NIST SP 800-46
802.11 - In wireless LAN (WLAN) technology, 802.11 refers to a family of specifications developed by a working group of the Institute of Electrical and Electronics Engineers (IEEE). There are three specifications in the family: 802.11, 802.11a, and 802.11b. All three specify the use of CSMA/CA (carrier sense multiple access with collision avoidance) as the path-sharing protocol. The 802.11 and 802.11b specifications apply to wireless Ethernet LANs and operate at frequencies in the 2.4-GHz region of the radio spectrum. Data speeds are generally 1 Mbps or 2 Mbps for 802.11, and 5.5 Mbps or 11 Mbps for 802.11b, although speeds up to about 20 Mbps are realizable with 802.11b. The 802.11b standard is backward compatible with 802.11.The 802.11a specification applies to wireless Asynchronous Transfer Mode (ATM) systems and operates at radio frequencies between 5 GHz and 6 GHz. A modulation scheme known as OFDM (orthogonal frequency-division multiplexing) makes possible data speeds as high as 54 Mbps, but most commonly, communications take place at 6 Mbps, 12 Mbps, or 24 Mbps.