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802.11 Last modified: Tuesday, August 26, 2008
802.11 and 802.11x refers to a family of specifications developed by the IEEE for wireless LAN (WLAN) technology. 802.11 specifies an over-the-air interface between a wireless client and a base station or between two wireless clients. The IEEE accepted the specification in 1997. There are several specifications in the 802.11 family: 802.11 — applies to wireless LANs and provides 1 or 2 Mbps transmission in the 2.4 GHz band using either frequency hopping spread spectrum (FHSS) or direct sequence spread spectrum (DSSS). 802.11a — an extension to 802.11 that applies to wireless LANs and provides up to 54-Mbps in the 5GHz band. 802.11a uses an orthogonal frequency division multiplexing encoding scheme rather than FHSS or DSSS. 802.11b (also referred to as 802.11 High Rate or Wi-Fi) — an extension to 802.11 that applies to wireless LANS and provides 11 Mbps transmission (with a fallback to 5.5, 2 and 1-Mbps) in the 2.4 GHz band. 802.11b uses only DSSS. 802.11b was a 1999 ratification to the original 802.11 standard, allowing wireless functionality comparable to Ethernet. 802.11e — a wireless draft standard that defines the Quality of Service (QoS) support for LANs, and is an enhancement to the 802.11a and 802.11b wireless LAN (WLAN) specifications. 802.11e adds QoS features and multimedia support to the existing IEEE 802.11b and IEEE 802.11a wireless standards, while maintaining full backward compatibility with these standards. 802.11g — applies to wireless LANs and is used for transmission over short distances at up to 54-Mbps in the 2.4 GHz bands. 802.11n — 802.11n builds upon previous 802.11 standards by adding multiple-input multiple-output (MIMO). The additional transmitter and receiver antennas allow for increased data throughput through spatial multiplexing and increased range by exploiting the spatial diversity through coding schemes like Alamouti coding. The real speed would be 100 Mbit/s (even 250 Mbit/s in PHY level), and so up to 4-5 times faster than 802.11g. 802.1X — Not to be confused with 802.11x (which is the term used to describe the family of 802.11 standards) 802.1X is an IEEE standard for port-based Network Access Control that allows network administrators to restricted use of IEEE 802 LAN service access points to secure communication between authenticated and authorized devices.  See 802.11 for a complete overview of the 802.11x family of specifications. Also see the "Wireless LAN Standards chart" in the Quick Reference section of Webopedia. See also "How Wireless Networks Work" in the Did You Know... section of Webopedia.
802.11 Alphabet Soup What do all those letters mean? 802.11a: An Excellent Long Term Solution Since the debut of 802.11a products in 2001, network managers have been struggling with whether to install 802.11b or 802.11a. Here's why you should strongly consider the use of 802.11a for your next wireless LAN deployment. Did You Know... How Wireless Networks Work A wireless network or Wireless Local Area Network (WLAN) serves the same purpose as a wired one . to link a group of computers. Because "wireless" doesn't require costly wiring, the main benefit is that it's generally easier, faster and cheaper to set up. IEEE Unable to Agree on 802.11g Standards InternetNews.com article from May 2001. Improving WLAN Performance with Fragmentation Learn how the optional fragmentation function of 802.11 operates, and understand when and how to use it. Minimizing 802.11 Interference Issues RF interference will continue to plague current and future 802.11b implementations unless an adequate site survey is conducted - preferably prior to actual network installation. Minimizing WLAN Security Threats Most wireless LANs do not invoke adequate security measures to guard against attacks. Learn what security threats exist for wireless LANs as the basis for deploying effective security measures. Sizing Up Your WLAN This tutorial tells you what you need to know about what you need to have - in terms of APs - for your WLAN to actually work. The BIG Question: 802.11a or 802.11b? Both 802.11b and 802.11a have distinct merits and appropriate applications. A WLAN expert shows how to make the best decision for particular needs. Tools Simplify 802.11 Deployments Wireless LAN installation is tricky. The construction of a facility and silent sources of RF interference impact the propagation of radio waves, often in odd ways. Webopedia's "Did You Know...?" Section Use this Webopedia knowledge section for an in-depth overview of specific technologies and occurrences in the areas of Computer Science, The Internet, and Computer Hardware and Software. Webopedia's Quick Reference Section Use this Webopedia reference section for information on common Internet and computer facts and occurrences. Wi-Fi Alliance A resource page for Wi-Fi technology. Wi-Fi Planet 802.11 news, commentary and information. Wi-FiHotSpotList.com Search this directory for Wi-Fi hotspots in your region. Wireless Privacy: An Oxymoron? ISPs deploying 802.11b for public broadband or fixed wireless Internet access should consider the risks associated with this emerging technology before network security is compromised.	Related Categories Communications Standards Networking Standards Wireless Computing Related Terms 802.11a 802.11b 802.11e 802.11g 802.11n 802.16 802.1x ad-hoc mode AP CDMA COR CSMA/CD DSSS EAP FHSS HiperLAN HomeRF infrastructure mode LOS Mobile IP NLOS OFDM PEAP RF roaming ROR Shared Wireless Access Protocol SSID WCDMA WECA WEP Wi-Fi WLAN WPA