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class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#O-persistent"> <div class="vector-toc-text"> <span class="vector-toc-numb">1.4</span> <span>O-persistent</span> </div> </a> <ul id="toc-O-persistent-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Protocol_modifications" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Protocol_modifications"> <div class="vector-toc-text"> <span class="vector-toc-numb">2</span> <span>Protocol modifications</span> </div> </a> <button aria-controls="toc-Protocol_modifications-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span class="vector-icon mw-ui-icon-wikimedia-expand"></span> <span>Toggle Protocol modifications subsection</span> </button> <ul id="toc-Protocol_modifications-sublist" class="vector-toc-list"> <li id="toc-Carrier-sense_multiple_access_with_collision_detection" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Carrier-sense_multiple_access_with_collision_detection"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.1</span> <span>Carrier-sense multiple access with collision detection</span> </div> </a> <ul id="toc-Carrier-sense_multiple_access_with_collision_detection-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Carrier-sense_multiple_access_with_collision_avoidance" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Carrier-sense_multiple_access_with_collision_avoidance"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.2</span> <span>Carrier-sense multiple access with collision avoidance</span> </div> </a> <ul id="toc-Carrier-sense_multiple_access_with_collision_avoidance-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-CSMA_with_Collision_Resolution" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#CSMA_with_Collision_Resolution"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.3</span> <span>CSMA with Collision Resolution</span> </div> </a> <ul id="toc-CSMA_with_Collision_Resolution-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Virtual_time_CSMA" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Virtual_time_CSMA"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.4</span> <span>Virtual time CSMA</span> </div> </a> <ul id="toc-Virtual_time_CSMA-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-See_also" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#See_also"> <div class="vector-toc-text"> <span class="vector-toc-numb">3</span> <span>See also</span> </div> </a> <ul id="toc-See_also-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-References" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#References"> <div class="vector-toc-text"> <span class="vector-toc-numb">4</span> <span>References</span> </div> </a> <ul id="toc-References-sublist" class="vector-toc-list"> </ul> </li> </ul> </div> </div> </nav> </div> </div> <div class="mw-content-container"> <main id="content" class="mw-body"> <header class="mw-body-header vector-page-titlebar"> <nav aria-label="Contents" class="vector-toc-landmark"> <div id="vector-page-titlebar-toc" class="vector-dropdown vector-page-titlebar-toc vector-button-flush-left" title="Table of Contents" > <input type="checkbox" id="vector-page-titlebar-toc-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-page-titlebar-toc" class="vector-dropdown-checkbox " aria-label="Toggle the table of contents" > <label id="vector-page-titlebar-toc-label" for="vector-page-titlebar-toc-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button 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Available in 19 languages" > <label id="p-lang-btn-label" for="p-lang-btn-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--action-progressive mw-portlet-lang-heading-19" aria-hidden="true" ><span class="vector-icon mw-ui-icon-language-progressive mw-ui-icon-wikimedia-language-progressive"></span> <span class="vector-dropdown-label-text">19 languages</span> </label> <div class="vector-dropdown-content"> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li class="interlanguage-link interwiki-ar mw-list-item"><a href="https://ar.wikipedia.org/wiki/%D9%88%D8%B5%D9%88%D9%84_%D9%85%D8%AA%D8%B9%D8%AF%D8%AF_%D8%A8%D8%A7%D8%B3%D8%AA%D8%B4%D8%B9%D8%A7%D8%B1_%D8%A7%D9%84%D8%AD%D8%A7%D9%85%D9%84" title="وصول متعدد باستشعار الحامل – Arabic" lang="ar" hreflang="ar" data-title="وصول متعدد باستشعار الحامل" data-language-autonym="العربية" data-language-local-name="Arabic" class="interlanguage-link-target"><span>العربية</span></a></li><li class="interlanguage-link interwiki-ca mw-list-item"><a href="https://ca.wikipedia.org/wiki/CSMA" title="CSMA – Catalan" lang="ca" hreflang="ca" data-title="CSMA" data-language-autonym="Català" data-language-local-name="Catalan" class="interlanguage-link-target"><span>Català</span></a></li><li class="interlanguage-link interwiki-cs mw-list-item"><a href="https://cs.wikipedia.org/wiki/CSMA" title="CSMA – Czech" lang="cs" hreflang="cs" data-title="CSMA" data-language-autonym="Čeština" data-language-local-name="Czech" class="interlanguage-link-target"><span>Čeština</span></a></li><li class="interlanguage-link interwiki-da mw-list-item"><a href="https://da.wikipedia.org/wiki/CSMA" title="CSMA – Danish" lang="da" hreflang="da" data-title="CSMA" data-language-autonym="Dansk" data-language-local-name="Danish" class="interlanguage-link-target"><span>Dansk</span></a></li><li class="interlanguage-link interwiki-de mw-list-item"><a