ARISTA 1105
`
`1
`
`ARISTA 1105
`
`

`
`Cisco Routers
`
`702 Habm/em
`
`Networking Overview
`LAN Review 7
`The OSI Model and Network Protocols 33
`Wide Area Networking 53
`internetworking Basics 67
`How a Router Works 77
`
`Router Design and Basic Configuration
`Understanding Router Interfaces 99
`Setting Up a New Fiouter 111
`Basic Fiouter Configuration 123
`Working with the Cisco iOS 141
`
`Routing LAN Protocols
`TCP/lP Primer 167
`Configuring IP Routing 195
`Routing Novell IPX 211
`Routing AppleTall( 227
`
`Advanced Configuration and Configuration
`Tools
`Filtering Router Traffic with Access Lists 243
`Configuring WAN Protocols 259
`Configuring the Router with Cisco
`ConfigMaker 271
`Using a TFTP Server for Router Configuration
`Storage 289
`Basic Router Troubleshooting 301
`
`Appendixes
`Basic Router Command Summary 323
`Selected Clsco Router Specifications 337
`Glossary 343
`
`Index 359
`
`A Division of Macmillan Computer Publishing. USA
`201 W. 103rd Street
`Indianapolis, Indiana 46290
`
`2
`
`

`
`Praetiea fiiseo Routers
`
`Copyright © 1999 by Que Corporation
`
`All rights reserved. No part of this book shall be reproduced, stored in
`a retrieval system, or transmitted by any means, electronic, mechanical,
`photocopying, recording, or otherwise, without written permission
`from the publisher. No patent liability is assumed with respect to the
`use of the information contained herein. Although every precaution has
`been taken in the preparation of this book, the publisher and author
`assume no responsibility for errors or omissions. Neither is any liability
`assumed for damages resulting from the use of the information con-
`tained herein.
`
`international Standard Book Number: 0-7897-2103-1
`
`Library of Congress Catalog Card Number: 99453284
`
`Printed in the United States of America
`First Printing: September 1999
`
`01
`
`O0
`
`99
`
`4
`
`3
`
`2
`
`1
`
`Trademarks
`
`All terms mentioned in this book that are known to be trademarks or
`service marks have been appropriately capitalized. Que Corporation
`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
`Every effort has been made to make this book as complete and as accu-
`rate as possible, but no warranty or fitness is implied. The information
`provided is on an “as is” basis. The author and the ‘publisher 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.
`
`3
`
`

`
`Cements
`
`Introduction
`
`1
`
`About This Book
`
`1
`
`2 The OSI Model and Network Protocols
`
`33
`
`OSI—The Theoretical Networking Protocol
`Stack
`34
`
`How This Book Is Organized
`
`2
`
`Who Should Use This Book 3
`
`Conventions Used In This Book
`
`3
`
`Networking Overview
`
`LAN Review 7
`
`The Advent of the PC 8
`
`8
`Networking PCs
`Peer-to-Peer NEt7U07'kS 9
`.S'crve7'—Bzzsed Networks
`1 0
`
`12
`Making the Connection
`13
`Network Intcifacc Cimir
`Dealing with IRQJ‘ and I/O Pom‘
`Network Cabling
`17
`Hubs, Repeaters, and MAU:
`
`19
`
`14
`
`Understanding Network Topologies
`B21: Network
`21
`SW‘ Network
`22
`
`20
`
`Ring Ybpology
`Mesh Topology
`
`23
`25'
`
`Understanding Network Architectures
`Ethernet 26
`IBM'F2kenRi7zg
`FDDI
`29
`
`28
`
`25
`
`Appleflhlk 30
`
`38
`38
`
`The OSI Layers 35
`'1 he Ap[ili£flZiD7l Layer
`The Pmrerztrttioiz Layer
`The Sen‘i07z Layer
`38
`40
`The '1i'tImport Layer
`The Netzvor/e Layer 40
`The Dzzt/r~Lz'nk Layer
`The Phyximl Layer
`
`41
`
`43
`
`The Data-Link Sublayers
`
`43
`
`Real—World Network Protocols 44
`NetBEUI 45
`TCP/IP 45'
`IPMSPX 48
`
`Applflhlk
`
`49
`
`Wide Area Networking 53
`
`Understanding Wide Area Connectivity 54
`
`Getting Connected 54
`Dir:l— Up Cowmectiom 5'5
`Leased Line:
`5'6
`
`Switched Network OVC1‘ViCW 59
`
`Circuit Switching
`PzrcketS'witching
`
`60
`61
`
`WAN Packet Switching Protocols
`X25 62
`
`62
`
`64
`Frame Relay
`Asymhrrmam 7?‘/1mfe1'Morle (ATJW 64
`
`Other WAN Protocols
`
`65'
`
`4
`
`

