IEEE 802.11 MAC

Stations can operate in two configurations

• independent configuration; the stations communicate directly to each other, so there is no infra-structure need to be installed. That is why we call this ``ad-hoc'' networks. It is easy to operate, but the disadvantage is that the coverage area is limited. Stations in such configuration are in a Basic Service Set (BSS).
• infra-structure configuration; the stations communicate to Accesspoints which are part of a Distribution System. An Accesspoint serves the stations in a BSS The set of BSSs are called Extended Service Set (ESS). Note that 802.11 only specifies the air-interface,that is the interface between stations and between stations and Accesspoints. With a Distribution system, the coverage area can be extended to whatever the internals of the distribution system for instance with bridged wired LANs.

  The draft standard provides the above mentioned services with the following functionality: roaming within a ESS and Power Management (stations can switch off their transceivers to conserve power). The MAC protocol is Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA)

The above is from http://stdsbbs.ieee.org/groups/802/11/index.html