802.11 Wireless Networks: The Definitive Guide, 2nd Edition

Chapter 3. 802.11 MAC Fundamentals

This chapter begins our exploration of the 802.11 standard in depth. Chapter 2 provided a high-level overview of the standard and discussed some of its fundamental attributes. You are now at a fork in the book. Straight ahead lies a great deal of information on the 802.11 specification and the various related standards that it uses liberally. It is possible, however, to build a wired network without a thorough and detailed understanding of the protocols, and the same is true for wireless networks. However, there are a number of situations in which you may need a deeper knowledge of the machinery under the hood:

• Although 802.11 has been widely and rapidly adopted, security issues have continued to grab headlines. Network managers will undoubtedly be asked to comment on security issues, especially in any wireless LAN proposals. To understand and participate in these discussions, read Chapter 5 and 6. WEP with static keys should be considered fully broken. Solutions based on 802.1X and dynamic WEP keying are significantly stronger, with the full complement of protocols in 802.11i described in Chapter 7 stronger still.

• Troubleshooting wireless networks is similar to troubleshooting wired networks but can be much more complex. As always, a trusty packet sniffer can be an invaluable aid. To take full advantage of a packet sniffer, though, you need to understand what the packets mean to interpret your network’s behavior.

• Tuning a wireless network is tied ...