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Wireless Networks
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Article 2: How WLANs Work
Wireless networks are to
wired computer networks what your cell phone is
to regular telephones. They’re more mobile, more
flexible and more convenient.
WLANs use invisible high frequency radio waves
to send and receive data among devices, but
without the limitations, trouble and expense of
yards of cables and wires. WLANs can communicate
through walls, although some dense materials can
impede communications.
Often a WLAN is installed on an already wired
network as a seamless supplement to the existing
system. But WLANs also operate independently.
Indeed, some major corporations including
Microsoft reportedly have begun unwiring their
networks in favor of WLANs.
Wi-Fi, the most popular WLAN standard, sends and
receives data at speeds comparable to that of
many wired networks. And like wired networks,
wireless LANs require special hardware to
connect computers and other devices.
WLANs can be configured two ways. One is
peer-to-peer communications between two devices,
each equipped with wireless Network Interface
Cards (NICs). Such a system enables transferring
data between two laptops. Addition of an access
point allows the two devices to connect at
greater distances. The second option is an
infrastructure mode that also requires an access
point to connect the machines, but the access
point is typically also connected by wire to a
wired network.
To understand access points, think of radio
repeater antennas receiving signals, amplifying
them and passing them on. An access point
greatly extends the coverage of a wireless
system, making it possible to communicate with
another networked device up to 1,800 feet away.
Access points come in a variety of strengths and
capabilities, some able to serve dozens of PCs
and some with added security protection against
hackers.
In either configuration option, all the
networked devices require plug-in cards or
equivalent capability, which serve the same
function as more commonplace Ethernet cards, but
without wired connections.
Wireless networks enable users to communicate
with one another and access centralized
databases. They can also be used as a
server-client network with application software
residing on a centralized computer and run on
laptops over the network. So-called “wireless
thin-clients” perform similarly to many wired
networks with users’ computers acting as smart
displays. An advantage of the “thin-client”
system is that all data and applications reside
on the server, not on the client laptop or
desktop computer.
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