MACMILLAN
`TECHNICAL
`
`,u ILISHING
`
`U•S•A
`
`MACMILLAN NETWORK
`ARCHITECTURE &
`DEVELOPMENT SERIES
`
`Implementing Interoperable Networks
`
`Ji111 Ccicr
`
`1
`
`Comcast, Ex. 1134
`
`

`

`Wireless LANs
`
`Implementing Interoperable Networks
`
`Jim Geier
`
`MACMILLAN,
`TECHNICAL
`PUBLISHING
`U•S•A
`
`2
`
`

`

`Wireless LANs: Implementing Interoperable Networks
`Copyright © 1999 by Macmillan Technical Publishing
`
`Publisher
`Jim Le Valley
`
`Executive Editor
`Linda Ratts Engelman
`
`Managing Editor
`Caroline Roop
`
`Acquisitions Editor
`Karen Wachs
`
`Development Editor
`Thomas Cirtin
`
`Project Editor
`Laura N. Williams
`
`Copy Editor
`Keith Cline
`
`Indexer
`Tim Wright
`
`Proofreader
`Julie Searls
`
`Acquisitions Coordinator
`Amy Lewis
`
`Manufacturing Coordinator
`Brook Farling
`
`Book Designer
`Gary Adair
`
`Cover Designer
`Sandra Schroeder
`
`Production Team Supervisor
`Tricia Fl odder
`
`Production
`EricS. Miller
`
`FIRST EDITION
`
`All rights reserved. No part of this book may be reproduced or transmit(cid:173)
`ted in any form or by any means, electronic or mechanical, including
`photocopying, recording, or by any information storage and retrieval sys(cid:173)
`tem, without written permission from the publisher, except for the
`inclusion of brief quotations in a review.
`
`International Standard Book Number: 1-57870-081-7
`
`Library of Congress Catalog Card Number: 98-85498
`
`2001 00 99 98 4 3 2 1
`
`Interpretation of the printing code: The rightmost double-digit number
`is the year of the book's printing; the rightmost single-digit, the number
`of the book's printing. For example, the printing code 98-1 shows that
`the first printing of the book occurred in 1998.
`
`Composed in Bergamo and MCPdigital by Macmillan Computer Publishing
`Printed in the United States ef America
`Trademark Acknowledgments
`All terms mentioned in this book that are known to be trademarks or
`service marks have been appropriately capitalized. Macmillan Technical
`Publishing 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 wireless LAN tech(cid:173)
`nology. 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 and
`Macmillan Technical Publishing shall have neither liability nor responsi(cid:173)
`bility 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.
`
`Feedback Information
`At Macmillan Technical Publishing, our goal is to create in-depth techni(cid:173)
`cal 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 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 at
`networktech@mcp.com. Please make sure to include the book title and
`ISBN in your message.
`
`We greatly appreciate your assistance.
`
`3
`
`