href="https://de.wikipedia.org/wiki/Carrier_Sense_Multiple_Access" title="Carrier Sense Multiple Access – German" lang="de" hreflang="de" data-title="Carrier Sense Multiple Access" data-language-autonym="Deutsch" data-language-local-name="German" class="interlanguage-link-target"><span>Deutsch</span></a></li><li class="interlanguage-link interwiki-es mw-list-item"><a href="https://es.wikipedia.org/wiki/Carrier_sense_multiple_access" title="Carrier sense multiple access – Spanish" lang="es" hreflang="es" data-title="Carrier sense multiple access" data-language-autonym="Español" data-language-local-name="Spanish" class="interlanguage-link-target"><span>Español</span></a></li><li class="interlanguage-link interwiki-eu mw-list-item"><a href="https://eu.wikipedia.org/wiki/CSMA" title="CSMA – Basque" lang="eu" hreflang="eu" data-title="CSMA" data-language-autonym="Euskara" data-language-local-name="Basque" class="interlanguage-link-target"><span>Euskara</span></a></li><li class="interlanguage-link interwiki-fr mw-list-item"><a href="https://fr.wikipedia.org/wiki/CSMA" title="CSMA – French" lang="fr" hreflang="fr" data-title="CSMA" data-language-autonym="Français" data-language-local-name="French" class="interlanguage-link-target"><span>Français</span></a></li><li class="interlanguage-link interwiki-ko mw-list-item"><a href="https://ko.wikipedia.org/wiki/%EB%B0%98%EC%86%A1%ED%8C%8C_%EA%B0%90%EC%A7%80_%EB%8B%A4%EC%A4%91_%EC%A0%91%EC%86%8D" title="반송파 감지 다중 접속 – Korean" lang="ko" hreflang="ko" data-title="반송파 감지 다중 접속" data-language-autonym="한국어" data-language-local-name="Korean" class="interlanguage-link-target"><span>한국어</span></a></li><li class="interlanguage-link interwiki-it mw-list-item"><a href="https://it.wikipedia.org/wiki/CSMA" title="CSMA – Italian" lang="it" hreflang="it" data-title="CSMA" data-language-autonym="Italiano" data-language-local-name="Italian" class="interlanguage-link-target"><span>Italiano</span></a></li><li class="interlanguage-link interwiki-he mw-list-item"><a href="https://he.wikipedia.org/wiki/CSMA" title="CSMA – Hebrew" lang="he" hreflang="he" data-title="CSMA" data-language-autonym="עברית" data-language-local-name="Hebrew" class="interlanguage-link-target"><span>עברית</span></a></li><li class="interlanguage-link interwiki-my mw-list-item"><a href="https://my.wikipedia.org/wiki/%E1%80%85%E1%80%AE%E1%80%A1%E1%80%80%E1%80%BA%E1%80%85%E1%80%BA%E1%80%A1%E1%80%99%E1%80%BA%E1%80%A1%E1%80%B1" title="စီအက်စ်အမ်အေ – Burmese" lang="my" hreflang="my" data-title="စီအက်စ်အမ်အေ" data-language-autonym="မြန်မာဘာသာ" data-language-local-name="Burmese" class="interlanguage-link-target"><span>မြန်မာဘာသာ</span></a></li><li class="interlanguage-link interwiki-pl mw-list-item"><a href="https://pl.wikipedia.org/wiki/Carrier_Sense_Multiple_Access" title="Carrier Sense Multiple Access – Polish" lang="pl" hreflang="pl" data-title="Carrier Sense Multiple Access" data-language-autonym="Polski" data-language-local-name="Polish" class="interlanguage-link-target"><span>Polski</span></a></li><li class="interlanguage-link interwiki-pt mw-list-item"><a href="https://pt.wikipedia.org/wiki/CSMA" title="CSMA – Portuguese" lang="pt" hreflang="pt" data-title="CSMA" data-language-autonym="Português" data-language-local-name="Portuguese" class="interlanguage-link-target"><span>Português</span></a></li><li class="interlanguage-link interwiki-ru mw-list-item"><a href="https://ru.wikipedia.org/wiki/Carrier_Sense_Multiple_Access" title="Carrier Sense Multiple Access – Russian" lang="ru" hreflang="ru" data-title="Carrier Sense Multiple Access" data-language-autonym="Русский" data-language-local-name="Russian" class="interlanguage-link-target"><span>Русский</span></a></li><li class="interlanguage-link interwiki-simple mw-list-item"><a href="https://simple.wikipedia.org/wiki/Carrier-sense_multiple_access" title="Carrier-sense multiple access – Simple English" lang="en-simple" hreflang="en-simple" data-title="Carrier-sense multiple access" data-language-autonym="Simple English" data-language-local-name="Simple English" class="interlanguage-link-target"><span>Simple English</span></a></li><li class="interlanguage-link interwiki-sr mw-list-item"><a href="https://sr.wikipedia.org/wiki/%D0%92%D0%B8%D1%88%D0%B5%D1%81%D1%82%D1%80%D1%83%D0%BA%D0%B8_%D0%BF%D1%80%D0%B8%D1%81%D1%82%D1%83%D0%BF_%D1%81%D0%B0_%D0%BE%D1%81%D0%BB%D1%83%D1%88%D0%BA%D0%B8%D0%B2%D0%B0%D1%9A%D0%B5%D0%BC_%D0%BD%D0%BE%D1%81%D0%B8%D0%BE%D1%86%D0%B0" title="Вишеструки приступ са ослушкивањем носиоца – Serbian" lang="sr" hreflang="sr" data-title="Вишеструки приступ са ослушкивањем носиоца" data-language-autonym="Српски / srpski" data-language-local-name="Serbian" class="interlanguage-link-target"><span>Српски / srpski</span></a></li><li class="interlanguage-link interwiki-sv mw-list-item"><a href="https://sv.wikipedia.org/wiki/Carrier_Sense_Multiple_Access" title="Carrier Sense Multiple Access – Swedish" lang="sv" hreflang="sv" data-title="Carrier Sense Multiple Access" data-language-autonym="Svenska" data-language-local-name="Swedish" class="interlanguage-link-target"><span>Svenska</span></a></li><li class="interlanguage-link interwiki-zh mw-list-item"><a href="https://zh.wikipedia.org/wiki/%E8%BD%BD%E6%B3%A2%E4%BE%A6%E5%90%AC%E5%A4%9A%E8%B7%AF%E8%AE%BF%E9%97%AE" title="载波侦听多路访问 – Chinese" lang="zh" hreflang="zh" data-title="载波侦听多路访问" data-language-autonym="中文" data-language-local-name="Chinese" class="interlanguage-link-target"><span>中文</span></a></li> </ul> <div