`
`PRACTICAL Cisco Routers
`
`4 Internetworking Basics
`
`67
`
`What Is Internetworking?
`
`68
`
`68
`
`Internetworking D evices
`Repeater:
`70
`Bridger
`71
`Swz'tc}7e.v
`73
`Routerr
`73
`Gateway:
`74
`
`Building a Campus Network
`
`75'
`
`1 08
`Logical Interfaces
`Ltmplmtle Intevf/Ice:
`108
`N11/II7lte}fflCe5
`109
`Yinmel Interface:
`1 09
`
`7 Setting Up a New Router
`
`111
`
`Becoming Familiar with Your Router
`
`112
`
`Cisco Router Design
`Router CPU:
`113
`Router Mammy Components
`
`113
`
`113
`
`5 Hnwa Routerworks
`
`77
`
`Connecting the Console
`
`115
`
`78
`Routing Basics
`Park Detcrmimttinn
`
`78
`
`Logical /md HtI7'dwzzre Ada'7‘esres
`Packet Switching
`81
`Routing Yhble:
`82
`
`80
`
`Routable Protocols
`
`85'
`
`Routing Protocols
`
`85
`
`Routing Protocol Basics
`Routing Algoritbwls
`Routing Metric:
`89
`
`8 7
`
`87
`
`91
`Types of Routing Protocols
`93
`Ivzterior Gateway Protocol:
`Exterior Gntewzly Protocol: 95
`
`II Router Design and Basic
`Configuration
`
`6 Understanding Router Interfaces
`
`99
`
`Router Interfaces
`
`100
`
`LAN interfaces
`
`102
`
`Serial Interfaces
`
`104
`
`Configuring the Router Console
`
`117
`
`Working with the Terminal Emulation
`Software
`1 1 8
`
`Connecting the Router to the Network
`LAN Cmmertiom 119
`Serial Cnmzaations
`121
`
`119
`
`A Final Word on Physical Router
`Connections
`122
`
`Basic Router Configuration
`
`123
`
`Configuring a Router
`
`124
`
`Router Boot Sequence
`
`126
`
`Worldng with the System (]onfig11ration
`Dialog Box
`128
`Starting the Samp Dialog Box
`Configuring Rtmted Protocol:
`Cmfig1m‘ng Renter I71tezfirrer
`
`129 A
`131
`1 32
`
`Using the Different Router Modes
`Um‘ (Unprivileged) Made
`135
`Privileged A/[ode
`136
`Coizfigmvltion Made
`13 7
`Getting Arauml Last Prm'word.r
`
`134
`
`139
`
`5
`
`

