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Wi-Fi
Wi-Fi
(or 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 to connect to the Internet by moving
within e.g. 15 meters of an access point, called
"hotspot".
Wifi
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 SocketIP
and Symbol
Technologies are offering telephony platforms (Central
Office replacements and terminals
(phones))
that use Wi-Fi transport.
Commercial
Wi-Fi
Areas with Wi-Fi service are called "hotspots" and can
either be free or for a fee. There may be metered access or with
a pass for e.g. 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
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.
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.
External
links
This
content from Wikipedia
is licensed under the GNU
Free Documentation License.
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