class="after-portlet after-portlet-lang"><span class="wb-langlinks-edit wb-langlinks-link"><a href="https://www.wikidata.org/wiki/Special:EntityPage/Q1045106#sitelinks-wikipedia" title="Edit interlanguage links" class="wbc-editpage">Edit links</a></span></div> </div> </div> </div> </header> <div class="vector-page-toolbar"> <div class="vector-page-toolbar-container"> <div id="left-navigation"> <nav 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<div class="vector-column-end"> <div class="vector-sticky-pinned-container"> <nav class="vector-page-tools-landmark" aria-label="Page tools"> <div id="vector-page-tools-pinned-container" class="vector-pinned-container"> </div> </nav> <nav class="vector-appearance-landmark" aria-label="Appearance"> <div id="vector-appearance-pinned-container" class="vector-pinned-container"> <div id="vector-appearance" class="vector-appearance vector-pinnable-element"> <div class="vector-pinnable-header vector-appearance-pinnable-header vector-pinnable-header-pinned" data-feature-name="appearance-pinned" data-pinnable-element-id="vector-appearance" data-pinned-container-id="vector-appearance-pinned-container" data-unpinned-container-id="vector-appearance-unpinned-container" > <div class="vector-pinnable-header-label">Appearance</div> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-appearance.pin">move to sidebar</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-appearance.unpin">hide</button> </div> </div> </div> </nav> </div> </div> <div id="bodyContent" class="vector-body" aria-labelledby="firstHeading" data-mw-ve-target-container> <div class="vector-body-before-content"> <div class="mw-indicators"> </div> <div id="siteSub" class="noprint">From Wikipedia, the free encyclopedia</div> </div> <div id="contentSub"><div id="mw-content-subtitle"></div></div> <div id="mw-content-text" class="mw-body-content"><div class="mw-content-ltr mw-parser-output" lang="en" dir="ltr"><div class="shortdescription nomobile noexcerpt noprint searchaux" style="display:none">System allowing transmitters to take turns on a shared media</div> <p><b>Carrier-sense multiple access</b> (<b>CSMA</b>) is a <a href="/wiki/Medium_access_control" title="Medium access control">medium access control</a> (MAC) protocol in which a node verifies the absence of other <a href="/wiki/Network_traffic" title="Network traffic">traffic</a> before <a href="/wiki/Transmission_(telecommunications)" class="mw-redirect" title="Transmission (telecommunications)">transmitting</a> on a shared <a href="/wiki/Transmission_medium" title="Transmission medium">transmission medium</a>, such as an <a href="/wiki/Bus_(computing)" title="Bus (computing)">electrical bus</a> or a band of the <a href="/wiki/Electromagnetic_spectrum" title="Electromagnetic spectrum">electromagnetic spectrum</a>. </p><p>Under CSMA, a <a href="/wiki/Transmitter" title="Transmitter">transmitter</a> uses a carrier-sense mechanism to determine whether another transmission is in progress before initiating a transmission. That is, it tries to detect the presence of a <a href="/wiki/Carrier_signal" class="mw-redirect" title="Carrier signal">carrier signal</a> from another node before attempting to transmit. If a carrier is sensed, the node waits for the transmission in progress to end before initiating its own transmission. Using CSMA, multiple nodes may, in turn, send and receive on the same medium. Transmissions by one node are generally received by all other nodes connected to the medium. </p><p>Variations on basic CSMA include addition of <a href="/wiki/Collision_(telecommunications)" title="Collision (telecommunications)">collision</a>-avoidance (<a href="/wiki/CSMA/CA" class="mw-redirect" title="CSMA/CA">CSMA/CA</a>), collision-detection (<a href="/wiki/CSMA/CD" class="mw-redirect" title="CSMA/CD">CSMA/CD</a>) and collision-resolution techniques. </p> <meta property="mw:PageProp/toc" /> <div class="mw-heading mw-heading2"><h2 id="Access_modes">Access modes</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Carrier-sense_multiple_access&action=edit&section=1" title="Edit section: Access modes"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Variations of CSMA use different algorithms to determine when to initiate transmission onto the shared medium. A key distinguishing feature of these algorithms is how aggressive or persistent they are in initiating transmission. A more aggressive algorithm may begin transmission more quickly and utilize a greater percentage of the available bandwidth of the medium. This is typically at the expense of an increased likelihood of collision with other transmitters. </p> <div class="mw-heading mw-heading3"><h3 id="1-persistent">1-persistent</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Carrier-sense_multiple_access&action=edit&section=2" title="Edit section: 1-persistent"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>1-persistent CSMA is an aggressive transmission algorithm. When the transmitting node is ready to transmit, it senses the transmission medium for idle or busy. If idle, then it transmits immediately. If busy, then it senses the transmission medium continuously until it becomes idle, then transmits the message (a <a href="/wiki/Frame_(telecommunications)" class="mw-redirect" title="Frame (telecommunications)">frame</a>) unconditionally (i.e. with probability=1). In case of a <a href="/wiki/Collision_(telecommunications)" title="Collision (telecommunications)">collision</a>, the sender waits for a <a href="/wiki/Randomness" title="Randomness">random</a> period of time and attempts the same procedure again. 