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id="toc-Router_connectivity_and_learning_routes-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Route_selection_process" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Route_selection_process"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.3</span> <span>Route selection process</span> </div> </a> <ul id="toc-Route_selection_process-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Communities" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Communities"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.4</span> <span>Communities</span> </div> </a> <ul id="toc-Communities-sublist" class="vector-toc-list"> <li id="toc-BGP_Extended_Community_Attribute" class="vector-toc-list-item vector-toc-level-3"> <a class="vector-toc-link" href="#BGP_Extended_Community_Attribute"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.4.1</span> <span>BGP Extended Community Attribute</span> </div> </a> <ul id="toc-BGP_Extended_Community_Attribute-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Multi-exit_discriminators" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Multi-exit_discriminators"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.5</span> <span>Multi-exit discriminators</span> </div> </a> <ul id="toc-Multi-exit_discriminators-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Packet_format" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Packet_format"> <div class="vector-toc-text"> <span class="vector-toc-numb">3</span> <span>Packet format</span> </div> </a> <button aria-controls="toc-Packet_format-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span class="vector-icon mw-ui-icon-wikimedia-expand"></span> <span>Toggle Packet format subsection</span> </button> <ul id="toc-Packet_format-sublist" class="vector-toc-list"> <li id="toc-Message_header_format" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Message_header_format"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.1</span> <span>Message header format</span> </div> </a> <ul id="toc-Message_header_format-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Open_Packet" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Open_Packet"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.2</span> <span>Open Packet</span> </div> </a> <ul id="toc-Open_Packet-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Update_Packet" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Update_Packet"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.3</span> <span>Update Packet</span> </div> </a> <ul id="toc-Update_Packet-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Notification" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Notification"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.4</span> <span>Notification</span> </div> </a> <ul id="toc-Notification-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-KeepAlive" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#KeepAlive"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.5</span> <span>KeepAlive</span> </div> </a> <ul id="toc-KeepAlive-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Route-Refresh" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Route-Refresh"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.6</span> <span>Route-Refresh</span> </div> </a> <ul id="toc-Route-Refresh-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Internal_scalability" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Internal_scalability"> <div class="vector-toc-text"> <span class="vector-toc-numb">4</span> <span>Internal scalability</span> </div> </a> <button aria-controls="toc-Internal_scalability-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span class="vector-icon mw-ui-icon-wikimedia-expand"></span> <span>Toggle Internal scalability subsection</span> </button> <ul id="toc-Internal_scalability-sublist" class="vector-toc-list"> <li id="toc-Route_reflectors" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Route_reflectors"> <div class="vector-toc-text"> <span class="vector-toc-numb">4.1</span> <span>Route reflectors</span> </div> </a> <ul id="toc-Route_reflectors-sublist" class="vector-toc-list"> <li id="toc-Rules" class="vector-toc-list-item vector-toc-level-3"> <a class="vector-toc-link" href="#Rules"> <div class="vector-toc-text"> <span class="vector-toc-numb">4.1.1</span> <span>Rules</span> </div> </a> <ul id="toc-Rules-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Cluster" class="vector-toc-list-item vector-toc-level-3"> <a class="vector-toc-link" href="#Cluster"> <div class="vector-toc-text"> <span class="vector-toc-numb">4.1.2</span> <span>Cluster</span> </div> </a> <ul id="toc-Cluster-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Confederation" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Confederation"> <div class="vector-toc-text"> <span class="vector-toc-numb">4.2</span> <span>Confederation</span> </div> </a> <ul id="toc-Confederation-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Stability" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Stability"> <div class="vector-toc-text"> <span class="vector-toc-numb">5</span> <span>Stability</span> </div> </a> <ul id="toc-Stability-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Routing_table_growth" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Routing_table_growth"> <div class="vector-toc-text"> <span class="vector-toc-numb">6</span> <span>Routing table growth</span> </div> </a> <button aria-controls="toc-Routing_table_growth-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span class="vector-icon mw-ui-icon-wikimedia-expand"></span> <span>Toggle Routing table growth subsection</span> </button> <ul id="toc-Routing_table_growth-sublist" class="vector-toc-list"> <li id="toc-512k_day" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#512k_day"> <div class="vector-toc-text"> <span class="vector-toc-numb">6.1</span> <span>512k day</span> </div> </a> <ul id="toc-512k_day-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-AS_number_depletion_and_32-bit_ASNs" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#AS_number_depletion_and_32-bit_ASNs"> <div class="vector-toc-text"> <span class="vector-toc-numb">6.2</span> <span>AS number depletion and 32-bit ASNs</span> </div> </a> <ul id="toc-AS_number_depletion_and_32-bit_ASNs-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Load_balancing" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Load_balancing"> <div class="vector-toc-text"> <span class="vector-toc-numb">6.3</span> <span>Load balancing</span> </div> </a> <ul id="toc-Load_balancing-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Security" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Security"> <div class="vector-toc-text"> <span class="vector-toc-numb">7</span> <span>Security</span> </div> </a> <ul id="toc-Security-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Extensions" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Extensions"> <div class="vector-toc-text"> <span class="vector-toc-numb">8</span> <span>Extensions</span> </div> </a> <ul id="toc-Extensions-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Uses" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Uses"> <div class="vector-toc-text"> <span class="vector-toc-numb">9</span> <span>Uses</span> </div> </a> <ul id="toc-Uses-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Implementations" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Implementations"> <div class="vector-toc-text"> <span class="vector-toc-numb">10</span> <span>Implementations</span> </div> </a> <ul id="toc-Implementations-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-See_also" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#See_also"> <div class="vector-toc-text"> <span class="vector-toc-numb">11</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"> <a class="vector-toc-link" href="#Notes"> <div class="vector-toc-text"> <span class="vector-toc-numb">12</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"> <a class="vector-toc-link" href="#References"> <div class="vector-toc-text"> <span class="vector-toc-numb">13</span> <span>References</span> </div> </a> <ul id="toc-References-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Further_reading" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Further_reading"> <div class="vector-toc-text"> <span class="vector-toc-numb">14</span> <span>Further reading</span> </div> </a> <button aria-controls="toc-Further_reading-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> <span class="vector-icon mw-ui-icon-wikimedia-expand"></span> <span>Toggle Further reading subsection</span> </button> <ul id="toc-Further_reading-sublist" class="vector-toc-list"> <li id="toc-Standards_documents" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Standards_documents"> <div class="vector-toc-text"> <span class="vector-toc-numb">14.1</span> <span>Standards documents</span> </div> </a> <ul id="toc-Standards_documents-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-External_links" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#External_links"> <div class="vector-toc-text"> <span class="vector-toc-numb">15</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" title="Table of Contents" > <input type="checkbox" id="vector-page-titlebar-toc-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-page-titlebar-toc" class="vector-dropdown-checkbox " aria-label="Toggle the table of contents" > <label id="vector-page-titlebar-toc-label" for="vector-page-titlebar-toc-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button 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">Border Gateway Protocol</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 38 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-38" 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">38 languages</span> </label> <div class="vector-dropdown-content"> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li class="interlanguage-link interwiki-ar mw-list-item"><a href="https://ar.wikipedia.org/wiki/%D8%A8%D8%B1%D9%88%D8%AA%D9%88%D9%83%D9%88%D9%84_%D8%A7%D9%84%D8%A8%D9%88%D8%A7%D8%A8%D8%A9_%D8%A7%D9%84%D8%AD%D8%AF%D9%88%D8%AF%D9%8A%D8%A9" title="بروتوكول البوابة الحدودية – Arabic" lang="ar" hreflang="ar" data-title="بروتوكول البوابة الحدودية" data-language-autonym="العربية" data-language-local-name="Arabic" class="interlanguage-link-target"><span>العربية</span></a></li><li class="interlanguage-link interwiki-bg mw-list-item"><a href="https://bg.wikipedia.org/wiki/BGP" title="BGP – Bulgarian" lang="bg" hreflang="bg" data-title="BGP" data-language-autonym="Български" data-language-local-name="Bulgarian" class="interlanguage-link-target"><span>Български</span></a></li><li class="interlanguage-link interwiki-ca mw-list-item"><a href="https://ca.wikipedia.org/wiki/Border_Gateway_Protocol" title="Border Gateway Protocol – Catalan" lang="ca" hreflang="ca" data-title="Border Gateway Protocol" data-language-autonym="Català" data-language-local-name="Catalan" class="interlanguage-link-target"><span>Català</span></a></li><li class="interlanguage-link interwiki-cs mw-list-item"><a href="https://cs.wikipedia.org/wiki/Border_Gateway_Protocol" title="Border Gateway Protocol – Czech" lang="cs" hreflang="cs" data-title="Border Gateway Protocol" data-language-autonym="Čeština" data-language-local-name="Czech" class="interlanguage-link-target"><span>Čeština</span></a></li><li class="interlanguage-link interwiki-de mw-list-item"><a href="https://de.wikipedia.org/wiki/Border_Gateway_Protocol" title="Border Gateway Protocol – German" lang="de" hreflang="de" data-title="Border Gateway Protocol" data-language-autonym="Deutsch" data-language-local-name="German" class="interlanguage-link-target"><span>Deutsch</span></a></li><li class="interlanguage-link interwiki-el mw-list-item"><a href="https://el.wikipedia.org/wiki/Border_Gateway_Protocol" title="Border Gateway Protocol – Greek" lang="el" hreflang="el" data-title="Border Gateway Protocol" data-language-autonym="Ελληνικά" data-language-local-name="Greek" class="interlanguage-link-target"><span>Ελληνικά</span></a></li><li class="interlanguage-link interwiki-es mw-list-item"><a href="https://es.wikipedia.org/wiki/Border_Gateway_Protocol" title="Border Gateway Protocol – Spanish" lang="es" hreflang="es" data-title="Border Gateway Protocol" data-language-autonym="Español" data-language-local-name="Spanish" class="interlanguage-link-target"><span>Español</span></a></li><li class="interlanguage-link interwiki-fa mw-list-item"><a href="https://fa.wikipedia.org/wiki/%D9%BE%D8%B1%D9%88%D8%AA%DA%A9%D9%84_%D8%AF%D8%B1%D9%88%D8%A7%D8%B2%D9%87%E2%80%8C%D8%A7%DB%8C_%D9%85%D8%B1%D8%B2%DB%8C" title="پروتکل دروازه‌ای مرزی – Persian" lang="fa" hreflang="fa" data-title="پروتکل دروازه‌ای مرزی" data-language-autonym="فارسی" data-language-local-name="Persian" class="interlanguage-link-target"><span>فارسی</span></a></li><li class="interlanguage-link interwiki-fr mw-list-item"><a href="https://fr.wikipedia.org/wiki/Border_Gateway_Protocol" title="Border Gateway Protocol – French" lang="fr" hreflang="fr" data-title="Border Gateway Protocol" 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/%EA%B2%BD%EA%B3%84_%EA%B2%BD%EB%A1%9C_%ED%94%84%EB%A1%9C%ED%86%A0%EC%BD%9C" title="경계 경로 프로토콜 – Korean" lang="ko" hreflang="ko" data-title="경계 경로 프로토콜" data-language-autonym="한국어" data-language-local-name="Korean" class="interlanguage-link-target"><span>한국어</span></a></li><li class="interlanguage-link interwiki-hr mw-list-item"><a