In-Depth

Alphabet soup

Keeping track of the established and emerging 802.11 specifications can be confusing. What do the letters mean? They stand for the various task groups of the Institute of Electrical and Electronic Engineers (IEEE), the standards body that ratifies the 802.11 specification. For example, Task Group B was responsible for 802.11b, and so on.

Here is a list of the latest additions and revisions to the spec:

802.11: This is the original WLAN standard, finalized in June 1997, and ratified by the Institute of Electrical and Electronic Engineers (IEEE). This standard specified a 2.4 GHz operating frequency with data rates of 1 Mbps and 2 Mbps.

802.11a: A high-speed WLAN standard for the 5 GHz band. 802.11a specifies eight available radio channels, uses Orthogonal Frequency Division Multiplexing (OFDM) and supports data rates up to 54 Mbps.

802.11b: The WLAN standard for 2.4 GHz band, 802.11b uses High Rate DSSS and supports data rates of up to 11 Mbps. It specifies three available radio channels. Most wireless LAN installations today comply with 802.11b, which is also the basis for Wi-Fi certification from the Wireless Ethernet Compatibility Alliance (WECA).

802.11c: This specification provides required information to ensure proper bridge operations. Product developers utilize this standard when developing access points.

802.11d: This specification is supplementary to the Media Access Control (MAC) layer in 802.11. It allows access points to communicate information on the permissible radio channels with acceptable power levels for user devices. The 802.11 standards cannot legally operate in some countries; its purpose is to add features and restrictions to allow WLANs to operate within the rules of these countries.

802.11e: The 802.11e task group is currently refining the 802.11 MAC layer to improve quality of service for better support of audio and video applications, such as MPEG-2.

802.11f: The 802.11 standard does not currently specify the communications between access points from different vendors. This specification, still in development, defines inter-access-point communications to facilitate multiple vendor-distributed WLAN networks.

802.11g: This specification will allow for higher-speed extensions in the 2.4 GHz band, up to 54 Mbps, while implementing all mandatory elements of 802.11b. It also uses OFDM instead of DSSS as the basis for providing the higher data rate extensions.

802.11h: This specification defines the spectrum management of the 5 GHz band for use in Europe and in APAC. It provides dynamic channel selection (DCS) and transmits power control (TPC) for devices operating in the 5 GHz band (802.11a). 802.11h is enabling sales of 802.11a networks in Europe.

802.11i: This is the specification that seeks to address weaknesses in the Wired Equivalent Privacy (WEP) encryption protocol. 802.11i is actively defining enhancements to the MAC Layer to counter problems. 802.11i will incorporate 802.1x and stronger encryption techniques, such as Advanced Encryption Standard (AES).

See the related story ''Cutting the cable.''

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