1-persistent CSMA is used in CSMA/CD systems including <a href="/wiki/Ethernet" title="Ethernet">Ethernet</a>. </p> <div class="mw-heading mw-heading3"><h3 id="Non-persistent">Non-persistent</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Carrier-sense_multiple_access&action=edit&section=3" title="Edit section: Non-persistent"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Non persistent CSMA is a non-aggressive transmission algorithm. When the transmitting node is ready to transmit data, it senses the transmission medium for idle or busy. If idle, then it transmits immediately. If busy, it jumps to the final random waiting step of 1-persistent CSMA directly before repeating the whole logic cycle again: it does not persist in checking the busy channel trying to get its transmission through, hence the name. This approach reduces the chance of collision and results in overall higher medium throughput but with a penalty of longer initial delay compared to 1–persistent. </p> <div class="mw-heading mw-heading3"><h3 id="P-persistent">P-persistent</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Carrier-sense_multiple_access&action=edit&section=4" title="Edit section: P-persistent"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>This approach lies between the 1-persistent and non-persistent CSMA access modes.<sup id="cite_ref-1" class="reference"><a href="#cite_note-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> When the transmitting node is ready to transmit data, it senses the transmission medium for idle or busy. If idle, then it transmits immediately. If busy, then it senses the transmission medium continuously until it becomes idle, then transmits with probability <i>p</i>. If the node does not transmit (the probability of this event is <i>1-p</i>), it waits for a <a href="/wiki/Randomness" title="Randomness">random</a> period of time before re-attempting the same procedure, using the same probability <i>p</i>.<sup id="cite_ref-2" class="reference"><a href="#cite_note-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup> If the transmission medium is not busy, it transmits again with the same probability <i>p</i>. This probabilistic hold-off repeats until the frame is finally transmitted or when the medium is found to become busy again (i.e. some other node has already started transmitting). In the latter case the node repeats the whole logic cycle (which started with sensing the transmission medium for idle or busy) again. p-persistent CSMA is used in CSMA/CA systems including <a href="/wiki/Wi-Fi" title="Wi-Fi">Wi-Fi</a> and other <a href="/wiki/Packet_radio" title="Packet radio">packet radio</a> systems. Note that <i>p = 0</i>-persistent CSMA is different from non-persistent CSMA. Both can only transmit at the start of the procedure (if the channel is idle), but their behaviour on a busy channel differs: non-persistent CSMA doesn't attempt to sense the channel and restarts its logical cycle, whilst <i>p = 0</i> necessarily gets stuck in an infinite loop of waiting (since it has zero probability of transmission even if the channel goes back to being idle). </p> <div class="mw-heading mw-heading3"><h3 id="O-persistent">O-persistent</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Carrier-sense_multiple_access&action=edit&section=5" title="Edit section: O-persistent"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Each node is assigned a transmission order by a supervisory node. When the transmission medium goes idle, nodes wait for their time slot in accordance with their assigned transmission order. The node assigned to transmit first transmits immediately. The node assigned to transmit second waits one time slot (but by that time the first node has already started transmitting). Nodes monitor the medium for transmissions from other nodes and update their assigned order with each detected transmission (i.e. they move one position closer to the front of the queue).<sup id="cite_ref-3" class="reference"><a href="#cite_note-3"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup> O-persistent CSMA is used by <a href="/wiki/CobraNet" title="CobraNet">CobraNet</a>, <a href="/wiki/LonWorks" title="LonWorks">LonWorks</a> and the <a href="/wiki/Controller_area_network" class="mw-redirect" title="Controller area network">controller area network</a>. </p> <div class="mw-heading mw-heading2"><h2 id="Protocol_modifications">Protocol modifications</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Carrier-sense_multiple_access&action=edit&section=6" title="Edit section: Protocol modifications"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>When broadcasting over vehicular ad hoc networks, the original 1-persistence and p-persistence strategies often cause the <a href="/wiki/Broadcast_storm" title="Broadcast storm">broadcast storm</a> problem.<sup class="noprint Inline-Template Template-Fact" style="white-space:nowrap;">[<i><a href="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed"><span title="This claim needs references to reliable sources. (November 2018)">citation needed</span></a></i>]</sup> To improve performance, engineers developed three modified techniques: weighted p-persistence, slotted 1-persistence, and slotted p-persistence.