`

`About the Author
`Jim Geier is an internationally known consultant, author, and speaker on wireless
`LAN technologies and implementation strategies. He is currently the director of
`Network and Software Systems at Monarch Marking Systems, an international leader
`in providing bar code system solutions. Jim's department develops wireless system
`tools and application software for companies and organizations worldwide.
`
`Jim is the author of Wireless Networking Handbook (1996, New Riders Publishing) and
`Network Reengineering (1996, McGraw-Hill), as well as numerous articles in leading
`publications, including Network Magazine and Byte. Jim has instructed courses inter(cid:173)
`nationally on computer-related topics, including wireless networking, software devel(cid:173)
`opment, and project management, for George Washington University and
`Technotogy Training Corporation. He speaks regularly at conferences and
`tradeshows held throughout the world.
`
`Jim served as chairman of the Institute of Electrical and Electronic Engineers (IEEE)
`Computer Society, Dayton Section, and chairman of the IEEE International
`Conference on Wireless LAN Implementation. He was an active member of the
`IEEE 802.11 working group, responsible for developing international standards for
`wireless LAN s.
`
`Jim's past 20 years of experience include a variety of consulting and management
`positions. At Wright-Patterson Air Force Base in Ohio, Jim managed the design and
`operational support of numerous LANs and a wide area network that supports over
`10,000 users. For the base, he evaluated the effectiveness of wireless network tech(cid:173)
`nologies for use in mobile and portable office environments. He led the development
`of a tool to aid engineers in the installation of wireless networks and evaluated com(cid:173)
`mercial network technologies for use with U.S. government mobile sensor systems.
`
`He was the principal investigator for a small business innovative research grant to
`develop an automated software tool that assists engineers in planning, upgrading, and
`maintaining information systems. He managed a test team responsible for testing
`computer networks throughout the world. He has developed corporate information
`system standards for companies migrating from mainframe to client/server systems,
`'
`Jim holds a B.S. degree from California State University, Sacramento, and an M.S.
`degree from Air Force Institute of Technology, both in electrical engineering with
`emphasis in computer networks. As part of his master's thesis, he developed and
`implemented an adaptive automatic routing algorithm for a worldwide packet radio
`network.
`
`Jim's hobbies include sailing and amateur radio (KC8KQH). He resides with his wife
`and four sons in Yellow Springs, Ohio. You can reach him at j imgeier@aol.com.
`
`4
`
`

`

`Dedication
`I dedicate this book to my wife, Debbie, for her loving support of my writing efforts.
`
`Acknowledgments
`When writing this book, I was fortunate to work with an excellent team at
`Macmillan Technical Publishing, whose contributions vastly improved the presenta(cid:173)
`tion of this book. In particular, Tom Cirtin, development editor, did an outstanding
`job guiding me through the revision of the text. Tom's ideas and his editing
`enhanced this book's readability and use as a tool for implementing wireless LANs.
`
`I' cl also like to give special thanks to Ed Lamprecht for performing the technical
`review of the book's manuscript. Ed's valuable suggestions greatly refined this book.
`
`5
`
`

`

`About the Technical Reviewers
`These reviewers contributed their considerable practical expertise to the entire devel(cid:173)
`opment process for Wireless LANs. As the book was being written, these folks
`reviewed all the material for technical content, organization, and flow. Their feed(cid:173)
`back was critical to ensuring that Wireless LANs fits our readers' need for the highest
`quality technical information.
`
`D. Ed Lamprecht is a Senior Systems Engineer at Monarch Marking Systems with
`15 years of programming experience in applications and operating systems. He
`received a bachelor's degree in 1983 from the University of Northern Iowa and start(cid:173)
`ed his career with NCR Corporation programming operating systems in assembly for
`retail computing systems. It was during this time that Ed also developed applications
`for other platforms, including UNIX and DOS.
`
`In 1988, Ed joined Monarch Marking Systems, a company specializing in bar code
`printers and labels. Here he developed bar code applications for MS-DOS and
`Microsoft Windows 2.0 and later, including PC drivers and TSRs and connectivity
`software. Since 1996, Ed has been involved in data collection systems providing wire(cid:173)
`less network connectivity solutions ofhandheld printers and data collection terminals
`for retail, industrial, manufacturing, and health care markets.
`
`At Monarch, Ed has developed client/server applications, visited customer sites for
`analysis and problem solving, and provided international training on products and
`wireless connectivity. Ed holds six patents in bar code software and handheld printer
`and data collectors.
`
`Ed lives with his wife, Michelle, and his son, Colin, in Dayton, Ohio. When not tin(cid:173)
`kering with PCs and networks at home, he enjoys model railroading, railroad memo(cid:173)
`rabilia collecting, golfing, traveling, and spending time with his son.
`
`Peter Rysavy is a consultant specializing in wireless communication and other tech(cid:173)
`nologies related to personal and mobile communication. His firm, Rysavy Research,
`assists clients with market research, product and business development, and technolo(cid:173)
`gy assessment. Peter is the chairman of the standards committee of the Portable
`Computing and Communications Association (PCCA), a standards group that pro(cid:173)
`duces wireless-data standards.
`
`Since 1993, Peter has worked as a consultant with numerous clients on projects
`involving mobile and wireless communication. Clients include cellular carriers, com(cid:173)
`munications software companies, network hardware companies, investment firms,
`automotive electronics companies, research organizations, and universities. He also
`teaches seminars and writes articles about wireless communication.
`
`6
`
`

