CINXE.COM

<!DOCTYPE html> <html class="client-nojs vector-feature-language-in-header-enabled vector-feature-language-in-main-page-header-disabled vector-feature-sticky-header-disabled vector-feature-page-tools-pinned-disabled vector-feature-toc-pinned-clientpref-1 vector-feature-main-menu-pinned-disabled vector-feature-limited-width-clientpref-1 vector-feature-limited-width-content-enabled vector-feature-custom-font-size-clientpref-1 vector-feature-appearance-pinned-clientpref-1 vector-feature-night-mode-enabled skin-theme-clientpref-day vector-toc-available" lang="en" dir="ltr"> <head> <meta charset="UTF-8"> <title>Autonegotiation - Wikipedia</title> <script>(function(){var className="client-js vector-feature-language-in-header-enabled vector-feature-language-in-main-page-header-disabled vector-feature-sticky-header-disabled vector-feature-page-tools-pinned-disabled vector-feature-toc-pinned-clientpref-1 vector-feature-main-menu-pinned-disabled vector-feature-limited-width-clientpref-1 vector-feature-limited-width-content-enabled vector-feature-custom-font-size-clientpref-1 vector-feature-appearance-pinned-clientpref-1 vector-feature-night-mode-enabled skin-theme-clientpref-day vector-toc-available";var cookie=document.cookie.match(/(?:^|; )enwikimwclientpreferences=([^;]+)/);if(cookie){cookie[1].split('%2C').forEach(function(pref){className=className.replace(new RegExp('(^| )'+pref.replace(/-clientpref-\w+$|[^\w-]+/g,'')+'-clientpref-\\w+( |$)'),'$1'+pref+'$2');});}document.documentElement.className=className;}());RLCONF={"wgBreakFrames":false,"wgSeparatorTransformTable":["",""],"wgDigitTransformTable":["",""],"wgDefaultDateFormat":"dmy", "wgMonthNames":["","January","February","March","April","May","June","July","August","September","October","November","December"],"wgRequestId":"b63567bb-d2c6-4890-8134-8a69f6bcc91f","wgCanonicalNamespace":"","wgCanonicalSpecialPageName":false,"wgNamespaceNumber":0,"wgPageName":"Autonegotiation","wgTitle":"Autonegotiation","wgCurRevisionId":1247082771,"wgRevisionId":1247082771,"wgArticleId":2268114,"wgIsArticle":true,"wgIsRedirect":false,"wgAction":"view","wgUserName":null,"wgUserGroups":["*"],"wgCategories":["All articles with dead external links","Articles with dead external links from July 2024","CS1 maint: multiple names: authors list","CS1 maint: archived copy as title","Articles with short description","Short description is different from Wikidata","Ethernet","Network protocols"],"wgPageViewLanguage":"en","wgPageContentLanguage":"en","wgPageContentModel":"wikitext","wgRelevantPageName":"Autonegotiation","wgRelevantArticleId":2268114,"wgIsProbablyEditable":true, "wgRelevantPageIsProbablyEditable":true,"wgRestrictionEdit":[],"wgRestrictionMove":[],"wgNoticeProject":"wikipedia","wgCiteReferencePreviewsActive":false,"wgFlaggedRevsParams":{"tags":{"status":{"levels":1}}},"wgMediaViewerOnClick":true,"wgMediaViewerEnabledByDefault":true,"wgPopupsFlags":0,"wgVisualEditor":{"pageLanguageCode":"en","pageLanguageDir":"ltr","pageVariantFallbacks":"en"},"wgMFDisplayWikibaseDescriptions":{"search":true,"watchlist":true,"tagline":false,"nearby":true},"wgWMESchemaEditAttemptStepOversample":false,"wgWMEPageLength":20000,"wgRelatedArticlesCompat":[],"wgCentralAuthMobileDomain":false,"wgEditSubmitButtonLabelPublish":true,"wgULSPosition":"interlanguage","wgULSisCompactLinksEnabled":false,"wgVector2022LanguageInHeader":true,"wgULSisLanguageSelectorEmpty":false,"wgWikibaseItemId":"Q366052","wgCheckUserClientHintsHeadersJsApi":["brands","architecture","bitness","fullVersionList","mobile","model","platform","platformVersion"],"GEHomepageSuggestedEditsEnableTopics": true,"wgGETopicsMatchModeEnabled":false,"wgGEStructuredTaskRejectionReasonTextInputEnabled":false,"wgGELevelingUpEnabledForUser":false};RLSTATE={"ext.globalCssJs.user.styles":"ready","site.styles":"ready","user.styles":"ready","ext.globalCssJs.user":"ready","user":"ready","user.options":"loading","ext.cite.styles":"ready","skins.vector.search.codex.styles":"ready","skins.vector.styles":"ready","skins.vector.icons":"ready","jquery.makeCollapsible.styles":"ready","ext.wikimediamessages.styles":"ready","ext.visualEditor.desktopArticleTarget.noscript":"ready","ext.uls.interlanguage":"ready","wikibase.client.init":"ready","ext.wikimediaBadges":"ready"};RLPAGEMODULES=["ext.cite.ux-enhancements","mediawiki.page.media","site","mediawiki.page.ready","jquery.makeCollapsible","mediawiki.toc","skins.vector.js","ext.centralNotice.geoIP","ext.centralNotice.startUp","ext.gadget.ReferenceTooltips","ext.gadget.switcher","ext.urlShortener.toolbar","ext.centralauth.centralautologin","mmv.bootstrap", "ext.popups","ext.visualEditor.desktopArticleTarget.init","ext.visualEditor.targetLoader","ext.echo.centralauth","ext.eventLogging","ext.wikimediaEvents","ext.navigationTiming","ext.uls.interface","ext.cx.eventlogging.campaigns","ext.cx.uls.quick.actions","wikibase.client.vector-2022","ext.checkUser.clientHints","ext.growthExperiments.SuggestedEditSession","wikibase.sidebar.tracking"];</script> <script>(RLQ=window.RLQ||[]).push(function(){mw.loader.impl(function(){return["user.options@12s5i",function($,jQuery,require,module){mw.user.tokens.set({"patrolToken":"+\\","watchToken":"+\\","csrfToken":"+\\"}); }];});});</script> <link rel="stylesheet" href="/w/load.php?lang=en&modules=ext.cite.styles%7Cext.uls.interlanguage%7Cext.visualEditor.desktopArticleTarget.noscript%7Cext.wikimediaBadges%7Cext.wikimediamessages.styles%7Cjquery.makeCollapsible.styles%7Cskins.vector.icons%2Cstyles%7Cskins.vector.search.codex.styles%7Cwikibase.client.init&only=styles&skin=vector-2022"> <script async="" src="/w/load.php?lang=en&modules=startup&only=scripts&raw=1&skin=vector-2022"></script> <meta name="ResourceLoaderDynamicStyles" content=""> <link rel="stylesheet" href="/w/load.php?lang=en&modules=site.styles&only=styles&skin=vector-2022"> <meta name="generator" content="MediaWiki 1.44.0-wmf.4"> <meta name="referrer" content="origin"> <meta name="referrer" content="origin-when-cross-origin"> <meta name="robots" content="max-image-preview:standard"> <meta name="format-detection" content="telephone=no"> <meta name="viewport" content="width=1120"> <meta property="og:title" content="Autonegotiation - Wikipedia"> <meta property="og:type" content="website"> <link rel="preconnect" href="//upload.wikimedia.org"> <link rel="alternate" media="only screen and (max-width: 640px)" href="//en.m.wikipedia.org/wiki/Autonegotiation"> <link rel="alternate" type="application/x-wiki" title="Edit this page" href="/w/index.php?title=Autonegotiation&action=edit"> <link rel="apple-touch-icon" href="/static/apple-touch/wikipedia.png"> <link rel="icon" href="/static/favicon/wikipedia.ico"> <link rel="search" type="application/opensearchdescription+xml" href="/w/rest.php/v1/search" title="Wikipedia (en)"> <link rel="EditURI" type="application/rsd+xml" href="//en.wikipedia.org/w/api.php?action=rsd"> <link rel="canonical" href="https://en.wikipedia.org/wiki/Autonegotiation"> <link rel="license" href="https://creativecommons.org/licenses/by-sa/4.0/deed.en"> <link rel="alternate" type="application/atom+xml" title="Wikipedia Atom feed" href="/w/index.php?title=Special:RecentChanges&feed=atom"> <link rel="dns-prefetch" href="//meta.wikimedia.org" /> <link rel="dns-prefetch" href="//login.wikimedia.org"> </head> <body class="skin--responsive skin-vector skin-vector-search-vue mediawiki ltr sitedir-ltr mw-hide-empty-elt ns-0 ns-subject mw-editable page-Autonegotiation rootpage-Autonegotiation skin-vector-2022 action-view"><a class="mw-jump-link" href="#bodyContent">Jump to content</a> <div class="vector-header-container"> <header class="vector-header mw-header"> <div class="vector-header-start"> <nav class="vector-main-menu-landmark" aria-label="Site"> <div id="vector-main-menu-dropdown" class="vector-dropdown vector-main-menu-dropdown vector-button-flush-left vector-button-flush-right" > <input type="checkbox" id="vector-main-menu-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-main-menu-dropdown" class="vector-dropdown-checkbox " aria-label="Main menu" > <label id="vector-main-menu-dropdown-label" for="vector-main-menu-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-menu mw-ui-icon-wikimedia-menu"></span> <span class="vector-dropdown-label-text">Main menu</span> </label> <div class="vector-dropdown-content"> <div id="vector-main-menu-unpinned-container" class="vector-unpinned-container"> <div id="vector-main-menu" class="vector-main-menu vector-pinnable-element"> <div class="vector-pinnable-header vector-main-menu-pinnable-header vector-pinnable-header-unpinned" data-feature-name="main-menu-pinned" data-pinnable-element-id="vector-main-menu" data-pinned-container-id="vector-main-menu-pinned-container" data-unpinned-container-id="vector-main-menu-unpinned-container" > <div class="vector-pinnable-header-label">Main menu</div> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-main-menu.pin">move to sidebar</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-main-menu.unpin">hide</button> </div> <div id="p-navigation" class="vector-menu mw-portlet mw-portlet-navigation" > <div class="vector-menu-heading"> Navigation </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="n-mainpage-description" class="mw-list-item"><a href="/wiki/Main_Page" title="Visit the main page [z]" accesskey="z"><span>Main page</span></a></li><li id="n-contents" class="mw-list-item"><a href="/wiki/Wikipedia:Contents" title="Guides to browsing Wikipedia"><span>Contents</span></a></li><li id="n-currentevents" class="mw-list-item"><a href="/wiki/Portal:Current_events" title="Articles related to current events"><span>Current events</span></a></li><li id="n-randompage" class="mw-list-item"><a href="/wiki/Special:Random" title="Visit a randomly selected article [x]" accesskey="x"><span>Random article</span></a></li><li id="n-aboutsite" class="mw-list-item"><a href="/wiki/Wikipedia:About" title="Learn about Wikipedia and how it works"><span>About Wikipedia</span></a></li><li id="n-contactpage" class="mw-list-item"><a href="//en.wikipedia.org/wiki/Wikipedia:Contact_us" title="How to contact Wikipedia"><span>Contact us</span></a></li> </ul> </div> </div> <div id="p-interaction" class="vector-menu mw-portlet mw-portlet-interaction" > <div class="vector-menu-heading"> Contribute </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="n-help" class="mw-list-item"><a href="/wiki/Help:Contents" title="Guidance on how to use and edit Wikipedia"><span>Help</span></a></li><li id="n-introduction" class="mw-list-item"><a href="/wiki/Help:Introduction" title="Learn how to edit Wikipedia"><span>Learn to edit</span></a></li><li id="n-portal" class="mw-list-item"><a href="/wiki/Wikipedia:Community_portal" title="The hub for editors"><span>Community portal</span></a></li><li id="n-recentchanges" class="mw-list-item"><a href="/wiki/Special:RecentChanges" title="A list of recent changes to Wikipedia [r]" accesskey="r"><span>Recent changes</span></a></li><li id="n-upload" class="mw-list-item"><a href="/wiki/Wikipedia:File_upload_wizard" title="Add images or other media for use on Wikipedia"><span>Upload file</span></a></li> </ul> </div> </div> </div> </div> </div> </div> </nav> <a href="/wiki/Main_Page" class="mw-logo"> <img class="mw-logo-icon" src="/static/images/icons/wikipedia.png" alt="" aria-hidden="true" height="50" width="50"> <span class="mw-logo-container skin-invert"> <img class="mw-logo-wordmark" alt="Wikipedia" src="/static/images/mobile/copyright/wikipedia-wordmark-en.svg" style="width: 7.5em; height: 