<sup id="cite_ref-4" class="reference"><a href="#cite_note-4"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-5" class="reference"><a href="#cite_note-5"><span class="cite-bracket">[</span>5<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading3"><h3 id="Carrier-sense_multiple_access_with_collision_detection">Carrier-sense multiple access with collision detection</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Carrier-sense_multiple_access&action=edit&section=7" title="Edit section: Carrier-sense multiple access with collision detection"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p><a href="/wiki/CSMA/CD" class="mw-redirect" title="CSMA/CD">CSMA/CD</a> is used to improve CSMA performance by terminating transmission as soon as a collision is detected, thus shortening the time required before a retry can be attempted. CSMA/CD is used by <a href="/wiki/Ethernet" title="Ethernet">Ethernet</a>. </p> <div class="mw-heading mw-heading3"><h3 id="Carrier-sense_multiple_access_with_collision_avoidance">Carrier-sense multiple access with collision avoidance</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Carrier-sense_multiple_access&action=edit&section=8" title="Edit section: Carrier-sense multiple access with collision avoidance"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>In <a href="/wiki/CSMA/CA" class="mw-redirect" title="CSMA/CA">CSMA/CA</a> collision avoidance is used to improve the performance of CSMA. If the transmission medium is sensed busy before transmission, then the transmission is deferred for a random interval. This random interval reduces the likelihood that two or more nodes waiting to transmit will simultaneously begin transmission upon termination of the detected transmission, thus reducing the incidence of collision. CSMA/CA is used by <a href="/wiki/Wi-Fi" title="Wi-Fi">Wi-Fi</a>. </p> <div class="mw-heading mw-heading3"><h3 id="CSMA_with_Collision_Resolution">CSMA with Collision Resolution</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Carrier-sense_multiple_access&action=edit&section=9" title="Edit section: CSMA with Collision Resolution"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>CSMA/CR uses priorities in the frame header to avoid collisions. It is used in the <a href="/wiki/Controller_Area_Network" class="mw-redirect" title="Controller Area Network">Controller Area Network</a>. </p> <div class="mw-heading mw-heading3"><h3 id="Virtual_time_CSMA">Virtual time CSMA</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Carrier-sense_multiple_access&action=edit&section=10" title="Edit section: Virtual time CSMA"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>VTCSMA is designed to avoid collision generated by nodes transmitting signals simultaneously, used mostly in hard <a href="/wiki/Real-time_computing" title="Real-time computing">real-time systems</a>. It uses two clocks to prioritize messages based on their deadline.<sup id="cite_ref-6" class="reference"><a href="#cite_note-6"><span class="cite-bracket">[</span>6<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="See_also">See also</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Carrier-sense_multiple_access&action=edit&section=11" title="Edit section: See also"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><a href="/wiki/Local_collision" class="mw-redirect" title="Local collision">Local collision</a></li> <li><a href="/wiki/Remote_collision" class="mw-redirect" title="Remote collision">Remote collision</a></li></ul> <div class="mw-heading mw-heading2"><h2 id="References">References</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Carrier-sense_multiple_access&action=edit&section=12" title="Edit section: References"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1239543626">.mw-parser-output .reflist{margin-bottom:0.5em;list-style-type:decimal}@media screen{.mw-parser-output .reflist{font-size:90%}}.mw-parser-output .reflist .references{font-size:100%;margin-bottom:0;list-style-type:inherit}.mw-parser-output .reflist-columns-2{column-width:30em}.mw-parser-output .reflist-columns-3{column-width:25em}.mw-parser-output .reflist-columns{margin-top:0.3em}.mw-parser-output .reflist-columns ol{margin-top:0}.mw-parser-output .reflist-columns li{page-break-inside:avoid;break-inside:avoid-column}.mw-parser-output .reflist-upper-alpha{list-style-type:upper-alpha}.mw-parser-output .reflist-upper-roman{list-style-type:upper-roman}.mw-parser-output .reflist-lower-alpha{list-style-type:lower-alpha}.mw-parser-output .reflist-lower-greek{list-style-type:lower-greek}.mw-parser-output .reflist-lower-roman{list-style-type:lower-roman}</style><div class="reflist"> <div class="mw-references-wrap"><ol class="references"> <li id="cite_note-1"><span class="mw-cite-backlink"><b><a href="#cite_ref-1">^</a></b></span> <span class="reference-text">F. Calí, M. Conti, and E. Gregori, "Dynamic IEEE 802.11: design, modeling and performance evaluation," IEEE J. Selected Areas Commun., vol. 18, pp. 1774–1786, Sept. 2000</span> </li> <li id="cite_note-2"><span class="mw-cite-backlink"><b><a href="#cite_ref-2">^</a></b></span> <span class="reference-text"><style data-mw-deduplicate="TemplateStyles:r1238218222">.mw-parser-output cite.citation{font-style:inherit;word-wrap:break-word}.mw-parser-output .citation q{quotes:"\"""\"""'""'"}.mw-parser-output .citation:target{background-color:rgba(0,127,255,0.133)}.mw-parser-output .id-lock-free.id-lock-free a{background:url("//upload.wikimedia.org/wikipedia/commons/6/65/Lock-green.