802.11无线网络权威指南：移动与灵活的无线通信详解

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"802.11 Wireless Networks: The Definitive Guide, 2nd Edition" 是一本由O'Reilly出版社在2005年4月发行的经典教程，专注于802.11无线局域网（WLAN）技术，该标准包括广为人知的Wi-Fi（802.11b）及其更快版本802.11g。此书的重要性在于，它针对无线网络相对于固定（有线）网络的诸多优势提供了详尽的阐述。首先，移动性是802.11无线网络的主要优势，用户不再受桌面位置的限制，摆脱了Ethernet电缆的束缚，实现了真正的自由。无线网络的灵活性、速度提升以及用户体验的改善都是其魅力所在。部署和维护成本也相对较低，使得无线网络更加普及和经济高效。作为行业的事实标准，802.11协议对于构建和管理无线网络至关重要。尽管市面上易于安装的802.11硬件产品琳琅满目，使许多人容易倾向于无线计算，但了解这些协议的能力和潜在风险是非常明智的。本书第二版包含了全面的内容，覆盖了无线技术的所有基础知识，旨在帮助系统管理员和对无线网络有深度需求的专业人士深入理解802.11的各种特性、配置方法、安全措施以及可能遇到的问题与挑战。书中不仅涵盖了如何设计和实施802.11网络架构，还包括了无线网络规划、性能优化、干扰管理和网络安全策略等内容。此外，还讨论了不同版本的802.11（如802.11a、802.11n和802.11ac等）的特点与升级路径，以及与蓝牙（Bluetooth）等其他无线技术的协同工作。对于想要在无线网络领域取得成功的人来说，这本书是一本不可或缺的参考书籍，它提供了一个全面的指南，帮助读者避免常见问题，最大化无线网络的潜力，并确保其在实际环境中的稳定性和安全性。无论是初学者还是资深的专业人士，通过阅读这本书，都能深入了解和掌握802.11无线网络的方方面面。

technology path of "faster, better, and cheaper," the data rate of most 802.11 interfaces has shot

from 2 or 11 Mbps with 802.11b to 54 Mbps with 802.11a and 802.11g. Increased speed with

backwards compatibility has proved to be a commercially successful formula for 802.11g, even if it

has limitations when used for large-scale networks. The coming standardization of 802.11n is set to

boost speeds even farther. New developments in PHY technology are anxiously awaited by users, as

shown by the popular releases of pre-standard technology. Two entirely new chapters are devoted to

802.11g and 802.11n. European adoption of 802.11a was contingent on the development of

spectrum management in 802.11h, which resulted in extensive revisions to the management

chapter.

When the first edition was released in 2002, the perception of insecurity dominated discussions of the

technology. WEP was clearly insufficient, but there was no good alternative. Most network

administrators were making do with remote access systems turned inward, rather than their natural

outward orientation. The development of 802.11i was done a great deal to simplify network security.

Security is now built in to the specification, rather than something which must be added on after

getting the network right. Security improvements permeate the book, from new chapters showing

how the new protocols work, to showing how they can be used on the client side, to how to sort

through different options when building a network. Sorting through security options is much more

complex now than it was three years ago, and made it necessary to expand a section of the

deployment discussion in the first edition into its own chapter.

Three years ago, most access points were expensive devices that did not work well in large numbers.

Network deployment was often an exercise in working around the limitations of the devices of the

time. Three years later, vastly more capable devices allow much more flexible deployment models.

Rather than just a "one size fits all" deployment model, there are now multiple options to sort

through. Security protocols have improved enough that discussions of deploying technology are

based on what it can do for the organization, not on fear and how to keep it controlled. As a result,

the original chapter on network deployment has grown into three, each tackling a major part of the

deployment process.

