Building Wireless Community Networks

Chapter 3. Network Layout

In many ways, 802.11b networking is very much like Ethernet networking. Assuming you want to connect your wireless clients to the Internet, you’ll want to provide all of the usual TCP/IP services, such as Domain Name Service (DNS) and Dynamic Host Configuration Protocol (DHCP), that make networking so much fun. To the rest of your network, wireless clients look just like any other Ethernet interface and are treated no differently than the wired printer down the hall. You can route, rewrite, tunnel, fold, spindle, and/or mutilate packets from your wireless clients just as you can with any other network device.

Presumably, no matter how many wireless clients you intend to support, you will eventually need to “hit the wire” in order to access other networks (such as the Internet). How do packets find their way from the unbridled freedom of the airwaves to the established, hyper-interconnected labyrinth of the Internet? This chapter describes what you need to know to do that.

Wireless Infrastructure: Cathedral Versus Bazaar

As with any network supporting different physical mediums, network bridges must exist that are capable of exchanging data between the various network types. A wireless gateway consists of a radio card and a network card (usually Ethernet). In the case of 802.11b, radios participating in the wireless network must operate in one of two modes: BSS or IBSS .

BSS stands for Basic Service Set. In this operating mode, a piece of hardware called ...