`
`9 Working with the Cisco I03
`
`141
`
`Introducing the Intemetxvorking Operating
`System 142
`Command Structure
`Exec Caiimm-ml:
`
`144
`144
`
`(}n1y‘igumtion. Mode
`
`145
`
`The IOS Help System 147
`Router Examination Commands
`
`149
`
`Using the Privileged Mode
`
`153
`
`Checking Router Memory
`
`154
`
`Checking Out the Internctwork
`Neighborhood
`1 57
`"
`U7m‘lei72g ruitlr CDP
`
`157
`
`Viewing CDP Neighbors
`Using Ping
`1 60
`
`159
`
`Creating a Router Banner
`
`161
`
`III Routing LAN Protocols
`
`10 TCP/IP Primer
`
`167
`
`The TCP/[P Protocol Stack 168
`
`TCP/IF and the OSI Model
`
`168
`
`1 70
`1 71
`
`Application Layer
`Hort-to—Hort Layer
`Imfemet Lrr_-yer
`1 71
`Network Acres: Layer
`
`1 72
`
`VVorking with IP Addresses
`IP Clzrsrer
`I 75
`
`174
`
`Binary Eqlliv/Ilerzts mm’ Fim‘ Octal‘:
`Bzlric S1/lmet Ma.rkv
`I73
`
`1 77
`
`180
`Subnetting IP Addresses
`Birrmy 177211 Decimrll Co7J.ve7‘:1'0713
`Crerltirzg Szlbliets on (I Class/1
`Networ/e
`I 82
`
`181
`
`CONTENTS
`
`1 84
`
`188
`
`188
`
`Crerrti71g tlae Network S111;-Izet Mar]:
`C/Il:1IlrIt1'7/g IP S1/[met Rrmger
`1 86
`Ca/mlating Available Node Addresrcr
`
`Creating Class B and Class C Subnefs
`Cl/z.r.r R Swbzietting
`188
`Cl/m‘ C Sflbzlettirzg
`190
`U7Idm"17mrli11g Submit 0
`
`192
`
`A Final Word on Subnetting
`
`194
`
`Configuring IP Routing
`
`195
`
`Configuring Router Interfaces
`.LANI71te7frrce.r
`198
`U7/INInte7frIcar
`200
`
`Configuring a Routing Protocol
`Co11fig1n'1'71g RIP 202
`Configm?‘/1g IGRP
`204
`
`I96
`
`201
`
`Dynamic Rouring Versus Static Routing
`
`207
`
`_ Using Telnet 209
`
`Routing Novel! IPX 211
`
`Introducing IPX/SPX 212
`Ro1Iti71g-Related IPX/SPXPratawl.v
`
`213
`
`Understanding IPX Addressing
`Urzrlerxtandiizg SAP 216
`
`214
`
`Configu1ingIPX Routing
`
`21 7
`
`Configuring Router Interfaces with IPX 219
`LANIntc1]‘}1ce5 220
`I/W1NIme7fIIcer 222
`
`Monitoring IPX Routing
`
`223
`
`Routing AppleTa|k 227
`
`228
`Understanding AppleTalk
`Appleifillk Adzl7‘e:si71g 229
`/1pple']7Ille Zones
`232
`
`6
`
`

`
`PRACTICAL Cisco Routers
`
`Configuring AppleTalk Routing Z32
`Cmzfigurirzg LAN Inteifrluer
`235
`Corlfigzzriwzg WI‘1NI7zte7fiIres
`236
`
`1\1onitoring Applerfalk Routing
`
`23 7
`
`IV Advanced Configuration and
`
`- Configuration Tools
`
`14 Filtering Router Traffic with Access
`List
`243
`
`Understanding Access Lists
`How Accent Lin‘: Work
`244
`
`244
`
`Brtilrling rm Arm: Lin‘ 246
`
`W/urlcing with IP Access Lists
`IP I/W/dc/mi ll/I11:/as
`249
`
`247
`
`Crczrting the Accets List 252
`G7‘ouping the Access Lirt to 1m
`Inteifllce
`253
`
`Creating IPX Standard Access Lists
`
`254
`
`Creating AppleTalk Standard Access
`Lists
`256
`
`Configuring WAN Protocols
`
`259
`
`Understanding Serial and VVAN
`Interfaces
`260
`
`(lonfiguring I-Iigh—Level Data Link
`Control (HDLC)
`261
`
`Configuring PPP Z62
`
`Configuring X25
`
`263
`
`Configuring Frame Relay
`
`265'
`
`Configuring ISDN 268
`
`‘I6 Configuring the Router with Cisco
`Contigiiiiaker
`271
`
`What Is Cisco ConfigMaker?
`
`272
`
`Downloading ConfigMakcr
`
`272
`
`Installing ConfigMaker
`
`273
`
`Designing Your Internetwork with
`CoufigMaker
`274
`Adrizozg Deuitet Z76
`Corzwzcctirzg LANX to Rzm.tm'
`Comzettiug Routers to Router:
`
`276‘
`281
`
`Delivering the Configuration to a Router 284
`
`Using a TFl'P Server for Router Configuration
`Storage
`289
`
`290
`What Is a TFTP Server?
`Ol-trIim'ng TFTP Safiwnrr:
`291
`
`Installing the Cisco TFTP Server Software
`
`292
`
`Copying to the TFTP Server 294
`
`Copying from the TFTP Server
`
`295
`
`Loading a New IOS from the TBTP Server
`
`297
`
`Basic Router Troubleshooting 301
`
`Troubleshooting Hardware Problems
`Ra11te1'Prolr1e71/t
`302
`Other Hrmiwrlre P1'abIem.t
`
`305'
`
`302
`
`5'06
`Crzliling Prob/E7//.s
`A Final lVo7‘d on Hrmlwrrre
`
`307
`
`307
`Troubleshooting LAN lrrterfaces
`T1‘ar/lwlet/Jaoting Ethernet wit]: Show 3 07
`'Ii‘o1rI1lz:lJooti11g '12:/zen Ring with Show 309
`
`Troubleshooting WAN Interfaces 31]
`
`7
`
`