`

`Peter graduated with an MSEE from Stanford University in 1979, where he was
`involved in several collaborations between academia and industry. Joining Fluke
`Corporation in 1979, he designed communications hardware and software for data(cid:173)
`acquisition products. From 1981 to 1983, he designed ethernet networking hardware
`at Time Office Computers in Australia. He rejoined Fluke, and until 1988 managed
`the development of a family of communication-oriented touch terminals. From 1988
`to 1993, Peter was VP of Engineering and Technology at Traveling Software (makers
`ofLapLink). His last major project was LapLink Wireless. He also managed the
`development ofLapLink and connectivity solutions for a broad variety of mobile
`platforms.
`
`7
`
`

`

`Contents at a Glance
`Introduction
`
`Part I: Wireless Networks-A First Look
`
`Introduction to Wireless Networks
`1
`2 Wireless Network Configurations
`3 Overview of the IEEE 802.11 Standard
`
`Part II: Inside IEEE 802.11
`
`4 Medium Access Control (MAC) Layer
`5 Physical (PHY) Layer
`
`Part Ill: Deple>,ying Wireless LANs
`
`6 Wireless System Integration
`7 Planning a Wireless LAN
`8
`Implementing a Wireless LAN
`
`Appendices
`
`A Automatic Identification and Data Capture (AIDC)
`B Products, Companies, and Organizations
`Glossary
`Index
`
`1
`
`5
`
`7
`43
`89
`
`127
`
`129
`·159
`
`191
`
`193
`235
`281
`
`323
`
`325
`353
`367
`391
`
`8
`
`

`

`Contents
`
`Introduction
`
`Part I: Wireless Networks-A First Look
`
`1
`
`5
`
`7
`1 Introduction to Wireless Networks
`The Benefits ofWireless Networking ............................................................ 8
`Mobility .............................................................................................. 8
`Cost Savings ........................................................................................ 8
`Wireless Network Markets and Applications ................................................. 14
`Retail ................................................................................................. 14
`Warehouses ..................................................................................... , .. 15
`Healthcare .......................................................................................... 16
`Real Estate ......................................................................................... 17
`Hospitality ......................................................................................... 18
`Utilities ............................. , ................................................................ 18
`Field Service ...................................................................................... 20
`Field Sales .......................................................................................... 20
`Vending ....................................................... , .................................... .20
`Wireless Network Concerns ........................................................................ 21
`Radio Signal Interference .......................................................... _ ......... 21
`Power Management .......................................................................... .23
`System Interoperability ....................................................................... 24
`Network Security ..................................................... , ........................ .24
`Connection Problems ....................................................................... .27
`Installation Issues ............................................................................... .27
`Health Risks ..................................................................................... .28
`The Components of a Wireless Network ..................................................... 29
`Physical Architecture of a Wireless Network ....................................... 29
`Logical Architecture of a Wireless Network ........................................ 37
`The History of Wireless Networks ............................................................... 39
`The Future ofWireless Networks ..................................................•............. .41
`
`43
`2 Wireless Network Configurations
`Wireless LAN\,-···························································································43
`Radio-Based Wireless LANs ............................................................. .44
`Infrared Light-Based Wireless LANs ...................... : ........................... .58
`Carrier Current LANs ....................................................................... 62
`Wireless Point-to-Point Networks ............................................................... 63
`Wireless Point-to-Point Network Applications ................................... 64
`Radio-Based Wireless Point-to-Point Networks ................................. 65
`Laser-Based Wireless Point-to-Point Networks ................................... 69
`
`9
`
`