href="https://hr.wikipedia.org/wiki/BGP" title="BGP – Croatian" lang="hr" hreflang="hr" data-title="BGP" data-language-autonym="Hrvatski" data-language-local-name="Croatian" class="interlanguage-link-target"><span>Hrvatski</span></a></li><li class="interlanguage-link interwiki-id mw-list-item"><a href="https://id.wikipedia.org/wiki/Protokol_batas_gerbang" title="Protokol batas gerbang – Indonesian" lang="id" hreflang="id" data-title="Protokol batas gerbang" data-language-autonym="Bahasa Indonesia" data-language-local-name="Indonesian" class="interlanguage-link-target"><span>Bahasa Indonesia</span></a></li><li class="interlanguage-link interwiki-it mw-list-item"><a href="https://it.wikipedia.org/wiki/Border_Gateway_Protocol" title="Border Gateway Protocol – Italian" lang="it" hreflang="it" data-title="Border Gateway Protocol" data-language-autonym="Italiano" data-language-local-name="Italian" class="interlanguage-link-target"><span>Italiano</span></a></li><li class="interlanguage-link interwiki-he mw-list-item"><a href="https://he.wikipedia.org/wiki/BGP" title="BGP – Hebrew" lang="he" hreflang="he" data-title="BGP" data-language-autonym="עברית" data-language-local-name="Hebrew" class="interlanguage-link-target"><span>עברית</span></a></li><li class="interlanguage-link interwiki-lv mw-list-item"><a href="https://lv.wikipedia.org/wiki/Border_Gateway_Protocol" title="Border Gateway Protocol – Latvian" lang="lv" hreflang="lv" data-title="Border Gateway Protocol" data-language-autonym="Latviešu" data-language-local-name="Latvian" class="interlanguage-link-target"><span>Latviešu</span></a></li><li class="interlanguage-link interwiki-lmo mw-list-item"><a href="https://lmo.wikipedia.org/wiki/Border_Gateway_Protocol" title="Border Gateway Protocol – Lombard" lang="lmo" hreflang="lmo" data-title="Border Gateway Protocol" data-language-autonym="Lombard" data-language-local-name="Lombard" class="interlanguage-link-target"><span>Lombard</span></a></li><li class="interlanguage-link interwiki-mk mw-list-item"><a href="https://mk.wikipedia.org/wiki/Border_Gateway_Protocol" title="Border Gateway Protocol – Macedonian" lang="mk" hreflang="mk" data-title="Border Gateway Protocol" data-language-autonym="Македонски" data-language-local-name="Macedonian" class="interlanguage-link-target"><span>Македонски</span></a></li><li class="interlanguage-link interwiki-ml mw-list-item"><a href="https://ml.wikipedia.org/wiki/%E0%B4%AC%E0%B5%8B%E0%B5%BC%E0%B4%A1%E0%B5%BC_%E0%B4%97%E0%B5%87%E0%B4%B1%E0%B5%8D%E0%B4%B1%E0%B5%8D%E2%80%8C%E0%B4%B5%E0%B5%87_%E0%B4%AA%E0%B5%8D%E0%B4%B0%E0%B5%8B%E0%B4%9F%E0%B5%8D%E0%B4%9F%E0%B5%8B%E0%B4%95%E0%B5%8B%E0%B5%BE" title="ബോർഡർ ഗേറ്റ്‌വേ പ്രോട്ടോകോൾ – Malayalam" lang="ml" hreflang="ml" data-title="ബോർഡർ ഗേറ്റ്‌വേ പ്രോട്ടോകോൾ" data-language-autonym="മലയാളം" data-language-local-name="Malayalam" class="interlanguage-link-target"><span>മലയാളം</span></a></li><li class="interlanguage-link interwiki-ms mw-list-item"><a href="https://ms.wikipedia.org/wiki/Protokol_Laluan_Sempadan" title="Protokol Laluan Sempadan – Malay" lang="ms" hreflang="ms" data-title="Protokol Laluan Sempadan" data-language-autonym="Bahasa Melayu" data-language-local-name="Malay" class="interlanguage-link-target"><span>Bahasa Melayu</span></a></li><li class="interlanguage-link interwiki-mn mw-list-item"><a href="https://mn.wikipedia.org/wiki/BGP" title="BGP – Mongolian" lang="mn" hreflang="mn" data-title="BGP" data-language-autonym="Монгол" data-language-local-name="Mongolian" class="interlanguage-link-target"><span>Монгол</span></a></li><li class="interlanguage-link interwiki-nl mw-list-item"><a href="https://nl.wikipedia.org/wiki/Border_Gateway_Protocol" title="Border Gateway Protocol – Dutch" lang="nl" hreflang="nl" data-title="Border Gateway Protocol" 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/Border_Gateway_Protocol" title="Border Gateway Protocol – Japanese" lang="ja" hreflang="ja" data-title="Border Gateway Protocol" 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-no mw-list-item"><a href="https://no.wikipedia.org/wiki/Border_Gateway_Protocol" title="Border Gateway Protocol – Norwegian Bokmål" lang="nb" hreflang="nb" data-title="Border Gateway Protocol" data-language-autonym="Norsk bokmål" data-language-local-name="Norwegian Bokmål" class="interlanguage-link-target"><span>Norsk bokmål</span></a></li><li class="interlanguage-link interwiki-nn mw-list-item"><a href="https://nn.wikipedia.org/wiki/Border_Gateway_Protocol" title="Border Gateway Protocol – Norwegian Nynorsk" lang="nn" hreflang="nn" data-title="Border Gateway Protocol" data-language-autonym="Norsk nynorsk" data-language-local-name="Norwegian Nynorsk" class="interlanguage-link-target"><span>Norsk nynorsk</span></a></li><li class="interlanguage-link interwiki-pl mw-list-item"><a href="https://pl.wikipedia.org/wiki/Border_Gateway_Protocol" title="Border Gateway Protocol – Polish" lang="pl" hreflang="pl" data-title="Border Gateway Protocol" data-language-autonym="Polski" data-language-local-name="Polish" class="interlanguage-link-target"><span>Polski</span></a></li><li class="interlanguage-link interwiki-pt mw-list-item"><a href="https://pt.wikipedia.org/wiki/Border_Gateway_Protocol" title="Border Gateway Protocol – Portuguese" lang="pt" hreflang="pt" data-title="Border Gateway Protocol" data-language-autonym="Português" data-language-local-name="Portuguese" class="interlanguage-link-target"><span>Português</span></a></li><li class="interlanguage-link interwiki-ro mw-list-item"><a href="https://ro.wikipedia.org/wiki/Border_Gateway_Protocol" title="Border Gateway Protocol – Romanian" lang="ro" hreflang="ro" data-title="Border Gateway Protocol" data-language-autonym="Română" data-language-local-name="Romanian" class="interlanguage-link-target"><span>Română</span></a></li><li class="interlanguage-link interwiki-ru mw-list-item"><a href="https://ru.wikipedia.org/wiki/Border_Gateway_Protocol" title="Border Gateway Protocol – Russian" lang="ru" hreflang="ru" data-title="Border Gateway Protocol" data-language-autonym="Русский" data-language-local-name="Russian" class="interlanguage-link-target"><span>Русский</span></a></li><li class="interlanguage-link interwiki-sq mw-list-item"><a href="https://sq.wikipedia.org/wiki/BGP" title="BGP – Albanian" lang="sq" hreflang="sq" data-title="BGP" data-language-autonym="Shqip" data-language-local-name="Albanian" class="interlanguage-link-target"><span>Shqip</span></a></li><li class="interlanguage-link interwiki-simple mw-list-item"><a href="https://simple.wikipedia.org/wiki/Border_Gateway_Protocol" title="Border Gateway Protocol – Simple English" lang="en-simple" hreflang="en-simple" data-title="Border Gateway Protocol" data-language-autonym="Simple English" data-language-local-name="Simple English" class="interlanguage-link-target"><span>Simple English</span></a></li><li class="interlanguage-link interwiki-ckb mw-list-item"><a href="https://ckb.wikipedia.org/wiki/%D9%BE%D8%B1%DB%86%D8%AA%DB%86%DA%A9%DB%86%D9%84%DB%8C_%D8%AF%DB%95%D8%B1%DB%95%DA%95%DB%8E%DB%8C_%D8%B3%D9%86%D9%88%D9%88%D8%B1%DB%8C" title="پرۆتۆکۆلی دەرەڕێی سنووری – Central Kurdish" lang="ckb" hreflang="ckb" data-title="پرۆتۆکۆلی دەرەڕێی سنووری" data-language-autonym="کوردی" data-language-local-name="Central Kurdish" class="interlanguage-link-target"><span>کوردی</span></a></li><li class="interlanguage-link interwiki-fi mw-list-item"><a href="https://fi.wikipedia.org/wiki/BGP" title="BGP – Finnish" lang="fi" hreflang="fi" data-title="BGP" data-language-autonym="Suomi" data-language-local-name="Finnish" class="interlanguage-link-target"><span>Suomi</span></a></li><li class="interlanguage-link interwiki-sv mw-list-item"><a href="https://sv.wikipedia.org/wiki/Border_Gateway_Protocol" title="Border Gateway Protocol – Swedish" lang="sv" hreflang="sv" data-title="Border Gateway Protocol" data-language-autonym="Svenska" data-language-local-name="Swedish" class="interlanguage-link-target"><span>Svenska</span></a></li><li class="interlanguage-link interwiki-tr mw-list-item"><a href="https://tr.wikipedia.org/wiki/S%C4%B1n%C4%B1r_Ge%C3%A7it_Protokol%C3%BC" title="Sınır Geçit Protokolü – Turkish" lang="tr" hreflang="tr" data-title="Sınır Geçit Protokolü" data-language-autonym="Türkçe" data-language-local-name="Turkish" class="interlanguage-link-target"><span>Türkçe</span></a></li><li class="interlanguage-link interwiki-uk mw-list-item"><a href="https://uk.wikipedia.org/wiki/BGP" title="BGP – Ukrainian" lang="uk" hreflang="uk" data-title="BGP" data-language-autonym="Українська" data-language-local-name="Ukrainian" class="interlanguage-link-target"><span>Українська</span></a></li><li class="interlanguage-link interwiki-vi mw-list-item"><a href="https://vi.wikipedia.org/wiki/BGP" title="BGP – Vietnamese" lang="vi" hreflang="vi" data-title="BGP" data-language-autonym="Tiếng Việt" 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0.5em;text-align:center}.mw-parser-output .ambox .mbox-imageright{border:none;padding:2px 0.5em 2px 0;text-align:center}.mw-parser-output .ambox .mbox-empty-cell{border:none;padding:0;width:1px}.mw-parser-output .ambox .mbox-image-div{width:52px}@media(min-width:720px){.mw-parser-output .ambox{margin:0 10%}}@media print{body.ns-0 .mw-parser-output .ambox{display:none!important}}</style><table class="box-Dark_mode_problems plainlinks metadata ambox ambox-style" role="presentation"><tbody><tr><td class="mbox-image"><div class="mbox-image-div"><span typeof="mw:File"><span><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/f/f2/Edit-clear.svg/40px-Edit-clear.svg.png" decoding="async" width="40" height="40" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/f/f2/Edit-clear.svg/60px-Edit-clear.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/f/f2/Edit-clear.svg/80px-Edit-clear.svg.png 2x" data-file-width="48" data-file-height="48" /></span></span></div></td><td class="mbox-text"><div class="mbox-text-span">This article <b>has problems when viewed in dark mode</b>. Desktop readers can switch to light mode temporarily using the eyeglasses icon at the top of the page.<span class="hide-when-compact"> You can <a class="external text" href="https://en.wikipedia.org/w/index.php?title=Border_Gateway_Protocol&action=edit">help fix these problems</a>; see the <a href="https://www.mediawiki.org/wiki/Recommendations_for_night_mode_compatibility_on_Wikimedia_wikis" class="extiw" title="mw:Recommendations for night mode compatibility on Wikimedia wikis">official how-to</a>.</span></div></td></tr></tbody></table> <div class="shortdescription nomobile noexcerpt noprint searchaux" style="display:none">Protocol for communicating routing information on the Internet</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">"BGP" redirects here. For other uses, see <a href="/wiki/BGP_(disambiguation)" class="mw-disambig" title="BGP (disambiguation)">BGP (disambiguation)</a>.</div> <style data-mw-deduplicate="TemplateStyles:r1257001546">.mw-parser-output .infobox-subbox{padding:0;border:none;margin:-3px;width:auto;min-width:100%;font-size:100%;clear:none;float:none;background-color:transparent}.mw-parser-output .infobox-3cols-child{margin:auto}.mw-parser-output .infobox .navbar{font-size:100%}@media screen{html.skin-theme-clientpref-night .mw-parser-output .infobox-full-data:not(.notheme)>div:not(.notheme)[style]{background:#1f1f23!important;color:#f8f9fa}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .infobox-full-data:not(.notheme) div:not(.notheme){background:#1f1f23!important;color:#f8f9fa}}@media(min-width:640px){body.skin--responsive .mw-parser-output .infobox-table{display:table!important}body.skin--responsive .mw-parser-output .infobox-table>caption{display:table-caption!important}body.skin--responsive .mw-parser-output .infobox-table>tbody{display:table-row-group}body.skin--responsive .mw-parser-output .infobox-table tr{display:table-row!important}body.skin--responsive .mw-parser-output .infobox-table th,body.skin--responsive .mw-parser-output .infobox-table td{padding-left:inherit;padding-right:inherit}}</style><table class="infobox vevent" style="width:26em;"><caption class="infobox-title summary">Border Gateway Protocol</caption><tbody><tr><td colspan="2" class="infobox-subheader"><a href="/wiki/Communication_protocol" title="Communication protocol">Communication protocol</a></td></tr><tr><td colspan="2" class="infobox-image"><span typeof="mw:File"><a href="/wiki/File:BGP_FSM.svg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/a/a8/BGP_FSM.svg/300px-BGP_FSM.svg.png" decoding="async" width="300" height="180" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/a/a8/BGP_FSM.svg/450px-BGP_FSM.