Wi-Fi (802.11 standard)

Contributor(s): David Morris, Jack Hanlin, Derek Walker, Lisa Phifer

Wi-Fi is a term for certain types of wireless local area networks (WLAN) that use specifications in the 802.11 family. Products that pass the Wi-Fi Alliance tests for interoperability, security and application-specific protocols are labeled "Wi-Fi CERTIFIED," a registered trademark of the Alliance.

Wi-Fi is widely used in businesses, agencies, schools, and homes as an alternative to a wired LAN. Many airports, hotels, and fast-food facilities offer public access to Wi-Fi networks. These locations are known as hot spots. Many charge a daily or hourly rate for access, but some are free. An interconnected area of hot spots and network access points is known as a hot zone.

Unless adequately protected, a Wi-Fi network can be susceptible to access by unauthorized users who use the access as a free Internet connection. The activity of locating and exploiting security-exposed wireless LANs is called war driving. An identifying iconography, called war chalking, has evolved. Any entity that has a wireless LAN should use security safeguards such as the Wired Equivalent Privacy (WEP) encryption standard, the more recent Wi-Fi Protected Access (WPA), Internet Protocol Security (IPsec), or a virtual private network (VPN). 

The term Wi-Fi was created the Wi-Fi Alliance as a play on "Hi-Fi," an abbreviation for "high fidelity," which referred to high-quality audio reproduction. Similarly, Wi-Fi is often thought to be short for wireless fidelity. However, according to the Wi-Fi Alliance, "Wi-Fi" is not an abbreviation. The confusion may stem from the fact that the Alliance briefly used "The standard for wireless fidelity" as a slogan for Wi-Fi. 

Originally, Wi-Fi certification was applicable only to products using the 802.11b standard. Today, Wi-Fi can apply to products that use any 802.11 standard. The 802.11 specifications are part of an evolving set of wireless network standards known as the 802.11 family. The particular specification under which a Wi-Fi network operates is called the "flavor" of the network. 

