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Wi-Fi

Wi-Fi (for "Wireless Fidelity") is a set of standards for wireless networks based on the IEEE 802.11 Wireless Ethernet standards. Certified products includes Wi-Fi logo, that indicates the product it´s interoperable with anyone else that includes the logo.

Wi-Fi was intended to be used for wireless LANs, but is now often also used for Internet access.

Wi-Fi is a trademark of the Wi-Fi Alliance (formerly the Wireless Ethernet Compatibility Alliance), the trade organization that defines the Wi-Fi standards.

There are at least three types of Wi-Fi, each based on an IEEE 802.11 standard.

IEEE 802.11b enjoys international acceptance, as the 2.4-GHz radio frequency band is almost universally available. 802.11b hardware can transmit data at speeds of up to 11 megabits per second (Mbps). The first commercial use of the 802.11b standard for networking was made by Apple Computer under the trademark AirPort.
IEEE 802.11g[?] operates in the same frequency band as 802.11b, and is therefore backwards compatible with certain older Wi-Fi hardware. 802.11g hardware can transfer data at up to 54 Mbps. The first commercial use of 802.11g was also made by Apple, under the trademark AirPort Extreme.
IEEE 802.11a[?], which operates around the 5 GHz band, enjoys relatively clear-channel operation in the United States and Japan. In other areas, such as the EU, 802.11a is not yet approved for operation in the 5 GHz band, and European regulators are still considering the use of the European HIPERLAN standard.

Some argue that Wi-Fi and related consumer technologies hold the key to replacing cellular telephone networks such as GSM. Some obstacles to this happening in the near future are missing roaming and authentication features (see 802.1x[?], SIM cards and RADIUS) and the narrowness of the available spectrum. Despite such problems, companies like SocketIP[?] and Symbol Technologies[?] are offering telephony platforms (Central Office[?] replacements and terminals (phones)) that use Wi-Fi transport.

An American company Boingo[?] provides Wi-Fi Internet service.