Rating: 

For a lot of folks, implementing an 802.11 network involves selecting and purchasing an access point and adapter cards, and installing or compiling the proper drivers. From there, we are off and running, usually in under an hour. However for the few, the proud, the sysadmins of the world it’s a whole different ballgame. Sysadmins need a deeper understanding of network technologies to be able effectively design, deploy and debug them.

What's Bad?

Most of the book is right on the mark when it comes to the sysadmin audience, however chapters 8 (the PCF, for contention free service), 10 (the ISM PHYs), 11 (802.11a overview) are only of interest to folks who are implementing 802.11 hardware, IMHO. These chapters contain very low level material about the 802.11 transmisison protocol, and will not be generally useful since equipment manufacturers do not provide access to this layer. A dead giveaway that you can skip over chapter 8 is the phrase “The PCF has not been widely implemented.” If it’s not widely implemented, chances are you won’t have the option of using it in a deployment.

After this bellycrawl through the weeds, chapters 12 and 14 give click by click instructions about installing two commercially available 802.11 access point/client adapter pairs on your Windows box. The selected products are Nokia’s A032 Access Point along with their C110/C111 and Lucent’s Orinoco (formerly WaveLan) Access Point and client adapter. It's worth noting that these are two of the most expensive 802.11 solutions available on the market and have enhanced features that are not present in other models. These chapters are simply rehashed vendor installation documentation for these products and provide very little addede value. There's nothing that I hate more than paying $30-$50 for a book which repackages documentation that is freely available on the web. Skip these chapters, the rest of the book is excellent.

What's Good?

This book starts off with six strong chapters that cover the 802.11 protocol specification, why WEP is vulnerable and some of the upcoming security specifications. The first six chapters are invaluable reading for any sysadmin that is planning/currently responsible for an 802.11 deployment. This is your ammunition when users come and ask why the wireless network is slower than the wired network with fewer users (preventing contention adds more overhead in wireless) or why they really really should tunnel every wireless connection over SSH (because WEP is fundamentally flawed). The chapter that covers the current WEP implementation demystifies the "40 bit" vs. "64 bit" key length sleight of hand that some vendors play. The standard WEP key length is 64 bits. However, 24 of those bits are used as WEP's initialization vector for the RC4 cipher. These bits aren't encrypted in an 802.11 packet, so by sniffing 802.11 traffic you can examine the IVs of the packets and see how many distict keys are in use, and even retrieve the actual key once you have captured enough packets. AirSnort retrieves WEP keys by implementing the Fluhrer/Martin/Shamir attack (orig paper, Stubblefield paper). Chapter 16 covers using tools such as Airsnort and Ethereal to analyze the 802.11 traffic on your network. Remember to use your powers for good and not evil.

The final 3 chapters address deployment, analysis and tuning of 802.11 networks. These chapters, combined with the first six are the heart of this book and the whole motivation for buying the book. The analysis chapter has a particularly wonderful section about gathering user requirements with respect to 802.11 specific issues (security requirements, roaming...) and a very practical section about physical installation that clearly illustrates the author's mastery of integrating 802.11 technologies into an existing infrastructure.

So What's In It For Me?

If you're an sysadmin and implementing 802.11 technologies is on the horizon, this book is a solid reference of the current state of 802.11 solutions, the good and bad. It pulls no punches in presenting issues and weaknesses with the current solutions and documents forthcoming standards that are being proposed/developed to address them. If you're considering a smaller deployment at home, the security aspects of the text are still applicable, but the design/deployment sections are more rigorous than you will need. There is a bit of starch (repackaged vendor installation documentation) and unnecessary details (knowing that 802.11 frequency hopping uses Gaussian frequency shift keying is good for impressing women at parties, but doesn't really impact the design/deployment of an 802.11 network) but the other chapters redeem themselves and make this a very valuable text.