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

Revision as of 20:01, 18 May 2019

Revision as of 17:38, 15 September 2019

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{{Use American English|date = March 2019}}

{{Short description|Computer network multiple access method}}

'''Carrier-sense multiple access with collision avoidance''' ('''CSMA/CA''') in [[computer network]]ing, is a network [[multiple access method]] in which [[Carrier signal|carrier]] sensing is used, but [[Node (networking)|node]]s attempt to avoid collisions by beginning transmission only after the channel is sensed to be "idle".<ref name="federalstandard">{{cite web|url=http://www.its.bldrdoc.gov/fs-1037/fs-1037c.htm |title=Federal Standard 1037C |publisher=Its.bldrdoc.gov |date= |accessdate=2012-09-09}}</ref><ref name="atis">{{cite web |url=http://www.atis.org/tg2k/ |title=American National Standard T1.523-2001, Telecom Glossary 2000 |publisher=Atis.org |date= |accessdate=2012-09-09 |deadurlurl-status=yesdead |archiveurl=https://web.archive.org/web/20080302071329/http://www.atis.org/tg2k/ |archivedate=2008-03-02 |df= }}</ref> When they do transmit, nodes transmit their packet data in its entirety.

It is particularly important for wireless networks, where the collision detection of the alternative [[Carrier-sense multiple access with collision detection|CSMA/CD]] is not possible due to wireless transmitters desensing their receivers during packet transmission.

CSMA/CA is unreliable due to the [[hidden node problem]].<ref>{{cite web |url=http://www.eunice-forum.org/eunice99/027.pdf |title=Study of different CSMA/CA IEEE 802.11-based implementations, Universitat Politècnica de Catalunya |format=PDF |date= |accessdate=2012-09-09 |archive-url=https://web.archive.org/web/20120306051958/http://www.eunice-forum.org/eunice99/027.pdf# |archive-date=2012-03-06 |deadurl-url=yes |dfstatus=dead }}</ref><ref name="eunice">{{cite web|url=https://arxiv.org/ftp/arxiv/papers/1003/1003.4070.pdf |title=Comparative study of hidden node problem and solution using different techniques and protocols, Journal of Computing |format=PDF |date=2010 |accessdate=2016-01-05|author1=Viral V. Kapadia |author2=Sudarshan N. Patel |author3=Rutvij H. Jhaveri }}</ref>

CSMA/CA is a protocol that operates in the [[Data Link Layer]] (Layer 2) of the [[OSI model]].