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Installing, Troubleshooting, and Repairing Wireless Networks This page intentionally left blank. Installing, Troubleshooting, and Repairing Wireless Networks Jim Aspinwall McGraw-Hill New York Chicago San Francisco Lisbon London Madrid Mexico City Milan New Delhi San Juan Seoul Singapore Sydney Toronto Copyright © 2003 by The McGraw-Hill Companies, Inc. All rights reserved. Manufactured in the United States of America. Except as permitted under the United States Copyright Act of 1976, no part of this publication may be reproduced or distributed in any form or by any means, or stored in a database or retrieval system, without the prior written permission of the publisher. 0-07-142925-5 The material in this eBook also appears in the print version of this title: 0-07-141070-8. All trademarks are trademarks of their respective owners. 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DOI: 10.1036/0071429255 DEDICATION Most authors select one or a few people that have inspired them through their work—and for those few special people who have inspired me there are many, many more who have fueled their inspirations and ability to inspire. I cannot limit myself to the select few without calling to mind the many—by name or your inspirational efforts. Events of the past 2–3 years have provided the truly exceptional opportunity and pleasure of working with so many wonderful people applying themselves in many different fields and ways towards worthy causes. Just as I feel strongly about acknowledging the work of the people behind projects such as this, I feel moved to elation and tears by people applying themselves towards the basics of life that make it possible to write, produce and ultimately read the work we produce. There is so much that touches us one way or the other—and it can affect us and those around us deeply and most importantly—and I feel it deserves some thought and taking advantage of an opportunity for a call to action. To that, my modest words to recognize and apply positive energy to all efforts of awareness, enlightenment, encouragement, education and action. Technology is nothing without the people we share it with. First and perhaps specifically—to the literally thousands and thousands of people who have given incredible amounts of time and physical effort participating or in support of charitable efforts to raise funds for those baffling diseases we have yet to solve. Almost anyone can fix myriad computer problems—it takes thousands, perhaps millions of us together working towards treatment and cures for the many cancers and disorders that alter our lives or the lives of those we know and love in some way, and too all to many who unfortunately pay the ultimate sacrifice. The monsters must be conquered. And so to the walkers, crews and volunteers of the Avon breast cancer fundraising efforts—we know the love, the work, the tears—eventually vi Dedication we will know the cure. We do not want any more of our families or friends to know this monster. “Just a little bit farther” my friends! To the efforts of the participants and teams contributing to leukemia and lymphoma. One of my “fan club” of people frequently asking for help with her computer was recently diagnosed with leukemia—I cannot cure her disease but I hope someone can so that she and others are able to continue to experience and accomplish computer challenges, and more importantly the essential qualities a long healthy life has to offer! To those who work towards detecting and solving diabetes—some of my very best mentors have been affected and I want them and others to be well and mentoring others. To mentors and teachers—the ability and dedication to share information to enrich our lives through raising interest and improving abilities is so special indeed. Hopefully you are inspired directly or indirectly by the lives you help move forward. To our audience—those new to my work and those who make up the market and inspiration to produce such works. I would have no reason to do this if it were not for you. To my wonderful wife Kathy—an all too frequent “author’s widow” through the creation of this work and my hobbies, and a two-time Avon walker and crew member who exposed me to the most awesome opportunities for awareness and inspiration I may ever know. I love you. “Good job. Keep going!” For more information about this title, click here. CONTENTS Foreword xiii Acknowledgments Chapter 1 xv Wireless Essentials Wireless Defined Wireless Equals Infrared Wireless Equals Radio Frequencies Wireless Networking Radio Spectrum Summary Chapter 2 Wireless Network Criteria and Expectations Performance—What To Expect Do You Need Wireless Technology? Is the Site Wireless-Friendly? Can You Use Wireless Technology? Who Will Design, Install, and Maintain Your Wireless System? The Cost of Wireless Summary Chapter 3 1 3 3 4 16 18 19 21 23 23 25 29 30 32 Wireless Network Basics 33 Ready for Wireless? How Did Wireless Suddenly Come to Involve Wires? Summary 36 41 42 vii Copyright 2003 by The McGraw-Hill Companies, Inc. Click Here for Terms of Use. viii Contents Chapter 4 Antennas and Cables 43 Antennas Omnidirectional Antennas Directional Yagi Antennas Antenna Radiation Polarity and Diversity Wires Connectors Type N TNC SMA MC and MMCX Remote Mounted Access Points and Amplifiers Summary 44 46 50 56 57 62 63 63 64 65 65 66 Chapter 5 Common Wireless Network Components Client-Side Wireless Adapters PC Card CF Card Adapter PC Card PCI Bus Adapter PCI Bus Card ISA Bus Interface USB Interface Network-Side Wireless Equipment Access Points Wireless Bridges Wireless Gateways and Routers Wireless Signal Power Amplifiers Power Limitations for 802.11b Systems Point-to-Point Configurations 802.11a Point-to-Multipoint Summary Chapter 6 Typical Wireless Installations Wireless at Home Wireless at Work Wireless on Campus Wireless in the Community Wireless Internet Service Providers Summary 69 70 71 72 72 73 73 73 74 74 75 76 77 78 80 82 82 83 85 88 95 98 100 103 ix Contents Chapter 7 Hardware Installation and Setup Single Access Point Installations What the Instruction Manual Will Tell You Hardware Configuration Concerns Connecting and Configuring Your Access Point Connecting and Configuring Your Client Adapters Configuring Your Wireless Adapter Windows XP Windows 98, 98SE, and Me First Connect Problems Common Connection Problems Summary Chapter 8 Extending and Maintaining Coverage Multipath Solving Multipath Problems Antennas Line-of-Sight—Placing an Antenna So It Can “See” Clients Antennas versus Adding a Bridge and Access Point Signal Amplifiers Radiating Cable Passive Repeaters Multiple Access Point Networks Avoiding Channel Overlap and Other Networks Summary Chapter 9 Wireless Network Security Threats Theft of Service or Information Denial of Service Detection Identifying Interference Identifying Intervention Preventive Measures Access Control Systems and WEP Alternatives Summary 105 106 108 110 111 112 114 114 120 123 125 131 133 134 137 138 138 140 140 142 143 145 146 148 151 153 153 154 155 157 157 159 160 161