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Wireless LAN Standards 145
Standard
Table 6.1 : (Continued)
Key features
802.11T Recommended practices on measurement methods, performance metrics and test
procedures to assess the performance of 802.11 equipment and networks. The capital T
denotes a recommended practice rather than a technical standard.
802.11u Amendments to both PHY and MAC layers to provide a generic and standardized
approach to inter-working with non-802.11 networks, such as Bluetooth, ZigBee and
WiMAX.
802.11v Enhancements to increase throughput, reduce interference and improve reliability through
network management.
802.11w Increased network security by extending 802.11 protection to management as well as
data frames.
3 Network layer
2
1
Data link layer
Physical layer
Logical Link Control
(LLC)
Medium Access Control
(MAC)
Physical layer
(PHY)
OSI model layers
802.11 specifications
Figure 6.1 : 802.11 logical architecture
802.11 networks are composed of three basic components: stations, access points and a
distribution system, as described in Table 6.2 .
In the 802.11 standard, WLANs are based on a cellular structure where each cell, under
the control of an access point, is known as a basic service set (BSS). When a number of
stations are working in a BSS it means that they all transmit and receive on the same RF
channel, use a common BSSID, use the same set of data rates and are all synchronized
to a common timer. These BSS parameters are included in “ beacon frames ” that are
broadcast at regular intervals either by individual stations or by the access point.
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