`

`WIRHLl!SS LANs
`·- - x I
`
`Wireless WANs ........................................................................................... 71
`Packet Radio WANs .......................................................................... 72
`Packet Radio Architecture .................................................................. 72
`Analog Cellular WANs ....................................................................... 78
`Analog Cellular Technology ............................................................... 79
`Cellular Digital Packet Data (CDPD) WANs ...................................... 80
`Satellite Communications ................................................................... 83
`Meteor Burst Communications .......................................................... 84
`Combining Location Devices with Wireless WANs ............................ 85
`GPSfWireless Applications ................................................................. 86
`
`3 Overview of the IEEE 802.11 Standard
`89
`The Importance of Standards ....................................................................... 90
`Types of Standards ............................................................................. 91
`Benefits of the 802.11 Standard ......................................................... 93
`IEEE 802 LAN Standards Family ................................................................. 96
`IEEE 802.2 LLC Overview ................................................................ 97
`IEEE 802.2 LLC Services ................................................................... 98
`LLC/MAC Layer Service Primitives .................................................. 104
`Introduction ·to the IEEE 802.11 Standard .................................................. 105
`IEEE 802.11 Topology ............................................................................... 108
`Independent Basic Service Set (IBSS) Networks ................................ 108
`Extended Service Set (ESS) Networks ........................................ , ...... 109
`IEEE 802.11 Logical Architecture ............................................................... 111
`IEEE 802.11 MAC Layer .................................................................. 111
`IEEE 802.11 Physical Layers .............................................................. 111
`IEEE 802.11 Services .................................................................................. 113
`Station Services ................................................................................ 113
`Distribution System Services ............................................................. 115
`Station States and Corresponding Frame Types ................................. 116
`Implications of the IEEE 802.11 Standard ................................................... 118
`IEEE 802.11 Standard Compliance ............................................................. 118
`Vendor Compliance .......................................................................... 118
`WLI Forum ..................................................................................... 120
`End-User Compliance ...................................................................... 120
`International Electromagnetic Compliance ........................................ 121
`IEEE 802.11 Working Group Operations ................................................... 123
`Future of the IEEE 802.11 Standard ........................................................... 123
`
`10
`
`

`

`CONTENTS
`!xi
`
`Part II: Inside IEEE 802.11
`
`127
`
`129
`4 Medium Access Control (MAC) Layer
`MAC Layer Operations .............................................................................. 129
`Accessing the Wireless Medium ........................................................ 130
`Joining a Network ............................................................................ 137
`Providing Authentication and Privacy ............................................... 138
`MAC Frame Structure ............................................................................... 142
`Overall MAC Frame Format ...................................................................... 142
`Frame Control Field ......................................................................... 144
`MAC Frame Types .................................................................................... 148
`Management Frames ......................................................................... 148
`Control Frames ...................................................................... , ......... 153
`Data Frames ..................................................................................... 157
`
`5 Physical (PHY) Layer
`159
`Physical Layer Architecture ........................................................................ 160
`Physical Layer Operations .......................................................................... 160
`Physical Layer Service Primitives ....................................................... 161
`Carrier Sense Function ..................................................................... 162
`Transmit Function ........................................................................... 163
`Receive Function ............................................................................. 163
`Frequency Hopping Spread Spectrum (FHSS) Physical Layer ...................... 164
`FHSS Physical Layer Convergence Procedure ................................... 166
`FHSS Physical Medium Dependent (PMD) Sublayer ........................ 168
`Direct Sequence Spread Spectrum (DSSS) Physical Layer.. .......................... 175
`DSSS Physical Layer Convergence Procedure (PLCP) Sublayer .......... 176
`DSSS Physical Medium Dependent (PMD) Sublayer. ........................ 177
`Infrared (IR) Physical Layer ........................................................................ 184
`IR Physical Layer Convergence Procedure (PLCP) Sublayer .............. 185
`IR Physical Medium Dependent (PMD) Sublayer ............................. 187
`
`Part Ill: Deploying Wireless LANs
`
`191
`
`193
`6 Wireless System Integration
`Wireless System Architecture ..................................................................... 194
`Network Distribution Systems ................................................................... 194
`IEEE 802.3 Carrier Sense Multiple Access (CSMA) ......................... 195
`IEEE 802.5 Token Ring .................................................................. 202
`ANS{mber Distril:>uted Data Interface (FDDI) ................................ .203
`Wide Area Networking Concepts ..................................................... 204
`Private Versus Public WANs ............................................................. 206
`
`11
`
`

