . . . . . . . . . . . . . . . . . . . . . . .166 The Radio Wave/Microwave Spectrum. . . . . . . . . . . . . . . . . .168 Signals and Noise on a WLAN. . . . . . . . . . . . . . . . . . . . . . . .169 Wireless Security . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .170 WEP. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .170 VPN, EAP, and LEAP. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .171 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .172 Key Terms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .174 Check Your Understanding . . . . . . . . . . . . . . . . . . . . . . . . . . . .176 Chapter 4 Cable Testing and Cabling LANs and WANs . . . . . . . . . . . . . . .183 Background for Studying Frequency-Based Cable Testing . . . . .184 Waves. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .184 Sine Waves and Square Waves . . . . . . . . . . . . . . . . . . . . . . . .185 Exponents and Logarithms. . . . . . . . . . . . . . . . . . . . . . . . . . .186 Decibels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .187 Viewing Signals in Time and Frequency. . . . . . . . . . . . . . . . . . .188 Noise in Time and Frequency . . . . . . . . . . . . . . . . . . . . . . . . . .189 Analog and Digital Bandwidth . . . . . . . . . . . . . . . . . . . . . . . . .190 Signals and Noise on Networking Media . . . . . . . . . . . . . . . . .191 Signaling over Copper and Fiber-Optic Cabling . . . . . . . . . . .192 Attenuation and Insertion Loss on Copper Media . . . . . . . . .195 Source of Noise on Copper Media . . . . . . . . . . . . . . . . . . . . .196 Cable Testing Standards . . . . . . . . . . . . . . . . . . . . . . . . . . . . .199 Other Test Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .202 Time-Based Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . .202 Testing Fiber-Optic Cables . . . . . . . . . . . . . . . . . . . . . . . . . . .203 A New Cabling Standard . . . . . . . . . . . . . . . . . . . . . . . . . . . .204 Cabling the LANs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .205 LAN Physical Layer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .205