Revision as of 04:51, 1 November 2003 edit Garybaus (talk \| contribs) 12 edits AppleTalk article doesn't discuss CSMA/CA, so I made the reference a little clearer in the text. ← Previous edit		Revision as of 05:12, 1 November 2003 edit undo Garybaus (talk \| contribs) 12 edits Explain preference for CA in media where collision detection is impossible. Move 802.11 ghost link to implementation list. Next edit →
Line 3: CSMA/CA is a modification of pure [[Carrier Sense Multiple Access]] ('''CSMA'''). Please visit this article for a complete description of the basic protocol. 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"~~, which is implemented as~~ in '''~~Request To Send~~CSMA/CA''' ~~in some versions (for example, see [[802.11 RTS/CTS]])~~. 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. [[AppleTalk]] 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. Compare use of the jamming signal in [[Carrier sense multiple access with collision detection]] ('''CSMA/CD'''), which uses another technique to improve '''CSMA''' performance.

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