1.125em;"> <img class="mw-logo-tagline" alt="The Free Encyclopedia" src="/static/images/mobile/copyright/wikipedia-tagline-en.svg" width="117" height="13" style="width: 7.3125em; height: 0.8125em;"> </span> </a> </div> <div class="vector-header-end"> <div id="p-search" role="search" class="vector-search-box-vue vector-search-box-collapses vector-search-box-show-thumbnail vector-search-box-auto-expand-width vector-search-box"> <a href="/wiki/Special:Search" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only search-toggle" title="Search Wikipedia [f]" accesskey="f"><span class="vector-icon mw-ui-icon-search mw-ui-icon-wikimedia-search"></span> <span>Search</span> </a> <div class="vector-typeahead-search-container"> <div class="cdx-typeahead-search cdx-typeahead-search--show-thumbnail cdx-typeahead-search--auto-expand-width"> <form action="/w/index.php" id="searchform" class="cdx-search-input cdx-search-input--has-end-button"> <div id="simpleSearch" class="cdx-search-input__input-wrapper" data-search-loc="header-moved"> <div class="cdx-text-input cdx-text-input--has-start-icon"> <input class="cdx-text-input__input" type="search" name="search" placeholder="Search Wikipedia" aria-label="Search Wikipedia" autocapitalize="sentences" title="Search Wikipedia [f]" accesskey="f" id="searchInput" > <span class="cdx-text-input__icon cdx-text-input__start-icon"></span> </div> <input type="hidden" name="title" value="Special:Search"> </div> <button class="cdx-button cdx-search-input__end-button">Search</button> </form> </div> </div> </div> <nav class="vector-user-links vector-user-links-wide" aria-label="Personal tools"> <div class="vector-user-links-main"> <div id="p-vector-user-menu-preferences" class="vector-menu mw-portlet emptyPortlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> </ul> </div> </div> <div id="p-vector-user-menu-userpage" class="vector-menu mw-portlet emptyPortlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> </ul> </div> </div> <nav class="vector-appearance-landmark" aria-label="Appearance"> <div id="vector-appearance-dropdown" class="vector-dropdown " title="Change the appearance of the page's font size, width, and color" > <input type="checkbox" id="vector-appearance-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-appearance-dropdown" class="vector-dropdown-checkbox " aria-label="Appearance" > <label id="vector-appearance-dropdown-label" for="vector-appearance-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-appearance mw-ui-icon-wikimedia-appearance"></span> <span class="vector-dropdown-label-text">Appearance</span> </label> <div class="vector-dropdown-content"> <div id="vector-appearance-unpinned-container" class="vector-unpinned-container"> </div> </div> </div> </nav> <div id="p-vector-user-menu-notifications" class="vector-menu mw-portlet emptyPortlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> </ul> </div> </div> <div id="p-vector-user-menu-overflow" class="vector-menu mw-portlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="pt-sitesupport-2" class="user-links-collapsible-item mw-list-item user-links-collapsible-item"><a data-mw="interface" href="https://donate.wikimedia.org/wiki/Special:FundraiserRedirector?utm_source=donate&utm_medium=sidebar&utm_campaign=C13_en.wikipedia.org&uselang=en" class=""><span>Donate</span></a> </li> <li id="pt-createaccount-2" class="user-links-collapsible-item mw-list-item user-links-collapsible-item"><a data-mw="interface" href="/w/index.php?title=Special:CreateAccount&returnto=Autonegotiation" title="You are encouraged to create an account and log in; however, it is not mandatory" class=""><span>Create account</span></a> </li> <li id="pt-login-2" class="user-links-collapsible-item mw-list-item user-links-collapsible-item"><a data-mw="interface" href="/w/index.php?title=Special:UserLogin&returnto=Autonegotiation" title="You're encouraged to log in; however, it's not mandatory. [o]" accesskey="o" class=""><span>Log in</span></a> </li> </ul> </div> </div> </div> <div id="vector-user-links-dropdown" class="vector-dropdown vector-user-menu vector-button-flush-right vector-user-menu-logged-out" title="Log in and more options" > <input type="checkbox" id="vector-user-links-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-user-links-dropdown" class="vector-dropdown-checkbox " aria-label="Personal tools" > <label id="vector-user-links-dropdown-label" for="vector-user-links-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-ellipsis mw-ui-icon-wikimedia-ellipsis"></span> <span class="vector-dropdown-label-text">Personal tools</span> </label> <div class="vector-dropdown-content"> <div id="p-personal" class="vector-menu mw-portlet mw-portlet-personal user-links-collapsible-item" title="User menu" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="pt-sitesupport" class="user-links-collapsible-item mw-list-item"><a href="https://donate.wikimedia.org/wiki/Special:FundraiserRedirector?utm_source=donate&utm_medium=sidebar&utm_campaign=C13_en.wikipedia.org&uselang=en"><span>Donate</span></a></li><li id="pt-createaccount" class="user-links-collapsible-item mw-list-item"><a href="/w/index.php?title=Special:CreateAccount&returnto=Autonegotiation" title="You are encouraged to create an account and log in; however, it is not mandatory"><span class="vector-icon mw-ui-icon-userAdd mw-ui-icon-wikimedia-userAdd"></span> <span>Create account</span></a></li><li id="pt-login" class="user-links-collapsible-item mw-list-item"><a href="/w/index.php?title=Special:UserLogin&returnto=Autonegotiation" title="You're encouraged to log in; however, it's not mandatory. [o]" accesskey="o"><span class="vector-icon mw-ui-icon-logIn mw-ui-icon-wikimedia-logIn"></span> <span>Log in</span></a></li> </ul> </div> </div> <div id="p-user-menu-anon-editor" class="vector-menu mw-portlet mw-portlet-user-menu-anon-editor" > <div class="vector-menu-heading"> Pages for logged out editors <a href="/wiki/Help:Introduction" aria-label="Learn more about editing"><span>learn more</span></a> </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="pt-anoncontribs" class="mw-list-item"><a href="/wiki/Special:MyContributions" title="A list of edits made from this IP address [y]" accesskey="y"><span>Contributions</span></a></li><li id="pt-anontalk" class="mw-list-item"><a href="/wiki/Special:MyTalk" title="Discussion about edits from this IP address [n]" accesskey="n"><span>Talk</span></a></li> </ul> </div> </div> </div> </div> </nav> </div> </header> </div> <div class="mw-page-container"> <div class="mw-page-container-inner"> <div class="vector-sitenotice-container"> <div id="siteNotice"></div> </div> <div class="vector-column-start"> <div class="vector-main-menu-container"> <div id="mw-navigation"> <nav id="mw-panel" class="vector-main-menu-landmark" aria-label="Site"> <div id="vector-main-menu-pinned-container" class="vector-pinned-container"> </div> </nav> </div> </div> <div class="vector-sticky-pinned-container"> <nav id="mw-panel-toc" aria-label="Contents" data-event-name="ui.sidebar-toc" class="mw-table-of-contents-container vector-toc-landmark"> <div id="vector-toc-pinned-container" class="vector-pinned-container"> <div id="vector-toc" class="vector-toc vector-pinnable-element"> <div class="vector-pinnable-header vector-toc-pinnable-header vector-pinnable-header-pinned" data-feature-name="toc-pinned" data-pinnable-element-id="vector-toc" > <h2 class="vector-pinnable-header-label">Contents</h2> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-toc.pin">move to sidebar</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-toc.unpin">hide</button> </div> <ul class="vector-toc-contents" id="mw-panel-toc-list"> <li id="toc-mw-content-text" class="vector-toc-list-item vector-toc-level-1"> <a href="#" class="vector-toc-link"> <div class="vector-toc-text">(Top)</div> </a> </li> <li id="toc-Standardization_and_interoperability" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Standardization_and_interoperability"> <div class="vector-toc-text"> <span class="vector-toc-numb">1</span> <span>Standardization and interoperability</span> </div> </a> <ul id="toc-Standardization_and_interoperability-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Function" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Function"> <div class="vector-toc-text"> <span class="vector-toc-numb">2</span> <span>Function</span> </div> </a> <ul id="toc-Function-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Priority" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Priority"> <div class="vector-toc-text"> <span class="vector-toc-numb">3</span> <span>Priority</span> </div> </a> <ul id="toc-Priority-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Electrical_signals" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Electrical_signals"> <div class="vector-toc-text"> <span class="vector-toc-numb">4</span> <span>Electrical signals</span> </div> </a> <ul id="toc-Electrical_signals-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-The_base_link_code_word" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#The_base_link_code_word"> <div class="vector-toc-text"> <span class="vector-toc-numb">5</span> <span>The base link code word</span> </div> </a> <ul id="toc-The_base_link_code_word-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Message_and_unformatted_next_page" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Message_and_unformatted_next_page"> <div class="vector-toc-text"> <span class="vector-toc-numb">6</span> <span>Message and unformatted next page</span> </div> </a> <ul id="toc-Message_and_unformatted_next_page-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Duplex_mismatch" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Duplex_mismatch"> <div class="vector-toc-text"> <span class="vector-toc-numb">7</span> <span>Duplex mismatch</span> </div> </a> <ul id="toc-Duplex_mismatch-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Patents" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Patents"> <div class="vector-toc-text"> <span class="vector-toc-numb">8</span> <span>Patents</span> </div> </a> <ul id="toc-Patents-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Auto-Negotiation_for_single-pair_Ethernet" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Auto-Negotiation_for_single-pair_Ethernet"> <div class="vector-toc-text"> <span class="vector-toc-numb">9</span> <span>Auto-Negotiation for single-pair Ethernet</span> </div> </a> <ul id="toc-Auto-Negotiation_for_single-pair_Ethernet-sublist" class="vector-toc-list"> </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">10</span> <span>See also</span> </div> </a> <ul id="toc-See_also-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Notes" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Notes"> <div class="vector-toc-text"> <span class="vector-toc-numb">11</span> <span>Notes</span> </div> </a> <ul id="toc-Notes-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">12</span> <span>References</span> </div> </a> <ul id="toc-References-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-External_links" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#External_links"> <div class="vector-toc-text"> <span class="vector-toc-numb">13</span> <span>External links</span> </div> </a> <ul id="toc-External_links-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" > <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 cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-listBullet mw-ui-icon-wikimedia-listBullet"></span> <span class="vector-dropdown-label-text">Toggle the