Carrier-sense multiple access with collision avoidance: Difference between revisions

Revision as of 09:15, 24 March 2005

Revision as of 12:42, 1 April 2005

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Collision avoidance is used to improve the performance of '''CSMA''' by attempting to reserve the network for a single transmitter. This is the function of the "jamming signal" in '''CSMA/CA'''. The performance improvement is achieved by reducing the probability of collision and retry. Extra overhead is added due to the jamming signal wait time, so other techniques give better performance. Collision avoidance is particularly useful in media such as radio, where reliable collision detection is not possible.

*[[AppleTalkApple Computer|Apple's]] [[LocalTalk]] implemented '''CSMA/CA''' on an electrical bus using a three-byte jamming signal.

*[[802.11 RTS/CTS]] implements '''CSMA/CA''' using short '''Request to Send''' and '''Clear to Send''' messages.