View source for CSMA/CA

'''Carrier Sense Multiple Access (with Collision Avoidance)'''
 
CSMA checks wether the medium is free before accessing it.

Collisions resulting from simultaneous access are avoided by deferring access to the medium.

The ''Distributed Coordination Function'' (DCF) builds the main method of the CSMA/CA mechanism.
Stations choose random backoff time after each transmission, the one with the lowest number occupies
the channel first.

The ''Point Coordination Function''(PCF) provides contention-free transmission. 
Chosen stations called ''Point Coordinators'' (situated in ''access points'') are used to
define which station is allowed to transmit at a given time.
So PCF is bound to infrastructured networks.