Wifi

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  • Topic: Wi-Fi, Wireless LAN, Wireless access point
  • Pages : 5 (1363 words )
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  • Published : June 3, 2012
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Wi-Fi ( /'wa?fa?/, sometimes spelled Wifi or WiFi) is a popular technology that allows an electronic device to exchange data wirelessly (using radio waves) over a computer network, including high-speed Internet connections. The Wi-Fi Alliance defines Wi-Fi as any "wireless local area network (WLAN) products that are based on the Institute of Electrical and Electronics Engineers' (IEEE) 802.11 standards".[1] However, since most modern WLANs are based on these standards, the term "Wi-Fi" is used in general English as a synonym for "WLAN".

A device that can use Wi-Fi (such as a personal computer, video game console, smartphone, tablet, or digital audio player) can connect to a network resource such as the Internet via a wireless network access point. Such an access point (or hotspot) has a range of about 20 meters (65 feet) indoors and a greater range outdoors. Hotspot coverage can comprise an area as small as a single room with walls that block radio waves or as large as many square miles — this is achieved by using multiple overlapping access points.
"Wi-Fi" is a trademark of the Wi-Fi Alliance and the brand name for products using the IEEE 802.11 family of standards. Only Wi-Fi products that complete Wi-Fi Alliance interoperability certification testing successfully may use the "Wi-Fi CERTIFIED" designation and trademark.

Wi-Fi has had a checkered security history. Its earliest encryption system, WEP, proved easy to break. Much higher quality protocols, WPA and WPA2, were added later. However, an optional feature added in 2007, called Wi-Fi Protected Setup (WPS), has a flaw that allows a remote attacker to recover the router's WPA or WPA2 password in a few hours on most implementations.[2] Some manufacturers have recommended turning off the WPS feature. The Wi-Fi Alliance has since updated its test plan and certification program to ensure all newly-certified devices resist brute-force AP PIN attacks.

Contents
[hide] 1 History 1.1 The name Wi-Fi
1.2 Wi-Fi certification

2 Uses 2.1 Internet access 2.1.1 City-wide Wi-Fi
2.1.2 Campus-wide Wi-Fi

2.2 Direct computer-to-computer communications

3 Advantages and limitations 3.1 Advantages
3.2 Limitations
3.3 Range
3.4 Data security risks
3.5 Interference

4 Hardware 4.1 Standard devices
4.2 Distance records
4.3 Embedded systems
4.4 Multiple access points

5 Network security 5.1 Securing methods
5.2 Piggybacking

6 Health issues
7 See also
8 Notes
9 References
10 Further reading
11 External links

[edit] History

Main article: History of IEEE 802.11

802.11 technology has its origins in a 1985 ruling by the US Federal Communications Commission that released the ISM band for unlicensed use.[3] In 1991 NCR Corporation with AT&T invented the precursor to 802.11 intended for use in cashier systems. The first wireless products were under the name WaveLAN.

Vic Hayes has been called the "father of Wi-Fi". He was involved in designing the initial standards within the IEEE.[4][5]
A large number of patents by many companies are used in 802.11 standard.[6] In 1992 and 1996, Australian organisation the CSIRO obtained patents for a method later used in Wi-Fi to "unsmear" the signal.[7] In April 2009, 14 tech companies agreed to pay CSIRO $250 million for infringements on the CSIRO patents.[8] This led to WiFi being attributed as an Australian invention,[9] though this has been the subject of some controversy.[10][11] The CSIRO won a further $220 million settlement for Wi-Fi patent infringements in 2012 with global firms in the United States required to pay the CSIRO licensing rights estimated to be worth an additional $1 billion in royalties.[12][13][8]

In 1999, the Wi-Fi Alliance was formed as a trade association to hold the Wi-Fi trademark under which most products are sold.[14]
[edit] The name Wi-Fi

The term Wi-Fi, first used commercially in August 1999,[15] was coined by a brand-consulting firm...
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