table of contents</span> </label> <div class="vector-dropdown-content"> <div id="vector-page-titlebar-toc-unpinned-container" class="vector-unpinned-container"> </div> </div> </div> </nav> <h1 id="firstHeading" class="firstHeading mw-first-heading"><span class="mw-page-title-main">Autonegotiation</span></h1> <div id="p-lang-btn" class="vector-dropdown mw-portlet mw-portlet-lang" > <input type="checkbox" id="p-lang-btn-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-p-lang-btn" class="vector-dropdown-checkbox mw-interlanguage-selector" aria-label="Go to an article in another language. Available in 7 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-7" 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">7 languages</span> </label> <div class="vector-dropdown-content"> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li class="interlanguage-link interwiki-de mw-list-item"><a href="https://de.wikipedia.org/wiki/Autonegotiation" title="Autonegotiation – German" lang="de" hreflang="de" data-title="Autonegotiation" data-language-autonym="Deutsch" data-language-local-name="German" class="interlanguage-link-target"><span>Deutsch</span></a></li><li class="interlanguage-link interwiki-fr mw-list-item"><a href="https://fr.wikipedia.org/wiki/Auton%C3%A9gociation" title="Autonégociation – French" lang="fr" hreflang="fr" data-title="Autonégociation" 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/%EC%9E%90%EB%8F%99_%ED%98%91%EC%83%81" title="자동 협상 – Korean" lang="ko" hreflang="ko" data-title="자동 협상" data-language-autonym="한국어" data-language-local-name="Korean" class="interlanguage-link-target"><span>한국어</span></a></li><li class="interlanguage-link interwiki-he badge-Q70894304 mw-list-item" title=""><a href="https://he.wikipedia.org/wiki/Autonegotiation" title="Autonegotiation – Hebrew" lang="he" hreflang="he" data-title="Autonegotiation" data-language-autonym="עברית" data-language-local-name="Hebrew" class="interlanguage-link-target"><span>עברית</span></a></li><li class="interlanguage-link interwiki-nl mw-list-item"><a href="https://nl.wikipedia.org/wiki/Autonegotiatie" title="Autonegotiatie – Dutch" lang="nl" hreflang="nl" data-title="Autonegotiatie" data-language-autonym="Nederlands" data-language-local-name="Dutch" class="interlanguage-link-target"><span>Nederlands</span></a></li><li class="interlanguage-link interwiki-ja mw-list-item"><a href="https://ja.wikipedia.org/wiki/%E3%82%AA%E3%83%BC%E3%83%88%E3%83%8D%E3%82%B4%E3%82%B7%E3%82%A8%E3%83%BC%E3%82%B7%E3%83%A7%E3%83%B3" title="オートネゴシエーション – Japanese" lang="ja" hreflang="ja" data-title="オートネゴシエーション" data-language-autonym="日本語" data-language-local-name="Japanese" class="interlanguage-link-target"><span>日本語</span></a></li><li class="interlanguage-link interwiki-ru mw-list-item"><a href="https://ru.wikipedia.org/wiki/%D0%90%D0%B2%D1%82%D0%BE%D1%81%D0%BE%D0%B3%D0%BB%D0%B0%D1%81%D0%BE%D0%B2%D0%B0%D0%BD%D0%B8%D0%B5" title="Автосогласование – Russian" lang="ru" hreflang="ru" data-title="Автосогласование" data-language-autonym="Русский" data-language-local-name="Russian" class="interlanguage-link-target"><span>Русский</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/Q366052#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 aria-label="Namespaces"> <div id="p-associated-pages" class="vector-menu vector-menu-tabs mw-portlet mw-portlet-associated-pages" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="ca-nstab-main" class="selected vector-tab-noicon mw-list-item"><a href="/wiki/Autonegotiation" title="View the content page [c]" accesskey="c"><span>Article</span></a></li><li id="ca-talk" class="vector-tab-noicon mw-list-item"><a href="/wiki/Talk:Autonegotiation" rel="discussion" title="Discuss improvements to the content page [t]" accesskey="t"><span>Talk</span></a></li> </ul> </div> </div> <div id="vector-variants-dropdown" class="vector-dropdown emptyPortlet" > <input type="checkbox" id="vector-variants-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-variants-dropdown" class="vector-dropdown-checkbox " aria-label="Change language variant" > <label id="vector-variants-dropdown-label" for="vector-variants-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet" aria-hidden="true" ><span class="vector-dropdown-label-text">English</span> </label> <div class="vector-dropdown-content"> <div id="p-variants" class="vector-menu mw-portlet mw-portlet-variants emptyPortlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> </ul> </div> </div> </div> </div> </nav> </div> <div id="right-navigation" class="vector-collapsible"> <nav aria-label="Views"> <div id="p-views" class="vector-menu vector-menu-tabs mw-portlet mw-portlet-views" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="ca-view" class="selected vector-tab-noicon mw-list-item"><a href="/wiki/Autonegotiation"><span>Read</span></a></li><li id="ca-edit" class="vector-tab-noicon mw-list-item"><a href="/w/index.php?title=Autonegotiation&action=edit" title="Edit this page [e]" accesskey="e"><span>Edit</span></a></li><li id="ca-history" class="vector-tab-noicon mw-list-item"><a href="/w/index.php?title=Autonegotiation&action=history" title="Past revisions of this page [h]" accesskey="h"><span>View history</span></a></li> </ul> </div> </div> </nav> <nav class="vector-page-tools-landmark" aria-label="Page tools"> <div id="vector-page-tools-dropdown" class="vector-dropdown vector-page-tools-dropdown" > <input type="checkbox" id="vector-page-tools-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-page-tools-dropdown" class="vector-dropdown-checkbox " aria-label="Tools" > <label id="vector-page-tools-dropdown-label" for="vector-page-tools-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet" aria-hidden="true" ><span class="vector-dropdown-label-text">Tools</span> </label> <div class="vector-dropdown-content"> <div id="vector-page-tools-unpinned-container" class="vector-unpinned-container"> <div id="vector-page-tools" class="vector-page-tools vector-pinnable-element"> <div class="vector-pinnable-header vector-page-tools-pinnable-header vector-pinnable-header-unpinned" data-feature-name="page-tools-pinned" data-pinnable-element-id="vector-page-tools" data-pinned-container-id="vector-page-tools-pinned-container" data-unpinned-container-id="vector-page-tools-unpinned-container" > <div class="vector-pinnable-header-label">Tools</div> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-page-tools.pin">move to sidebar</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-page-tools.unpin">hide</button> </div> <div id="p-cactions" class="vector-menu mw-portlet mw-portlet-cactions emptyPortlet vector-has-collapsible-items" title="More options" > <div class="vector-menu-heading"> Actions </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="ca-more-view" class="selected vector-more-collapsible-item mw-list-item"><a href="/wiki/Autonegotiation"><span>Read</span></a></li><li id="ca-more-edit" class="vector-more-collapsible-item mw-list-item"><a href="/w/index.php?title=Autonegotiation&action=edit" title="Edit this page [e]" accesskey="e"><span>Edit</span></a></li><li id="ca-more-history" class="vector-more-collapsible-item mw-list-item"><a href="/w/index.php?title=Autonegotiation&action=history"><span>View history</span></a></li> </ul> </div> </div> <div id="p-tb" class="vector-menu mw-portlet mw-portlet-tb" > <div class="vector-menu-heading"> General </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="t-whatlinkshere" class="mw-list-item"><a href="/wiki/Special:WhatLinksHere/Autonegotiation" title="List of all English Wikipedia pages containing links to this page [j]" accesskey="j"><span>What links here</span></a></li><li id="t-recentchangeslinked" class="mw-list-item"><a href="/wiki/Special:RecentChangesLinked/Autonegotiation" rel="nofollow" title="Recent changes in pages linked from this page [k]" accesskey="k"><span>Related changes</span></a></li><li id="t-upload" class="mw-list-item"><a href="/wiki/Wikipedia:File_Upload_Wizard" title="Upload files [u]" accesskey="u"><span>Upload file</span></a></li><li id="t-specialpages" class="mw-list-item"><a href="/wiki/Special:SpecialPages" title="A list of all special pages [q]" accesskey="q"><span>Special pages</span></a></li><li id="t-permalink" class="mw-list-item"><a href="/w/index.php?title=Autonegotiation&oldid=1247082771" title="Permanent link to this revision of this page"><span>Permanent link</span></a></li><li id="t-info" class="mw-list-item"><a href="/w/index.php?title=Autonegotiation&action=info" title="More information about this page"><span>Page information</span></a></li><li id="t-cite" class="mw-list-item"><a href="/w/index.php?title=Special:CiteThisPage&page=Autonegotiation&id=1247082771&wpFormIdentifier=titleform" title="Information on how to cite this page"><span>Cite this page</span></a></li><li id="t-urlshortener" class="mw-list-item"><a href="/w/index.php?title=Special:UrlShortener&url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FAutonegotiation"><span>Get shortened URL</span></a></li><li id="t-urlshortener-qrcode" class="mw-list-item"><a href="/w/index.php?title=Special:QrCode&url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FAutonegotiation"><span>Download QR code</span></a></li> </ul> </div> </div> <div id="p-coll-print_export" class="vector-menu mw-portlet mw-portlet-coll-print_export" > <div class="vector-menu-heading"> Print/export </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="coll-download-as-rl" class="mw-list-item"><a href="/w/index.php?title=Special:DownloadAsPdf&page=Autonegotiation&action=show-download-screen" title="Download this page as a PDF file"><span>Download as PDF</span></a></li><li id="t-print" class="mw-list-item"><a href="/w/index.php?title=Autonegotiation&printable=yes" title="Printable version of this page [p]" accesskey="p"><span>Printable version</span></a></li> </ul> </div> </div> <div id="p-wikibase-otherprojects" class="vector-menu mw-portlet mw-portlet-wikibase-otherprojects" > <div class="vector-menu-heading"> In other projects </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="t-wikibase" class="wb-otherproject-link wb-otherproject-wikibase-dataitem mw-list-item"><a href="https://www.wikidata.org/wiki/Special:EntityPage/Q366052" title="Structured data on this page hosted by Wikidata [g]" accesskey="g"><span>Wikidata item</span></a></li> </ul> </div> </div> </div> </div> </div> </div> </nav> </div> </div> </div> <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">Ethernet connection signaling mechanism</div> <style data-mw-deduplicate="TemplateStyles:r1236090951">.mw-parser-output .hatnote{font-style:italic}.mw-parser-output div.hatnote{padding-left:1.6em;margin-bottom:0.5em}.mw-parser-output .hatnote i{font-style:normal}.mw-parser-output .hatnote+link+.hatnote{margin-top:-0.5em}@media print{body.ns-0 .mw-parser-output .hatnote{display:none!important}}</style><div role="note" class="hatnote navigation-not-searchable">Not to be confused with <a href="/wiki/Automatic_negotiation" class="mw-redirect" title="Automatic negotiation">Automatic negotiation</a>.</div> <p><b>Autonegotiation</b> is a signaling mechanism and procedure used by <a href="/wiki/Ethernet_over_twisted_pair" title="Ethernet over twisted pair">Ethernet over twisted pair</a> by which two connected devices choose common transmission parameters, such as speed, <a href="/wiki/Duplex_(telecommunications)" title="Duplex (telecommunications)">duplex</a> mode, and <a href="/wiki/Flow_control_(data)" title="Flow control (data)">flow control</a>. In this process, the connected devices first share their capabilities regarding these parameters and then choose the highest-performance transmission mode they both support. </p><p>Autonegotiation for twisted pair is defined in clause 28 of IEEE 802.3.