Acknowledgments

As much as I would like to believe that you are reading this book for its entertainment value, I know

better. Technical books are valued because they get the details right, and convey them in an easier

fashion than the unadorned technical specification. Behind every technical book, there is a review

team that saw the first draft and helped to improve it. My review team caught numerous mistakes

and made the book significantly better. Dr. Malik Audeh of Tropos Networks is, for lack of a better

term, my radio conscience. I am no radio expertwhat I know about radio, I learned because of my

interest in 802.11. Malik knew radio technology before 802.11, and I have been privileged to share in

his insight. Gerry Creager of Texas A&M offered insight into the FCC rules and regulations for

unlicensed devices, which was valuable because wireless LANs have been upending the rules in

recent years. When Glenn Fleishman agreed to write the foreword, I had no idea that he would offer

so much help in placing 802.11 within its larger context. Many of the details he suggested were

references to articles that had run in the past years on his own Wi-Fi Networking News site. As a

writer himself, Glenn also pointed out several locations where better examples would make my points

much clearer. Finally, Terry Simons of the Open1X project has worked extensively with 802.11 on

Linux, and with nearly every 802.1X supplicant on the major operating systems. Terry also is one of

the architects of the wireless authentication system at the University of Utah. His expertise can be

felt throughout the early part of the book on security specifications, as well as in the practical matter

of using supplicants and building an authentication system.

I am also indebted to many others who help keep me abreast of current developments in 802.11,

and share their knowledge with me. Since 2002, I have been privileged to participate in the Interop

Labs initiatives related to wireless security and 802.1X. The real world is far too messy for the

classroom. Every year, I learn more about the state of the art by volunteering than I ever could by

taking a prepared class. Through the Interop Labs, I met Chris Hessing, the development lead for

xsupplicant. Chris has always generously explained how all the keying bits move around in 802.11,

which is no small feat! Sudheer Matta, a colleague of mine, always has time to explain what is

happening in the standards world, and how the minute details of the MAC work.

The large supporting cast at O'Reilly was tremendously helpful in a wide variety of ways. Ellie

Volckhausen designed a stunning cover that has adorned my cubicle as well as most of the personal

electronics devices I own since 2001, when I began writing the first edition. (It even looks good as

the wallpaper on my mobile telephone!) Jessamyn Read took a huge mass of raw sketches and

converted every last one into something that is worth looking at, and did so on a grueling schedule. I

do not know how many hours Colleen Gorman, the production editor, put into this book to get it

finished, but I hope her family and her cat, Phineas, forgive me. And, as always, I am thankful for

the wisdom of Mike Loukides, the editor. Mike kept this project moving forward in the innumerable

ways I have been accustomed to from our past collaborations, and his background as a ham radio

operator proved especially useful when I started writing about the dark and forbidding world of

antennas and RF transmission. (Among many, many other items, you have him to thank for the

footnote on the gain of the Aricebo radio telescope!)

As with so much in life, the devil of writing is in the details. Getting it right means rewriting, and then

probably rewriting some more. I did not attempt a large writing project until college, when I took

Brad Bateman's U.S. Financial System class. Although I certainly learned about the flow of money

through the economy and the tools that the Federal Reserve uses in formulating policy, what I most

value in retrospect was the highly structured process of writing a lengthy paper throughout the

semester. In addition to simply producing a large document, Dr. Bateman stressed the revision

process, a skill that I had to use repeatedly in the preparation of this book and its second edition. It

would be a mistake, however, for me to simply credit Dr. Bateman as an outstanding writing teacher

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802.11无线网络权威指南：移动与灵活的无线通信详解

802.11 Wireless Networks- The Definitive Guide, 2nd Edition.mobi

《802.11无线网络权威指南》英文原版以及中文版电子书

802.11ac A Survival guide 原文高清PDF

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802.11 Wireless Networks The Definitive Guide, 2nd Edition

802.11 Wireless Networks- The Definitive Guide, 2nd Edition

802.11无线网络权威指南英文版

802.11 无线网络权威指南第二版英文版

802.11无线网络详解与核心技术

802.11无线网络详解：第二版权威指南

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