`
`BONTENTS
`
`B Seiecterl Cisco Router Specifications
`'
`Router Selecuon
`
`335’
`
`337
`
`Cisco 7500 Routers
`
`Cisco 4500 Routers
`
`Cisco 2500 Routers
`Cisco 1000 Routers
`
`338
`
`339
`
`340
`341
`
`AFina1 Note
`
`342
`
`‘
`
`Gmssan,
`
`343
`
`Index 359
`
`Troubleshooting TCP/IP 313
`’
`U51‘ngp1'7zg 314
`Unvng twm 315
`
`Tmubleshoou-Hg IPX 316
`
`T1'oub1esh00ti11g App1e'Ihlk
`
`317
`
`A Final Word on Troubleshooting 318
`
`V Appendixes
`
`A Basic Router Command Summary 323
`Cisco IOS Command Summa
`324
`Router Examination Ca//17mz:zyzlr
`324
`Router Memmy Commmzdx 325
`Przmuord and Router Name Cmzfigvzmztion
`Commzmds 326
`
`Interfizce Configzmztian Commamir
`IP—RelaIezl Commands
`328
`IPX~RelatedCw71mmIdr
`330
`
`327
`
`331
`Apple7?zlk—Relzzted Carmma72d:
`I/W1N~RelateLlCa7im11t'm1'.v
`332
`
`T7'oubleJ‘b0uti71g Communal: 334
`Mi.rcell:IneousCom7mma1r
`334
`
`8
`
`

`
`About the Aether
`
`Joe Habraken is an information technology consultant and best-
`selling author whose publications include The Covizp/etc Idiot’: Guide to
`Mimzsofi.‘ Access 2000, Microsoft Oflice 2000 8411-], Easy Publisher 2000,
`and Sums F2115/7 YourselfMimrsoft Outlook 2000 in 10 A/Ii1mtes.]oe has
`a Masters degree from the American University in Washington.,_D.C.
`and over 12 years of experience as an educator, author, and consul—
`tant in the information technology field. Joe is 2 Microsoft Certified
`Professional and currently provides consulting services in the NT
`Server and internetworking arenas to companies and organizations.
`He also currently serves as the lead instructor for the Networking
`Technologies program at Globe College in St. Paul, Minnesota.
`
`9
`
`

`
`eslieafiien
`
`To all the NSS students at Globe College.
`
`Good luck with your careers, and thanks for staying awake in my
`Cisco class (even when I babbled excitedly about internetworking
`and routing technology).
`
`Acknowledgments
`
`Creating a book like this takes a real team effort, and this particular
`book was created by a team of incredibly dedicated professionals. I
`would like to thankjenny Watson, our acquisitions editor, who
`worked very hard to assemble the team that made this book a reality
`and always made sure the right pieces ended up in the right places.
`
`I would also like to thank Rick Kughen, who served as the develop-
`ment editor for this book and who came up with many great ideas
`for improving its content. He always asked the right questions and
`wasn’t afraid to burn the midnight oil to get the job done.
`
`Also a tip of the hat and a thanks to Ariel Silverstone, who as the
`technical editor for the project did a fantastic job making sure that
`everything was correct and suggested several additions that made the
`book even more technically sound. Finally, a great big thanks to our
`production editor, Tonya Simpson, who ran the last leg of the race
`and made sure the book made it to press on time—what a great team
`of professionals.
`
`10
`
`

`
`Tefi 353 What Vets "fitiniél
`
`As the reader of this book, you are our most important critic and
`commentator. We Value your opinion and want to know what we’re
`doing right, what we could do better, what areas you’d like to see us
`publish in, and any other words of wisdom you’re willing to pass our
`way.
`
`As an Associate Publisher for Que Corporation, I welcome your
`comments. You can Fax, email, or write me directly to let me know
`what you did or didn’t like about this book—as well as what we can
`do to make our books stronger.
`
`Please note that I cannot laefii you wit}: teclmicalpralalems related to the
`topic of this book, and that due to the high volume ofmail I receive, I might
`not be able to reply to every message.
`
`When you write, please be sure to include this books title and
`author as well as your name and phone or fax number. I will carefully
`review your comments and share them with the author and editors
`who worked on the book.
`
`Fax:
`
`317—581—4666
`
`Email:
`
`hardwarecdmcp . com
`
`Mail:
`
`Jim Minatel
`Associate Publisher
`
`Que Corporation
`201 West 103rd Street
`
`Indianapolis, IN 46290 USA
`
`11
`
`