<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> and was originally an optional component in the <a href="/wiki/Fast_Ethernet" title="Fast Ethernet">Fast Ethernet</a> standard.<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> It is backwards compatible with the <b>normal link pulses</b> (<b>NLP</b>) used by <a href="/wiki/10BASE-T" class="mw-redirect" title="10BASE-T">10BASE-T</a>.<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> The protocol was significantly extended in the <a href="/wiki/Gigabit_Ethernet" title="Gigabit Ethernet">Gigabit Ethernet</a> standard, and is mandatory for 1000BASE-T gigabit Ethernet over twisted pair.<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> </p><p>In the <a href="/wiki/OSI_model" title="OSI model">OSI model</a>, autonegotiation resides in the <a href="/wiki/Physical_layer" title="Physical layer">physical layer</a>. </p> <meta property="mw:PageProp/toc" /> <div class="mw-heading mw-heading2"><h2 id="Standardization_and_interoperability">Standardization and interoperability</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Autonegotiation&action=edit&section=1" title="Edit section: Standardization and interoperability"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>In 1995, the <a href="/wiki/Fast_Ethernet" title="Fast Ethernet">Fast Ethernet</a> standard was released. Because this introduced a new speed option for the same wires, it included a means for connected network adapters to negotiate the best possible shared mode of operation. The autonegotiation protocol included in <a href="/wiki/IEEE_802.3" title="IEEE 802.3">IEEE 802.3</a> clause 28 was developed from a patented technology by <a href="/wiki/National_Semiconductor" title="National Semiconductor">National Semiconductor</a> known as <b>NWay</b>. The company gave a letter of assurance for anyone to use their system for a one time license fee.<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> Another company has since bought the rights to that patent.<sup id="cite_ref-nwaylic_6-0" class="reference"><a href="#cite_note-nwaylic-6"><span class="cite-bracket">[</span>6<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-Expire_7-0" class="reference"><a href="#cite_note-Expire-7"><span class="cite-bracket">[</span>a<span class="cite-bracket">]</span></a></sup> </p><p>The first version of the autonegotiation specification, in the 1995 IEEE 802.3u <a href="/wiki/Fast_Ethernet" title="Fast Ethernet">Fast Ethernet</a> standard, was implemented differently by different manufacturers leading to <a href="/wiki/Interoperability" title="Interoperability">interoperability</a> issues. These problems led many network administrators to manually set the speed and duplex mode of each network interface. However, the use of manual configurations may lead to <a href="/wiki/Duplex_mismatch" title="Duplex mismatch">duplex mismatches</a>. These can be difficult to diagnose because the network is nominally working. Simple network testing utilities such as <a href="/wiki/Ping_(networking_utility)" title="Ping (networking utility)">ping</a> may report a valid connection. However, network performance will be significantly impacted by transmission aborts and subsequent <a href="/wiki/Ethernet" title="Ethernet">Ethernet</a> frame drops that result from a duplex mismatch. When a duplex mismatch is occurring, the side of the connection that is using half-duplex will report late collisions, while the side using full-duplex will report <a href="/wiki/Frame_check_sequence" title="Frame check sequence">FCS</a> errors. </p><p>The autonegotiation specification was improved in the 1998 release of IEEE 802.3. This was followed by the release of the IEEE 802.3ab <a href="/wiki/Gigabit_Ethernet" title="Gigabit Ethernet">Gigabit Ethernet</a> standard in 1999 which specified mandatory autonegotiation for <a href="/wiki/1000BASE-T" class="mw-redirect" title="1000BASE-T">1000BASE-T</a>. Autonegotiation is also mandatory for <a href="/wiki/1000BASE-TX" class="mw-redirect" title="1000BASE-TX">1000BASE-TX</a> and <a href="/wiki/10GBASE-T" class="mw-redirect" title="10GBASE-T">10GBASE-T</a> implementations. Currently, most network equipment manufacturers recommend using autonegotiation on all access ports and enable it as a factory default setting.<sup id="cite_ref-8" class="reference"><a href="#cite_note-8"><span class="cite-bracket">[</span>7<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-9" class="reference"><a href="#cite_note-9"><span class="cite-bracket">[</span>8<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-10" class="reference"><a href="#cite_note-10"><span class="cite-bracket">[</span>9<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="Function">Function</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Autonegotiation&action=edit&section=2" title="Edit section: Function"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Autonegotiation can be used by devices that are capable of more than one transmission rate, different <a href="/wiki/Duplex_(telecommunications)" title="Duplex (telecommunications)">duplex modes</a> (half duplex and full duplex), and different transmission standards at the same speed (though in practice only one standard at each speed is widely supported). </p><p>During autonegotiation, each device declares its <i>technology abilities</i>, that is, its possible modes of operation. The best common mode is chosen, with higher speed preferred over lower, and full duplex preferred over half duplex at the same speed. </p><p>Parallel detection is used when a device that is capable of autonegotiation is connected to one that is not. This happens if a device does not support autonegotiation or autonegotiation is disabled on a device. In this condition, the device that is capable of autonegotiation can determine and match speed with the other device. This procedure cannot determine duplex capability, so half duplex is always assumed. </p><p>Other than speed and duplex mode, autonegotiation is used to communicate the master-slave parameters for <a href="/wiki/Gigabit_Ethernet" title="Gigabit Ethernet">gigabit Ethernet</a>.<sup id="cite_ref-11" class="reference"><a href="#cite_note-11"><span class="cite-bracket">[</span>10<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-12" class="reference"><a href="#cite_note-12"><span class="cite-bracket">[</span>11<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="Priority">Priority</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Autonegotiation&action=edit&section=3" title="Edit section: Priority"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Upon receipt of the technology abilities of the other device, both devices decide the best possible mode of operation supported by both devices. Among the modes that are supported by both devices, each device chooses the one that is highest priority. The priority among modes is as follows:<sup id="cite_ref-13" class="reference"><a href="#cite_note-13"><span class="cite-bracket">[</span>12<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-14" class="reference"><a href="#cite_note-14"><span class="cite-bracket">[</span>13<span class="cite-bracket">]</span></a></sup> </p> <ol><li>40GBASE-T full duplex</li> <li>25GBASE-T full duplex</li> <li>10GBASE-T full duplex</li> <li>5GBASE-T full duplex</li> <li>2.5GBASE-T full duplex</li> <li>1000BASE-T full duplex</li> <li>1000BASE-T half duplex</li> <li>100BASE-T2 full duplex</li> <li>100BASE-TX full duplex</li> <li>100BASE-T2 half duplex</li> <li>100BASE-T4 half duplex</li> <li>100BASE-TX half duplex</li> <li>10BASE-T full duplex</li> <li>10BASE-T half duplex</li></ol> <div class="mw-heading mw-heading2"><h2 id="Electrical_signals">Electrical signals</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Autonegotiation&action=edit&section=4" title="Edit section: Electrical signals"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure class="mw-default-size mw-halign-right" typeof="mw:File/Thumb"><a href="/wiki/File:Normal-link-pulses.svg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/5/59/Normal-link-pulses.svg/220px-Normal-link-pulses.svg.png" decoding="async" width="220" height="94" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/5/59/Normal-link-pulses.svg/330px-Normal-link-pulses.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/5/59/Normal-link-pulses.svg/440px-Normal-link-pulses.svg.png 2x" data-file-width="252" data-file-height="108" /></a><figcaption>A sequence of normal link pulses, used by 10BASE-T devices to establish link integrity.</figcaption></figure> <p>Autonegotiation is based on pulses similar to those used by <a href="/wiki/10BASE-T" class="mw-redirect" title="10BASE-T">10BASE-T</a> devices to detect the presence of a connection to another device. These <i>link integrity test</i> (LIT) pulses are sent by Ethernet devices when they are not sending or receiving any frames. They are <a href="/wiki/Unipolar_encoding" title="Unipolar encoding">unipolar</a> positive-only electrical pulses of a nominal duration of <span class="nowrap"><span data-sort-value="6993100000000000000♠"></span>100 ns</span>, with a maximum pulse width of <span class="nowrap"><span data-sort-value="6993200000000000000♠"></span>200 ns</span>,<sup id="cite_ref-negotiateddata-nway-spec_15-0" class="reference"><a href="#cite_note-negotiateddata-nway-spec-15"><span class="cite-bracket">[</span>14<span class="cite-bracket">]</span></a></sup> generated at a <span class="nowrap"><span data-sort-value="6998160000000000000♠"></span>16 ms</span> time interval with a timing variation tolerance of <span class="nowrap"><span data-sort-value="6997800000000000000♠"></span>8 ms</span>. A device detects the failure of a link if neither a frame nor two of the LIT pulses is received for 50-150 ms. For this scheme to work, devices must send LIT pulses regardless of receiving any. In the autonegotiation specification, these pulses are called <b>normal link pulses</b> (NLP). </p> <figure class="mw-default-size mw-halign-right" typeof="mw:File/Thumb"><a href="/wiki/File:Fast-link-pulses.svg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/5/5a/Fast-link-pulses.svg/220px-Fast-link-pulses.svg.png" decoding="async" width="220" height="94" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/5/5a/Fast-link-pulses.svg/330px-Fast-link-pulses.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/5/5a/Fast-link-pulses.svg/440px-Fast-link-pulses.svg.png 2x" data-file-width="252" data-file-height="108" /></a><figcaption>Three bursts of <i>fast link pulses</i>, used by autonegotiating devices to declare their capabilities.</figcaption></figure> <p>NLPs used by autonegotiation are still unipolar, positive-only, and with a nominal duration of <span class="nowrap"><span data-sort-value="6993100000000000000♠"></span>100 ns</span>; but each LIT is replaced by a pulse burst consisting of 17 to 33 pulses sent <span class="nowrap"><span data-sort-value="6996125000000000000♠"></span>125 μs</span> apart. Each pulse burst is called a <b>fast link pulse</b> (FLP) burst. The time interval between the start of each FLP burst is the same <span class="nowrap"><span data-sort-value="6998160000000000000♠"></span>16 ms</span> as between NLPs. </p> <figure class="mw-default-size mw-halign-right" typeof="mw:File/Thumb"><a href="/wiki/File:Link-code-word.svg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/1/15/Link-code-word.svg/220px-Link-code-word.svg.png" decoding="async" width="220" height="88" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/1/15/Link-code-word.svg/330px-Link-code-word.