802.11® Wireless Networks The Definitive Guide By Matthew Gast ............................................... Publisher: O'Reilly Pub Date: April 2005 ISBN: 0-596-10052-3 Pages: 656 Table of Contents | Index As we all know by now, wireless networks offer many advantages over fixed (or wired) networks. Foremost on that list is mobility, since going wireless frees you from the tether of an Ethernet cable at a desk. But that's just the tip of the cable-free iceberg. Wireless networks are also more flexible, faster and easier for you to use, and more affordable to deploy and maintain. The de facto standard for wireless networking is the 802.11 protocol, which includes Wi-Fi (the wireless standard known as 802.11b) and its faster cousin, 802.11g. With easy-to-install 802.11 network hardware available everywhere you turn, the choice seems simple, and many people dive into wireless computing with less thought and planning than they'd give to a wired network. But it's wise to be familiar with both the capabilities and risks associated with the 802.11 protocols. And 802.11 Wireless Networks: The Definitive Guide, 2nd Edition is the perfect place to start. This updated edition covers everything you'll ever need to know about wireless technology. Designed with the system administrator or serious home user in mind, it's a no-nonsense guide for setting up 802.11 on Windows and Linux. Among the wide range of topics covered are discussions on: deployment considerations network monitoring and performance tuning wireless security issues how to use and select access points network monitoring essentials wireless card configuration security issues unique to wireless networks With wireless technology, the advantages to its users are indeed plentiful. Companies no longer have to deal with the hassle and expense of wiring buildings, and households with several computers can avoid fights over who's online. And now, with 802.11 Wireless Networks: The Definitive Guide, 2nd Edition, you can integrate wireless technology into your current infrastructure with the utmost confidence. 802.11® Wireless Networks The Definitive Guide By Matthew Gast ............................................... Publisher: O'Reilly Pub Date: April 2005 ISBN: 0-596-10052-3 Pages: 656 Table of Contents | Index Copyright Foreword Preface Prometheus Untethered: The Possibilities of Wireless LANs Audience Overture for Book in Black and White, Opus 2 Conventions Used in This Book How to Contact Us Safari Enabled Acknowledgments Chapter 1. Introduction to Wireless Networking Why Wireless? What Makes Wireless Networks Different A Network by Any Other Name... Chapter 2. Overview of 802.11 Networks IEEE 802 Network Technology Family Tree 802.11 Nomenclature and Design 802.11 Network Operations Mobility Support Chapter 3. 802.11 MAC Fundamentals Challenges for the MAC MAC Access Modes and Timing Contention-Based Access Using the DCF Fragmentation and Reassembly Frame Format Encapsulation of Higher-Layer Protocols Within 802.11 Contention-Based Data Service Frame Processing and Bridging Chapter 4. 802.11 Framing in Detail Data Frames Control Frames Management Frames Frame Transmission and Association and Authentication States Chapter 5. Wired Equivalent Privacy (WEP) Cryptographic Background to WEP WEP Cryptographic Operations Problems with WEP Dynamic WEP Chapter 6. User Authentication with 802.1X The Extensible Authentication Protocol EAP Methods 802.1X: Network Port Authentication 802.1X on Wireless LANs Chapter 7. 802.11i: Robust Security Networks, TKIP, and CCMP The Temporal Key Integrity Protocol (TKIP) Counter Mode with CBC-MAC (CCMP) Robust Security Network (RSN) Operations Chapter 8. Management Operations Management Architecture Scanning Authentication Preauthentication Association Power Conservation Timer Synchronization Spectrum Management Chapter 9. Contention-Free Service with the PCF Contention-Free Access Using the PCF Detailed PCF Framing Power Management and the PCF Chapter 10. Physical Layer Overview Physical-Layer Architecture The Radio Link RF Propagation with 802.11 RF Engineering for 802.11 Chapter 11. The Frequency-Hopping (FH) PHY Frequency-Hopping Transmission Gaussian Frequency Shift Keying (GFSK) FH PHY Convergence Procedure (PLCP) Frequency-Hopping PMD Sublayer Characteristics of the FH PHY Chapter 12. The Direct Sequence PHYs: DSSS and HR/DSSS (802.11b) Direct Sequence Transmission Differential Phase Shift Keying (DPSK) The "Original" Direct Sequence PHY Complementary Code Keying High Rate Direct Sequence PHY Chapter 13. 802.11a and 802.11j: 5-GHz OFDM PHY Orthogonal Frequency Division Multiplexing (OFDM) OFDM as Applied by 802.11a OFDM PLCP OFDM PMD Characteristics of the OFDM PHY Chapter 14. 