CWNA ® Certified Wireless Network Administrator Official Study Guide (EXAM PW0-100) FOURTH EDITION Tom Carpenter Joel Barrett Series Editor McGraw-Hill is an independent entity from Planet3 Wireless and is not affiliated with Planet3 Wireless in any manner This publication may be used in assisting students to prepare for the CWNA Exam Neither Planet3 Wireless nor McGraw-Hill warrant that use of this publication will ensure passing any exam CWNA and CWNP are registered trademarks of Planet3 Wireless in the United States and/or other countries New York Chicago San Francisco Lisbon London Madrid Mexico City Milan New Delhi San Juan Seoul Singapore Sydney Toronto Copyright © 2008 by The McGraw-Hill Companies 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 0-07-159551-1 The material in this eBook also appears in the print version of this title: 0-07-149490-1 All trademarks are trademarks of their respective owners Rather than put a trademark symbol after every occurrence of a trademarked name, we use names in an editorial fashion only, and to the benefit of the trademark owner, with no intention of infringement of the trademark Where such designations appear in this book, they have been printed with initial caps McGraw-Hill eBooks are available at special quantity discounts to use as premiums and sales promotions, or for use in corporate training programs For more information, please contact George Hoare, Special Sales, at george_hoare@mcgraw-hill.com or (212) 904-4069 TERMS OF USE This is a copyrighted work and The McGraw-Hill Companies, Inc (“McGraw-Hill”) and its licensors reserve all rights in and to the work Use of this work is subject to these terms Except as permitted under the Copyright Act of 1976 and the right to store and retrieve one copy of the work, you may not decompile, disassemble, reverse engineer, reproduce, modify, create derivative works based upon, transmit, distribute, disseminate, sell, publish or sublicense the work or any part of it without McGraw-Hill’s prior consent You may use the work for your own noncommercial and personal use; any other use of the work is strictly prohibited Your right to use the work may be terminated if you fail to comply with these terms THE WORK IS PROVIDED “AS IS.” McGRAW-HILL AND ITS LICENSORS MAKE NO GUARANTEES OR WARRANTIES AS TO THE ACCURACY, ADEQUACY OR COMPLETENESS OF OR RESULTS TO BE OBTAINED FROM USING THE WORK, INCLUDING ANY INFORMATION THAT CAN BE ACCESSED THROUGH THE WORK VIA HYPERLINK OR OTHERWISE, AND EXPRESSLY DISCLAIM ANY WARRANTY, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE McGraw-Hill and its licensors not warrant or guarantee that the functions contained in the work will meet your requirements or that its operation will be uninterrupted or error free Neither McGraw-Hill nor its licensors shall be liable to you or anyone else for any inaccuracy, error or omission, regardless of cause, in the work or for any damages resulting therefrom McGraw-Hill has no responsibility for the content of any information accessed through the work Under no circumstances shall McGraw-Hill and/or its licensors be liable for any indirect, incidental, special, punitive, consequential or similar damages that result from the use of or inability to use the work, even if any of them has been advised of the possibility of such damages This limitation of liability shall apply to any claim or cause whatsoever whether such claim or cause arises in contract, tort or otherwise Professional Want to learn more? 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If you’d like more information about this book, its author, or related books and websites, please click here I dedicate this book to my God, Jesus Christ, without whom I could not have written a single word, and to my amazing wife, Tracy, and my children, Faith, Rachel, Thomas, and Sarah, who tolerated my odd hours and lack of attention during the writing of this book Tracy, you are the most amazing and wonderful thing that has ever happened to me and this book exists because of your faith in me—you have my eternal gratitude Acknowledgments I would like to acknowledge the helpful staff at McGraw-Hill for bearing with my delays on this project Writing two books at the same time is quite a challenge, but we did it together I want to thank Criss Hyde particularly His technical knowledge of the IEEE 802.11 standard (among other standards) is amazing, and he is an exceptional technical editor I also want to thank Joel Barrett, the series editor for this book, who helped to keep me sane during the rough stages Thanks everyone The book turned out very well, and it could not have happened without you all About the Author Tom Carpenter is a technical experts’ expert He teaches in-depth courses on Microsoft technologies, wireless networking, and security, and professional development skills such as project management, team leadership, and