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/1/15/Link-code-word.svg/440px-Link-code-word.svg.png 2x" data-file-width="315" data-file-height="126" /></a><figcaption>How a link code word (a 16-bit word) is encoded in a fast link pulse burst</figcaption></figure> <p>The FLP burst consists of 17 NLP at a <span class="nowrap"><span data-sort-value="6996125000000000000♠"></span>125 μs</span> time interval with a tolerance of <span class="nowrap"><span data-sort-value="6995140000000000000♠"></span>14 μs</span>. Between each pair of two consecutive NLPs (i.e. at <span class="nowrap"><span data-sort-value="6995625000000000000♠"></span>62.5 μs</span> after the first NLP of the pulse pair), an additional positive pulse may be present. The presence of this additional pulse indicates a logical 1, its absence a logical 0. As a result, every FLP contains a 16-bit data word. This data word is called a <i>link code word</i> (LCW). The bits of the LCW are numbered from 0 to 15, where bit 0 corresponds to the first possible pulse in time and bit 15 to the last. </p> <div class="mw-heading mw-heading2"><h2 id="The_base_link_code_word">The base link code word</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Autonegotiation&action=edit&section=5" title="Edit section: The base link code word"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Every fast link pulse burst transmits 16 bits of data known as a link code word. The first such word is known as a <i>base link code word</i>, and its bits are used as follows: </p> <ul><li>0–4: selector field – indicates which standard is used between IEEE 802.3 and IEEE 802.9</li> <li>5–12: technology ability field – a sequence of bits that encode the possible modes of operations among the 100BASE-T and 10BASE-T modes (see below)</li> <li>13: remote fault – set to one when the device is detecting a link failure</li> <li>14: acknowledgement – the device sets this to one to indicate the correct reception of the base link code word from the other party; this is detected by the reception of at least three identical base code words. Upon receiving these three identical copies, the device sends a link code word with the acknowledge bit set to one from six times to eight times.</li> <li>15: next page – used to indicate the intention of sending other link code words after the base link code word</li></ul> <p>The technology ability field is composed of eight bits. For IEEE 802.3, these are as follows: </p> <ul><li>bit 0: device supports 10BASE-T</li> <li>bit 1: device supports 10BASE-T in full duplex</li> <li>bit 2: device supports 100BASE-TX</li> <li>bit 3: device supports 100BASE-TX in full duplex</li> <li>bit 4: device supports 100BASE-T4</li> <li>bit 5: device supports <a href="/wiki/Pause_frame" class="mw-redirect" title="Pause frame">pause frame</a></li> <li>bit 6: device supports asymmetric pause for full duplex</li> <li>bit 7: reserved</li></ul> <p>The link code words are also called <i>pages</i>. The base link code word is therefore called a base page. The next page bit of the base page is 1 when the device intends to send other pages, which can be used to communicate other abilities. These additional pages are sent only if both devices have sent base pages with a next page bit set to 1. The additional pages are still encoded as link code words (using 17 clock pulses and up to 16-bit pulses). </p> <div class="mw-heading mw-heading2"><h2 id="Message_and_unformatted_next_page">Message and unformatted next page</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Autonegotiation&action=edit&section=6" title="Edit section: Message and unformatted next page"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The base page is sufficient for devices to advertise which ones among the 10BASE-T, 100BASE-TX and 100BASE-T4 modes they support. For gigabit Ethernet, two other pages are required. These pages are sent if both devices have sent base pages with a next page bit set to one. </p><p>The additional pages are of two kinds: <i>message pages</i> and <i>unformatted pages</i>. These pages are still 16-bit words encoded as pulses in the same way as the base page. Their first eleven bits are data, while their second-to-last bit indicates whether the page is a message page or an unformatted page. The last bit of each page indicates the presence of an additional page.<sup id="cite_ref-16" class="reference"><a href="#cite_note-16"><span class="cite-bracket">[</span>15<span class="cite-bracket">]</span></a></sup> </p><p>The 1000BASE-T supported modes and master-slave data (which is used to decide which of the two devices acts as the master, and which one acts as the slave) are sent using a single message page, followed by a single unformatted page. The message page contains: </p> <ul><li>half duplex capability</li> <li>whether the device is single port or multiport</li> <li>whether master/slave is manually configured or not</li> <li>whether the device is manually configured as master or slave</li></ul> <p>The unformatted page contains a 10-bit word, called a master-slave seed value. </p> <div class="mw-heading mw-heading2"><h2 id="Duplex_mismatch">Duplex mismatch</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Autonegotiation&action=edit&section=7" title="Edit section: Duplex mismatch"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/wiki/Duplex_mismatch" title="Duplex mismatch">Duplex mismatch</a></div> <p>A duplex mismatch occurs when two connected devices are configured in different duplex modes. This may happen, for example, if one is configured for autonegotiation while the other one has a fixed mode of operation that is full duplex (no autonegotiation). In such conditions, the autonegotiation device correctly detects the speed of operation but is unable to correctly detect the duplex mode. As a result, it sets the correct speed but assumes half-duplex mode. </p><p>When a device is operating in full duplex while the other one operates in half duplex, the connection works reliably only at a very low throughput. A full-duplex device may transmit data while it is receiving. However, if the half-duplex device receives data while it is sending, it senses a <a href="/wiki/Collision_(telecommunications)" title="Collision (telecommunications)">collision</a> and aborts transmission and then attempts to resend the frame. The full-duplex device will report <a href="/wiki/Frame_check_sequence" title="Frame check sequence">frame check sequence</a> (FCS) errors on the aborted transmissions. Depending on timing, the half-duplex device may sense a <a href="/wiki/Late_collision" class="mw-redirect" title="Late collision">late collision</a>, which it will interpret as a hard error rather than a normal consequence of CSMA/CD and may not attempt to resend the frame. The full-duplex device does not detect any collision and assumes the frame was received without error. This combination of (late) collisions reported at the half-duplex end and FCS errors reported by the full-duplex end are indicators that a duplex mismatch is present. </p> <div class="mw-heading mw-heading2"><h2 id="Patents">Patents</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Autonegotiation&action=edit&section=8" title="Edit section: Patents"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Autonegotiation is covered by the US patents <span><a rel="nofollow" class="external text" href="https://patents.google.com/patent/US5617418">U.S. patent 5,617,418</a></span>, <span><a rel="nofollow" class="external text" href="https://patents.google.com/patent/US5687174">U.S. patent 5,687,174</a></span>, <span><a rel="nofollow" class="external text" href="https://patents.google.com/patent/USRE39405">E U.S. patent RE39,405 E</a></span>, <span><a rel="nofollow" class="external text" href="https://patents.google.com/patent/USRE39116">E U.S. patent RE39,116 E</a></span>, <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"><a rel="nofollow" class="external text" href="https://worldwide.espacenet.com/textdoc?DB=EPODOC&IDX=US971018">US application 971018</a></span><span class="Z3988" title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Apatent&rft.applnumber=971018&rft.cc=US&rft.title="><span style="display: none;"> </span></span> (filed 1992-11-02), <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1041539562"><span class="citation patent"><a rel="nofollow" class="external text" href="https://worldwide.espacenet.com/textdoc?DB=EPODOC&IDX=US146729">US application 146729</a></span><span class="Z3988" title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Apatent&rft.applnumber=146729&rft.cc=US&rft.title="><span style="display: none;"> </span></span> (filed 1993-11-01), <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1041539562"><span class="citation patent"><a rel="nofollow" class="external text" href="https://worldwide.espacenet.com/textdoc?DB=EPODOC&IDX=US430143">US application 430143</a></span><span class="Z3988" title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Apatent&rft.applnumber=430143&rft.cc=US&rft.title="><span style="display: none;"> </span></span> (filed 1995-04-26);<sup id="cite_ref-nwaylic_6-1" class="reference"><a href="#cite_note-nwaylic-6"><span class="cite-bracket">[</span>6<span class="cite-bracket">]</span></a></sup><sup class="reference nowrap"><span title="Page / location: 6">: 6 </span></sup> European Patent Applications SN 93308568.0 (DE, FR, GB, IT, NL); Korean Patent No. 286791; Taiwanese Patent No. 098359; Japanese Patent No. 3705610; Japanese Patent 4234. Applications SN H5-274147; Korean Patent Applications SN 22995/93; Taiwanese Patent Applications SN 83104531.<sup id="cite_ref-Expire_7-1" class="reference"><a href="#cite_note-Expire-7"><span class="cite-bracket">[</span>a<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="Auto-Negotiation_for_single-pair_Ethernet">Auto-Negotiation for single-pair Ethernet</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Autonegotiation&action=edit&section=9" title="Edit section: Auto-Negotiation for single-pair Ethernet"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Due to its nature, single-pair Ethernet has its own, optional variant of Auto-Negotiation. It uses differential Manchester encoding (DME) pages to negotiate capabilities in a half-duplex manner. Two different signaling speeds are used: 10/5/2.5GBASE-T1, 1000BASE-T1, 100BASE-T1, and 10BASE-T1S support high-speed mode (HSM) at 16.667 Mbit/s and optionally low-speed mode (LSM) at 625 kbit/s, while 10BASE-T1L supports LSM and optionally HSM.<sup id="cite_ref-17" class="reference"><a href="#cite_note-17"><span class="cite-bracket">[</span>16<span class="cite-bracket">]</span></a></sup> </p><p>The selection priority for negotiated modes are:<sup id="cite_ref-18" class="reference"><a href="#cite_note-18"><span class="cite-bracket">[</span>17<span class="cite-bracket">]</span></a></sup> </p> <ol><li>10GBASE-T1</li> <li>5GBASE-T1</li> <li>2.5GBASE-T1</li> <li>1000BASE-T1</li> <li>100BASE-T1</li> <li>10BASE-T1S full duplex</li> <li>10BASE-T1S half duplex</li> <li>10BASE-T1L</li></ol> <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=Autonegotiation&action=edit&section=10" title="Edit section: See also"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><a href="/wiki/Auto_MDI-X" class="mw-redirect" title="Auto MDI-X">Auto MDI-X</a> for automatic configuration of straight-through or crossover-cable connection</li></ul> <div class="mw-heading mw-heading2"><h2 id="Notes">Notes</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Autonegotiation&action=edit&section=11" title="Edit section: Notes"><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 reflist-lower-alpha"> <div class="mw-references-wrap"><ol class="references"> <li id="cite_note-Expire-7"><span class="mw-cite-backlink">^ <a href="#cite_ref-Expire_7-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Expire_7-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text">Patents expire 20 years after issue date.