`
`find it amazing how rapidly computer technology has changed
`over the last 10 years. Technology once considered too costly or too
`complex for small or inediu1n—sized companies is now being embraced
`at breakneck speed. Intei-net3vorl<ing devices, and routers in particu-
`lar, are some of the former “big—cornpany” technologies now being
`used by even the smallest companies.
`
`Inexpensive, low-end routers provide the connection to service
`providers and the public switched telephone network for small com-
`panies (and even individuals) who are looking for more bandwidth as
`they increasingly use the Internet as a communication and marketing
`tool. And as companies grow, they also look for strategies to conserve
`the bandwidth on their company—owned LANS; LAN segmentation
`with routers has become a viable and eost—effective solution.
`
`With this explosion of internetworking technology hitting the busi-
`ness world, there has been a growing need for professionals to config-
`ure, manage, and troubleshoot routers and other internetworldng
`devices. And although several excellent books and training materials
`that relate to internetworlcing and Cisco products are available, most
`of these materials have been written for IT professionals with many
`years of experience or training already under their belts. A basic
`primer and entry—level book on the subject really hasn’t been avail-
`able—unu'l now.
`
`Abner This Beale
`
`Vi/hen I sat down to write this book, I wanted to do two things: share
`my excitement about internetworlcing and Cisco router configuration
`and provide a book that someone new to this technology could use to
`explore the incredible possibilities this technology offers. 1 also
`wanted to create a solid learning tool and make the book useful as a
`reference for someone with little internetworking background, who
`suddenly found working with Cisco routers part of their job descrip-
`tion. And although that sounds like somewhat of a tall order, I knew
`that I would have help.
`
`12
`
`

`
`PRACTICAL Cisco Routers
`
`Skilled designers and editors at Macmillan Publishing have worked
`very hard to create a book design that embraces fresh ideas and
`approaches that will provide an environment in which you can get
`the informauon you need quickly and efficiently. You will find that
`this book embraces a streamlined, conversational approach to the
`subject matter that will help you learn the concepts and become
`familiar with the hardware and software facts that you need to get
`the job done.
`
`Eiowihis mitts
`
`rgauizeafi
`
`Part 1, “Networking Overview”—~This section of the book helps
`you get up to speed or review several networking technologies.
`Information is provided on LAN5, WANs, and internetworking.
`A chapter also provides information on the Open System
`Interconnection reference model and how it relates to rca1—world
`
`network protocols. The basics on how routers Work is also
`included in this section.
`
`Part II, “Router Design and Basic C0nfig11ration”——This section
`walks you through the hardware components of a typical Cisco
`router. You are also introduced to the basic configuration of
`routers and learn an overview of the Cisco Internetwork
`
`Operating System.
`
`Part III, “Routing LAN Protoeols”—This section provides
`information about popular LAN protocols, such as TCP/IP,
`IPX/SPX, and AppleTalk. You learn conceptual information on
`each of these protocol stacks. You also walk through the steps of
`configuring a Cisco router for each of these protocols.
`Part TV, “Advanced Configuration and Configuration Tools”—
`This section helps you become familiar with several WAN tech-
`nologies available and how they are configured on a Cisco
`router. Restricting access to your routers and troubleshooting
`routers are also covered to give you a complete picture of work—
`ing with internetworking devices. Information on using Cisco’s
`ConfigMaker router configuration software is also included in
`this section. It provides someone who must get a router con-
`
`13
`
`

`
`INTRODUCTION
`
`nectcd and configured in a hurry, a step—by—step look at how to
`use the ConfigMaker software.
`
`Who Shane Use This oak
`
`This book is for anyone who needs a primer on internetworking and
`the configuration of Cisco routers. And Whether you work for a big
`company, small company or are just beginning your education to
`become a network professional, this book is an excellent first step as
`you build your knowledge base.
`
`Conventions flsed En This oak
`
`Commands, directions, and explanations in this book are presented
`in the clearest format possible. The following items are some of the
`features that will make this book easier for you to use:
`
`n Commands that you must enter—Router commands that you’ll
`need to type are easily identified by a monospace font. For
`example, if I direct you to get the encapsulation (the WAN pro-
`tocol set) for a serial interface, I’ll display the command like this:
`show interface serial 12). This tells you that you’ll need to enter
`this command exactly as it is shown.
`Combination and shortcut keystrokes—'Iext that direct}: you to
`hold down several keys simultaneously is connected with a plus
`sign (+), such as Ctrl+P.
`
`Cross references—If there’s a related topic that is prerequisite to
`the section or steps you are reading, or a topic that builds fur-
`ther on what you are reading, you’ll find the cross reference to it
`at the end of the section, like this:
`SEE ALSO
`
`7”” '1]; ICE bow to create vlewxp/Ipez‘ Cl}/‘Il7}I)iS, see page xx.
`
`n Glossary terms——For all the terms that appear in the glossary,
`you’1l find the first appearance of that term in the text in italic
`along with its definition.
`
`14
`
`