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/a/a8/BGP_FSM.svg/600px-BGP_FSM.svg.png 2x" data-file-width="670" data-file-height="403" /></a></span><div class="infobox-caption">BGP state machine</div></td></tr><tr><th scope="row" class="infobox-label" style="white-space: nowrap; width:25%;">Abbreviation</th><td class="infobox-data">BGP</td></tr><tr><th scope="row" class="infobox-label" style="white-space: nowrap; width:25%;">Purpose</th><td class="infobox-data">exchange <a href="/wiki/Internet_Protocol" title="Internet Protocol">Internet Protocol</a> routing information</td></tr><tr><th scope="row" class="infobox-label" style="white-space: nowrap; width:25%;">Introduction</th><td class="infobox-data">June 1, 1989<span class="noprint">; 35 years ago</span><span style="display:none"> (<span class="bday dtstart published updated">1989-06-01</span>)</span><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></td></tr><tr><th scope="row" class="infobox-label" style="white-space: nowrap; width:25%;">Based on</th><td class="infobox-data"><a href="/wiki/Exterior_Gateway_Protocol" title="Exterior Gateway Protocol">EGP</a></td></tr><tr><th scope="row" class="infobox-label" style="white-space: nowrap; width:25%;"><a href="/wiki/OSI_model" title="OSI model">OSI layer</a></th><td class="infobox-data"><a href="/wiki/Application_layer" title="Application layer">Application layer</a></td></tr><tr><th scope="row" class="infobox-label" style="white-space: nowrap; width:25%;"><a href="/wiki/Port_(computer_networking)" title="Port (computer networking)">Port(s)</a></th><td class="infobox-data">tcp/179</td></tr><tr><th scope="row" class="infobox-label" style="white-space: nowrap; width:25%;"><a href="/wiki/Request_for_Comments" title="Request for Comments">RFC(s)</a></th><td class="infobox-data"><a href="#Standards_documents">§ Standards documents</a></td></tr></tbody></table> <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:" · 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.sidebar:not(.notheme) .sidebar-list-title,html.skin-theme-clientpref-night .mw-parser-output .sidebar:not(.notheme) .sidebar-title-with-pretitle{background:transparent!important}html.skin-theme-clientpref-night .mw-parser-output .sidebar:not(.notheme) .sidebar-title-with-pretitle a{color:var(--color-progressive)!important}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .sidebar:not(.notheme) .sidebar-list-title,html.skin-theme-clientpref-os .mw-parser-output .sidebar:not(.notheme) .sidebar-title-with-pretitle{background:transparent!important}html.skin-theme-clientpref-os .mw-parser-output .sidebar:not(.notheme) .sidebar-title-with-pretitle a{color:var(--color-progressive)!important}}@media print{body.ns-0 .mw-parser-output .sidebar{display:none!important}}</style><table class="sidebar nomobile nowraplinks hlist"><tbody><tr><th class="sidebar-title"><a href="/wiki/Internet_protocol_suite" title="Internet protocol suite">Internet protocol suite</a></th></tr><tr><th class="sidebar-heading"> <a href="/wiki/Application_layer" title="Application layer">Application layer</a></th></tr><tr><td class="sidebar-content"> <ul><li><a class="mw-selflink selflink">BGP</a></li> <li><a href="/wiki/Dynamic_Host_Configuration_Protocol" title="Dynamic Host Configuration Protocol">DHCP</a> (<a href="/wiki/DHCPv6" title="DHCPv6">v6</a>)</li> <li><a href="/wiki/Domain_Name_System" title="Domain Name System">DNS</a></li> <li><a href="/wiki/File_Transfer_Protocol" title="File Transfer Protocol">FTP</a></li> <li><a href="/wiki/HTTP" title="HTTP">HTTP</a> (<a href="/wiki/HTTP/3" title="HTTP/3">HTTP/3</a>)</li> <li><a href="/wiki/HTTPS" title="HTTPS">HTTPS</a></li> <li><a href="/wiki/Internet_Message_Access_Protocol" title="Internet Message Access Protocol">IMAP</a></li> <li><a href="/wiki/IRC" title="IRC">IRC</a></li> <li><a href="/wiki/Lightweight_Directory_Access_Protocol" title="Lightweight Directory Access Protocol">LDAP</a></li> <li><a href="/wiki/Media_Gateway_Control_Protocol" title="Media Gateway Control Protocol">MGCP</a></li> <li><a href="/wiki/MQTT" title="MQTT">MQTT</a></li> <li><a href="/wiki/Network_News_Transfer_Protocol" title="Network News Transfer Protocol">NNTP</a></li> <li><a href="/wiki/Network_Time_Protocol" title="Network Time Protocol">NTP</a></li> <li><a href="/wiki/Open_Shortest_Path_First" title="Open Shortest Path First">OSPF</a></li> <li><a href="/wiki/Post_Office_Protocol" title="Post Office Protocol">POP</a></li> <li><a href="/wiki/Precision_Time_Protocol" title="Precision Time Protocol">PTP</a></li> <li><a href="/wiki/Open_Network_Computing_Remote_Procedure_Call" class="mw-redirect" title="Open Network Computing Remote Procedure Call">ONC/RPC</a></li> <li><a href="/wiki/Real-time_Transport_Protocol" title="Real-time Transport Protocol">RTP</a></li> <li><a href="/wiki/Real-Time_Streaming_Protocol" title="Real-Time Streaming Protocol">RTSP</a></li> <li><a href="/wiki/Routing_Information_Protocol" title="Routing Information Protocol">RIP</a></li> <li><a href="/wiki/Session_Initiation_Protocol" title="Session Initiation Protocol">SIP</a></li> <li><a href="/wiki/Simple_Mail_Transfer_Protocol" title="Simple Mail Transfer Protocol">SMTP</a></li> <li><a href="/wiki/Simple_Network_Management_Protocol" title="Simple Network Management Protocol">SNMP</a></li> <li><a href="/wiki/Secure_Shell" title="Secure Shell">SSH</a></li> <li><a href="/wiki/Telnet" title="Telnet">Telnet</a></li> <li><a href="/wiki/Transport_Layer_Security" title="Transport Layer Security">TLS/SSL</a></li> <li><a href="/wiki/XMPP" title="XMPP">XMPP</a></li> <li><a href="/wiki/Category:Application_layer_protocols" title="Category:Application layer protocols"><i>more...</i></a></li></ul></td> </tr><tr><th class="sidebar-heading"> <a href="/wiki/Transport_layer" title="Transport layer">Transport layer</a></th></tr><tr><td class="sidebar-content"> <ul><li><a href="/wiki/Transmission_Control_Protocol" title="Transmission Control Protocol">TCP</a></li> <li><a href="/wiki/User_Datagram_Protocol" title="User Datagram Protocol">UDP</a></li> <li><a href="/wiki/Datagram_Congestion_Control_Protocol" title="Datagram Congestion Control Protocol">DCCP</a></li> <li><a href="/wiki/Stream_Control_Transmission_Protocol" title="Stream Control Transmission Protocol">SCTP</a></li> <li><a href="/wiki/Resource_Reservation_Protocol" title="Resource Reservation Protocol">RSVP</a></li> <li><a href="/wiki/QUIC" title="QUIC">QUIC</a></li> <li><a href="/wiki/Category:Transport_layer_protocols" title="Category:Transport layer protocols"><i>more...</i></a></li></ul></td> </tr><tr><th class="sidebar-heading"> <a href="/wiki/Internet_layer" title="Internet layer">Internet layer</a></th></tr><tr><td class="sidebar-content"> <ul><li><a href="/wiki/Internet_Protocol" title="Internet Protocol">IP</a> <ul><li><a href="/wiki/IPv4" title="IPv4">v4</a></li> <li><a href="/wiki/IPv6" title="IPv6">v6</a></li></ul></li> <li><a href="/wiki/Internet_Control_Message_Protocol" title="Internet Control Message Protocol">ICMP</a> (<a href="/wiki/ICMPv6" title="ICMPv6">v6</a>)</li> <li><a href="/wiki/Neighbor_Discovery_Protocol" title="Neighbor Discovery Protocol">NDP</a></li> <li><a href="/wiki/Explicit_Congestion_Notification" title="Explicit Congestion Notification">ECN</a></li> <li><a href="/wiki/Internet_Group_Management_Protocol" title="Internet Group Management Protocol">IGMP</a></li> <li><a href="/wiki/IPsec" title="IPsec">IPsec</a></li> <li><a href="/wiki/Category:Internet_layer_protocols" title="Category:Internet layer protocols"><i>more...</i></a></li></ul></td> </tr><tr><th class="sidebar-heading"> <a href="/wiki/Link_layer" title="Link layer">Link layer</a></th></tr><tr><td class="sidebar-content"> <ul><li><a href="/wiki/Address_Resolution_Protocol" title="Address Resolution Protocol">ARP</a></li> <li><a href="/wiki/Tunneling_protocol" title="Tunneling protocol">Tunnels</a></li> <li><a href="/wiki/Point-to-Point_Protocol" title="Point-to-Point Protocol">PPP</a></li> <li><a href="/wiki/Medium_access_control" title="Medium access control">MAC</a></li> <li><a href="/wiki/Category:Link_protocols" title="Category:Link protocols"><i>more...</i></a></li></ul></td> </tr><tr><td class="sidebar-navbar"><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:Internet_protocol_suite" title="Template:Internet protocol suite"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Internet_protocol_suite" title="Template talk:Internet protocol suite"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Internet_protocol_suite" title="Special:EditPage/Template:Internet protocol suite"><abbr title="Edit this template">e</abbr></a></li></ul></div></td></tr></tbody></table> <table cellpadding="1" class="mw-collapsible mw-collapsed" style="width: 220px; float: right; clear: right; border: 1px solid #8888aa; padding: 5px; margin: 0 0 15px 15px; text-align: left;"> <tbody><tr> <td style="background: #ccf; text-align: center;"><span class="anchor" id="Internet_History_Timeline"></span><span class="anchor" id="Internet_history_timeline"></span><b>Internet history timeline</b> </td></tr> <tr> <td> <p><i><b>Early research and development:</b></i> </p> <ul><li><span class="vevent">1960–4<span style="display:none"> (<span class="bday dtstart published updated itvstart">1960–4</span>)</span>: <span class="summary"><a href="/wiki/RAND" class="mw-redirect" title="RAND">RAND</a> networking concepts developed</span></span></li> <li><span class="vevent">1962–4<span style="display:none"> (<span class="bday dtstart published updated itvstart">1962–4</span>)</span>: <span class="summary"><a href="/wiki/DARPA" title="DARPA">ARPA</a> networking ideas</span></span></li> <li><span class="vevent">1965<span style="display:none"> (<span class="bday dtstart published updated itvstart">1965</span>)</span>: <span class="summary"><a href="/wiki/NPL_network" title="NPL network">NPL network</a> concepts conceived</span></span></li> <li><span class="vevent">1966<span style="display:none"> (<span class="bday dtstart published updated itvstart">1966</span>)</span>: <span class="summary"><a href="/wiki/Merit_Network" title="Merit Network">Merit Network</a> founded</span></span></li> <li><span class="vevent">1967<span style="display:none"> (<span class="bday dtstart published updated itvstart">1967</span>)</span>: <span class="summary"><a href="/wiki/ARPANET" title="ARPANET">ARPANET</a> planning begins</span></span></li> <li><span class="vevent">1967<span style="display:none"> (<span class="bday dtstart published updated itvstart">1967</span>)</span>: <span class="summary"><a href="/wiki/Symposium_on_Operating_Systems_Principles" title="Symposium on Operating Systems Principles">Symposium on Operating Systems Principles</a></span></span></li> <li><span class="vevent">1969<span style="display:none"> (<span class="bday dtstart published updated itvstart">1969</span>)</span>: <span class="summary">NPL followed by the ARPANET carry their first packets</span></span></li> <li><span class="vevent">1970<span style="display:none"> (<span class="bday dtstart published updated itvstart">1970</span>)</span>: <span class="summary"><a href="/wiki/InterNIC#History" title="InterNIC">Network Information Center</a> (NIC)</span></span></li> <li><span class="vevent">1971<span style="display:none"> (<span class="bday dtstart published updated itvstart">1971</span>)</span>: <span class="summary"><a href="/wiki/Tymnet" title="Tymnet">Tymnet</a> switched-circuit network</span></span></li> <li><span class="vevent">1972<span style="display:none"> (<span class="bday dtstart published updated itvstart">1972</span>)</span>: <span class="summary">Merit Network's packet-switched network operational</span></span></li> <li><span class="vevent">1972<span style="display:none"> (<span class="bday dtstart published updated itvstart">1972</span>)</span>: <span class="summary"><a href="/wiki/Internet_Assigned_Numbers_Authority" title="Internet Assigned Numbers Authority">Internet Assigned Numbers Authority</a> (IANA) established</span></span></li> <li><span class="vevent">1973<span style="display:none"> (<span class="bday dtstart published updated itvstart">1973</span>)</span>: <span class="summary"><a href="/wiki/CYCLADES" title="CYCLADES">CYCLADES</a> network demonstrated</span></span></li> <li><span class="vevent">1973<span style="display:none"> (<span class="bday dtstart published updated itvstart">1973</span>)</span>: <span class="summary"><a href="/wiki/PARC_Universal_Packet" title="PARC Universal Packet">PARC Universal Packet</a> development begins</span></span></li> <li><span class="vevent">1974<span style="display:none"> (<span class="bday dtstart published updated itvstart">1974</span>)</span>: <span class="summary"><a href="/wiki/Transmission_Control_Program" class="mw-redirect" title="Transmission Control Program">Transmission Control Program</a> specification published</span></span></li> <li><span class="vevent">1975<span style="display:none"> (<span class="bday dtstart published updated itvstart">1975</span>)</span>: <span class="summary"><a href="/wiki/Telenet" title="Telenet">Telenet</a> commercial packet-switched network</span></span></li> <li><span class="vevent">1976<span style="display:none"> (<span class="bday dtstart published updated itvstart">1976</span>)</span>: <span class="summary"><a href="/wiki/X.25" title="X.25">X.25</a> protocol approved and deployed on <a href="/wiki/Public_data_network" title="Public data network">public data networks</a></span></span></li> <li><span class="vevent">1978<span style="display:none"> (<span class="bday dtstart published updated itvstart">1978</span>)</span>: <span class="summary"><a href="/wiki/Minitel" title="Minitel">Minitel</a> introduced</span></span></li> <li><span class="vevent">1979<span style="display:none"> (<span class="bday dtstart published updated itvstart">1979</span>)</span>: <span class="summary"><a href="/wiki/Internet_Architecture_Board" title="Internet Architecture Board">Internet Activities Board</a> (IAB)</span></span></li> <li><span class="vevent">1980<span style="display:none"> (<span class="bday dtstart published updated itvstart">1980</span>)</span>: <span class="summary"><a href="/wiki/Usenet" title="Usenet">USENET</a> news using <a href="/wiki/UUCP" title="UUCP">UUCP</a></span></span></li> <li><span class="vevent">1980<span style="display:none"> (<span class="bday dtstart published updated itvstart">1980</span>)</span>: <span class="summary"><a href="/wiki/Ethernet" title="Ethernet">Ethernet</a> standard introduced</span></span></li> <li><span class="vevent">1981<span