</span> </li> </ol></div></div> <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=Autonegotiation&action=edit&section=12" title="Edit section: References"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1239543626"><div class="reflist"> <div class="mw-references-wrap mw-references-columns"><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"><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 class="citation cs2">"Clause 28: Physical Layer link signaling for Auto-Negotiation on twisted pair", <span class="id-lock-registration" title="Free registration required"><a rel="nofollow" class="external text" href="https://ieeexplore.ieee.org/servlet/opac?punumber=8457467"><i>IEEE Standard for Ethernet</i></a></span>, p. 278, <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%2FIEEESTD.2018.8457469">10.1109/IEEESTD.2018.8457469</a>, <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-1-5044-5090-4" title="Special:BookSources/978-1-5044-5090-4"><bdi>978-1-5044-5090-4</bdi></a></cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=bookitem&rft.atitle=Clause+28%3A+Physical+Layer+link+signaling+for+Auto-Negotiation+on+twisted+pair&rft.btitle=IEEE+Standard+for+Ethernet&rft.pages=278&rft_id=info%3Adoi%2F10.1109%2FIEEESTD.2018.8457469&rft.isbn=978-1-5044-5090-4&rft_id=https%3A%2F%2Fieeexplore.ieee.org%2Fservlet%2Fopac%3Fpunumber%3D8457467&rfr_id=info%3Asid%2Fen.wikipedia.org%3AAutonegotiation" class="Z3988"></span><sup class="noprint Inline-Template"><span style="white-space: nowrap;">[<i><a href="/wiki/Wikipedia:Link_rot" title="Wikipedia:Link rot"><span title=" Dead link tagged July 2024">dead link</span></a></i><span style="visibility:hidden; color:transparent; padding-left:2px">‍</span>]</span></sup></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"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFJayaswal2005" class="citation book cs1">Jayaswal, Kailash (2005). <i>Administering Data Centers Servers, Storage, and Voice over IP</i>. Hoboken: John Wiley & Sons. p. 168. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/0471783358" title="Special:BookSources/0471783358"><bdi>0471783358</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Administering+Data+Centers+Servers%2C+Storage%2C+and+Voice+over+IP.&rft.place=Hoboken&rft.pages=168&rft.pub=John+Wiley+%26+Sons&rft.date=2005&rft.isbn=0471783358&rft.aulast=Jayaswal&rft.aufirst=Kailash&rfr_id=info%3Asid%2Fen.wikipedia.org%3AAutonegotiation" 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"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFSchmidt1998" class="citation book cs1">Schmidt, Daniel Minoli, Andrew (1998). <i>Switched network services</i>. New York: Wiley Computer Pub. p. 93. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/0471190802" title="Special:BookSources/0471190802"><bdi>0471190802</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Switched+network+services&rft.place=New+York&rft.pages=93&rft.pub=Wiley+Computer+Pub.&rft.date=1998&rft.isbn=0471190802&rft.aulast=Schmidt&rft.aufirst=Daniel+Minoli%2C+Andrew&rfr_id=info%3Asid%2Fen.wikipedia.org%3AAutonegotiation" class="Z3988"></span><span class="cs1-maint citation-comment"><code class="cs1-code">{{<a href="/wiki/Template:Cite_book" title="Template:Cite book">cite book</a>}}</code>: CS1 maint: multiple names: authors list (<a href="/wiki/Category:CS1_maint:_multiple_names:_authors_list" title="Category:CS1 maint: multiple names: authors list">link</a>)</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"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFIEEE" class="citation web cs1">IEEE. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20131126043152/http://standards.ieee.org/getieee802/download/802.3-2012_section2.pdf">"Part 3: Carrier Sense Multiple Access with Collision Detection (CSMA/CD) access method and Physical Layer specifications"</a> <span class="cs1-format">(PDF)</span>. SECTION TWO: This section includes Clause21 through Clause 33 and Annex 22A through Annex 33E. Archived from <a rel="nofollow" class="external text" href="http://standards.ieee.org/getieee802/download/802.3-2012_section2.pdf">the original</a> <span class="cs1-format">(PDF)</span> on November 26, 2013<span class="reference-accessdate">. Retrieved <span class="nowrap">2014-06-03</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Part+3%3A+Carrier+Sense+Multiple+Access+with+Collision+Detection+%28CSMA%2FCD%29+access+method+and+Physical+Layer+specifications&rft.pub=SECTION+TWO%3A+This+section+includes+Clause21+through+Clause+33+and+Annex+22A+through+Annex+33E.&rft.au=IEEE&rft_id=http%3A%2F%2Fstandards.ieee.org%2Fgetieee802%2Fdownload%2F802.3-2012_section2.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AAutonegotiation" class="Z3988"></span></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"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20081119230235/http://www.negotiateddata.com/files/Grant_Letter_060794.pdf">"Archived copy"</a> <span class="cs1-format">(PDF)</span>. Archived from <a rel="nofollow" class="external text" href="http://www.negotiateddata.com/files/Grant_Letter_060794.pdf">the original</a> <span class="cs1-format">(PDF)</span> on 2008-11-19<span class="reference-accessdate">. Retrieved <span class="nowrap">2009-12-02</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Archived+copy&rft_id=http%3A%2F%2Fwww.negotiateddata.com%2Ffiles%2FGrant_Letter_060794.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AAutonegotiation" class="Z3988"></span><span class="cs1-maint citation-comment"><code class="cs1-code">{{<a href="/wiki/Template:Cite_web" title="Template:Cite web">cite web</a>}}</code>: CS1 maint: archived copy as title (<a href="/wiki/Category:CS1_maint:_archived_copy_as_title" title="Category:CS1 maint: archived copy as title">link</a>)</span></span> </li> <li id="cite_note-nwaylic-6"><span class="mw-cite-backlink">^ <a href="#cite_ref-nwaylic_6-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-nwaylic_6-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFNegotiated_Data_Solutions_LLC" class="citation web cs1">Negotiated Data Solutions LLC. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20090106202500/http://negotiateddata.com/node/2">"NWay/IEEE Standard Patent License Offer | Negotiated Data Solutions LLC"</a>. Negotiateddata.com. Archived from <a rel="nofollow" class="external text" href="http://www.negotiateddata.com/node/2">the original</a> on 2009-01-06<span class="reference-accessdate">. Retrieved <span class="nowrap">2010-02-02</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=NWay%2FIEEE+Standard+Patent+License+Offer+%26%23124%3B+Negotiated+Data+Solutions+LLC&rft.pub=Negotiateddata.com&rft.au=Negotiated+Data+Solutions+LLC&rft_id=http%3A%2F%2Fwww.negotiateddata.com%2Fnode%2F2&rfr_id=info%3Asid%2Fen.wikipedia.org%3AAutonegotiation" class="Z3988"></span></span> </li> <li id="cite_note-8"><span class="mw-cite-backlink"><b><a href="#cite_ref-8">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.cisco.com/en/US/tech/tk389/tk214/technologies_tech_note09186a0080094781.shtml">"Configuring and Troubleshooting Ethernet 10/100/1000Mb Half/Full Duplex Auto-Negotiation"</a>. <a href="/wiki/Cisco" title="Cisco">Cisco</a><span class="reference-accessdate">. Retrieved <span class="nowrap">2012-01-12</span></span>. <q>Cisco recommends to leave auto-negotiation on for those devices compliant with <a href="/wiki/802.3u" class="mw-redirect" title="802.3u">802.3u</a>.</q></cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Configuring+and+Troubleshooting+Ethernet+10%2F100%2F1000Mb+Half%2FFull+Duplex+Auto-Negotiation&rft.pub=Cisco&rft_id=http%3A%2F%2Fwww.cisco.com%2Fen%2FUS%2Ftech%2Ftk389%2Ftk214%2Ftechnologies_tech_note09186a0080094781.shtml&rfr_id=info%3Asid%2Fen.wikipedia.org%3AAutonegotiation" class="Z3988"></span></span> </li> <li id="cite_note-9"><span class="mw-cite-backlink"><b><a href="#cite_ref-9">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFJim_Eggers_and_Steve_Hodnett2004" class="citation web cs1">Jim Eggers and Steve Hodnett (July 2004). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20110520185854/http://www.sun.com/blueprints/0704/817-7526.pdf">"Ethernet Autonegotiation Best Practices"</a> <span class="cs1-format">(PDF)</span>. <a href="/wiki/Sun_Microsystems" title="Sun Microsystems">Sun Microsystems</a>. Archived from <a rel="nofollow" class="external text" href="http://www.sun.com/blueprints/0704/817-7526.pdf">the original</a> <span class="cs1-format">(PDF)</span> on 2011-05-20. <q>Using autonegotiation is the IEEE 802.3 standard and customers are encouraged to follow the "intent" of IEEE 802.3u/z standards and implement autonegotiation in their Ethernet environments.</q></cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Ethernet+Autonegotiation+Best+Practices&rft.pub=Sun+Microsystems&rft.date=2004-07&rft.au=Jim+Eggers+and+Steve+Hodnett&rft_id=http%3A%2F%2Fwww.sun.com%2Fblueprints%2F0704%2F817-7526.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AAutonegotiation" class="Z3988"></span></span> </li> <li id="cite_note-10"><span class="mw-cite-backlink"><b><a href="#cite_ref-10">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFRich_Hernandez2001" class="citation web cs1">Rich Hernandez (2001). <a rel="nofollow" class="external text" href="http://www.dell.com/content/topics/global.aspx/power/en/ps1q01_hernan?c=us&l=en&cs=555">"Gigabit Ethernet Auto-Negotiation"</a>. <a href="/wiki/Dell" title="Dell">Dell</a><span class="reference-accessdate">. Retrieved <span class="nowrap">2012-01-12</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Gigabit+Ethernet+Auto-Negotiation&rft.pub=Dell&rft.date=2001&rft.au=Rich+Hernandez&rft_id=http%3A%2F%2Fwww.dell.com%2Fcontent%2Ftopics%2Fglobal.aspx%2Fpower%2Fen%2Fps1q01_hernan%3Fc%3Dus%26l%3Den%26cs%3D555&rfr_id=info%3Asid%2Fen.wikipedia.org%3AAutonegotiation" class="Z3988"></span></span> </li> <li id="cite_note-11"><span class="mw-cite-backlink"><b><a href="#cite_ref-11">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20060130134410/http://standards.ieee.org/reading/ieee/interp/IEEE802.3af-2003interp-6.pdf">"Auto-Negotiation; 802.3-2002"</a> <span class="cs1-format">(PDF)</span>. <i>IEEE Standards Interpretations</i>. IEEE. Archived from <a rel="nofollow" class="external text" href="http://standards.ieee.org/reading/ieee/interp/IEEE802.3af-2003interp-6.pdf">the original</a> <span class="cs1-format">(PDF)</span> on January 30, 2006<span class="reference-accessdate">. Retrieved <span class="nowrap">November 5,</span> 2007</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=IEEE+Standards+Interpretations&rft.atitle=Auto-Negotiation%3B+802.3-2002&rft_id=http%3A%2F%2Fstandards.ieee.org%2Freading%2Fieee%2Finterp%2FIEEE802.3af-2003interp-6.