`
`PRACTICAL Cisco Routers
`
`u Sidenotes—Information related to the task at hand, or “inside”
`information from the author, is offset in sidebars that don‘t
`interfere with the task at hand. This valuable information is also
`
`easier to find. Each of these sidebars has a short title to help you
`quickly identify the information you’ll find there. You’ll find the
`same kind of information in these that you might find in notes,
`tips, or warnings in other books but here, the titles should be
`more informative.
`
`15
`
`

`
`16
`
`

`
`17
`
`

`
`PARTI Networking Overview
`CHAPTER? LAN Review
`
`We Meant ei the P3
`
`How and where people use computer technology has changed dra«
`matically over the past 30 years. In the 19605, computing revolved
`around large mainframe computers. In the early days, users typically
`interfaced with this highly centralized computer through an interme-
`diary: an IS administrator or programmer. As computer technology
`evolved further, mainframe users were able to directly communicate
`with the computer using a dumb terminal (basically, a monitor and a
`keyboard hard—Wired to the mainframe). In the 1970s, the Ininiframc
`gained dominance in the computing world, making computer tech-
`nology accessible to a larger number of companies and organizations
`(even though these companies paid a premium for their ability to
`compute). All storage and computing power was still centralized,
`however, much the same as in the mainframe environment.
`
`In the 19805 the personal computer (particularly the IBM Personal
`Computer) revolutionized the way you compute. Computing power
`was brought to the individual desktop. Not only was this new type of
`computer relatively easy to use (when compared to mainframes and
`miniframes) but also it was very affordable. The only flaw in this
`computing renaissance was the inability of users to collaborate and
`share resources. The individuality of the PC isolated its users.
`
`Netwettitg We
`
`To overcome this decentralized computing model offered by the PC,
`software and hardware were developed in the 19805 and 19903 to
`connect PCs into networks that could share resources (such as print-
`ers and files). Networked PCs made it easy to design a collaborative
`computing environment for any business situation. Networked com-
`puters can share a‘ variety of resources, including hardware (printers,
`modems), software (application software), and user—created files.
`
`Different networking models arose to fit different types of networle
`ing needs. In situations where a few Computers needed to share a
`particular hardware device, such as a printer, but did not require cen—
`tralized file storage, the pec1'—t0—peer72ez'zvork evolved. The only fime
`individual users interfaced with this type of network was when they
`
`18
`
`

`
`*""_'"___""'_"l
`
`PART I
`
`Networking PCs CHAPTER 1
`
`printed. The alternative to the pecr—to-peer network was a network
`with more centralized control of resources and better security. This
`type of networlc—a SBTUE7‘-IJIISBEZ 1zet’work—«uses a server computer (the
`central controller of the network) to authenticate users on the net-
`Work and provide central file storage (as well as access to 3 number
`of different hardware and software resources). How these two net—
`working models differ deserves some additional discussion.
`
`Peer~to«Peer Networks
`
`Peer—to—peer networks provide an easy way to share resources, such
`as files and printers, without the need for an actual server computer.
`Peer computers act as both rliemir (the users of resources) and 5677257":
`(the providers of resources). The only real requirements for building
`a peer-to-peer network are installing an operating system on the PCs
`that supports peer-to-peer networking and physically connecting the
`PCS.
`
`Several operating systems, such as Nlicrosoft Windows 3.11,
`Microsoft Wuidows 95/98, and Microsoft VV1ndows NT
`VVorl<station, have peerAto—peer networking capabilities built in.
`_Local drives, folders, and printers can be shared with others on the
`peer—to—peer network (see Figure 1.1).
`
`19
`
`