802 Overview Basics of physical and logical networking concepts.
802.1 Bridging LAN/MAN bridging and management. Covers management and the lower sub-layers of OSI Layer 2, including MAC-based bridging (Media Access Control), virtual LANs and port-based access control.
802.2 Logical Link Commonly referred to as the LLC or Logical Link Control specification. The LLC is the top sub-layer in the data-link layer, OSI Layer 2. Interfaces with the network Layer 3.
802.3 Ethernet "Grandaddy" of the 802 specifications. Provides asynchronous networking using "carrier sense, multiple access with collision detect" (CSMA/CD) over coax, twisted-pair copper, and fiber media. Current speeds range from 10 Mbps to 10 Gbps. Click for a list of the "hot" 802.3 technologies.
802.4 Token Bus Disbanded
802.5 Token Ring The original token-passing standard for twisted-pair, shielded copper cables. Supports copper and fiber cabling from 4 Mbps to 100 Mbps. Often called "IBM Token-Ring."
802.6 Distributed queue dual bus (DQDB) "Superseded **Revision of 802.1D-1990 edition (ISO/IEC 10038). 802.1D incorporates P802.1p and P802.12e. It also incorporates and supersedes published standards 802.1j and 802.6k. Superseded by 802.1D-2004." (See IEEE status page.)
802.7 Broadband LAN Practices Withdrawn Standard. Withdrawn Date: Feb 07, 2003. No longer endorsed by the IEEE. (See IEEE status page.)
802.8 Fiber Optic Practices Withdrawn PAR. Standards project no longer endorsed by the IEEE. (See IEEE status page.)
802.9 Integrated Services LAN Withdrawn PAR. Standards project no longer endorsed by the IEEE. (See IEEE status page.)
802.10 Interoperable LAN security Superseded **Contains: IEEE Std 802.10b-1992. (See IEEE status page.)
802.11  Wi-Fi Wireless LAN Media Access Control and Physical Layer specification. 802.11a,b,g,etc. are amendments to the original 802.11 standard. Products that implement 802.11 standards must pass tests and are referred to as "Wi-Fi certified."
  • Specifies a PHY that operates in the 5 GHz U-NII band in the US - initially 5.15-5.35 AND 5.725-5.85 - since expanded to additional frequencies
  • Uses Orthogonal Frequency-Division Multiplexing
  • Enhanced data speed to 54 Mbps
  • Ratified after 802.11b
  • Enhancement to 802.11 that added higher data rate modes to the DSSS (Direct Sequence Spread Spectrum) already defined in the original 802.11 standard
  • Boosted data speed to 11 Mbps
  • 22 MHz Bandwidth yields 3 non-overlaping channels in the frequency range of 2.400 GHz to 2.4835 GHz
  • Beacons at 1 Mbps, falls back to 5.5, 2, or 1 Mbps from 11 Mbps max.
  • Enhancement to 802.11a and 802.11b that allows for global roaming
  • Particulars can be set at Media Access Control (MAC) layer
  • Enhancement to 802.11 that includes quality of service (QoS) features
  • Facilitates prioritization of data, voice, and video transmissions
  • Extends the maximum data rate of WLAN devices that operate in the 2.4 GHz band, in a fashion that permits interoperation with 802.11b devices
  • Uses OFDM Modulation (Orthogonal FDM)
  • Operates at up to 54 megabits per second (Mbps), with fall-back speeds that include the "b" speeds
  • Enhancement to 802.11a that resolves interference issues
  • Dynamic frequency selection (DFS)
  • Transmit power control (TPC)
  • Enhancement to 802.11 that offers additional security for WLAN applications
  • Defines more robust encryption, authentication, and key exchange, as well as options for key caching and pre-authentication
  • Japanese regulatory extensions to 802.11a specification
  • Frequency range 4.9 GHz to 5.0 GHz
  • Radio resource measurements for networks using 802.11 family specifications
  • Maintenance of 802.11 family specifications
  • Corrections and amendments to existing documentation
  • Higher-speed standards
  • Several competing and non-compatible technologies; often called "pre-n"
  • Top speeds claimed of 108, 240, and 350+ MHz
  • Competing proposals come from the groups, EWC, TGn Sync, and WWiSE and are all variations based on MIMO (multiple input, multiple output)
  • Mis-used "generic" term for 802.11 family specifications
802.12 Demand Priority Increases Ethernet data rate to 100 Mbps by controlling media utilization.
802.13 Not used Not used
802.14 Cable modems Withdrawn PAR. Standards project no longer endorsed by the IEEE.
 802.15 Wireless Personal Area Networks Communications specification that was approved in early 2002 by the IEEE for wireless personal area networks (WPANs).
802.15.1 Bluetooth Short range (10m) wireless technology for cordless mouse, keyboard, and hands-free headset at 2.4 GHz.
802.15.3a UWB Short range, high-bandwidth "ultra wideband" link
802.15.4 ZigBee Short range wireless sensor networks
802.15.5 Mesh Network
  • Extension of network coverage without increasing the transmit power or the receiver sensitivity
  • Enhanced reliability via route redundancy
  • Easier network configuration - Better device battery life
802.16 Wireless Metropolitan Area Networks This family of standards covers Fixed and Mobile Broadband Wireless Access methods used to create Wireless Metropolitan Area Networks (WMANs.) Connects Base Stations to the Internet using OFDM in unlicensed (900 MHz, 2.4, 5.8 GHz) or licensed (700 MHz, 2.5 – 3.6 GHz) frequency bands. Products that implement 802.16 standards can undergo WiMAX certification testing.
802.17 Resilient Packet Ring IEEE working group description
802.18 Radio Regulatory TAG  IEEE 802.18 standards committee
802.19 Coexistence IEEE 802.19 Coexistence Technical Advisory Group
802.20 Mobile Broadband Wireless Access IEEE 802.20 mission and project scope
802.21 Media Independent Handoff IEEE 802.21 mission and project scope
802.22 Wireless Regional Area Network  IEEE 802.22 mission and project scope
This was last updated in October 2015

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That's an amazing list of specifications. Well, as they say, the wonderful thing about standards is that we have so many of them.


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