802.11g: The Extended-Rate PHY (ERP) 802.11g Components ERP Physical Layer Convergence (PLCP) ERP Physical Medium Dependent (PMD) Layer Chapter 15. A Peek Ahead at 802.11n: MIMO-OFDM Common Features WWiSE TGnSync Comparison and Conclusions Chapter 16. 802.11 Hardware General Structure of an 802.11 Interface Implementation-Specific Behavior Reading the Specification Sheet Chapter 17. Using 802.11 on Windows Windows XP Windows 2000 Windows Computer Authentication Chapter 18. 802.11 on the Macintosh The AirPort Extreme Card 802.1X on the AirPort Chapter 19. Using 802.11 on Linux PCMCIA Support on Linux Linux Wireless Extensions and Tools Agere (Lucent) Orinoco Atheros-Based cards and MADwifi 802.1X on Linux with xsupplicant Chapter 20. Using 802.11 Access Points General Functions of an Access Point Power over Ethernet (PoE) Selecting Access Points Cisco 1200 Access Point Apple AirPort Chapter 21. Logical Wireless Network Architecture Evaluating a Logical Architecture Topology Examples Choosing Your Logical Architecture Chapter 22. Security Architecture Security Definition and Analysis Authentication and Access Control Ensuring Secrecy Through Encryption Selecting Security Protocols Rogue Access Points Chapter 23. Site Planning and Project Management Project Planning and Requirements Network Requirements Physical Layer Selection and Design Planning Access-Point Placement Using Antennas to Tailor Coverage Chapter 24. 802.11 Network Analysis Network Analyzers Ethereal 802.11 Network Analysis Checklist Other Tools Chapter 25. 802.11 Performance Tuning 802.11 Performance Calculations Improving Performance Tunable 802.11 Parameters Chapter 26. Conclusions and Predictions Standards Work Current Trends in Wireless Networking The End glossary About the Author Colophon Index 802.11® Wireless Networks: The Definitive Guide, Second Edition by Matthew S. Gast Copyright © 2005 Matthew S. Gast. All rights reserved. Printed in the United States of America. Published by O'Reilly Media, Inc., 1005 Gravenstein Highway North, Sebastopol, CA 95472. O'Reilly books may be purchased for educational, business, or sales promotional use. Online editions are also available for most titles (safari.oreilly.com). For more information, contact our corporate/institutional sales department: (800) 998-9938 or [email protected]. Editor: Mike Loukides Production Editor: Colleen Gorman Cover Designer: Ellie Volckhausen Interior Designer: David Futato Printing History: April 2002: First Edition. April 2005: Second Edition. Nutshell Handbook, the Nutshell Handbook logo, and the O'Reilly logo are registered trademarks of O'Reilly Media, Inc. 802.11® Wireless Networks: The Definitive Guide, Second Edition, the image of a horseshoe bat, and related trade dress are trademarks of O'Reilly Media, Inc. 802.11® and all 802.11-based trademarks and logos are trademarks or registered trademarks of IEEE, Inc. in the United States and other countries. O'Reilly Media, Inc. is independent of IEEE. Many of the designations used by manufacturers and sellers to distinguish their products are claimed as trademarks. Where those designations appear in this book, and O'Reilly Media, Inc. was aware of a trademark claim, the designations have been printed in caps or initial caps. While every precaution has been taken in the preparation of this book, the publisher and author assume no responsibility for errors or omissions, or for damages resulting from the use of the information contained herein. ISBN: 0-596-10052-3 [M] Foreword Matthew Gast was my mentor long before I met him. I began reporting on wireless data networking in October 2000 when I discovered that Apple's claims for its 802.11b-based AirPort Base Station were actually true. I'd been burned with another form of wireless networking that used infrared, and had spent many fruitless hours using other "interesting" networking technologies that led to dead ends. I figured 802.11b was just another one. Was I glad I was wrong! This discovery took me down a path that led, inexorably, to the first edition of 802.11 Wireless Networks. How did this stuff actually work as advertised? I knew plenty about the ISO model, TCP/IP, and Ethernet frames, but I couldn't reconcile a medium in which all parties talked in the same space with what I knew about Ethernet's methods of coping with shared contention. Matthew taught me through words and figures that I didn't originally understand, but returned to again and again as I descended further into technical detail in my attempts to explain Wi-Fi to a broader and broader audience through articles in The New York Times, The Seattle Times, PC World, and my own Wi-Fi Networking News (http://www.wifinetnews.com) site over the last five years. I starting learning acronyms from 802.11 Wireless Networks and used Matthew's book to go beyond