style="display:none"> (<span class="bday dtstart published updated itvstart">1981</span>)</span>: <span class="summary"><a href="/wiki/BITNET" title="BITNET">BITNET</a> established</span></span></li></ul> <p><i><b>Merging the networks and creating the Internet:</b></i> </p> <ul><li><span class="vevent">1981<span style="display:none"> (<span class="bday dtstart published updated itvstart">1981</span>)</span>: <span class="summary"><a href="/wiki/CSNET" title="CSNET">Computer Science Network</a> (CSNET)</span></span></li> <li><span class="vevent">1982<span style="display:none"> (<span class="bday dtstart published updated itvstart">1982</span>)</span>: <span class="summary"><a href="/wiki/Internet_protocol_suite" title="Internet protocol suite">TCP/IP</a> protocol suite formalized</span></span></li> <li><span class="vevent">1982<span style="display:none"> (<span class="bday dtstart published updated itvstart">1982</span>)</span>: <span class="summary"><a href="/wiki/Simple_Mail_Transfer_Protocol" title="Simple Mail Transfer Protocol">Simple Mail Transfer Protocol</a> (SMTP)</span></span></li> <li><span class="vevent">1983<span style="display:none"> (<span class="bday dtstart published updated itvstart">1983</span>)</span>: <span class="summary"><a href="/wiki/Domain_Name_System" title="Domain Name System">Domain Name System</a> (DNS)</span></span></li> <li><span class="vevent">1983<span style="display:none"> (<span class="bday dtstart published updated itvstart">1983</span>)</span>: <span class="summary"><a href="/wiki/MILNET" title="MILNET">MILNET</a> split off from ARPANET</span></span></li> <li><span class="vevent">1984<span style="display:none"> (<span class="bday dtstart published updated itvstart">1984</span>)</span>: <span class="summary"><a href="/wiki/OSI_model" title="OSI model">OSI Reference Model</a> released</span></span></li> <li><span class="vevent">1985<span style="display:none"> (<span class="bday dtstart published updated itvstart">1985</span>)</span>: <span class="summary"><a href="/wiki/Domain_names#Domain_name_registration" class="mw-redirect" title="Domain names">First .COM domain name registered</a></span></span></li> <li><span class="vevent">1986<span style="display:none"> (<span class="bday dtstart published updated itvstart">1986</span>)</span>: <span class="summary"><a href="/wiki/National_Science_Foundation_Network" title="National Science Foundation Network">NSFNET</a> with 56 kbit/s links</span></span></li> <li><span class="vevent">1986<span style="display:none"> (<span class="bday dtstart published updated itvstart">1986</span>)</span>: <span class="summary"><a href="/wiki/Internet_Engineering_Task_Force" title="Internet Engineering Task Force">Internet Engineering Task Force</a> (IETF)</span></span></li> <li><span class="vevent">1987<span style="display:none"> (<span class="bday dtstart published updated itvstart">1987</span>)</span>: <span class="summary"><a href="/wiki/UUNET" title="UUNET">UUNET</a> founded</span></span></li> <li><span class="vevent">1988<span style="display:none"> (<span class="bday dtstart published updated itvstart">1988</span>)</span>: <span class="summary"><a href="/wiki/National_Science_Foundation_Network" title="National Science Foundation Network">NSFNET</a> upgraded to 1.5 Mbit/s (T1)</span></span></li> <li><span class="vevent">1988<span style="display:none"> (<span class="bday dtstart published updated itvstart">1988</span>)</span>: <span class="summary"><a href="/wiki/Morris_worm" title="Morris worm">Morris worm</a></span></span></li> <li><span class="vevent">1988<span style="display:none"> (<span class="bday dtstart published updated itvstart">1988</span>)</span>: <span class="summary">Complete <a href="/wiki/Internet_protocol_suite" title="Internet protocol suite">Internet protocol suite</a></span></span></li> <li><span class="vevent">1989<span style="display:none"> (<span class="bday dtstart published updated itvstart">1989</span>)</span>: <span class="summary"><a class="mw-selflink selflink">Border Gateway Protocol</a> (BGP)</span></span></li> <li><span class="vevent">1989<span style="display:none"> (<span class="bday dtstart published updated itvstart">1989</span>)</span>: <span class="summary"><a href="/wiki/PSINet" title="PSINet">PSINet</a> founded, allows commercial traffic</span></span></li> <li><span class="vevent">1989<span style="display:none"> (<span class="bday dtstart published updated itvstart">1989</span>)</span>: <span class="summary"><a href="/wiki/Federal_Internet_Exchange" title="Federal Internet Exchange">Federal Internet Exchanges (FIX East|FIXes)</a></span></span></li> <li><span class="vevent">1990<span style="display:none"> (<span class="bday dtstart published updated itvstart">1990</span>)</span>: <span class="summary"><a href="/wiki/Government_Open_Systems_Interconnection_Profile" title="Government Open Systems Interconnection Profile">GOSIP</a> (without <a href="/wiki/Internet_protocol_suite" title="Internet protocol suite">TCP/IP</a>)</span></span></li> <li><span class="vevent">1990<span style="display:none"> (<span class="bday dtstart published updated itvstart">1990</span>)</span>: <span class="summary">ARPANET decommissioned</span></span></li> <li><span class="vevent">1990<span style="display:none"> (<span class="bday dtstart published updated itvstart">1990</span>)</span>: <span class="summary"><a href="/wiki/Advanced_Network_and_Services" title="Advanced Network and Services">Advanced Network and Services</a> (ANS)</span></span></li> <li><span class="vevent">1990<span style="display:none"> (<span class="bday dtstart published updated itvstart">1990</span>)</span>: <span class="summary"><a href="/wiki/UUNET#Early_existence" title="UUNET">UUNET/Alternet</a> allows commercial traffic</span></span></li> <li><span class="vevent">1990<span style="display:none"> (<span class="bday dtstart published updated itvstart">1990</span>)</span>: <span class="summary"><a href="/wiki/Archie_(search_engine)" title="Archie (search engine)">Archie search engine</a></span></span></li> <li><span class="vevent">1991<span style="display:none"> (<span class="bday dtstart published updated itvstart">1991</span>)</span>: <span class="summary"><a href="/wiki/Wide_area_information_server" title="Wide area information server">Wide area information server</a> (WAIS)</span></span></li> <li><span class="vevent">1991<span style="display:none"> (<span class="bday dtstart published updated itvstart">1991</span>)</span>: <span class="summary"><a href="/wiki/Gopher_(protocol)" title="Gopher (protocol)">Gopher</a></span></span></li> <li><span class="vevent">1991<span style="display:none"> (<span class="bday dtstart published updated itvstart">1991</span>)</span>: <span class="summary"><a href="/wiki/Commercial_Internet_eXchange" title="Commercial Internet eXchange">Commercial Internet eXchange</a> (CIX)</span></span></li> <li><span class="vevent">1991<span style="display:none"> (<span class="bday dtstart published updated itvstart">1991</span>)</span>: <span class="summary"><a href="/wiki/Advanced_Network_and_Services" title="Advanced Network and Services">ANS CO+RE</a> allows commercial traffic</span></span></li> <li><span class="vevent">1991<span style="display:none"> (<span class="bday dtstart published updated itvstart">1991</span>)</span>: <span class="summary"><a href="/wiki/World_Wide_Web" title="World Wide Web">World Wide Web</a> (WWW)</span></span></li> <li><span class="vevent">1992<span style="display:none"> (<span class="bday dtstart published updated itvstart">1992</span>)</span>: <span class="summary"><a href="/wiki/National_Science_Foundation_Network" title="National Science Foundation Network">NSFNET</a> upgraded to 45 Mbit/s (T3)</span></span></li> <li><span class="vevent">1992<span style="display:none"> (<span class="bday dtstart published updated itvstart">1992</span>)</span>: <span class="summary"><a href="/wiki/Internet_Society" title="Internet Society">Internet Society</a> (ISOC) established</span></span></li> <li><span class="vevent">1993<span style="display:none"> (<span class="bday dtstart published updated itvstart">1993</span>)</span>: <span class="summary"><a href="/wiki/Classless_Inter-Domain_Routing" title="Classless Inter-Domain Routing">Classless Inter-Domain Routing</a> (CIDR)</span></span></li> <li><span class="vevent">1993<span style="display:none"> (<span class="bday dtstart published updated itvstart">1993</span>)</span>: <span class="summary"><a href="/wiki/InterNIC" title="InterNIC">InterNIC</a> established</span></span></li> <li><span class="vevent">1993<span style="display:none"> (<span class="bday dtstart published updated itvstart">1993</span>)</span>: <span class="summary"><a href="/wiki/AOL" title="AOL">AOL</a> added <a href="/wiki/Usenet" title="Usenet">USENET</a> access</span></span></li> <li><span class="vevent">1993<span style="display:none"> (<span class="bday dtstart published updated itvstart">1993</span>)</span>: <span class="summary"><a href="/wiki/NCSA_Mosaic" title="NCSA Mosaic">Mosaic web browser</a> released</span></span></li> <li><span class="vevent">1994<span style="display:none"> (<span class="bday dtstart published updated itvstart">1994</span>)</span>: <span class="summary"><a href="/wiki/Search_engine" title="Search engine">Full text web search engines</a></span></span></li> <li><span class="vevent">1994<span style="display:none"> (<span class="bday dtstart published updated itvstart">1994</span>)</span>: <span class="summary"><a href="/wiki/North_American_Network_Operators%27_Group" title="North American Network Operators' Group">North American Network Operators' Group</a> (NANOG) established</span></span></li></ul> <p><i><b>Commercialization, privatization, broader access leads to the modern Internet:</b></i> </p> <ul><li><span class="vevent">1995<span style="display:none"> (<span class="bday dtstart published updated itvstart">1995</span>)</span>: <span class="summary">New Internet architecture with commercial <a href="/wiki/Internet_service_provider" title="Internet service provider">ISPs</a> connected at <a href="/wiki/Network_Access_Point" class="mw-redirect" title="Network Access Point">NAPs</a></span></span></li> <li><span class="vevent">1995<span style="display:none"> (<span class="bday dtstart published updated itvstart">1995</span>)</span>: <span class="summary"><a href="/wiki/National_Science_Foundation_Network" title="National Science Foundation Network">NSFNET</a> decommissioned</span></span></li> <li><span class="vevent">1995<span style="display:none"> (<span class="bday dtstart published updated itvstart">1995</span>)</span>: <span class="summary"><a href="/wiki/GOSIP" class="mw-redirect" title="GOSIP">GOSIP</a> updated to allow <a href="/wiki/Internet_protocol_suite" title="Internet protocol suite">TCP/IP</a></span></span></li> <li><span class="vevent">1995<span style="display:none"> (<span class="bday dtstart published updated itvstart">1995</span>)</span>: <span class="summary"><a href="/wiki/Very_high-speed_Backbone_Network_Service" title="Very high-speed Backbone Network Service">very high-speed Backbone Network Service (vBNS)</a></span></span></li> <li><span class="vevent">1995<span style="display:none"> (<span class="bday dtstart published updated itvstart">1995</span>)</span>: <span class="summary"><a href="/wiki/IPv6" title="IPv6">IPv6</a> proposed</span></span></li> <li><span class="vevent">1996<span style="display:none"> (<span class="bday dtstart published updated itvstart">1996</span>)</span>: <span class="summary"><a href="/wiki/AOL" title="AOL">AOL</a> changes pricing model from hourly to monthly</span></span></li> <li><span class="vevent">1998<span style="display:none"> (<span class="bday dtstart published updated itvstart">1998</span>)</span>: <span class="summary"><a href="/wiki/ICANN" title="ICANN">Internet Corporation for Assigned Names and Numbers (ICANN)</a></span></span></li> <li><span class="vevent">1999<span style="display:none"> (<span class="bday dtstart published updated itvstart">1999</span>)</span>: <span class="summary"><a href="/wiki/IEEE_802.11" title="IEEE 802.11">IEEE 802.11b</a> wireless networking</span></span></li> <li><span class="vevent">1999<span style="display:none"> (<span class="bday dtstart published updated itvstart">1999</span>)</span>: <span class="summary"><a href="/wiki/Internet2" title="Internet2">Internet2</a>/<a href="/wiki/Abilene_Network" title="Abilene Network">Abilene Network</a></span></span></li> <li><span class="vevent">1999<span style="display:none"> (<span class="bday dtstart published updated itvstart">1999</span>)</span>: <span class="summary"><a href="/wiki/VBNS" class="mw-redirect" title="VBNS">vBNS+</a> allows broader access</span></span></li> <li><span class="vevent">2000<span style="display:none"> (<span class="bday dtstart published updated itvstart">2000</span>)</span>: <span class="summary"><a href="/wiki/Dot-com_bubble" title="Dot-com bubble">Dot-com bubble</a> bursts</span></span></li> <li><span class="vevent">2001<span style="display:none"> (<span class="bday dtstart published updated itvstart">2001</span>)</span>: <span class="summary"><a href="/wiki/Top-level_domain#Proposed_domains" title="Top-level domain">New top-level domain names activated</a></span></span></li> <li><span class="vevent">2001<span style="display:none"> (<span class="bday dtstart published updated itvstart">2001</span>)</span>: <span class="summary"><a href="/wiki/Code_Red_(computer_worm)" title="Code Red (computer worm)">Code Red I</a>, <a href="/wiki/Code_Red_II" title="Code Red II">Code Red II</a>, and <a href="/wiki/Nimda" title="Nimda">Nimda</a> worms</span></span></li> <li><span class="vevent">2003<span style="display:none"> (<span class="bday dtstart published updated itvstart">2003</span>)</span>: <span class="summary"><a href="/wiki/World_Summit_on_the_Information_Society" title="World Summit on the Information Society">UN World Summit on the Information Society (WSIS) phase I</a></span></span></li></ul> <ul><li><span class="vevent">2003<span style="display:none"> (<span class="bday dtstart published updated itvstart">2003</span>)</span>: <span class="summary"><a href="/wiki/National_LambdaRail" title="National LambdaRail">National LambdaRail</a> founded</span></span></li> <li><span class="vevent">2004<span style="display:none"> (<span class="bday dtstart published updated itvstart">2004</span>)</span>: <span class="summary"><a href="/wiki/Working_Group_on_Internet_Governance" title="Working Group on Internet Governance">UN Working Group on Internet Governance (WGIG)</a></span></span></li> <li><span class="vevent">2005<span style="display:none"> (<span class="bday dtstart published updated itvstart">2005</span>)</span>: <span class="summary"><a href="/wiki/World_Summit_on_the_Information_Society" title="World Summit on the Information Society">UN WSIS phase II</a></span></span></li> <li><span class="vevent">2006<span style="display:none"> (<span class="bday dtstart published updated itvstart">2006</span>)</span>: <span class="summary"><a href="/wiki/Internet_Governance_Forum" title="Internet Governance Forum">First meeting of the Internet Governance Forum</a></span></span></li> <li><span class="vevent">2010<span style="display:none"> (<span class="bday dtstart published updated itvstart">2010</span>)</span>: <span class="summary"><a href="/wiki/Top-level_domain#Internationalized_country_code_TLDs" title="Top-level domain">First internationalized country code top-level domains</a> registered</span></span></li> <li><span class="vevent">2012<span style="display:none"> (<span class="bday dtstart published updated itvstart">2012</span>)</span>: <span class="summary"><a href="/wiki/Generic_top-level_domain#New_top-level_domains" title="Generic top-level domain">ICANN begins accepting applications for new generic top-level domain names</a></span></span></li> <li><span class="vevent">2013<span style="display:none"> (<span class="bday dtstart published updated itvstart">2013</span>)</span>: <span class="summary"><a href="/wiki/Montevideo_Statement_on_the_Future_of_Internet_Cooperation" title="Montevideo Statement on the Future of Internet Cooperation">Montevideo Statement on the Future of Internet Cooperation</a></span></span></li> <li><span class="vevent">2014<span style="display:none"> (<span class="bday dtstart published updated itvstart">2014</span>)</span>: <span class="summary"><a href="/wiki/NetMundial_Initiative" title="NetMundial Initiative">NetMundial international Internet governance proposal</a></span></span></li> <li><span class="vevent">2016<span style="display:none"> (<span class="bday dtstart published updated itvstart">2016</span>)</span>: <span class="summary"><a href="/wiki/ICANN" title="ICANN">ICANN</a> contract with U.S. Dept. of Commerce ends, <a href="/wiki/Internet_Assigned_Numbers_Authority" title="Internet Assigned Numbers Authority">IANA</a> oversight passes to the global Internet community on October 1st</span></span></li></ul> <p><i><b>Examples of Internet services:</b></i> </p> <ul><li><span class="vevent">1989<span style="display:none"> (<span class="bday dtstart published updated itvstart">1989</span>)</span>: <span class="summary"><a href="/wiki/AOL" title="AOL">AOL</a> dial-up service provider, email, instant messaging, and web browser</span></span></li> <li><span class="vevent">1990<span style="display:none"> (<span class="bday dtstart published updated itvstart">1990</span>)</span>: <span class="summary"><a href="/wiki/IMDb" title="IMDb">IMDb</a> Internet movie database</span></span></li> <li><span class="vevent">1994<span style="display:none"> (<span class="bday dtstart published updated itvstart">1994</span>)</span>: <span class="summary"><a href="/wiki/Yahoo" title="Yahoo">Yahoo!</a> web directory</span></span></li> <li><span class="vevent">1995<span style="display:none"> (<span class="bday dtstart published updated itvstart">1995</span>)</span>: <span class="summary"><a href="/wiki/Amazon_(company)" title="Amazon (company)">Amazon</a> online retailer</span></span></li> <li><span class="vevent">1995<span style="display:none"> (<span class="bday dtstart published updated itvstart">1995</span>)</span>: <span class="summary"><a href="/wiki/EBay" title="EBay">eBay</a> online auction and shopping</span></span></li> <li><span class="vevent">1995<span style="display:none"> (<span class="bday dtstart published updated itvstart">1995</span>)</span>: <span class="summary"><a href="/wiki/Craigslist" title="Craigslist">Craigslist</a> classified advertisements</span></span></li> <li><span class="vevent">1995<span style="display:none"> (<span class="bday dtstart published updated itvstart">1995</span>)</span>: <span class="summary"><a href="/wiki/AltaVista" title="AltaVista">AltaVista</a> search engine</span></span></li> <li><span class="vevent">1996<span style="display:none"> (<span class="bday dtstart published updated itvstart">1996</span>)</span>: <span class="summary"><a href="/wiki/Outlook.com" title="Outlook.com">Outlook (formerly Hotmail)</a> free web-based e-mail</span></span></li> <li><span class="vevent">1996<span style="display:none"> (<span class="bday dtstart published updated itvstart">1996</span>)</span>: <span class="summary"><a href="/wiki/Baidu" title="Baidu">RankDex</a> search engine</span></span></li> <li><span class="vevent">1997<span style="display:none"> (<span class="bday dtstart published updated itvstart">1997</span>)</span>: <span class="summary"><a href="/wiki/Google_Search" title="Google Search">Google Search</a></span></span></li> <li><span class="vevent">1997<span style="display:none"> (<span class="bday dtstart published updated itvstart">1997</span>)</span>: <span class="summary"><a href="/wiki/Babel_Fish_(website)" title="Babel Fish (website)">Babel Fish</a> automatic translation</span></span></li> <li><span class="vevent">1998<span style="display:none"> (<span class="bday dtstart published updated itvstart">1998</span>)</span>: <span class="summary"><a href="/wiki/Yahoo_Groups" title="Yahoo Groups">Yahoo Groups (formerly Yahoo! Clubs)</a></span></span></li> <li><span class="vevent">1998<span style="display:none"> (<span class="bday dtstart published updated itvstart">1998</span>)</span>: <span class="summary"><a href="/wiki/PayPal" title="PayPal">PayPal</a> Internet payment system</span></span></li> <li><span class="vevent">1998<span style="display:none"> (<span class="bday dtstart published updated itvstart">1998</span>)</span>: <span class="summary"><a href="/wiki/Rotten_Tomatoes" title="Rotten Tomatoes">Rotten Tomatoes</a> review aggregator</span></span></li> <li><span class="vevent">1999<span style="display:none"> (<span class="bday dtstart published updated itvstart">1999</span>)</span>: <span class="summary"><a href="/wiki/2channel" title="2channel">2ch</a> Anonymous textboard</span></span></li> <li><span class="vevent">1999<span style="display:none"> (<span class="bday dtstart published updated itvstart">1999</span>)</span>: <span class="summary"><a href="/wiki/I-mode" title="I-mode">i-mode</a> mobile internet service</span></span></li> <li><span class="vevent">1999<span style="display:none"> (<span class="bday dtstart published updated itvstart">1999</span>)</span>: <span class="summary"><a href="/wiki/Napster" title="Napster">Napster</a> peer-to-peer file sharing</span></span></li> <li><span class="vevent">2000<span style="display:none"> (<span class="bday dtstart published updated itvstart">2000</span>)</span>: <span class="summary"><a href="/wiki/Baidu" title="Baidu">Baidu</a> search engine</span></span></li> <li><span class="vevent">2001<span style="display:none"> (<span class="bday dtstart published updated itvstart">2001</span>)</span>: <span class="summary"><a href="/wiki/Futaba_Channel" title="Futaba Channel">2chan</a> Anonymous imageboard</span></span></li> <li><span class="vevent">2001<span style="display:none"> (<span class="bday dtstart published updated itvstart">2001</span>)</span>: <span class="summary"><a href="/wiki/BitTorrent" title="BitTorrent">BitTorrent</a> peer-to-peer file sharing</span></span></li> <li><span class="vevent">2001<span style="display:none"> (<span class="bday dtstart published updated itvstart">2001</span>)</span>: <span class="summary"><a href="/wiki/Wikipedia" title="Wikipedia">Wikipedia</a>, the free encyclopedia</span></span></li> <li><span class="vevent">2003<span style="display:none"> (<span class="bday dtstart published updated itvstart">2003</span>)</span>: <span class="summary"><a href="/wiki/LinkedIn" title="LinkedIn">LinkedIn</a> business networking</span></span></li> <li><span class="vevent">2003<span style="display:none"> (<span class="bday dtstart published updated itvstart">2003</span>)</span>: <span class="summary"><a href="/wiki/Myspace" title="Myspace">Myspace</a> social networking site</span></span></li> <li><span class="vevent">2003<span style="display:none"> (<span class="bday dtstart published updated itvstart">2003</span>)</span>: <span class="summary"><a href="/wiki/Skype" title="Skype">Skype</a> Internet voice calls</span></span></li> <li><span class="vevent">2003<span style="display:none"> (<span class="bday dtstart published updated itvstart">2003</span>)</span>: <span class="summary"><a href="/wiki/ITunes_Store" title="ITunes Store">iTunes Store</a></span></span></li> <li><span class="vevent">2003<span style="display:none"> (<span class="bday dtstart published updated itvstart">2003</span>)</span>: <span class="summary"><a href="/wiki/4chan" title="4chan">4chan</a> Anonymous imageboard</span></span></li> <li><span class="vevent">2003<span style="display:none"> (<span class="bday dtstart published updated itvstart">2003</span>)</span>: <span class="summary"><a href="/wiki/The_Pirate_Bay" title="The Pirate Bay">The Pirate Bay</a>, <a href="/wiki/Torrent_file" title="Torrent file">torrent file</a> host</span></span></li> <li><span class="vevent">2004<span style="display:none"> (<span class="bday dtstart published updated itvstart">2004</span>)</span>: <span class="summary"><a href="/wiki/Facebook" title="Facebook">Facebook</a> social networking site</span></span></li> <li><span class="vevent">2004<span style="display:none"> (<span class="bday dtstart published updated itvstart">2004</span>)</span>: <span class="summary"><a href="/wiki/Podcast" title="Podcast">Podcast</a> media file series</span></span></li> <li><span class="vevent">2004<span style="display:none"> (<span class="bday dtstart published updated itvstart">2004</span>)</span>: <span class="summary"><a href="/wiki/Flickr" title="Flickr">Flickr</a> image hosting</span></span></li> <li><span class="vevent">2005<span style="display:none"> (<span class="bday dtstart published updated itvstart">2005</span>)</span>: <span class="summary"><a href="/wiki/YouTube" title="YouTube">YouTube</a> video sharing</span></span></li> <li><span class="vevent">2005<span style="display:none"> (<span class="bday dtstart published updated itvstart">2005</span>)</span>: <span class="summary"><a href="/wiki/Reddit" title="Reddit">Reddit</a> link voting</span></span></li> <li><span class="vevent">2005<span style="display:none"> (<span class="bday dtstart published updated itvstart">2005</span>)</span>: <span class="summary"><a href="/wiki/Google_Earth" title="Google Earth">Google Earth</a> virtual globe</span></span></li> <li><span class="vevent">2006<span style="display:none"> (<span class="bday dtstart published updated itvstart">2006</span>)</span>: <span class="summary"><a href="/wiki/Twitter" title="Twitter">Twitter</a> microblogging</span></span></li> <li><span class="vevent">2007<span style="display:none"> (<span class="bday dtstart published updated itvstart">2007</span>)</span>: <span class="summary"><a href="/wiki/WikiLeaks" title="WikiLeaks">WikiLeaks</a> anonymous news and information leaks</span></span></li> <li><span class="vevent">2007<span style="display:none"> (<span class="bday dtstart published updated itvstart">2007</span>)</span>: <span class="summary"><a href="/wiki/Google_Street_View" title="Google Street View">Google Street View</a></span></span></li> <li><span class="vevent">2007<span style="display:none"> (<span class="bday dtstart published updated itvstart">2007</span>)</span>: <span class="summary"><a href="/wiki/Amazon_Kindle" title="Amazon Kindle">Kindle</a>, <a href="/wiki/E-reader" title="E-reader">e-reader</a> and virtual bookshop</span></span></li> <li><span class="vevent">2008<span style="display:none"> (<span class="bday dtstart published updated itvstart">2008</span>)</span>: <span class="summary"><a href="/wiki/Amazon_Elastic_Compute_Cloud" title="Amazon Elastic Compute Cloud">Amazon Elastic Compute Cloud</a> (EC2)</span></span></li> <li><span class="vevent">2008<span style="display:none"> (<span class="bday dtstart published updated itvstart">2008</span>)</span>: <span class="summary"><a href="/wiki/Dropbox" title="Dropbox">Dropbox</a> cloud-based file hosting</span></span></li> <li><span class="vevent">2008<span style="display:none"> (<span class="bday dtstart published updated itvstart">2008</span>)</span>: <span class="summary"><a href="/wiki/Encyclopedia_of_Life" title="Encyclopedia