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.

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I found myself reading a chapter of this book, and then looking at the 802.11b standard itself (now available free on the website ieee.org) for more detailed information. I found only a couple of minor errors in this book. This book serves as an outstanding introduction to the protocol standard, which is large and which contains little or no practical information for the practitioner. However, I did also use Radia Perlman's book on Routing in conjunction with this book to help me understand IEEE 802.1 issues.

Gast attempts to be a be-all and end-all book for everyone. For example, he attempts to describe all 802.11 RF modulation schemes. He attempts to give a full description of all the packet formats. He attempts to describe which cards are based on which baseband (Intersil or Orinoco). This stuff is changing very fast but he gave it his best shot, and its very important to people installing *NIX drivers. He attempts to tell you how to set up an 802.11 Ethereal packet sniffer. All of his information is invaluable to anyone setting up 802.11b on any flavor of UNIX or Linux. Anyway, he makes a really valiant effort and I've never seen a networking book try to play in all 4 spaces at once - RF Theory, Network Protocols, Hardware Selection, and Practicum - all at the same time. He should be applauded for this attempt.

I have not found a book that is nearly as comprehensive (6/2003) and I've lent this book to at least 5 other people, most of them PhD's or VP's in EE or CS and/or wireless communications.

39 of 44 found the following review helpful:

Everything you need to know about 802.11 and wireless networJul 29, 2002
By Ben Rothke "Author of 'Computer Security: 20 Things Every Employee Should Know'"
802.11 Wireless Networks: The Definitive Guide lives up to its title and provides virtually everything you could need to know about 802.11 networks.

802.11 is a family of specifications for wireless networks developed by the Institute of Electrical and Electronics Engineers (IEEE). There are currently four specifications in the family: 802.11, 802.11a, 802.11b, and 802.11g, all of which use the basic Ethernet protocols.

Within the last few years, wireless networks have become extremely popular. No longer must a physical cable be run (at both a time and monetary expense) to each network host. With wireless technology, impromptu meetings can be set up just about anywhere, from conference rooms to airplanes, hotel rooms, and more.

Anyone who has looked at network standards can attest to how boring they are to read. However, Gast does a wonderful job writing about wireless Ethernet in a way that is not only "not boring," but actually interesting. This is due to his expertise with the subject matter and the many real-world scenarios that he shares.

Gast acknowledges that most readers who simply want a methodical, but not all-inclusive, overview of 802.11 can skip chapters 3 through 11, as they deal with the low level details of 802.11. He clearly states that just as it is quite possible to build a wired network without a thorough and detailed understanding of the protocols, the same is true for wireless networks. Nonetheless, there are a number of situations where one may need a deeper knowledge of the underpinnings of 802.11, and those underpinning are exhaustively detailed in chapters 3 through 11.

Chapters 3 and 4 address the MAC layer and 802.11 framing. Chapter 5 deals with the greatest weakness of 802.11 -- namely its lack of security. Chapter 5 clearly states the problems and inadequacies associated with 802.11 security and use of the WEP (Wired Equivalent Privacy) authentication protocol. However, despite all of the security weaknesses in 802.11, Gast never directly advises security conscious organizations to stay clear of 802.11. He does provide information on a possible successor to WEP, the Extensible Authentication Protocol (EAP).

WEP has numerous public security flaws. The first critical weakness was detailed in the now seminal paper, "Weaknesses in the Key Scheduling Algorithm of RC4." One of the paper's authors is Adi Shamir (Shamir is the S in RSA). Shamir's findings were considered somewhat of a death blow to WEP.

Chapter 8 deals with an unimplemented aspect of 802.11 -- the PCF (Point Coordination Function). Like PCF itself, much of chapters 3 through 11 are quite dry. The book includes relevant diversions into such topics as RF physics and issues such as the nonexistent microwave absorption peak of water.

Chapter 11 concludes the theory portion of the book, and chapters 12 and 13 deal with the very real issue of using 802.11 on Windows and Linux. Although most 802.11 installations are fairly straightforward, there are a number of specific configuration parameters that must be set correctly if the wireless network is to operate at peak efficiency.

Perhaps the most important chapter of the book is Chapter 15, "802.11 Network Deployment." As a security professional, I have seen many companies hastily deploy wireless technology, oblivious to the many wireless security weaknesses. The ease with which 802.11 can be deployed has allowed many organizations to overlook such critical issues as eavesdropping, scaling, radio interference, stability, and topology. Gast points out that proper deployment of a wireless LAN is a considerable undertaking, and that significant planning is required before one should even start thinking about the hardware.

Chapters 16 and 17 deal with network analysis and performance tuning. Gast describes what to look for when using a protocol analyzer on an 802.11 network and how to ensure its effective use. Chapter 16 includes three case studies using actual output from a sniffer. This chapter is quite valuable and also covers the use of AirSnort. AirSnort (http://airsnort.shmoo.com) is a wireless network tool used to recover WEP encryption keys. It works by passively monitoring network transmissions and then computing the WEP encryption key. AirSnort was one of the first publicly available tools to implement the attack described in the "Weaknesses in the Key Scheduling Algorithm of RC4" paper.