communication skills for technology professionals Tom holds a CWNA, CSWP, and Wireless# certification with the CWNP program and is also a Microsoft Certified Partner The Wireless Networking, Windows Administration, and IT Project Management Bootcamps that Tom offers annually provide the in-depth knowledge IT professionals need to succeed He lives with his lovely wife, Tracy, and their four children, Faith, Rachel, Thomas, and Sarah, in Ohio His company, SYSEDCO, provides training and consulting services throughout the United States For more information about Tom and the services offered by his company, visit www.SYSEDCO.com About the Series Editor Joel Barrett is a senior-level wireless networking expert with Cisco Systems Joel has attained networking certifications such as Cisco’s CCNP and CCDP, Microsoft’s MCSE, and Novell’s Master CNE For wireless certifications, he holds Cisco’s Wireless Design and Support specializations, as well as the CWNP Program’s Wireless#, CWNA, CWSP, CWAP, and CWNE certifications He is CWNE #6 and a founding member of the CWNE Roundtable, a steering committee for the CWNE certification program Joel is also certified to instruct Cisco’s Unified Wireless and Mesh Networking courses Within Cisco, Joel consults primarily with large enterprise customers concerning wireless deployments He is a senior advisor for Cisco’s wireless virtual team He is also an author and technical editor for books such as CWNP Dictionary of Terms and Acronyms, CWNP Wireless# Exam Mega Guide, Wireless Networks First-Step, CWSP Official Study Guide, First Edition, and Managing and Securing a Cisco Structured Wireless-Aware Network He is the series editor for McGraw-Hill’s CWNP Official Study Guides Joel and his wife, Barbara Kurth, live with their three children, Ashley, Shane, and Paige, in the Atlanta, Georgia, metro area Joel has two tenets he lives by: ■ ■ “Do what you love, the money will come.” “If it were easy, anyone could it.” About the Technical Editor Criss Hyde has thirty years of IT experience beginning with punch cards and Fortran He holds engineering and law degrees from Pennsylvania State University and George Mason University respectively, and current certifications from Apple, Cisco Systems, The CWNP Program, (ISC)2, Sun Microsystems, and WildPackets He became an early friend to The CWNP Program, has edited many of its books and exams, and has earned all of its certifications He has worked 16 years for Raytheon Company and is a member of the IEEE Standards Association and the Virginia Bar Association Criss is the husband of one wife and the father of eight home-schooled children He heartily agrees with Vint Cerf that for the good of mankind and the IPv6 Internet, the NAT boxes have to go away For more information about this title, click here Contents Introduction xv Part I Understanding Wireless Technologies Chapter Wireless Standards, Organizations, and Applications Roles Organizations Play Within the WLAN Industry Regulatory Domain Governing Bodies ITU-R IEEE IETF Wi-Fi Alliance Spread Spectrum Technology Uses Wireless LANs Wireless PANs Wireless MANs Wireless WANs Wireless LAN Technology Roles Corporate Data Access and End-User Mobility Network Extension to Remote Areas Building-to-Building Connectivity: Bridging Last-Mile Data Delivery: Wireless ISP Small Office/Home Office (SOHO) Use Mobile Office Networking Educational/Classroom Use Industrial: Warehousing and Manufacturing Health Care: Hospitals and Offices Hotspots: Public Network Access Summary Key Terms Review Questions 10 16 17 18 18 19 20 20 21 21 23 24 25 26 26 27 28 29 29 30 31 32 Radio Frequency and Antenna Fundamentals 35 Electromagnetic Waves: A Quick Tour History of Electromagnetic Waves Early Radio Technologies Fundamentals of Electromagnetic Waves RF Characteristics Wavelength Frequency Amplitude 37 37 38 39 42 42 44 46 Chapter vii viii CWNA Certified Wireless Network Administrator Official Study Guide Phase RF Behavior Gain Loss Reflection Refraction Diffraction Scattering Absorption VSWR Return Loss Amplification Attenuation Wave Propagation Free Space Path Loss Multipath and Delay Spread Basic RF Math Watt Milliwatt Decibel (dB) dBm dBi dBd SNR RSSI Link Budget and System Operating Margin (SOM) Fade Margin Intentional Radiator Equivalent Isotropically Radiated Power (EIRP) FCC Rules for Output Power RF Signal and Antenna Concepts Visual LOS RF LOS The Fresnel Zone Beamwidths Azimuth and Elevation Isotropic Radiator Polarization Antenna Diversity Antennas and Antenna Systems Omnidirectional/Dipole Antennas Semidirectional Antennas Highly Directional Antennas Sectorized and Phased-Array Antennas Multiple-Input, Multiple-Output (MIMO) Antenna Systems Summary Key Terms Review Questions 48 49 49 51 52 54 55 56 56 58 60 61 61 61 62 65 66 66 67 68 72 74 74 74 75 77 80 81 81 81 85 86 86 86 90 92 94 95 96 97 97 100 102 102 103 104 105 107