WiFi is a networking technology permitting the exchange of information through wireless (radio) connections.

The term "WiFi" comes from a trademark name, and is often referred to as "Wireless Fidelity", even though this is an incorrect development. One might also come across the term "WLAN", meaning "WireLess Area Network", an aggregation of hosts wirelessly interconnected.

Common advantages over Ethernet

  • No need for physical access to the network knot, allowing all kinds of devices to connect without space restrictions.
  • Cheaper infrastructure, no more cables, no more physical networking.
  • Cheaper implementation on devices, as wireless chips happen to be less and less expensive.
  • Global certification : all WiFi devices are inter-operative.
  • WiFi security is considered reliable, see Wi-Fi Protected Access (WPA-2).
  • Power saving mechanisms exist on most WiFi devices.

Common disadvantages

  • Range : a WiFi signal is available at 35 meters around the transmitter indoors, and 100 meters outdoors (approximately and theoretically).
  • Frequency and channels irregularity : according to the country, one may find more or less channels and frequencies available for WiFi signals to be transmitted on. There are more possibilities in Europe and Australia than in the US, or in Japan.
  • Security : without cables, anyone is capable of detecting and analysing the radio stream. Common wireless security protocols (WEP) have been shown unreliable. WPA however tends to solve this problem. In other more sensible infrastructures, additional layers ought to be added on the application side, such as SSL or secured VPNs.
  • Interference : having several WiFi transmitters within the same range might cause interferences, causing the signal's strength and quality to drop.

Most common usages

  • Domestic use : with the expansion of smartphones and other portable devices, WiFi has become very common on broadband infrastructures. Most operating systems and CPUs are able to handle WiFi connectivity.
  • Embedded devices : with the extension of Big Data and other analysis techniques, controlling small embedded devices wirelessly has become common use.
  • Widely connected infrastructure : WiFi allows network redundancy through signal relays, allowing big areas to be wirelessly connected, even with few transmitters available.
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