Wi-Fi: Wireless Fidelity and Wi-Fi Network

Wi-Fi networks use radio technologiesdefined by IEEE 802.11b, 802.11a, 802.11g or 802.11n (and 802.11y) . A Wi-Fi network can be used to connect computers to each other, to the Internet, and to wired networks using IEEE 802.3 or Ethernet. Wi-Fi networks operate in the unlicensed 2.4 and 5 GHz radio bands, with an 11 Mbps (802.11b) or 54 Mbps (802.11a or 802.11g) data rate or with products that contain both bands (dual band), so they can provide real-world performance similar to the basic 10BaseT wired Ethernet networks used in many offices. Unfortunately, 802.11a is not compatible with 802.11b/g.

Wi-Fi is a standard developed by the Wi-Fi Alliance who certifies vendor products to ensure 802.11 products on the market follow the various 802.11 specifications.

Wireless LANs are not sufficiently protected. It is vulnerable to virus attacks and information privacy invasion. Security technologies are developed to enhance the WLAN security, including, Wired Equivalent Privacy (WEP), Wireless Application Protocol (mainly for mobile devices) plus many vendor proprietary technologies.

The following components are required in a typical Wi-Fi wireless LAN: a WLAN card that is installed into a PC or other devices and an Access Point connected with the LAN that communicates with the WLAN enabled PC and other devices wirelessly.

The current Wi-Fi Standards:

IEEE 802.11 - The original WLAN standard (1997)
IEEE 802.11a – Enhancement to 802.11 with 54 Mbit/s at 5 GHz (1999)
IEEE 802.11b - Enhancements to 802.11 to support 5.5 and 11 Mbit/s (1999)
IEEE 802.11c - Bridge operation procedures; included in the IEEE 802.1D standard (2001)
IEEE 802.11d - International (country-to-country) roaming extensions (2001)
IEEE 802.11e - Enhancements: QOS, including packet bursting (2005)
IEEE 802.11f - Inter-Access Point Protocol (2003) Withdrawn February 2006
IEEE 802.11g – Enhancement to 802.11b and 802.11a (backwards compatible with b) (2003)
IEEE 802.11h - Spectrum Managed 802.11a (5 GHz) for European compatibility (2004)
IEEE 802.11i - Enhanced security (2004)
IEEE 802.11j - Extensions for Japan (2004)
IEEE 802.11-2007 - A release of the standard that includes 802.11 amendments a, b, d, e, g, h, i & j. (2007)
IEEE 802.11k - Radio resource measurement enhancements
IEEE 802.11m - Maintenance of the standard; odds and ends.
IEEE 802.11n – Enhancement to 802.11a,b,g with Higher throughput improvements using MIMO
IEEE 802.11p - WAVE - Wireless Access for the Vehicular Environment (such as ambulances and passenger cars)
IEEE 802.11r - Fast roaming
IEEE 802.11s - ESS Extended Service Set Mesh Networking 
IEEE 802.11t - Wireless Performance Prediction (WPP) - test methods and metrics recommendation
IEEE 802.11u - Interworking with non-802 networks (for example, cellular)
IEEE 802.11v - Wireless network management
IEEE 802.11w - Protected Management Frames
IEEE 802.11y - 3650-3700 Operation in the U.S.
IEEE 802.11z - Extensions to Direct Link Setup (DLS)