`
`sh‘
`:* but leaves resdur
`gfisgiczwiiitaghigidl/td tfiep I
`network,
`5
`V
`
`-
`‘
`
`PART! Networking Overview
`CHAPTER1 LAN Review
`
`Each resource that is shared (such as a drive or printer) potentially
`will have a different share password. This is one of the downsides of
`peer—to~peer networl<ing— — every resource is capable of having a sepa-
`rate password. If many resources are shared across the network, you
`will have to remember the password for each resource. This type of
`security is referred to as 5/J/Ire—leve1sec;2t1'it_y.
`Peer—to— eer networks also don’t re uire a
`P
`administration because each user can manage resources on l'11S own
`peer computer. Peer networks, however, do have their downsides:
`
`reat deal of additional
`
`n Increased performance hit on computers because of resource
`sharing
`No centralized location of shared files makes it difficult to back
`
`up data
`
`Security must be handled on a resource-by—resource level
`Decentrahzauon of resources makes it difficult for users to
`locate particular resources
`
`a Users might have to keep track of numerous passwords
`
`Although peer—to—peer networking may seem like a fast and cheap
`way to connect a group of computers, the biggest drawback in using
`this type of networking is that o11ly a small number of users can be
`accommodated. Peer networking isn’t scalable (meaning expandable,
`because most peer networks are limited to 10 peer computers) and so
`is certainly not the appropriate choice for a growing company.
`
`It is pretty much a consensus among IS managers that peer—to~peer
`networking works ideally with five or fewer peer machines.
`SEE ALSO
`
`For more infer/m1fion on the physical romlertionq see page 12.
`
`Servenfiesed Networks
`
`Server—based networks provide greater centralized control of
`resources and expandability if required. A server computer is basi-
`cally a speci-al—pu.rpose machine that logs in users and “serves” up
`resources to them. Because the server verifies users, this type of net-
`work makes it easier to manage your resources by providing different
`
`20
`
`

`
`PAHTI
`
`Networking PCs CHAPTER1
`
`access levels to the various users in your user pool. A uscrname and
`one password puts users onto the network and gives them access to
`any resource for which they have the appropriate permissions.
`
`A seiver—based network typically employs a more powerful (in terms
`of processor speed, RAM, and hard—drive capacity) computer to act
`as the server. In addition to hardware that can handle a large number
`of user requests for services, the server computer must run special
`software—a network operating system (NOS). Two commonly used
`network operating systems are Microsoft Vlfindows NT Server and
`Novell NetWare.
`
`Seiyenbased networks, as mentioned before, are scalable. This
`means that the network can grow along with your company. Sewers
`can be added to your network that take on specialized duties. For
`example, one server may handle user login and verification (a pri-
`mary domain controller on a VVindows NT network would be an
`example), while another server on the network may handle the email
`system (a communications server). Table 1.] lists some of the special-
`ized seivers you might use on a local area network.
`
`ServerType
`
`File server
`
`Communication server
`
`Application server
`
`Print server
`
`Use
`
`Stores shared user files and provides home directory
`space for users (such as :1 Novell NetVVare server)
`
`Provides communication services such as email (such as
`an NT Server nmning Microsoft Exchange Server)
`
`Provides access to a database or odier application (such
`as an SQL server database)
`
`Provides the print queue and other services related to a
`network printer
`
`A scrvcr—based network of computers that is limited to a fairly small
`geographical area such as a particular building is described as a local
`area network (LAN). LANs are found in small, medium, and large
`companies. VVhen several LANS are connected, you are dealing with
`an irzrmzerzvnrk, which is a network of networks (this type of network
`can also be referred to as a c/mzpm). VVhen you start connected ca1n~
`puses and create networks that span large geographical areas, you are
`working in the realm of the VV1de Area Network (WTAN).
`
`21
`
`

