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Wireless Networking Using 802.11b
Roaming
More than one WAP can be used to increase the wireless coverage in a
wireless LAN. The diagram below shows two WAPs configured to extend
coverage beyond that of a single unit. The overlapping area of each BSS is
called and Extended Service Set (ESS). When a wireless computer enters
the ESS, the computer evaluates the signal strength and link quality, then
chooses the WAP with the best quality signal and link. This activity is
known as roaming. To configure your WAPs to allow roaming inside of
the wireless network, each unit will be assigned the same Service Set
Identifier (SSID). Strategically placing multiple units around an office or
inside of the home can extend the wireless coverage to the entire premise.
The illustration below shows two Basic Service Sets overlapping to form
an Extended Service Set.
ESS
BSS2
BSS1
Desktop PC
Desktop PC
Switch
Wireless
Access Point
Wireless
Access Point