`

`W11u,Luss LANs
`-xiii
`
`Roaming Protocols .................................................................................... 209
`Proprietary Roaming Protocols ......................................................... 210
`Inter-Access Point Protocol (IAPP) ................................................... 213
`Communications Protocols ...................................................................... .214
`Transmission Control Protocol (TCP) .............................................. 214
`Internet Protocol (IP) ....................................................................... 216
`TCP/IP: Wireless LAN Issues ........................................................... 219
`Mobile IP ....................................................................................... .220
`Connectivity Software ............................................................................... 224
`Terminal Emulation ........................................................................ 225
`Direct Database Connectivity ........................................................... 228
`Intranet-Based Connectivity Software ............................................... 230
`Middleware ...................................................................................... 231
`
`235
`7 Planning a Wireless LAN
`Managing a Wireless LAN Implementation ................................................ 235
`Establishing Project Management Principles ..................................... 236
`Planning a Project ............................................................................ 236
`Executing the Project ....................................................................... 250
`Defining the Requirements for a Wireless LAN ......................................... 254
`Types of Requirements .................................................................... 255
`Eliciting Information ........................................................................ 259
`Defining Requirements .................................................................... 264
`Updating the Project Plan ................................................................. 270
`Analyzing the Feasibility of a Wireless LAN .............................................. 272
`Performing a Preliminary Design ..................................................... .273
`Developing a Business Case .............................................................. 273
`Making the Decision to Proceed ...................................................... .278
`
`281
`8 Implementing a Wireless LAN
`Designing a Wireless LAN ........................................................................ 281
`Defining Network Elements ............................................................. 282
`Selecting Products ............................................................................ 287
`Identifying the Location of Access Points .......................................... 288
`Verifying the Design ......................................................................... 291
`Documenting the Final Design ........................................................ .295
`Procuring Components .................................................................... 297
`Preparing for Operational Support of a Wireless LAN .............................. .298
`Training ........................................................................................... 299
`System Administration ..................................................................... 299
`Help Desk ........................................................................................ 299
`Network Monitoring ...................................................................... .299
`Maintenance and System Development ............................................. 300
`
`12
`
`

