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Networking Fundamentals
For nodes to communicate with each other on a wireless network, all nodes
must be inside the same broadcast area, called an overlap area. See Figure 4-21.
This is not always possible, especially with mobile devices such as laptops, PDAs,
cell phones, automobiles, and such. It is not unusual to have a mobile computer
outside of the normal overlap area. There is also the possibility of mobile users
moving in and out of the overlap area, further complicating communication. The
best logical choice of media access for a wireless network is CSMA/CA.
Figure 4-21.
Overlap area of
an ad hoc and
infrastructure
wireless network.
A—For computers
in an ad hoc
wireless network
to communicate
with each other, all
computers must be in
the same overlap area.
B—In an infrastructure
wireless network, the
Wireless Access Point
(WAP) must be in
the common overlap
area of the wireless
network computers.
The WAP controls all
communication.
A
Overlap area
B
Overlap area
Wireless Access Point