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AAutonegotiation" class="Z3988"></span></span> </li> <li id="cite_note-12"><span class="mw-cite-backlink"><b><a href="#cite_ref-12">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation cs2"><a rel="nofollow" class="external text" href="https://www.ti.com/lit/ds/symlink/dp83865.pdf?ts=1684523953413&ref_url=https%253A%252F%252Fwww.google.com%252F"><i>DP83865 datasheet</i></a> <span class="cs1-format">(PDF)</span>, p. 29<span class="reference-accessdate">, retrieved <span class="nowrap">2023-05-19</span></span></cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=DP83865+datasheet&rft.pages=29&rft_id=https%3A%2F%2Fwww.ti.com%2Flit%2Fds%2Fsymlink%2Fdp83865.pdf%3Fts%3D1684523953413%26ref_url%3Dhttps%25253A%25252F%25252Fwww.google.com%25252F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AAutonegotiation" class="Z3988"></span></span> </li> <li id="cite_note-13"><span class="mw-cite-backlink"><b><a href="#cite_ref-13">^</a></b></span> <span class="reference-text">IEEE 802.3-2018 Annex 28B</span> </li> <li id="cite_note-14"><span class="mw-cite-backlink"><b><a href="#cite_ref-14">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://docs.ruckuswireless.com/fastiron/08.0.70/fastiron-08070-managementguide/GUID-EDD7D44C-A627-4B76-A9FE-D7657FFF62D3.html">"Port speed and duplex mode configuration"</a>. <i>docs.ruckuswireless.com</i><span class="reference-accessdate">. Retrieved <span class="nowrap">2020-09-25</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=docs.ruckuswireless.com&rft.atitle=Port+speed+and+duplex+mode+configuration&rft_id=http%3A%2F%2Fdocs.ruckuswireless.com%2Ffastiron%2F08.0.70%2Ffastiron-08070-managementguide%2FGUID-EDD7D44C-A627-4B76-A9FE-D7657FFF62D3.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AAutonegotiation" class="Z3988"></span></span> </li> <li id="cite_note-negotiateddata-nway-spec-15"><span class="mw-cite-backlink"><b><a href="#cite_ref-negotiateddata-nway-spec_15-0">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20110714162407/http://www.negotiateddata.com/files/NWay_Specification_041094.pdf">"IEEE Link Task Force Autodetect, Specification for NWay Autodetect"</a> <span class="cs1-format">(PDF)</span>. p. 57. Archived from <a rel="nofollow" class="external text" href="http://www.negotiateddata.com/files/NWay_Specification_041094.pdf">the original</a> <span class="cs1-format">(PDF)</span> on 2011-07-14.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=IEEE+Link+Task+Force+Autodetect%2C+Specification+for+NWay+Autodetect&rft.pages=57&rft_id=http%3A%2F%2Fwww.negotiateddata.com%2Ffiles%2FNWay_Specification_041094.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AAutonegotiation" class="Z3988"></span></span> </li> <li id="cite_note-16"><span class="mw-cite-backlink"><b><a href="#cite_ref-16">^</a></b></span> <span class="reference-text">IEEE 802.3 Clause 28.2.1.2.6 <i>Next Page</i></span> </li> <li id="cite_note-17"><span class="mw-cite-backlink"><b><a href="#cite_ref-17">^</a></b></span> <span class="reference-text">IEEE 802.3 Clause 98</span> </li> <li id="cite_note-18"><span class="mw-cite-backlink"><b><a href="#cite_ref-18">^</a></b></span> <span class="reference-text">IEEE 802.3 Annex 98B</span> </li> </ol></div></div> <div class="mw-heading mw-heading2"><h2 id="External_links">External links</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Autonegotiation&action=edit&section=13" title="Edit section: External links"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><a rel="nofollow" class="external text" href="https://web.archive.org/web/20040724144554/http://www.sun.com/blueprints/0704/817-7526.pdf">Ethernet Autonegotiation Best Practices</a></li> <li><a rel="nofollow" class="external text" href="http://www.ethermanage.com/ethernet/pdf/dell-auto-neg.pdf">Gigabit Ethernet Auto-Negotiation</a></li> <li><a rel="nofollow" class="external text" href="https://www.iol.unh.edu/sites/default/files/knowledgebase/ethernet/Copper_ANEG_JEFF_LAPAK.pdf">Clause 28 & 40 AutoNegotiation An introduction to the Auto-Negotiation process</a></li> <li><a rel="nofollow" class="external text" href="https://web.archive.org/web/20100425014730/http://www.cisco.com/en/US/docs/switches/lan/catalyst2970/software/release/12.2_18_se/configuration/guide/swint.html#wp1080632">Cisco Catalyst Config Guide</a></li> <li><a rel="nofollow" class="external text" href="https://web.archive.org/web/20131111034703/http://myaccount.flukenetworks.com/fnet/en-us/supportAndDownloads/KB/IT%2BNetworking/OptiView%2BSeries%2BII%2BIntegrated%2BNetwork%2BAnalyzer/Auto-Negotiation__how_does_it_work">Auto-Negotiation, how does it work?</a></li> <li><a rel="nofollow" class="external text" href="http://www.ieee802.org/3/af/public/jan02/brown_1_0102.pdf">10/100/1000 Link Timing</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 dl,.mw-parser-output .hlist ul ol,.mw-parser-output .hlist ul ul{display:inline}.mw-parser-output .hlist .mw-empty-li{display:none}.mw-parser-output .hlist dt::after{content:": "}.mw-parser-output .hlist dd::after,.mw-parser-output .hlist li::after{content:" · ";font-weight:bold}.mw-parser-output .hlist dd:last-child::after,.mw-parser-output .hlist dt:last-child::after,.mw-parser-output .hlist li:last-child::after{content:none}.mw-parser-output .hlist dd dd:first-child::before,.mw-parser-output .hlist dd dt:first-child::before,.mw-parser-output .hlist dd li:first-child::before,.mw-parser-output .hlist dt dd:first-child::before,.mw-parser-output .hlist dt dt:first-child::before,.mw-parser-output .hlist dt li:first-child::before,.mw-parser-output .hlist li dd:first-child::before,.mw-parser-output .hlist li dt:first-child::before,.mw-parser-output .hlist li li:first-child::before{content:" (";font-weight:normal}.mw-parser-output .hlist dd dd:last-child::after,.mw-parser-output .hlist dd dt:last-child::after,.mw-parser-output .hlist dd li:last-child::after,.mw-parser-output .hlist dt dd:last-child::after,.mw-parser-output .hlist dt dt:last-child::after,.mw-parser-output .hlist dt li:last-child::after,.mw-parser-output .hlist li dd:last-child::after,.mw-parser-output .hlist li dt:last-child::after,.mw-parser-output .hlist li li:last-child::after{content:")";font-weight:normal}.mw-parser-output .hlist ol{counter-reset:listitem}.mw-parser-output .hlist ol>li{counter-increment:listitem}.mw-parser-output .hlist ol>li::before{content:" "counter(listitem)"\a0 "}.mw-parser-output .hlist dd ol>li:first-child::before,.mw-parser-output .hlist dt ol>li:first-child::before,.mw-parser-output .hlist li ol>li:first-child::before{content:" ("counter(listitem)"\a0 "}</style><style data-mw-deduplicate="TemplateStyles:r1236075235">.mw-parser-output .navbox{box-sizing:border-box;border:1px solid #a2a9b1;width:100%;clear:both;font-size:88%;text-align:center;padding:1px;margin:1em auto 0}.mw-parser-output .navbox .navbox{margin-top:0}.mw-parser-output .navbox+.navbox,.mw-parser-output .navbox+.navbox-styles+.navbox{margin-top:-1px}.mw-parser-output .navbox-inner,.mw-parser-output .navbox-subgroup{width:100%}.mw-parser-output .navbox-group,.mw-parser-output .navbox-title,.mw-parser-output .navbox-abovebelow{padding:0.25em 1em;line-height:1.5em;text-align:center}.mw-parser-output .navbox-group{white-space:nowrap;text-align:right}.mw-parser-output .navbox,.mw-parser-output .navbox-subgroup{background-color:#fdfdfd}.mw-parser-output .navbox-list{line-height:1.5em;border-color:#fdfdfd}.mw-parser-output .navbox-list-with-group{text-align:left;border-left-width:2px;border-left-style:solid}.mw-parser-output tr+tr>.navbox-abovebelow,.mw-parser-output tr+tr>.navbox-group,.mw-parser-output tr+tr>.navbox-image,.mw-parser-output tr+tr>.navbox-list{border-top:2px solid #fdfdfd}.mw-parser-output .navbox-title{background-color:#ccf}.mw-parser-output .navbox-abovebelow,.mw-parser-output .navbox-group,.mw-parser-output .navbox-subgroup .navbox-title{background-color:#ddf}.mw-parser-output .navbox-subgroup .navbox-group,.mw-parser-output .navbox-subgroup .navbox-abovebelow{background-color:#e6e6ff}.mw-parser-output .navbox-even{background-color:#f7f7f7}.mw-parser-output .navbox-odd{background-color:transparent}.mw-parser-output .navbox .hlist td dl,.mw-parser-output .navbox .hlist td ol,.mw-parser-output .navbox .hlist td ul,.mw-parser-output .navbox td.hlist dl,.mw-parser-output .navbox td.hlist ol,.mw-parser-output .navbox td.hlist ul{padding:0.125em 0}.mw-parser-output .navbox .navbar{display:block;font-size:100%}.mw-parser-output .navbox-title .navbar{float:left;text-align:left;margin-right:0.5em}body.skin--responsive .mw-parser-output .navbox-image img{max-width:none!important}@media print{body.ns-0 .mw-parser-output .navbox{display:none!important}}</style></div><div role="navigation" class="navbox" aria-labelledby="Ethernet_family_of_local_area_network_technologies" style="padding:3px"><table class="nowraplinks hlist 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:Ethernet" title="Template:Ethernet"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Ethernet" title="Template talk:Ethernet"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Ethernet" title="Special:EditPage/Template:Ethernet"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="Ethernet_family_of_local_area_network_technologies" style="font-size:114%;margin:0 4em"><a href="/wiki/Ethernet" title="Ethernet">Ethernet</a> family of <a href="/wiki/Local_area_network" title="Local area network">local area network</a> technologies</div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%">Speeds</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/Classic_Ethernet" title="Classic Ethernet">10 Mbit/s</a></li> <li><a href="/wiki/Fast_Ethernet" title="Fast Ethernet">100 Mbit/s</a></li> <li><a href="/wiki/Gigabit_Ethernet" title="Gigabit Ethernet">1 Gbit/s</a></li> <li><a href="/wiki/2.5GBASE-T_and_5GBASE-T" title="2.5GBASE-T and 5GBASE-T">2.5 and 5 Gbit/s</a></li> <li><a href="/wiki/10_Gigabit_Ethernet" title="10 Gigabit Ethernet">10 Gbit/s</a></li> <li><a href="/wiki/25_Gigabit_Ethernet" title="25 Gigabit Ethernet">25 and 50 Gbit/s</a></li> <li><a href="/wiki/100_Gigabit_Ethernet" title="100 Gigabit Ethernet">40 and 100 Gbit/s</a></li> <li><a href="/wiki/Terabit_Ethernet" title="Terabit Ethernet">200, 400, 800 and 1600 Gbit/s</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">General</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/Ethernet_physical_layer" title="Ethernet physical layer">Physical layer</a></li> <li><a class="mw-selflink selflink">Autonegotiation</a></li> <li><a href="/wiki/EtherType" title="EtherType">EtherType</a></li> <li><a href="/wiki/Ethernet_flow_control" title="Ethernet flow control">Flow control</a></li> <li><a href="/wiki/Ethernet_frame" title="Ethernet frame">Frames</a></li> <li><a href="/wiki/Jumbo_frame" title="Jumbo frame">Jumbos</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Organizations</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/IEEE_802.3" title="IEEE 802.3">IEEE 802.3</a></li> <li><a href="/wiki/Ethernet_Alliance" title="Ethernet Alliance">Ethernet Alliance</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Media</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/Ethernet_over_fiber" title="Ethernet over fiber">Fiber</a></li> <li><a href="/wiki/Ethernet_over_twisted_pair" title="Ethernet over twisted pair">Twisted pair</a></li> <li><a href="/wiki/Ethernet_over_coax" title="Ethernet over coax">Coaxial</a></li> <li><a href="/wiki/Ethernet_in_the_first_mile" title="Ethernet in the first mile">First mile</a> <ul><li><a