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-limited.id-lock-limited a,.mw-parser-output .id-lock-registration.id-lock-registration a{background:url("//upload.wikimedia.org/wikipedia/commons/d/d6/Lock-gray-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-subscription.id-lock-subscription a{background:url("//upload.wikimedia.org/wikipedia/commons/a/aa/Lock-red-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .cs1-ws-icon a{background:url("//upload.wikimedia.org/wikipedia/commons/4/4c/Wikisource-logo.svg")right 0.1em center/12px no-repeat}body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-free a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-limited a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-registration a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-subscription a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .cs1-ws-icon a{background-size:contain;padding:0 1em 0 0}.mw-parser-output .cs1-code{color:inherit;background:inherit;border:none;padding:inherit}.mw-parser-output .cs1-hidden-error{display:none;color:var(--color-error,#d33)}.mw-parser-output .cs1-visible-error{color:var(--color-error,#d33)}.mw-parser-output .cs1-maint{display:none;color:#085;margin-left:0.3em}.mw-parser-output .cs1-kern-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right{padding-right:0.2em}.mw-parser-output .citation .mw-selflink{font-weight:inherit}@media screen{.mw-parser-output .cs1-format{font-size:95%}html.skin-theme-clientpref-night .mw-parser-output .cs1-maint{color:#18911f}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .cs1-maint{color:#18911f}}</style><cite id="CITEREFKleinrockTobagi1975" class="citation journal cs1">Kleinrock, L.; Tobagi, F. (December 1975). <a rel="nofollow" class="external text" href="https://ieeexplore.ieee.org/document/1092768">"Packet Switching in Radio Channels: Part I--Carrier Sense Multiple-Access Modes and Their Throughput-Delay Characteristics"</a>. <i>IEEE Transactions on Communications</i>. <b>23</b> (12): <span class="nowrap">1400–</span>1416. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1109%2FTCOM.1975.1092768">10.1109/TCOM.1975.1092768</a>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/0096-2244">0096-2244</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:5879608">5879608</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=IEEE+Transactions+on+Communications&rft.atitle=Packet+Switching+in+Radio+Channels%3A+Part+I--Carrier+Sense+Multiple-Access+Modes+and+Their+Throughput-Delay+Characteristics&rft.volume=23&rft.issue=12&rft.pages=%3Cspan+class%3D%22nowrap%22%3E1400-%3C%2Fspan%3E1416&rft.date=1975-12&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A5879608%23id-name%3DS2CID&rft.issn=0096-2244&rft_id=info%3Adoi%2F10.1109%2FTCOM.1975.1092768&rft.aulast=Kleinrock&rft.aufirst=L.&rft.au=Tobagi%2C+F.&rft_id=https%3A%2F%2Fieeexplore.ieee.org%2Fdocument%2F1092768&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACarrier-sense+multiple+access" class="Z3988"></span></span> </li> <li id="cite_note-3"><span class="mw-cite-backlink"><b><a href="#cite_ref-3">^</a></b></span> <span class="reference-text"><style data-mw-deduplicate="TemplateStyles:r1041539562">.mw-parser-output .citation{word-wrap:break-word}.mw-parser-output .citation:target{background-color:rgba(0,127,255,0.133)}</style><span class="citation patent" id="CITEREFGrossAndersonLieb1998"><a rel="nofollow" class="external text" href="https://worldwide.espacenet.com/textdoc?DB=EPODOC&IDX=US5761431">US 5761431</a>, Gross, Kevin Paul; Anderson, Charles William & Lieb, Derek Wearin, "Order persistent timer for controlling events at multiple processing stations", published 1998-06-02,  assigned to Peak Audio Inc.</span><span class="Z3988" title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Apatent&rft.number=5761431&rft.cc=US&rft.title=Order+persistent+timer+for+controlling+events+at+multiple+processing+stations&rft.inventor=Gross&rft.assignee=Peak+Audio+Inc.&rft.pubdate=1998-06-02"><span style="display: none;"> </span></span></span> </li> <li id="cite_note-4"><span class="mw-cite-backlink"><b><a href="#cite_ref-4">^</a></b></span> <span class="reference-text"> Najafzadeh; Ithnin; Karimi. "An Analytical Model for Sparse and Dense Vehicular Ad hoc Networks". <a rel="nofollow" class="external text" href="https://books.google.com/books?id=d8AaeYeLVK8C">"Advances in Computer Science and Information Technology"</a>: First International Conference on Computer Science and Information Technology, CCSIT 2011. p. 211.</span> </li> <li id="cite_note-5"><span class="mw-cite-backlink"><b><a href="#cite_ref-5">^</a></b></span> <span class="reference-text"> Choi et al.: <a rel="nofollow" class="external text" href="https://www.researchgate.net/publication/269591370_Robust_broadcast_scheme_regardless_of_vehicle_distribution_in_vehicular_ad_hoc_networks">"Robust broadcast scheme regardless of vehicle distribution in vehicular ad hoc networks"</a>. EURASIP Journal on Wireless Communications and Networking 2014 2014:133. <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1186%2F1687-1499-2014-133">10.1186/1687-1499-2014-133</a> [accessed Sep 2, 2017].</span> </li> <li id="cite_note-6"><span class="mw-cite-backlink"><b><a href="#cite_ref-6">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><cite id="CITEREFKrishnaShin1997" class="citation book cs1">Krishna, C. M.; Shin, K. G. (1997). <i>Real-Time Systems</i>. McGraw-Hill Higher Education. p. 240. