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Wi-Fi (or Wi-fi,WiFi, Wifi, wifi), for
"Wireless Fidelity", is a set of standards for wireless local area networks (WLAN) based
on the IEEE 802.11 specifications (see also that article). Certified products
can use the official Wi-Fi logo, which indicates that the product is interoperable with any other product also showing the
logo.
Wi-Fi was intended to be used for wireless LANs, but is now often also used for Internet access. It enables a person with a wireless-enabled computer or personal digital assistant (PDA) to connect to the
Internet by moving within, for example, 15 meters of an access point,
called "hotspot".
Wi-Fi vs. cellular
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 Zyxel,
SocketIP and Symbol Technologies are
offering telephony platforms (Central Office replacements and terminals (phones)) that use Wi-Fi transport.
The term 4G is occasionally used for Wi-Fi, the implication being that the bandwidth and
capabilities offered are already greater than those promised by the 3G cellular telephone
standards.
Commercial Wi-Fi
Areas with Wi-Fi service are called "hotspots" and can either be accessed for free or for a fee. There may be metered access
or with a pass for, for example, a day, month or year, valid for one location or a whole chain. They are e.g. in coffee houses
and airports around the world. T-Mobile provides hotspots in many Starbucks Coffee houses in the US. Pacific Century Cyber Works has a similar arrangement with Pacific Coffee in Hong Kong. Other large hotspot providers in the US include Boingo, Wayport and iPass. Compared to
cellular, however, even the combined coverage is currently still very patchy.
Sify, India's largest Internet service
provider, has set up 120 wireless access points in Bangalore,India in hotels, malls and government offices.
Compare Internet cafe.
Advantages of Wi-Fi
- Many reliable and bug-free WiFi products on the market
- Competition amongst vendors has lowered prices considerably since their inception
- While connected on a WiFi network, it is possible to move about without breaking the network connection.
Disadvantages of Wi-Fi
- The 802.11b and 802.11g flavors of Wi-Fi use the 2.4 Ghz spectrum, which is crowded with other devices such as Bluetooth, microwave ovens,
cordless phones, or video sender devices, among many others. This may cause a degradation in performance. Other devices which use
microwave frequencies such as certain types of cell phones can also cause degradation in performance.
- Power consumption is fairly high compared to other standards, making battery life and heat a concern.
- Not always configured properly by user. Commonly uses WEP (Wired Equivalent Privacy) protocol for protection, though has been shown to be easily breakable.
Newer wireless solutions are slowly providing support for the superior WPA (Wi-Fi Protected Access) protocol, though many systems still employ WEP.
Wi-Fi and free software
Not a lot of Wi-Fi hardware is supported by the Linux kernel.
Trademark
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.
Unintended use by outsiders
Many business and residential users do not bother to protect their network, which
can therefore also be used by people just outside the building, see warchalking and wardriving.
See also
External links
Adapters with free, open drivers
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