The ‘Frankenstein’ spec

Some call 802.11g the “Frankenstein” specification because of the competitive number of supported communications relationships it supports – and the desire to have 802.11g components optionally backward compatible with 802.11b.

Some call 802.11g the “Frankenstein” specification because of the competitive number of supported communications relationships it supports – and the desire to have 802.11g components optionally backward compatible with 802.11b. There’s the problem – the multiple modes that need to be supported in 802.11b-compatibility mode demands a sophisticated access point architecture in a prestandard environment.

The 802.11g products use the same channels as 802.11b but gain their speed by using radio modulation schemes similar to those in 802.11a. The difference in modulation schemes is similar to advances in the early 1990s when modem speeds increased because of advances in modulation schemes.

Like 802.11b, there are three nonoverlapping channels of 11 total available in the U.S. (with more or less available worldwide). The number of overlapping channels is important because access point placement demands the ability to prevent two access points from affecting each other to prevent co-channel interference.

There are two modes for 802.11g – compatible with 802.11b, or strict 802.11g mode. In the compatibility mode, an 802.11g access point has to fall back to 802.11b speed if there are any 802.11b components in the local “air space.”

802.11g products are not compatible with 802.11a products because they use different operational radio frequencies – 2.4GHz for 802.11b and 802.11g, and 5GHz for 802.11a. Companies have come out with client cards (called 802.11a/b/g or 802.11a/g) that cover 802.11b and g, and optionally, but not yet concurrently, 802.11a. Cards do not concurrently access two different access points because routing and security problems might occur. This card is targeted at users desiring to use any of the three wireless LAN standards at will. In our tests, we used one trimode card, the Netgear WAG511.

Back to main review: “802.11g WLAN gear”