of Life">Encyclopedia of Life</a>, a collaborative encyclopedia intended to document all living species</span></span></li> <li><span class="vevent">2008<span style="display:none"> (<span class="bday dtstart published updated itvstart">2008</span>)</span>: <span class="summary"><a href="/wiki/Spotify" title="Spotify">Spotify</a>, a <a href="/wiki/Digital_rights_management" title="Digital rights management">DRM-based</a> music streaming service</span></span></li> <li><span class="vevent">2009<span style="display:none"> (<span class="bday dtstart published updated itvstart">2009</span>)</span>: <span class="summary"><a href="/wiki/Microsoft_Bing" title="Microsoft Bing">Bing</a> search engine</span></span></li> <li><span class="vevent">2009<span style="display:none"> (<span class="bday dtstart published updated itvstart">2009</span>)</span>: <span class="summary"><a href="/wiki/Google_Docs" title="Google Docs">Google Docs</a>, Web-based word processor, spreadsheet, presentation, form, and data storage service</span></span></li> <li><span class="vevent">2009<span style="display:none"> (<span class="bday dtstart published updated itvstart">2009</span>)</span>: <span class="summary"><a href="/wiki/Kickstarter" title="Kickstarter">Kickstarter</a>, a <a href="/wiki/Threshold_pledge_system" title="Threshold pledge system">threshold pledge system</a></span></span></li> <li><span class="vevent">2009<span style="display:none"> (<span class="bday dtstart published updated itvstart">2009</span>)</span>: <span class="summary"><a href="/wiki/Bitcoin" title="Bitcoin">Bitcoin</a>, a <a href="/wiki/Digital_currency" title="Digital currency">digital currency</a></span></span></li> <li><span class="vevent">2010<span style="display:none"> (<span class="bday dtstart published updated itvstart">2010</span>)</span>: <span class="summary"><a href="/wiki/Instagram" title="Instagram">Instagram</a>, <a href="/wiki/Photo_sharing" class="mw-redirect" title="Photo sharing">photo sharing</a> and <a href="/wiki/Social_networking" class="mw-redirect" title="Social networking">social networking</a></span></span></li> <li><span class="vevent">2011<span style="display:none"> (<span class="bday dtstart published updated itvstart">2011</span>)</span>: <span class="summary"><a href="/wiki/Google%2B" title="Google+">Google+</a>, <a href="/wiki/Social_networking" class="mw-redirect" title="Social networking">social networking</a></span></span></li> <li><span class="vevent">2011<span style="display:none"> (<span class="bday dtstart published updated itvstart">2011</span>)</span>: <span class="summary"><a href="/wiki/Snapchat" title="Snapchat">Snapchat</a>, <a href="/wiki/Photo_sharing" class="mw-redirect" title="Photo sharing">photo sharing</a></span></span></li> <li><span class="vevent">2012<span style="display:none"> (<span class="bday dtstart published updated itvstart">2012</span>)</span>: <span class="summary"><a href="/wiki/Coursera" title="Coursera">Coursera</a>, massive open online courses</span></span></li> <li><span class="vevent">2016<span style="display:none"> (<span class="bday dtstart published updated itvstart">2016</span>)</span>: <span class="summary"><a href="/wiki/TikTok" title="TikTok">TikTok</a>, <a href="/wiki/Video_sharing" class="mw-redirect" title="Video sharing">video sharing</a> and <a href="/wiki/Social_networking" class="mw-redirect" title="Social networking">social networking</a></span></span></li></ul> </td></tr></tbody></table> <p><b>Border Gateway Protocol</b> (<b>BGP</b>) is a standardized <a href="/wiki/Exterior_gateway_protocol" title="Exterior gateway protocol">exterior gateway protocol</a> designed to exchange <a href="/wiki/Routing" title="Routing">routing</a> and reachability information among <a href="/wiki/Autonomous_system_(Internet)" title="Autonomous system (Internet)">autonomous systems</a> (AS) on the <a href="/wiki/Internet" title="Internet">Internet</a>.<sup id="cite_ref-orbit_2-0" class="reference"><a href="#cite_note-orbit-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup> BGP is classified as a <a href="/wiki/Path-vector_routing_protocol" title="Path-vector routing protocol">path-vector routing protocol</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> and it makes routing decisions based on paths, network policies, or rule-sets configured by a <a href="/wiki/Network_administrator" title="Network administrator">network administrator</a>. </p><p>BGP used for routing within an autonomous system is called <b>Interior Border Gateway Protocol</b> (<b>iBGP</b>). In contrast, the Internet application of the protocol is called <b>Exterior Border Gateway Protocol</b> (<b>EBGP</b>). </p> <meta property="mw:PageProp/toc" /> <div class="mw-heading mw-heading2"><h2 id="History">History</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Border_Gateway_Protocol&action=edit&section=1" title="Edit section: History"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The genesis of BGP was in 1989 when <a href="/w/index.php?title=Kirk_Lougheed&action=edit&redlink=1" class="new" title="Kirk Lougheed (page does not exist)">Kirk Lougheed</a>, <a href="/wiki/Len_Bosack" class="mw-redirect" title="Len Bosack">Len Bosack</a> and <a href="/wiki/Yakov_Rekhter" title="Yakov Rekhter">Yakov Rekhter</a> were sharing a meal at an <a href="/wiki/IETF" class="mw-redirect" title="IETF">IETF</a> conference. They famously sketched the outline of their new routing protocol on the back of some napkins, hence often referenced to as the “Two Napkin Protocol”.<sup id="cite_ref-4" class="reference"><a href="#cite_note-4"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-5" class="reference"><a href="#cite_note-5"><span class="cite-bracket">[</span>5<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-6" class="reference"><a href="#cite_note-6"><span class="cite-bracket">[</span>6<span class="cite-bracket">]</span></a></sup> </p><p>It was first described in 1989 in RFC 1105, and has been in use on the Internet since 1994.<sup id="cite_ref-7" class="reference"><a href="#cite_note-7"><span class="cite-bracket">[</span>7<span class="cite-bracket">]</span></a></sup> <a href="/wiki/IPv6" title="IPv6">IPv6</a> BGP was first defined in <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><a href="/wiki/RFC_(identifier)" class="mw-redirect" title="RFC (identifier)">RFC</a> <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc1654">1654</a> in 1994, and it was improved to <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc2283">2283</a> in 1998. </p><p>The current version of BGP is version 4 (BGP4), which was first published as <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc1654">1654</a> in 1994, subsequently updated by <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc1771">1771</a> in 1995 and <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc4271">4271</a> in 2006.<sup id="cite_ref-8" class="reference"><a href="#cite_note-8"><span class="cite-bracket">[</span>8<span class="cite-bracket">]</span></a></sup> RFC 4271 corrected errors, clarified ambiguities and updated the specification with common industry practices. The major enhancement of BGP4 was the support for <a href="/wiki/Classless_Inter-Domain_Routing" title="Classless Inter-Domain Routing">Classless Inter-Domain Routing</a> (CIDR) and use of <a href="/wiki/Route_aggregation" class="mw-redirect" title="Route aggregation">route aggregation</a> to decrease the size of <a href="/wiki/Routing_table" title="Routing table">routing tables</a>. <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc4271">4271</a> allows BGP4 to carry a wide range of <a href="/wiki/IPv4" title="IPv4">IPv4</a> and IPv6 "address families". It is also called the Multiprotocol Extensions which is <a href="/wiki/Multiprotocol_BGP" title="Multiprotocol BGP">Multiprotocol BGP</a> (MP-BGP). </p> <div class="mw-heading mw-heading2"><h2 id="Operation">Operation</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Border_Gateway_Protocol&action=edit&section=2" title="Edit section: Operation"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>BGP neighbors, called peers, are established by manual configuration among <a href="/wiki/Router_(computing)" title="Router (computing)">routers</a> to create a <a href="/wiki/Transmission_Control_Protocol" title="Transmission Control Protocol">TCP</a> session on <a href="/wiki/Port_(computer_networking)" title="Port (computer networking)">port</a> 179. A BGP speaker sends 19-byte keep-alive messages every 30 seconds (protocol default value, tunable) to maintain the connection.<sup id="cite_ref-9" class="reference"><a href="#cite_note-9"><span class="cite-bracket">[</span>9<span class="cite-bracket">]</span></a></sup> Among routing protocols, BGP is unique in using TCP as its transport protocol. </p><p>When BGP runs between two peers in the same <a href="/wiki/Autonomous_system_(Internet)" title="Autonomous system (Internet)">autonomous system</a> (AS), it is referred to as <i>Internal BGP</i> (<i>iBGP</i> or <i>Interior Border Gateway Protocol</i>). When it runs between different autonomous systems, it is called <i>External BGP</i> (<i>eBGP</i> or <i>Exterior Border Gateway Protocol</i>). Routers on the boundary of one AS exchanging information with another AS are called <i>border</i> or <i>edge routers</i> or simply <i>eBGP peers</i> and are typically connected directly, while <i>iBGP peers</i> can be interconnected through other intermediate routers. Other deployment <a href="/wiki/Network_topology" title="Network topology">topologies</a> are also possible, such as running eBGP <a href="/wiki/Peering" title="Peering">peering</a> inside a <a href="/wiki/VPN" class="mw-redirect" title="VPN">VPN</a> tunnel, allowing two remote sites to exchange routing information in a secure and isolated manner. </p><p>The main difference between iBGP and eBGP peering is in the way routes that were received from one peer are typically propagated by default to other peers: </p> <ul><li>New routes learned from an eBGP peer are re-advertised to all iBGP and eBGP peers.</li> <li>New routes learned from an iBGP peer are re-advertised to all eBGP peers only.</li></ul> <p>These route-propagation rules effectively require that all iBGP peers inside an AS are interconnected in a full mesh with iBGP sessions. </p><p>How routes are propagated can be controlled in detail via the <i>route-maps</i> mechanism. This mechanism consists of a set of rules. Each rule describes, for routes matching some given criteria, what action should be taken. The action could be to drop the route, or it could be to modify some attributes of the route before inserting it in the routing table. </p> <div class="mw-heading mw-heading3"><h3 id="Extensions_negotiation">Extensions negotiation</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Border_Gateway_Protocol&action=edit&section=3" title="Edit section: Extensions negotiation"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>During the peering handshake, when OPEN messages are exchanged, BGP speakers can negotiate optional capabilities of the session,<sup id="cite_ref-10" class="reference"><a href="#cite_note-10"><span class="cite-bracket">[</span>10<span class="cite-bracket">]</span></a></sup> including <a href="/wiki/Multiprotocol_BGP" title="Multiprotocol BGP">multiprotocol extensions</a><sup id="cite_ref-11" class="reference"><a href="#cite_note-11"><span class="cite-bracket">[</span>11<span class="cite-bracket">]</span></a></sup> and various recovery modes. If the multiprotocol extensions to BGP are negotiated at the time of creation, the BGP speaker can prefix the Network Layer Reachability Information (NLRI) it advertises with an address family prefix. These families include the IPv4 (default), IPv6, IPv4/IPv6 Virtual Private Networks and multicast BGP. Increasingly, BGP is used as a generalized signaling protocol to carry information about routes that may not be part of the global Internet, such as VPNs.<sup id="cite_ref-12" class="reference"><a href="#cite_note-12"><span class="cite-bracket">[</span>12<span class="cite-bracket">]</span></a></sup> </p><p>In order to make decisions in its operations with peers, a BGP peer uses a simple <a href="/wiki/Finite-state_machine" title="Finite-state machine">finite-state machine</a> (FSM) that consists of six states: Idle; Connect; Active; OpenSent; OpenConfirm; and Established. For each peer-to-peer session, a BGP implementation maintains a state variable that tracks which of these six states the session is in. The BGP defines the messages that each peer should exchange in order to change the session from one state to another. </p><p>The first state is the Idle state. In the Idle state, BGP initializes all resources, refuses all inbound BGP connection attempts and initiates a TCP connection to the peer. The second state is Connect. In the Connect state, the router waits for the TCP connection to complete and transitions to the OpenSent state if successful. If unsuccessful, it starts the ConnectRetry timer and transitions to the Active state upon expiration. In the Active state, the router resets the ConnectRetry timer to zero and returns to the Connect state. In the OpenSent state, the router sends an Open message and waits for one in return in order to transition to the OpenConfirm state. Keepalive messages are exchanged and, upon successful receipt, the router is placed into the Established state. In the Established state, the router can send and receive: Keepalive; Update; and Notification messages to and from its peer. </p> <ul><li><b>Idle State</b>: <ul><li>Refuse all incoming BGP connections.