(WLAN) [ 28 ]. A wireless network uses the Wi-Fi (wireless fidelity) as a
standard of communication among different nodes or computers. There are
different types of Wi-Fi communication standard: 802.11b, 802.11a, and
802.11g [ 29 ].
802.11b was the oldest standard that was being used in WLAN.
After 802.11b, 802.11a was introduced. It offered better speed than the
previous one and was mostly used in business networks [ 28 ]. The latest
standard is 802.11g that removes the deficiencies of the previous two
standards. Since it offers best speed from the other two standards, it is also
the most expensive one [ 28 ]. The installation of this kind of network can be
done by two ways. The first one is ad-hoc mode and the second one is
infrastructure mode. The Ad-hoc mode allows wireless devices in a
network to communicate on the logic of peer to peer with each other [ 29 ].
However, the second mode is the most required mode as it allows wireless
devices in a network to communicate with a central device (access point)
which in turn communicates with the devices that are connected with
central device through wire. But both of these modes have one similarity
and that is they use wireless network adapters termed WLAN cards [ 45 ].
Figure 2. 8 : Wireless Network2.5. 1 WLAN Frame Format
The MAC layer frame consists of nine fields [30], as shown in
Figure 2. 9.