Appendix A. 802.11 Protocols

Appendix A Contents

Bands and Channels pg 247

Throughput pg 248

Network Capacity pg 249

Range pg 249

802.11b and 802.11g pg 250

802.11b pg 251

802.11g pg 251

802.11a pg 252

Multiband Solutions pg 253

The technology behind Wi-Fi networking is the 802.11x protocol. In your environmentsand using popular Cisco gearyou are likely to come into contact with three prevalent versions of this protocol: 802.11a, 802.11b, and 802.11g.

Like other computing and networking technologies, wireless started with slow and nonstandardized equipment. When wireless networking came into its own in the late 1990s, 802.11b was the standard. It was popular for a number of reasons, not the least of which was that it operated in the unlicensed, 2.4-GHz band. That meant anyone could buy it, deploy it, and use it without worrying about governmental permission. The standard also brought decent range (up to 120 meters) and a workable amount of throughout (11 Mbps). However, anyone who has been around computers in the past 20 years can tell you that what's "workable" today is substandard tomorrow. 802.11a and 802.11g have taken the limelight as the prevalent Wi-Fi standards.

Note

Look for the 802.11n standard in the future. This standard promises speeds of at least 100 Mbps. At this point, 802.11n is still a prestandardthat is, nothing is formalized and vendors are putting out their own versions of 802.11n equipment. 802.11n builds on existing standards by adding multiple-input, multiple-output (MIMO) technology. Additional transmitter and receiver antennas allow increased throughput and increased range.

These protocols offer something different and should be adopted based on performance and environmental needs. This appendix examines these protocols and provides more insight into their functionality, helping you determine which protocols might be best suited for your environment.