</li> <li>Start the initialization of event triggers.</li> <li>Initiates a TCP connection with its configured BGP peer.</li> <li>Listens for a TCP connection from its peer.</li> <li>Changes its state to Connect.</li> <li>If an error occurs at any state of the FSM process, the BGP session is terminated immediately and returned to the Idle state. Some of the reasons why a router does not progress from the Idle state are: <ul><li>TCP port 179 is not open.</li> <li>A random TCP port over 1023 is not open.</li> <li>Peer address configured incorrectly on either router.</li> <li>AS number configured incorrectly on either router.</li></ul></li></ul></li> <li><b>Connect State</b>: <ul><li>Waits for successful TCP negotiation with peer.</li> <li>BGP does not spend much time in this state if the TCP session has been successfully established.</li> <li>Sends Open message to peer and changes state to OpenSent.</li> <li>If an error occurs, BGP moves to the Active state. Some reasons for the error are: <ul><li>TCP port 179 is not open.</li> <li>A random TCP port over 1023 is not open.</li> <li>Peer address configured incorrectly on either router.</li> <li>AS number configured incorrectly on either router.</li></ul></li></ul></li> <li><b>Active State</b>: <ul><li>If the router was unable to establish a successful TCP session, then it ends up in the Active state.</li> <li>BGP FSM tries to restart another TCP session with the peer and, if successful, then it sends an Open message to the peer.</li> <li>If it is unsuccessful again, the FSM is reset to the Idle state.</li> <li>Repeated failures may result in a router cycling between the Idle and Active states. Some of the reasons for this include: <ul><li>TCP port 179 is not open.</li> <li>A random TCP port over 1023 is not open.</li> <li>BGP configuration error.</li> <li>Network congestion.</li> <li>Flapping network interface.</li></ul></li></ul></li> <li><b>OpenSent State</b>: <ul><li>BGP FSM listens for an Open message from its peer.</li> <li>Once the message has been received, the router checks the validity of the Open message.</li> <li>If there is an error it is because one of the fields in the Open message does not match between the peers, e.g., BGP version mismatch, the peering router expects a different My AS, etc. The router then sends a Notification message to the peer indicating why the error occurred.</li> <li>If there is no error, a Keepalive message is sent, various timers are set and the state is changed to OpenConfirm.</li></ul></li> <li><b>OpenConfirm State</b>: <ul><li>The peer is listening for a Keepalive message from its peer.</li> <li>If a Keepalive message is received and no timer has expired before reception of the Keepalive, BGP transitions to the Established state.</li> <li>If a timer expires before a Keepalive message is received, or if an error condition occurs, the router transitions back to the Idle state.</li></ul></li> <li><b>Established State</b>: <ul><li>In this state, the peers send Update messages to exchange information about each route being advertised to the BGP peer.</li> <li>If there is any error in the Update message then a Notification message is sent to the peer, and BGP transitions back to the Idle state.</li></ul></li></ul> <div class="mw-heading mw-heading3"><h3 id="Router_connectivity_and_learning_routes">Router connectivity and learning routes</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Border_Gateway_Protocol&action=edit&section=4" title="Edit section: Router connectivity and learning routes"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1251242444"><table class="box-Technical plainlinks metadata ambox ambox-style ambox-technical" role="presentation"><tbody><tr><td class="mbox-image"><div class="mbox-image-div"><span typeof="mw:File"><span><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/f/f2/Edit-clear.svg/40px-Edit-clear.svg.png" decoding="async" width="40" height="40" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/f/f2/Edit-clear.svg/60px-Edit-clear.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/f/f2/Edit-clear.svg/80px-Edit-clear.svg.png 2x" data-file-width="48" data-file-height="48" /></span></span></div></td><td class="mbox-text"><div class="mbox-text-span">This section <b>may be too technical for most readers to understand</b>.<span class="hide-when-compact"> Please <a class="external text" href="https://en.wikipedia.org/w/index.php?title=Border_Gateway_Protocol&action=edit">help improve it</a> to <a href="/wiki/Wikipedia:Make_technical_articles_understandable" title="Wikipedia:Make technical articles understandable">make it understandable to non-experts</a>, without removing the technical details.</span> <span class="date-container"><i>(<span class="date">April 2021</span>)</i></span><span class="hide-when-compact"><i> (<small><a href="/wiki/Help:Maintenance_template_removal" title="Help:Maintenance template removal">Learn how and when to remove this message</a></small>)</i></span></div></td></tr></tbody></table> <p>In the simplest arrangement, all routers within a single AS and participating in BGP routing must be configured in a full mesh: each router must be configured as a peer to every other router. This causes scaling problems, since the number of required connections <a href="/wiki/Quadratic_growth" title="Quadratic growth">grows quadratically</a> with the number of routers involved. To alleviate the problem, BGP implements two options: <a href="/wiki/Route_reflector" class="mw-redirect" title="Route reflector">route reflectors</a> (RFC 4456) and <a href="/wiki/BGP_confederation" class="mw-redirect" title="BGP confederation">BGP confederations</a> (RFC 5065). The following discussion of basic update processing assumes a full iBGP mesh. </p><p>A given BGP router may accept <a href="#Update_Packet">network-layer reachability information (NLRI) updates</a> from multiple neighbors and advertise NLRI to the same, or a different set, of neighbors. The BGP process maintains several <a href="/wiki/Routing_information_base" class="mw-redirect" title="Routing information base">routing information bases</a>: </p> <ul><li><code>RIB</code>: routers main routing information base table.</li> <li><code>Loc-RIB</code>: local routing information base BGP maintains its own master routing table separate from the main routing table of the router.</li> <li><code>Adj-RIB-In</code>: For each neighbor, the BGP process maintains a conceptual <i>adjacent routing information base, incoming</i>, containing the NLRI received from the neighbor.</li> <li><code>Adj-RIB-Out</code>: For each neighbor, the BGP process maintains a conceptual <i>adjacent routing information base, outgoing </i>, containing the NLRI send to the neighbor.</li></ul> <p>The physical storage and structure of these conceptual tables are decided by the implementer of the BGP code. Their structure is not visible to other BGP routers, although they usually can be interrogated with management commands on the local router. It is quite common, for example, to store the <code>Adj-RIB-In</code>, <code>Adj-RIB-Out</code> and the <code>Loc-RIB</code> together in the same data structure, with additional information attached to the RIB entries. The additional information tells the BGP process such things as whether individual entries belong in the <code>Adj-RIBs</code> for specific neighbors, whether the peer-neighbor route selection process made received policies eligible for the <code>Loc-RIB</code>, and whether <code>Loc-RIB</code> entries are eligible to be submitted to the local router's routing table management process. </p><p>BGP submits the routes that it considers best to the main routing table process. Depending on the implementation of that process, the BGP route is not necessarily selected. For example, a directly connected prefix, learned from the router's own hardware, is usually most preferred. As long as that directly connected route's interface is active, the BGP route to the destination will not be put into the routing table. Once the interface goes down, and there are no more preferred routes, the Loc-RIB route would be installed in the main routing table. </p><p>BGP carries the information with which rules inside BGP-speaking routers can make policy decisions. Some of the information carried that is explicitly intended to be used in policy decisions are: </p> <ul><li><a href="#Communities">Communities</a></li> <li><a href="#Multi-exit_discriminators">multi-exit discriminators</a> (MED).</li> <li><a href="/wiki/Autonomous_system_(Internet)" title="Autonomous system (Internet)">autonomous systems</a> (AS)</li></ul> <div class="mw-heading mw-heading3"><h3 id="Route_selection_process">Route selection process</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Border_Gateway_Protocol&action=edit&section=5" title="Edit section: Route selection process"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The BGP standard specifies a number of decision factors, more than the ones that are used by any other common routing process, for selecting NLRI to go into the Loc-RIB. The first decision point for evaluating NLRI is that its next-hop attribute must be reachable (or resolvable). Another way of saying the next-hop must be reachable is that there must be an active route, already in the main routing table of the router, to the prefix in which the next-hop address is reachable. </p><p>Next, for each neighbor, the BGP process applies various standard and implementation-dependent criteria to decide which routes conceptually should go into the Adj-RIB-In. The neighbor could send several possible routes to a destination, but the first level of preference is at the neighbor level. Only one route to each destination will be installed in the conceptual Adj-RIB-In. This process will also delete, from the Adj-RIB-In, any routes that are withdrawn by the neighbor. </p><p>Whenever a conceptual Adj-RIB-In changes, the main BGP process decides if any of the neighbor's new routes are preferred to routes already in the Loc-RIB. If so, it replaces them. If a given route is withdrawn by a neighbor, and there is no other route to that destination, the route is removed from the Loc-RIB and no longer sent by BGP to the main routing table manager. If the router does not have a route to that destination from any non-BGP source, the withdrawn route will be removed from the main routing table. </p><p>As long as there is <a href="/wiki/Tiebreaker" title="Tiebreaker">tiebreaker</a> the route selection process moves to the next step. </p> <table class="wikitable"> <caption>Steps to determine best path, in order of <a href="/wiki/Tiebreaker" title="Tiebreaker">tiebreaker</a>: <sup id="cite_ref-13" class="reference"><a href="#cite_note-13"><span class="cite-bracket">[</span>13<span class="cite-bracket">]</span></a></sup> <sup id="cite_ref-14" class="reference"><a href="#cite_note-14"><span class="cite-bracket">[</span>14<span class="cite-bracket">]</span></a></sup> </caption> <tbody><tr> <th>Step</th> <th>Scope</th> <th>Name</th> <th>Default</th> <th>Preferred</th> <th>BGP field</th> <th>NOTE </th></tr> <tr> <td>1</td> <td>Local to router</td> <td>local Weight</td> <td style="background: #EEE; color: black; vertical-align: middle; text-align: center;" class="table-no2">"Off"</td> <td>Higher</td> <td></td> <td>Cisco-specific parameter </td></tr> <tr> <td>2</td> <td rowspan="2">Internal to AS</td> <td>Local preference</td> <td style="background: #EEE; color: black; vertical-align: middle; text-align: center;" class="table-no2">"Off", all set to 100.