`
`PARTI Networking Overview
`CHAPTER’! LAN Review
`
`Server—based networks are really the standard for even small local
`area networks; these types of networks do have their downside, how-
`ever. Much of the downside, at least for the small company Wanting
`to set up a PC network, is cost—-the cost of at least one sewer PC
`and the cost of the network operating system. Server—based networks
`also typically require the hiring of a full—time administrator to main~
`tain and manage the network (and whereas management sees this as
`an additional cost, the network administrator sees it as money well
`spent).
`
`Other negatives associated with the server—based network revolve
`around server failures, I2rnmz'c/zst storm: (tons of broadcast traffic from
`devices on the network), and other hardware— and software—related
`disasters that are too numerous to mention in this book. Networks
`
`are by nature challenging, and that is why a good network adminjse
`trator is worth his or her weight in gold.
`SEE ALSO
`
`FW’1IIOI’e in_/inwzrztiazz on intemerwarlting, rec page 67.
`SEE ALSO
`
`F For more izzfizmmtiozz on 'wia'er11'm 11crwa7‘king rec page 53.
`
`Making the Sermeetien
`
`To create a computer network, you must use some type of connective
`medium that allows the transfer of your data. This medium can
`range from copper cable to microwave transmissions to a beam of
`infrared light (our discussion of network media will be restricted to
`copper and fiber—opn'c cables, with the understanding that there are a
`lot of possibilities for moving data from one point to another).
`
`After you choose a connective medium, such as copper cable, you
`also need a device that can prepare the data on the computer so that
`it can travel along your network cabling. This data restructuring is
`handled by a network interface card (NIC). A NIC is typically placed
`in one of the computers bus expansion slots and then the network
`cable is attached to a port on the NIC. Understanding how the NTC
`works, and your options as far as copper and fiber—optic cabling, will
`go a long way when you have to sit down and design even the small-
`est networks.
`
`22
`
`

`
`PARTI
`
`Making the Connection CHAPTER1
`
`Network interface Cards
`
`provides the connection between
`The network interface Card
`the PC and the networks physical medium (such as copper or fiber-
`optic cable). Data travels in parallel on the PC’s bus system; the net-
`work medium demands a serial transmission. The transceiver (a
`transmitter and receiver) on the NIC card is able to move data from
`parallel to serial and vice versa.
`
`Network interface cards each have a unique address that is burned
`onto a ROM Chip on each NIC. This addressing system is used to
`move data from one physical connection to another (and you will
`find that resolving logical addresses such as IP addresses to NIC
`hardware addresses is really what networking is all about).
`
`NICS are available for a number of bus types (Figure 1.2 shows a
`PCI Ethernet NIC), so make it a point to open up the PC or PCS
`that you are going to network and check to see what type of bus slots
`are available. Newer PCS will typically have PCI slots available.
`Older computers mean that you will have to deal with TSA and possi~
`bility EISA slots. Obviously, purchasing the appropriate card is
`extremely important in making the computer network-ready. The
`remainder of the battle is installing the network card and the appro-
`priate software drivers for the NIC and getting the computer to rec-
`ognize both.
`
`
`
`1:.L'I:m1':t¢JMai.'a':n'un«.a.':7vm'v<.<,.r1r.'.._.
`
`23
`
`

`
`PART! Networking Overview
`CHAPTER1 LAN Review
`
`Make sure you have the CD or disk set for the operating system l'l11’1—
`ning on the computer (such as Vl/"indows 98) and that you have any
`disks or CDs that came with the network card. Implement the fol-
`lowing steps to get the PC up and running on the network:
`
`Setting up the PC on the network
`
`‘I. Open the case on the computer and install the NIC in an open
`expansion slot.
`. Close the case and attach the network medium (typically
`twisted—pair cabling).
`-
`. Boot up the computer. If you purchased a plug—and—play network
`card and are using Windows 95/98, the card will be detected and
`the appropriate software drivers installed. You may he prompted
`to provide the drivers during this process (these drivers are on a
`disk or CD that came with the network card).
`
`. If you are using an operating system that docsn’t detect new
`hardware devices, you will have to manually install the NIC, If
`the card came with installation software, use that software to
`install the necessary drivers.
`
`. Some operating systems will require that you select an IRQ and
`I/O port for the new NIC (this is the case with Vlfindows NT
`%l)t>m the server and workstation OS; select an open IRQ and
`I/O port and then Complete the installation of the card as
`required by your operating system.
`
`After you physically install the card and add the appropriate driver to
`your software operating system, you should be up and running on
`the network (you might have to reboot the machine after installing
`any drivers for the NIC). Problems associated with NICs usually
`revolve around improper installation (press the card firmly into the
`expansion slot) and IRQ conflicts. The latter is discussed in the next
`section.
`V
`
`sailing with lflfls and E/O Ports
`
`One of the most common pitfalls when installing any new device
`into one of the expansion slots on a PC is an IRQ conflict. IRQ
`
`24
`
`

`
`PART 1
`
`Making the Connection CHAPTER‘!
`
`stands for I1ztermptReQuert. Each device in your computer, such as
`the mouse, keyboard, and NIC, are assigned an Interrupt Request
`line that the device uses to alert the microprocessor (CPU) that the
`device needs data processed. Each device must be assigned a unique
`IRQ or you have (yes, you guessed it) an IRQ conflict. Neither
`device will probably operate correctly if two device