In the simplest of terms, a wireless
local-area network (WLAN) does exactly what the name implies: it
provides all the features and benefits of traditional LAN
technologies, such as Ethernet and Token Ring, without the
limitations of wires or cables. But to view a WLAN just in terms
of the cables it does not have is to miss the point: WLANs redefine
the way we view LANs. Connectivity no longer implies attachment.
Local areas are measured not in feet or meters, but miles or
kilometers. An infrastructure does not need to be buried in the
ground or hidden behind the walls--an "infrastructure" can
move and change at the speed of the organization. This technology
has several immediate applications, including:
- IT professionals or business
executives who want mobility within the enterprise, perhaps in
addition to a traditional wired network
- Business owners or IT directors
who need flexibility for frequent LAN wiring changes, either
throughout the site or in selected areas
- Any company whose site is not
conducive to LAN wiring because of building or budget
limitations, such as older buildings, leased space, or temporary
sites
- Any company that needs the
flexibility and cost savings offered by a line-of-sight,
building-to-building bridge to avoid expensive trenches, leased
lines, or right-of-way issues
WLANs use a transmission medium, just like
wired LANs. Instead of using twisted-pair or fiber-optic cable,
WLANs use either infrared (IR) light or RF. Of the two, RF is far
more popular for its longer range, higher bandwidth, and wider
coverage. Most wireless LANs today use the 2.4-gigahertz (GHz)
frequency band, the only portion of the RF spectrum reserved around
the world for unlicensed devices. The freedom and flexibility of
wireless networking can be applied both within buildings and between
buildings.
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