Building Wireless Community Networks, Second Edition

Chapter 2. Defining Project Scope

The nice thing about standards is that there are so many to choose from.

—Andrew S. Tanenbaum, c.1980

What do you want to accomplish? As a system administrator, this is a question I ask whenever a user comes to me with a new request. It’s easy to get wrapped up in implementation details while forgetting exactly what it is you set out to do in the first place. As projects get more complex, it’s easy to find yourself “spinning your wheels” without actually getting anywhere.

The most common questions I’ve encountered about wireless networking seem to be the simplest:

• What is the difference between 802.11a/b/g, 802.16, and 802.1x?

• How much does it cost?

• How far will it go?

• Can I use it to do [fill in the blank]?

The first question is by far the most straightforward to answer—the rest all depend on your application and circumstances. Before we can start building networks, we need to have a clear idea of what we have to work with.

The Standards

Here’s a brief overview of the current (and future) standards that all fall under the 802 family:

802.11

The first wireless standard to be defined in the 802 family was 802.11. It was approved by the IEEE in 1997, and defines three possible physical layers: FHSS at 2.4GHz, DSSS at 2.4GHz, and Infrared. 802.11 could achieve data rates of 1 or 2Mbps. 802.11 radios that use DSSS are interoperable with 802.11b and 802.11g radios at those speeds, while FHSS radios and Infrared are obviously not.

802.11a

According to the specifications ...