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-07-070115-1" title="Special:BookSources/978-0-07-070115-1"><bdi>978-0-07-070115-1</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Real-Time+Systems&rft.pages=240&rft.pub=McGraw-Hill+Higher+Education&rft.date=1997&rft.isbn=978-0-07-070115-1&rft.aulast=Krishna&rft.aufirst=C.+M.&rft.au=Shin%2C+K.+G.&rfr_id=info%3Asid%2Fen.wikipedia.org%3ACarrier-sense+multiple+access" class="Z3988"></span></span> </li> </ol></div></div> <dl><dt>General</dt></dl> <ul><li><a href="/wiki/Andrew_S._Tanenbaum" title="Andrew S. Tanenbaum">Andrew S. Tanenbaum</a>, <i>Computer Networks</i>. Prentice Hall, Upper Saddle River, NJ (2003). 892 pp. <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222" /><a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/0-13-066102-3" title="Special:BookSources/0-13-066102-3">0-13-066102-3</a></li></ul> <div class="navbox-styles"><style data-mw-deduplicate="TemplateStyles:r1129693374">.mw-parser-output .hlist dl,.mw-parser-output .hlist ol,.mw-parser-output .hlist ul{margin:0;padding:0}.mw-parser-output .hlist dd,.mw-parser-output .hlist dt,.mw-parser-output .hlist li{margin:0;display:inline}.mw-parser-output .hlist.inline,.mw-parser-output .hlist.inline dl,.mw-parser-output .hlist.inline ol,.mw-parser-output .hlist.inline ul,.mw-parser-output .hlist dl dl,.mw-parser-output .hlist dl ol,.mw-parser-output .hlist dl ul,.mw-parser-output .hlist ol dl,.mw-parser-output .hlist ol ol,.mw-parser-output .hlist ol ul,.mw-parser-output .hlist ul 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aria-labelledby="Channel_access_methods_and_media_access_control194" style="padding:3px"><table class="nowraplinks mw-collapsible autocollapse navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="2"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374" /><style data-mw-deduplicate="TemplateStyles:r1239400231">.mw-parser-output .navbar{display:inline;font-size:88%;font-weight:normal}.mw-parser-output .navbar-collapse{float:left;text-align:left}.mw-parser-output .navbar-boxtext{word-spacing:0}.mw-parser-output .navbar ul{display:inline-block;white-space:nowrap;line-height:inherit}.mw-parser-output .navbar-brackets::before{margin-right:-0.125em;content:"[ "}.mw-parser-output .navbar-brackets::after{margin-left:-0.125em;content:" ]"}.mw-parser-output .navbar li{word-spacing:-0.125em}.mw-parser-output .navbar a>span,.mw-parser-output .navbar a>abbr{text-decoration:inherit}.mw-parser-output .navbar-mini abbr{font-variant:small-caps;border-bottom:none;text-decoration:none;cursor:inherit}.mw-parser-output .navbar-ct-full{font-size:114%;margin:0 7em}.mw-parser-output .navbar-ct-mini{font-size:114%;margin:0 4em}html.skin-theme-clientpref-night .mw-parser-output .navbar li a abbr{color:var(--color-base)!important}@media(prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .navbar li a abbr{color:var(--color-base)!important}}@media print{.mw-parser-output .navbar{display:none!important}}</style><div class="navbar plainlinks hlist navbar-mini"><ul><li class="nv-view"><a href="/wiki/Template:Channel_access_methods" title="Template:Channel access methods"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Channel_access_methods" title="Template talk:Channel access methods"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Channel_access_methods" title="Special:EditPage/Template:Channel access methods"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="Channel_access_methods_and_media_access_control194" style="font-size:114%;margin:0 4em"><a href="/wiki/Channel_access_method" title="Channel access method">Channel access methods</a> and <a href="/wiki/Medium_access_control" title="Medium access control">media access control</a></div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Circuit_switching" title="Circuit switching">Channel-based</a></th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Frequency-division_multiple_access" title="Frequency-division multiple access">FDMA</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Frequency-division_multiplexing" title="Frequency-division multiplexing">FDM</a> <ul><li><a href="/wiki/Orthogonal_frequency-division_multiple_access" title="Orthogonal frequency-division multiple access">OFDMA</a></li> <li><a href="/wiki/Single-carrier_FDMA" title="Single-carrier FDMA">SC-FDMA</a></li></ul></li> <li><a href="/wiki/Wavelength-division_multiplexing" title="Wavelength-division multiplexing">WDM</a> <ul><li><a href="/wiki/Wavelength-division_multiple_access" class="mw-redirect" title="Wavelength-division multiple access">WDMA</a></li></ul></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Time-division_multiple_access" title="Time-division multiple access">TDMA</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Multi-frequency_time-division_multiple_access" title="Multi-frequency time-division multiple access">MF-TDMA</a></li> <li><a href="/wiki/Self-organized_time-division_multiple_access" title="Self-organized time-division multiple access">STDMA</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Code-division_multiple_access" title="Code-division multiple access">CDMA</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/W-CDMA" class="mw-redirect" title="W-CDMA">W-CDMA</a></li> <li><a href="/wiki/TD-CDMA" class="mw-redirect" title="TD-CDMA">TD-CDMA</a></li> <li><a