href="/wiki/10G-EPON" title="10G-EPON">10G-EPON</a></li></ul></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Historic</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/Carrier-sense_multiple_access_with_collision_detection" title="Carrier-sense multiple access with collision detection">CSMA/CD</a></li> <li><a href="/wiki/StarLAN" title="StarLAN">StarLAN</a></li> <li><a href="/wiki/10BROAD36" title="10BROAD36">10BROAD36</a></li> <li><a href="/wiki/10BASE-FB" class="mw-redirect" title="10BASE-FB">10BASE-FB</a></li> <li><a href="/wiki/10BASE-FL" class="mw-redirect" title="10BASE-FL">10BASE-FL</a></li> <li><a href="/wiki/10BASE5" title="10BASE5">10BASE5</a></li> <li><a href="/wiki/10BASE2" title="10BASE2">10BASE2</a></li> <li><a href="/wiki/Medium_Attachment_Unit" title="Medium Attachment Unit">MAU</a></li> <li><a href="/wiki/Fiber-optic_inter-repeater_link" class="mw-redirect" title="Fiber-optic inter-repeater link">FOIRL</a></li> <li><a href="/wiki/100BaseVG" title="100BaseVG">100BaseVG</a></li> <li><a href="/wiki/LattisNet" title="LattisNet">LattisNet</a></li> <li><a href="/wiki/Long_Reach_Ethernet" title="Long Reach Ethernet">Long Reach</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Applications</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/Audio_over_Ethernet" title="Audio over Ethernet">Audio</a></li> <li><a href="/wiki/Automotive_Ethernet" class="mw-redirect" title="Automotive Ethernet">Automotive</a></li> <li><a href="/wiki/Carrier_Ethernet" title="Carrier Ethernet">Carrier</a></li> <li><a href="/wiki/Data_center_bridging" title="Data center bridging">Data center</a></li> <li><a href="/wiki/Energy-Efficient_Ethernet" title="Energy-Efficient Ethernet">Energy Efficiency</a></li> <li><a href="/wiki/Industrial_Ethernet" title="Industrial Ethernet">Industrial</a></li> <li><a href="/wiki/Metro_Ethernet" title="Metro Ethernet">Metro</a></li> <li><a href="/wiki/Power_over_Ethernet" title="Power over Ethernet">Power</a></li> <li><a href="/wiki/Synchronous_Ethernet" title="Synchronous Ethernet">Synchronous</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Transceiver" title="Transceiver">Transceivers</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/Gigabit_interface_converter" title="Gigabit interface converter">GBIC</a></li> <li><a href="/wiki/Small_Form-factor_Pluggable" title="Small Form-factor Pluggable">SFP/SFP+/QSFP/QSFP+/OSFP</a></li> <li><a href="/wiki/XENPAK" title="XENPAK">XENPAK</a>/<a href="/wiki/X2_transceiver" title="X2 transceiver">X2</a></li> <li><a href="/wiki/XFP_transceiver" title="XFP transceiver">XFP</a></li> <li><a href="/wiki/C_form-factor_pluggable" title="C form-factor pluggable">CFP</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Interfaces</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/Attachment_Unit_Interface" title="Attachment Unit Interface">AUI</a></li> <li><a href="/wiki/EAD_socket" title="EAD socket">EAD</a></li> <li><a href="/wiki/Medium-dependent_interface" title="Medium-dependent interface">MDI</a></li> <li><a href="/wiki/Media-independent_interface" title="Media-independent interface">MII</a></li> <li><a href="/wiki/Gigabit_media-independent_interface" class="mw-redirect" title="Gigabit media-independent interface">GMII</a></li> <li><a href="/wiki/10_gigabit_media-independent_interface" class="mw-redirect" title="10 gigabit media-independent interface">XGMII</a></li> <li><a href="/wiki/XAUI" title="XAUI">XAUI</a></li></ul> </div></td></tr><tr><td class="navbox-abovebelow" colspan="2"><div> <ul><li><span class="noviewer" typeof="mw:File"><span title="Category"><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/16px-Symbol_category_class.svg.png" decoding="async" width="16" height="16" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/23px-Symbol_category_class.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/31px-Symbol_category_class.svg.png 2x" data-file-width="180" data-file-height="185" /></span></span> <b><a href="/wiki/Category:Ethernet" title="Category:Ethernet">Category</a></b></li> <li><span class="noviewer" typeof="mw:File"><span title="Commons page"><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/4/4a/Commons-logo.svg/12px-Commons-logo.svg.png" decoding="async" width="12" height="16" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/4/4a/Commons-logo.svg/18px-Commons-logo.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/4/4a/Commons-logo.svg/24px-Commons-logo.svg.png 2x" data-file-width="1024" data-file-height="1376" /></span></span> <b><a href="https://commons.wikimedia.org/wiki/Category:Ethernet" class="extiw" title="commons:Category:Ethernet">Commons</a></b></li></ul> </div></td></tr></tbody></table></div>    </div><noscript><img src="https://login.wikimedia.org/wiki/Special:CentralAutoLogin/start?type=1x1" alt="" width="1" height="1" style="border: none; position: absolute;"></noscript> <div class="printfooter" data-nosnippet="">Retrieved from "<a dir="ltr" href="https://en.wikipedia.org/w/index.php?title=Autonegotiation&oldid=1247082771">https://en.wikipedia.org/w/index.php?title=Autonegotiation&oldid=1247082771</a>"</div></div> <div id="catlinks" class="catlinks" data-mw="interface"><div id="mw-normal-catlinks" class="mw-normal-catlinks"><a href="/wiki/Help:Category" title="Help:Category">Categories</a>: <ul><li><a href="/wiki/Category:Ethernet" title="Category:Ethernet">Ethernet</a></li><li><a href="/wiki/Category:Network_protocols" title="Category:Network protocols">Network protocols</a></li></ul></div><div id="mw-hidden-catlinks" class="mw-hidden-catlinks mw-hidden-cats-hidden">Hidden categories: <ul><li><a href="/wiki/Category:All_articles_with_dead_external_links" title="Category:All articles with dead external links">All articles with dead external links</a></li><li><a href="/wiki/Category:Articles_with_dead_external_links_from_July_2024" title="Category:Articles with dead external links from July 2024">Articles with dead external links from July 2024</a></li><li><a href="/wiki/Category:CS1_maint:_multiple_names:_authors_list" title="Category:CS1 maint: multiple names: authors list">CS1 maint: multiple names: authors list</a></li><li><a href="/wiki/Category:CS1_maint:_archived_copy_as_title" title="Category:CS1 maint: archived copy as title">CS1 maint: archived copy as title</a></li><li><a href="/wiki/Category:Articles_with_short_description" title="Category:Articles with short description">Articles with short description</a></li><li><a href="/wiki/Category:Short_description_is_different_from_Wikidata" title="Category:Short description is different from Wikidata">Short description is different from Wikidata</a></li></ul></div></div> </div> </main> </div> <div class="mw-footer-container"> <footer id="footer" class="mw-footer" > <ul id="footer-info"> <li id="footer-info-lastmod"> This page was last edited on 22 September 2024, at 18:38<span class="anonymous-show"> (UTC)</span>.</li> <li id="footer-info-copyright">Text is available under the <a href="/wiki/Wikipedia:Text_of_the_Creative_Commons_Attribution-ShareAlike_4.0_International_License" title="Wikipedia:Text of the Creative Commons Attribution-ShareAlike 4.0 International License">Creative Commons Attribution-ShareAlike 4.0 License</a>; additional terms may apply. By using this site, you agree to the <a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Terms_of_Use" class="extiw" title="foundation:Special:MyLanguage/Policy:Terms of Use">Terms of Use</a> and <a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Privacy_policy" class="extiw" title="foundation:Special:MyLanguage/Policy:Privacy policy">Privacy Policy</a>. Wikipedia® is a registered trademark of the <a rel="nofollow" class="external text" href="https://wikimediafoundation.org/">Wikimedia Foundation, Inc.</a>, a non-profit organization.</li> </ul> <ul id="footer-places"> <li id="footer-places-privacy"><a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Privacy_policy">Privacy policy</a></li> <li id="footer-places-about"><a href="/wiki/Wikipedia:About">About Wikipedia</a></li> <li id="footer-places-disclaimers"><a href="/wiki/Wikipedia:General_disclaimer">Disclaimers</a></li> <li id="footer-places-contact"><a href="//en.wikipedia.org/wiki/Wikipedia:Contact_us">Contact Wikipedia</a></li> <li id="footer-places-wm-codeofconduct"><a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Universal_Code_of_Conduct">Code of Conduct</a></li> <li id="footer-places-developers"><a href="https://developer.wikimedia.org">Developers</a></li> <li id="footer-places-statslink"><a href="https://stats.wikimedia.org/#/en.wikipedia.org">Statistics</a></li> <li id="footer-places-cookiestatement"><a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Cookie_statement">Cookie statement</a></li> <li id="footer-places-mobileview"><a href="//en.m.wikipedia.org/w/index.php?title=Autonegotiation&mobileaction=toggle_view_mobile" class="noprint stopMobileRedirectToggle">Mobile view</a></li> </ul> <ul id="footer-icons" class="noprint"> <li id="footer-copyrightico"><a href="https://wikimediafoundation.org/" class="cdx-button cdx-button--fake-button cdx-button--size-large cdx-button--fake-button--enabled"><img src="/static/images/footer/wikimedia-button.svg" width="84" height="29" alt="Wikimedia Foundation" loading="lazy"></a></li> <li id="footer-poweredbyico"><a href="https://www.mediawiki.org/" class="cdx-button cdx-button--fake-button cdx-button--size-large cdx-button--fake-button--enabled"><img src="/w/resources/assets/poweredby_mediawiki.svg" alt="Powered by MediaWiki" width="88" height="31" loading="lazy"></a></li> </ul> </footer> </div> </div> </div> <div class="vector-settings" id="p-dock-bottom"> <ul></ul> </div><script>(RLQ=window.RLQ||[]).push(function(){mw.config.set({"wgHostname":"mw-web.codfw.main-f69cdc8f6-k672k","wgBackendResponseTime":189,"wgPageParseReport":{"limitreport":{"cputime":"0.530","walltime":"0.687","ppvisitednodes":{"value":2901,"limit":1000000},"postexpandincludesize":{"value":51945,"limit":2097152},"templateargumentsize":{"value":2936,"limit":2097152},"expansiondepth":{"value":17,"limit":100},"expensivefunctioncount":{"value":4,"limit":500},"unstrip-depth":{"value":1,"limit":20},"unstrip-size":{"value":59673,"limit":5000000},"entityaccesscount":{"value":0,"limit":400},"timingprofile":["100.00% 619.230 1 -total"," 35.73% 221.277 2 Template:Reflist"," 16.09% 99.659 2 Template:Citation"," 15.61% 96.632 1 Template:Ethernet"," 15.08% 93.402 1 Template:Navbox"," 14.13% 87.489 1 Template:Short_description"," 9.63% 59.660 10 Template:Val"," 8.07% 49.946 1 Template:Distinguish"," 7.54% 46.664 2 Template:Pagetype"," 6.86% 42.501 1 Template:Dead_link"]},"scribunto":{"limitreport-timeusage":{"value":"0.320","limit":"10.000"},"limitreport-memusage":{"value":7686479,"limit":52428800}},"cachereport":{"origin":"mw-web.eqiad.main-5dc468848-2n2rg","timestamp":"20241122141504","ttl":2592000,"transientcontent":false}}});});</script> <script type="application/ld+json">{"@context":"https:\/\/schema.org","@type":"Article","name":"Autonegotiation","url":"https:\/\/en.wikipedia.org\/wiki\/Autonegotiation","sameAs":"http:\/\/www.wikidata.org\/entity\/Q366052","mainEntity":"http:\/\/www.wikidata.org\/entity\/Q366052","author":{"@type":"Organization","name":"Contributors to Wikimedia projects"},"publisher":{"@type":"Organization","name":"Wikimedia Foundation, Inc.","logo":{"@type":"ImageObject","url":"https:\/\/www.wikimedia.org\/static\/images\/wmf-hor-googpub.png"}},"datePublished":"2005-07-19T21:29:44Z","dateModified":"2024-09-22T18:38:58Z","headline":"signaling mechanism used by Ethernet by which devices choose common transmission parameters"}</script> </body> </html>