`

`CONTENTS
`I xiii
`
`Configuration Control ..................................................................... 300
`Documenting Plans for Operational Support .................................... 301
`Preparing for the Transfer to Operational Mode ............................... 302
`Installing a Wireless LAN .......................................................................... 303
`Developing an Installation Plan ......................................................... 303
`Coordinating the Installation ............................................................ 306
`Staging the Components .................................................................. 306
`Installing the Components ................................................................ 307
`Testing the Installation ...................................................................... 311
`Performing Testing .... , ...................................................................... 314
`Finalizing the Project ....................................................................... 320
`
`Appendices
`
`323
`
`325
`A Automatic Identification and Data Capture (AIDC)
`The Benefits of Using Bar Codes ............................................................... 325
`General Benefits of Bar Code Systems .............................................. 326
`Benefits of Wireless Systems ............................................................. 328
`Bar Code Applications ............................................................................... 328
`Receiving ......................................................................................... 328
`Cross Docking ................................................................................. 330
`Inventory Management .................................................................... 330
`Picking ............................................................................................. 331
`Shipping .......................................................................................... 332
`Purchasing ....................................................................................... 334
`Asset Management ........................................................................... 335
`Point-of-Sale (POS) Systems ................................ : ........................... 336
`Price Marking and Verification ......................................................... 336
`Compliance Labeling ........................................................................ 337
`The Concepts ofBar Code Technology ...................................................... 339
`One-Dimensional Symbologies ........................................................ 340
`Two-Dimensional Symbologies ........................................................ 342
`Bar Code Printing ............................................................................ 343
`Bar Code Readers ............................................................................ 345
`Radio Frequency Identification (RF/ID) .................................................... 347
`RF/ID Benefits ................................................................................ 348
`RF/ID Components ......................................................................... 349
`RF/ID Transmission Parameters ....................................................... 349
`RF/ID Applicanyns .... _ ...................................................................... 350
`
`353
`B Products, Companies, and Organizations
`Wireless Network Product Suppliers and System Integrators ....................... 353
`Organizations and Industry Groups ............................................................ 361
`American National Standards Institute (ANSI) .................................. 361
`.Automatic Identification Manufacturers (AIM) ................................. 361
`
`13
`
`

`

`WIRHLESS LANs
`·. xivl
`
`Infrared Data Association (IrDA) ...................................................... 362
`Instititute for Electrical and Electronic Engineers (IEEE) ................... 362
`International Organization for Standardization .................................. 363
`International Telecommunication Union (ITU) ................................ 363
`Internet Engineering Task Force (IETF) ........................................... 364
`Mobile and Portable Radio Research Group ..................................... 364
`Mobile Management Task Force (MMTF) ........................................ 364
`Boulder Creek Portable Computer
`and Communications Association (PCCA) ..................................... 365
`Wireless LAN Group ...................................................................... 365
`Wireless LAN Interoperability Forum (WLIF) .................................. 366
`Wireless Opportunities Coalition (WOC) ......................................... 366
`Wireless Research Group ................................................................. 366
`
`Glossary
`
`Index
`
`367
`
`391
`
`14
`
`

`

`Introduction
`
`Wireless LAN technology is rapidly becoming a crucial component of computer
`networks, and its use is growing by leaps and bounds. Thanks to the finalization of
`the IEEE 802.11 wireless LAN standard, wireless technology has emerged from the
`world of proprietary implementations to become an open solution for providing
`mobility as well as essential network services where wireline installations proved
`impractical. Now companies and organizations are increasingly investing in wireless
`networks to take advantage of mobile, real-time access to information.
`
`Most wireless LAN suppliers now have 802.11-conipliant products, allowing com(cid:173)
`panies to realize wireless network applications bas~d on open systems. The move
`toward 802.11 standardization is lowering prices and enabling multiple-vendor
`wireless LANs to interoperate. This is making the implementation of wireless net(cid:173)
`works more feasible than before, creating vast business opportunities for system
`implementation companies and consultants.
`
`Many end-user companies and system integrators, however, have little knowledge
`of, and experience in, developiiig and implementing wireless network systems. In
`many cases, there is also ,confusion over the capability and effectiveness of the
`802.11 standard. The implementation of wireless networks is much different from
`traditional wired networks. In contrast to ethernet, a wireless LAN has a large num(cid:173)
`ber of setup parameters that affect the performance and interoperability of the net(cid:173)
`work. An engineer designing the network and the person installing the network
`must understand these parameters and how they affect the network. To address
`wireless installation issues, this book is full of implementation notes, especially
`regarding 802.11-compliant solutions.
`
`15
`
`

`

`W11~Hwss LANs
`:n
`
`To optimize the operation of wireless systems, you need to be familiar with software
`options for interfacing wireless handheld appliances to application software and
`databases located on the network. Terminal emulation, direct database connectivity,
`and middleware are alternatives that provide connectivity depending on system
`requirements. This book describes each of these in detail, and explains how to
`choose one over the others.
`
`Altogether, this book provides a practical overvie