href="/wiki/TD-SCDMA" class="mw-redirect" title="TD-SCDMA">TD-SCDMA</a></li> <li><a href="/wiki/Direct-sequence_spread_spectrum" title="Direct-sequence spread spectrum">DS-CDMA</a></li> <li><a href="/wiki/Frequency-hopping_spread_spectrum" title="Frequency-hopping spread spectrum">FH-CDMA</a></li> <li><a href="/wiki/Multi-carrier_code-division_multiple_access" title="Multi-carrier code-division multiple access">MC-CDMA</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Space-division_multiple_access" title="Space-division multiple access">SDMA</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/IBurst" class="mw-redirect" title="IBurst">HC-SDMA</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Polarization-division_multiple_access" title="Polarization-division multiple access">PDMA</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li class="mw-empty-elt"></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Pulse-address_multiple_access" title="Pulse-address multiple access">PAMA</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li class="mw-empty-elt"></li></ul> </div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Packet_switching" title="Packet switching">Packet-based</a></th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Contention_(telecommunications)" title="Contention (telecommunications)">Collision recovery</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/ALOHAnet#The_ALOHA_protocol" title="ALOHAnet">ALOHA</a></li> <li><a href="/wiki/ALOHAnet" title="ALOHAnet">Slotted ALOHA</a></li> <li><a href="/wiki/Reservation_ALOHA" class="mw-redirect" title="Reservation ALOHA">R-ALOHA</a></li> <li><a href="/wiki/AX.25" title="AX.25">AX.25</a></li> <li><a href="/wiki/Carrier-sense_multiple_access_with_collision_detection" title="Carrier-sense multiple access with collision detection">CSMA/CD</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Contention_(telecommunications)" title="Contention (telecommunications)">Collision avoidance</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Multiple_Access_with_Collision_Avoidance" class="mw-redirect" title="Multiple Access with Collision Avoidance">MACA</a></li> <li><a href="/wiki/Multiple_Access_with_Collision_Avoidance_for_Wireless" title="Multiple Access with Collision Avoidance for Wireless">MACAW</a></li> <li><a class="mw-selflink selflink">CSMA</a></li> <li><a href="/wiki/Carrier-sense_multiple_access_with_collision_avoidance" title="Carrier-sense multiple access with collision avoidance">CSMA/CA</a></li> <li><a href="/wiki/Distributed_coordination_function" title="Distributed coordination function">DCF</a></li> <li><a href="/wiki/Point_coordination_function" title="Point coordination function">PCF</a></li> <li><a href="/wiki/IEEE_802.11e-2005#802.11e_MAC_protocol_operation" title="IEEE 802.11e-2005">HCF</a></li> <li><a href="/wiki/CSMA/CARP" class="mw-redirect" title="CSMA/CARP">CSMA/CARP</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Collision_domain" title="Collision domain">Collision-free</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Token_Ring" title="Token Ring">Token Ring</a></li> <li><a href="/wiki/Token_bus_network" title="Token bus network">Token bus</a></li> <li><a href="/wiki/Mobile_Slotted_Aloha" title="Mobile Slotted Aloha">MS-ALOHA</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Delay and disruption tolerant</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Mobile_ad_hoc_network" class="mw-redirect" title="Mobile ad hoc network">MANET</a></li> <li><a href="/wiki/Vehicular_ad-hoc_network" class="mw-redirect" title="Vehicular ad-hoc network">VANET</a></li> <li><a href="/wiki/Delay-tolerant_networking" title="Delay-tolerant networking">DTN</a></li> <li><a href="/wiki/Dynamic_Source_Routing" title="Dynamic Source Routing">Dynamic Source Routing</a></li></ul> </div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Duplex_(telecommunications)" title="Duplex 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id="ca-ve-edit-sticky-header" tabindex="-1" data-event-name="ve-edit-sticky-header"><span class="vector-icon mw-ui-icon-wikimedia-edit mw-ui-icon-wikimedia-wikimedia-edit"></span> <span></span> </a> <a href="#" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only" id="ca-viewsource-sticky-header" tabindex="-1" data-event-name="ve-edit-protected-sticky-header"><span class="vector-icon mw-ui-icon-wikimedia-editLock mw-ui-icon-wikimedia-wikimedia-editLock"></span> <span></span> </a> </div> <div class="vector-sticky-header-buttons"> <button class="cdx-button cdx-button--weight-quiet mw-interlanguage-selector" id="p-lang-btn-sticky-header" tabindex="-1" data-event-name="ui.dropdown-p-lang-btn-sticky-header"><span class="vector-icon mw-ui-icon-wikimedia-language mw-ui-icon-wikimedia-wikimedia-language"></span> <span>19 languages</span> </button> <a href="#" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--action-progressive" id="ca-addsection-sticky-header" tabindex="-1" data-event-name="addsection-sticky-header"><span class="vector-icon mw-ui-icon-speechBubbleAdd-progressive mw-ui-icon-wikimedia-speechBubbleAdd-progressive"></span> <span>Add topic</span> </a> </div> <div class="vector-sticky-header-icon-end"> <div class="vector-user-links"> </div> </div> </div> </div> </div> <div class="mw-portlet mw-portlet-dock-bottom emptyPortlet" id="p-dock-bottom"> <ul> </ul> </div> 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