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1.1 | |
Introduction to Wireless LANs | |
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What is a wireless LAN? |
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In the simplest of terms, a wireless LAN (WLAN) does exactly what the name implies. It
provides all the features and benefits of traditional LAN technologies
such as Ethernet and Token Ring, but without the limitations of wires
or cables. Thus, WLANs redefine the way the industry views LANs.
Connectivity no longer implies attachment. Local areas are measured
not in feet or meters, but in miles or kilometers. An infrastructure
need not be buried in the ground or hidden behind walls. An
infrastructure can be moved and changed based on the needs of an organization.
A WLAN, just like a LAN, requires a
physical medium through which transmission signals pass. Instead of using twisted-pair or fiber-optic cable, WLANs use infrared light (IR) or radio frequencies (RFs). The use of
RF is far more popular for its longer range, higher bandwidth, and
wider coverage. WLANs use the 2.4-gigahertz (GHz) and 5-GHz frequency
bands. These portions of the RF spectrum are reserved in most of the
world for unlicensed devices. Wireless networking provides the freedom
and flexibility to operate within buildings and between buildings.
Throughout this course, the icons and symbols displayed in Figures
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through
will be used to document the wireless networking devices and
infrastructure.