If you’ve wondered what the “802” and the numbers following after the dot mean, you’re not alone. The first part, 802, refers to the Institute of Electrical and Electronic Engineers (IEEE) family of standards for LANs and MANs.
The numbers and letters after the dot refer to different IEEE working groups and their published specifications, thus:
802.11
Wireless LANs working group, and the wireless specification; operates at 2.4GHz, with shared bandwidth of 1, 2 and 11Mbit/s. Uses a CSMA/CA — carrier sense multiple access with collision avoidance — scheme similar to ethernet to sense if the medium is busy before transmitting.
802.11a
Widely seen as the future wireless standard, 802.11a operates in the 5-6GHz frequency band using a frequency-division multiplexing scheme to increase the amount of data that can be transmitted. It offers speed increments of 6, 12, 24 and 54Mbit/s, and is said to be less susceptible to interference than 802.11b. However, 802.11a has a shorter range than its predecessor, and there are issues with public services using the higher frequency band.
802.11b
Also known as “Wi-Fi”; 802.11b is backwards-compatible with 802.11, but utilises an improved signal modulation scheme that minimises interference and boosts data transfer rates. Operates in the same frequency range and offers the same maximum performance as 802.11, in steps of 1, 2, 5.5 and 11Mbit/s. 802.11b also has rate-adaptation ability and can lower the speed to the abovementioned increments if the connection deteriorates.
802.11g
This is an extension to the 802.11b standard, and remains backwards-compatible with existing 802.11x applications, yet offers up to 54Mbit/s speed. 802.11g products should start to appear late this year, and some 802.11b products may be upgraded with new firmware.
802.1X
This user authentication protocol is officially known as Port Based Network Access Control, and comes under the auspices of the IEEE 802.1 working group which busies itself with hammering out a number of LAN/MAN and internetworking standards. 802.1X is seen as the panacea for today’s wireless security worries.
Other IEEE wireless working groups include 802.15 (for Bluetooth standards) and 802.16 (for wireless metroploitan area networks).