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Collision avoidance is used to improve the performance of the [[Carrier sense multiple access|CSMA]] method by attempting to divide the channel somewhat equally among all transmitting nodes within the collision ___domain.
# '''Carrier Sense''': prior to transmitting, a node first listens to the shared medium (such as listening for wireless signals in a wireless network) to determine whether another node is transmitting or not. Note that the [[hidden node problem]] means another node may be transmitting which goes undetected at this stage.love u
# '''Collision Avoidance''': if another node was heard, we wait for a period of time (usually random) for the node to stop transmitting before listening again for a free communications channel.
::* '''Request to Send/Clear to Send''' (RTS/CTS) may optionally be used at this point to mediate access to the shared medium. This goes some way to alleviating the problem of hidden nodes because, for instance, in a wireless network, the Access Point only issues a ''Clear to Send'' to one node at a time. However, wireless [[802.11]] implementations do not typically implement RTS/CTS for all transmissions; they may turn it off completely, or at least not use it for small packets (the overhead of RTS, CTS and transmission is too great for small data transfers).
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