Overall, 802.11 Wireless Networks: The Definitive Guide is an excellent guide for any network administrator or architect who needs to understand the ins and outs of 802.11 networking. It has all the necessary information for design and deployment of wireless networks in an easy to read and enjoyable style.

17 of 18 found the following review helpful:

Comprehensive, clear: other reviews misstate qualityJan 25, 2003
By Glenn Fleishman
I'm not sure what book two other [Amazon.com] reviewers were reading, but Matthew Gast's does not suffer from the flaws they state: it's a comprehensive book with a laser-beam focus, and they're criticizing a book this isn't. Why no Ethernet primer? Because it's a focused 802.11 book. Why no reporting of security flaws discovered in mid-2001? Because the book was being printed then -- but the book delves deeply into the security model underlying 802.11, which is what it's about.

I recommend this book highly for anyone who needs a protocol level on up view of 802.11 for planning, deploying, or understanding 802.11 networks. It's a constant reference guide for me, and it's never steered me wrong.

If you read the critical reviews carefully, the first (Kevin) complains about when it was published, and the second (anonymous) complains about the book but then admits he or she hasn't read other 802.11 books and doesn't explain whether he or she has relevant knowledge.

Because most systems deployed are 802.11b based, this book retains its utility. At some point, probably within the next six months, another edition will be needed to deal with the current draft 802.11g standard, the new WPA security protocol, and the coming 802.11i, h, e, and f protocols. But as long as you're dealing with 802.11b, this is the ultimate guide for network administrators and software developers.

41 of 49 found the following review helpful:

Lots of Substance Poorly WrittenAug 28, 2002

The author, Matthew Gast, seems to have a dearth of relevant experience on 802.11. His bio in the back of the book (and on O'Reilly's website) gives no single specific experience - academic, professional, or otherwise - he had relating to 802.11. The bio instead is left to boast that Gast is a "renaissance technologist" and a "voracious reader on science and economics". I find it telling that the publishers spent more space discussing the design of the book's cover than on Gast's bio. If you don't know a subject well, you'll have a difficult time teaching it to others, and that appears to be the case here.

I noticed that Gast wrote other networking books for O'Reilly, so I assume he's their go-to guy on networking. Why they would do that on a hot subject like 802.11 is a mystery, and it produced a poorly written mess.

As for the book, it appears that he researched as much substance on 802.11 and haphazardly threw it together. The flow of the book is atrocious and seems poorly planned. For example, he advises readers to skip more than half the middle of the book and come back to it later if necessary since he feels it may be too complicated for most. Why not put that portion of the book at the end, or better yet, write clearly enough so that it's not too complicated? This is an 802.11 book, after all.

He also spends the first two chapters explaining the most rudimentary details of wireless networks, yet expects the reader to be well versed in Ethernet. If Ethernet is so vital to understanding 802.11, why didn't Gast devote a chapter as an Ethernet primer, especially since he found it compelling to include two chapters of the most basic of wireless network primers?

His clarity is also awful. The book is very dense with acronyms and technical terms. This isn't a problem in itself, but the glossary only defines acronyms. You're left searching the text for the definition to other terms, if they're even defined therein. Even if they are defined, don't expect a clear definition.

For example, "atomic operation" (granted, it's a simple term, but that makes for an even better example) should have been defined with something like "an atomic operation is a unitary action that is essentially indivisible, unchangeable, whole, and irreducible." Gast never says anything of the sort and chooses instead to give an example of two nodes in a network communicating an acknowledgement of a received frame to each other and then says "[The example] is an atomic operation". The index then refers to atomic operation as being defined by the above line. The reader is therefore forced back to the bad example. What aspect of the communication does atomic operation refer to for the naive reader? I already knew what "atomic operation" referred to yet I was still thoroughly confused by his definition. Poorly defined terms like that pollute Gast's text. Further, he repeatedly uses these poorly defined terms, so knowledge of their meaning is essential to understanding the substance.

He also does a rather poor job discussing 802.11 security, particularly regarding the future of 802.11 security. I know it's a fast-developing subject, but this book is copyright 2002 and it's already outdated on this aspect of 802.11 in August of the same year. He could have done a bit more forecasting and research on this topic.

This was the first 802.11 book I've read, but not my first technical book. It definitely goes into the bottom quarter of the latter category. There must surely be a better 802.11 book out there.

9 of 9 found the following review helpful:

If you get one WLAN book, make it this one!May 30, 2003
By Michael J. Davis "The Krabler King"
I literally have the vast majority of books in print right now on wireless networking/802.11 and I can honestly say that this book is one of the top three (3) that you should have. I have taken many informational and certification classes on Wi-Fi or the 802.11x standard. The vast majority of them come right out of this book! It is written in a style that, even though it is highly technical at times, it is an easy read. Plus, this is all the technical information you could ever want and more! This will be a well and oft used reference if you work in this field. Like I said, if you have to get just one WLAN book, get this one!

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