CCNA 1 and 2 Companion Guide, Revised (Cisco Networking Academy Program) part 1 doc

Cisco Networking Academy Program
CCNA 1 and 2 Companion Guide
Third Edition
Cisco Systems, Inc.
Cisco Networking Academy Program
Cisco Press
201 West 103
rd
Street
Indianapolis, Indiana 46290 USA
www.ciscopress.com

1102.book Page i Tuesday, May 20, 2003 2:53 PM
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.
®

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Feedback Information
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Readers’ feedback is a natural continuation of this process. If you have any comments
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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

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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

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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

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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

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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

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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

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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

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