</td> <td>Higher</td> <td>LOCAL_PREF</td> <td>If there are several iBGP routes from the neighbor, the one with the highest local preference is selected unless there are several routes with the same local preference. </td></tr> <tr> <td>3</td> <td>Accumulated Interior Gateway Protocol (AIGP)</td> <td style="background: #EEE; color: black; vertical-align: middle; text-align: center;" class="table-no2">"Off"</td> <td>Lowest </td> <td>AIGP</td> <td>rfc7311 </td></tr> <tr> <td>4</td> <td rowspan="3">External to AS</td> <td>Autonomous system (AS) jumps</td> <td style="background: #BFD; color:black; vertical-align: middle; text-align: center;" class="yes2 table-yes2">"On", skipped if ignored in configuration</td> <td>Lowest </td> <td>AS-path</td> <td>AS jumps is the number of AS numbers that must be traversed to reach the advertised destination. AS1–AS2–AS3 is a shorter path with fewer jumps than AS4–AS5–AS6–AS7. </td></tr> <tr> <td>5</td> <td>origin type</td> <td>"IGP"</td> <td>Lowest </td> <td>ORIGIN</td> <td>0 = IGP<br />1 = EGP<br />2 = Incomplete </td></tr> <tr> <td>6</td> <td>multi-exit discriminator (MED)</td> <td style="background: #BFD; color:black; vertical-align: middle; text-align: center;" class="yes2 table-yes2">"on", imported from IGP</td> <td>Lowest </td> <td>MULTI_EXIT_DISC</td> <td>By default only route with the same autonomous system (AS) is compared. Can be set to ignore same autonomous system (AS). <br /> <p>By default Internal IGP is not added. Can be set to add IGP metric. Before the most recent edition of the BGP standard, if an update had no MED value, several implementations created a MED with the highest possible value. The current standard specifies that missing MEDs are treated as the lowest possible value. Since the current rule may cause different behavior than the vendor interpretations, BGP implementations that used the nonstandard default value have a configuration feature that allows the old or standard rule to be selected. </p> </td></tr> <tr> <td>7</td> <td rowspan="6">Local to router (Loc-RIB)</td> <td>eBGP over iBGP paths</td> <td>"on"</td> <td></td> <td></td> <td>Directly connected, over indirectly </td></tr> <tr> <td>8</td> <td>IGP metric to BGP next hop</td> <td>"on", imported from IGP</td> <td>Lowest </td> <td></td> <td>Continue, even if bestpath is already selected. Prefer the route with the lowest interior cost to the next hop, according to the main routing table. If two neighbors advertised the same route, but one neighbor is reachable via a low-bitrate link and the other by a high-bitrate link, and the <a href="/wiki/Interior_routing_protocol" class="mw-redirect" title="Interior routing protocol">interior routing protocol</a> calculates lowest cost based on highest bitrate, the route through the high-bitrate link would be preferred and other routes dropped. </td></tr> <tr> <td>9</td> <td>Path that was received first</td> <td>"on"</td> <td>oldest</td> <td></td> <td>Used to ignore changes on the steps 10+ </td></tr> <tr> <td>10</td> <td>Router ID</td> <td>"on"</td> <td>Lowest </td> <td></td> <td> </td></tr> <tr> <td>11</td> <td>Cluster list length</td> <td>"on"</td> <td>Lowest </td> <td></td> <td> </td></tr> <tr> <td>12</td> <td>Neighbor address</td> <td>"on"</td> <td>Lowest </td></tr></tbody></table> <p>The local preference, weight, and other criteria can be manipulated by local configuration and software capabilities. Such manipulation, although commonly used, is outside the scope of the standard. For example, the <i>community</i> attribute (see below) is not directly used by the BGP selection process. The BGP neighbor process can have a rule to set local preference or another factor based on a manually programmed rule to set the attribute if the community value matches some pattern-matching criterion. If the route was learned from an external peer the per-neighbor BGP process computes a local preference value from local policy rules and then compares the local preference of all routes from the neighbor. </p> <div class="mw-heading mw-heading3"><h3 id="Communities">Communities</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Border_Gateway_Protocol&action=edit&section=6" title="Edit section: Communities"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>BGP communities are attribute tags that can be applied to incoming or outgoing prefixes to achieve some common goal.<sup id="cite_ref-15" class="reference"><a href="#cite_note-15"><span class="cite-bracket">[</span>15<span class="cite-bracket">]</span></a></sup> While it is common to say that BGP allows an administrator to set policies on how prefixes are handled by ISPs, this is generally not possible, strictly speaking. For instance, BGP natively has no concept to allow one AS to tell another AS to restrict advertisement of a prefix to only North American peering customers. Instead, an ISP generally publishes a list of well-known or proprietary communities with a description for each one, which essentially becomes an agreement of how prefixes are to be treated. </p> <table class="wikitable"> <caption>Well-known BGP communities<sup id="cite_ref-16" class="reference"><a href="#cite_note-16"><span class="cite-bracket">[</span>16<span class="cite-bracket">]</span></a></sup> </caption> <tbody><tr> <th>Attribute value</th> <th>Attribute</th> <th>Description</th> <th>Reference </th></tr> <tr> <td>0x00000000-0x0000FFFF</td> <td>Reserved</td> <td></td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><a href="/wiki/RFC_(identifier)" class="mw-redirect" title="RFC (identifier)">RFC</a> <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc1997">1997</a> </td></tr> <tr> <td>0x00010000-0xFFFEFFFF</td> <td>Reserved for private use</td> <td></td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><a href="/wiki/RFC_(identifier)" class="mw-redirect" title="RFC (identifier)">RFC</a> <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc1997">1997</a> </td></tr> <tr> <td>0xFFFF0000</td> <td>GRACEFUL_SHUTDOWN</td> <td>At neighbor AS-peer, set LOCAL_PREF, lower to route away from source.</td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><a href="/wiki/RFC_(identifier)" class="mw-redirect" title="RFC (identifier)">RFC</a> <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc8326">8326</a> </td></tr> <tr> <td>0xFFFF0001</td> <td>ACCEPT_OWN</td> <td>Used to modify how a route originated within one VRF is imported into other VRFs</td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><a href="/wiki/RFC_(identifier)" class="mw-redirect" title="RFC (identifier)">RFC</a> <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc7611">7611</a> </td></tr> <tr> <td>0xFFFF0002</td> <td>ROUTE_FILTER_TRANSLATED_v4</td> <td></td> <td>RFC draft-l3vpn-legacy-rtc </td></tr> <tr> <td>0xFFFF0003</td> <td>ROUTE_FILTER_v4</td> <td></td> <td>RFC draft-l3vpn-legacy-rtc </td></tr> <tr> <td>0xFFFF0004</td> <td>ROUTE_FILTER_TRANSLATED_v6</td> <td></td> <td>RFC draft-l3vpn-legacy-rtc </td></tr> <tr> <td>0xFFFF0005</td> <td>ROUTE_FILTER_v6</td> <td></td> <td>RFC draft-l3vpn-legacy-rtc </td></tr> <tr> <td>0xFFFF0006</td> <td>LLGR_STALE</td> <td>Stale routes are retained for longer after a session failure</td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><a href="/wiki/RFC_(identifier)" class="mw-redirect" title="RFC (identifier)">RFC</a> <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc9494">9494</a> </td></tr> <tr> <td>0xFFFF0007</td> <td>NO_LLGR</td> <td>LLGR capability should not apply</td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><a href="/wiki/RFC_(identifier)" class="mw-redirect" title="RFC (identifier)">RFC</a> <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc9494">9494</a> </td></tr> <tr> <td>0xFFFF0008</td> <td>accept-own-nexthop</td> <td></td> <td>RFC draft-agrewal-idr-accept-own-nexthop </td></tr> <tr> <td>0xFFFF0009</td> <td>Standby PE</td> <td>Allow for faster recovery of connectivity on different types of failures, with multicast in BGP/MPLS VPNs.</td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><a href="/wiki/RFC_(identifier)" class="mw-redirect" title="RFC (identifier)">RFC</a> <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc9026">9026</a> </td></tr> <tr> <td>0xFFFF029A</td> <td>BLACKHOLE</td> <td>To temporarily protect against <a href="/wiki/Denial-of-service_attack" title="Denial-of-service attack">denial-of-service attack</a> by asking the neighbour AS to discard all traffic to the prefix (blackholing)</td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><a href="/wiki/RFC_(identifier)" class="mw-redirect" title="RFC (identifier)">RFC</a> <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc7999">7999</a> </td></tr> <tr> <td>0xFFFFFF01</td> <td>NO_EXPORT</td> <td>Limit to a BGP confederation boundary</td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><a href="/wiki/RFC_(identifier)" class="mw-redirect" title="RFC (identifier)">RFC</a> <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc1997">1997</a> </td></tr> <tr> <td>0xFFFFFF02</td> <td>NO_ADVERTISE</td> <td>Limit to a BGP peer</td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><a href="/wiki/RFC_(identifier)" class="mw-redirect" title="RFC (identifier)">RFC</a> <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc1997">1997</a> </td></tr> <tr> <td>0xFFFFFF03</td> <td>NO_EXPORT_SUBCONFED</td> <td>Limit to an AS</td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><a href="/wiki/RFC_(identifier)" class="mw-redirect" title="RFC (identifier)">RFC</a> <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc1997">1997</a> </td></tr> <tr> <td>0xFFFFFF04</td> <td>NOPEER</td> <td>"No need" to advertise over a peer link</td> <td><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><a href="/wiki/RFC_(identifier)" class="mw-redirect" title="RFC (identifier)">RFC</a> <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc3765">3765</a> </td></tr></tbody></table> <p>Examples of common communities include: </p> <ul><li>local preference adjustments,</li> <li>geographic</li> <li>peer type restrictions</li> <li><a href="/wiki/Denial-of-service_attack" title="Denial-of-service attack">denial-of-service attack</a> identification</li> <li>AS prepending options.</li></ul> <p>An ISP might state that any routes received from customers with following examples: </p> <ul><li>To Customers North America (East Coast) 3491:100</li> <li>To Customers North America (West Coast) 3491:200</li></ul> <p>The customer simply adjusts their configuration to include the correct community or communities for each route, and the ISP is responsible for controlling who the prefix is advertised to. The end user has no technical ability to enforce correct actions being taken by the ISP, though problems in this area are generally rare and accidental.<sup id="cite_ref-17" class="reference"><a href="#cite_note-17"><span class="cite-bracket">[</span>17<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-18" class="reference"><a href="#cite_note-18"><span class="cite-bracket">[</span>18<span class="cite-bracket">]</span></a></sup> </p><p>It is a common tactic for end customers to use BGP communities (usually ASN:70,80,90,100) to control the local preference the ISP assigns to advertised routes instead of using MED (the effect is similar). The community attribute is transitive, but communities applied by the customer very rarely propagated outside the next-hop AS. Not all ISPs give out their communities to the public.<sup id="cite_ref-19" class="reference"><a href="#cite_note-19"><span class="cite-bracket">[</span>19<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading4"><h4 id="BGP_Extended_Community_Attribute">BGP Extended Community Attribute</h4><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Border_Gateway_Protocol&action=edit&section=7" title="Edit section: BGP Extended Community Attribute"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The BGP Extended Community Attribute was added in 2006,<sup id="cite_ref-20" class="reference"><a href="#cite_note-20"><span class="cite-bracket">[</span>20<span class="cite-bracket">]</span></a></sup> in order to extend the range of such attributes and to provide a community attribute structuring by means of a type field. The extended format consists of one or two octets for the type field followed by seven or six octets for the respective community attribute content. The definition of this Extended Community Attribute is documented in RFC 4360. The IANA administers the registry for BGP Extended Communities Types.<sup id="cite_ref-21" class="reference"><a href="#cite_note-21"><span class="cite-bracket">[</span>21<span class="cite-bracket">]</span></a></sup> The Extended Communities Attribute itself is a transitive optional BGP attribute. A bit in the type field within the attribute decides whether the encoded extended community is of a transitive or non-transitive nature. The IANA registry therefore provides different number ranges for the attribute types. Due to the extended attribute range, its usage can be manifold. RFC 4360 exemplarily defines the "Two-Octet AS Specific Extended Community", the "IPv4 Address Specific Extended Community", the "Opaque Extended Community", the "Route Target Community", and the "Route Origin Community". A number of BGP QoS drafts also use this Extended Community Attribute structure for inter-domain QoS signalling.<sup id="cite_ref-22" class="reference"><a href="#cite_note-22"><span class="cite-bracket">[</span>22<span class="cite-bracket">]</span></a></sup> </p><p>With the introduction of 32-bit AS numbers, some issues were immediately obvious with the community attribute that only defines a 16-bit ASN field, which prevents the matching between this field and the real ASN value. Since RFC 7153, extended communities are compatible with 32-bit ASNs. RFC 8092 and RFC 8195 introduce a Large Community attribute of 12 bytes, divided in three field of 4 bytes each (AS:function:parameter).<sup id="cite_ref-23" class="reference"><a href="#cite_note-23"><span class="cite-bracket">[</span>23<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading3"><h3 id="Multi-exit_discriminators">Multi-exit discriminators</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Border_Gateway_Protocol&action=edit&section=8" title="Edit section: Multi-exit discriminators"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>MEDs, defined in the main BGP standard, were originally intended to show to another neighbor AS the advertising AS's preference as to which of several links are preferred for inbound traffic. Another application of MEDs is to advertise the value, typically based on delay, of multiple ASs that have a presence at an <a href="/wiki/IXP" class="mw-redirect" title="IXP">IXP</a>, that they impose to send traffic to some destination. </p><p>Some routers (like Juniper) will use the Metric from OSPF to set MED. </p><p><b>Examples of MED used with BGP when exported to BGP on Juniper SRX</b> </p> <div class="mw-highlight mw-highlight-lang-console mw-content-ltr" dir="ltr"><pre><span></span><span class="gp"># </span>run<span class="w"> </span>show<span class="w"> </span>ospf<span class="w"> </span>route<span class="w"> </span> <span class="go">Topology default Route Table:</span> <span class="go">Prefix Path Route NH Metric NextHop Nexthop </span> <span class="go"> Type Type Type Interface Address/LSP</span> <span class="go">10.32.37.0/24 Inter Discard IP 16777215</span> <span class="go">10.32.37.0/26 Intra Network IP 101 ge-0/0/1.0 10.32.37.241</span> <span class="go">10.32.37.64/26 Intra Network IP 102 ge-0/0/1.0 10.32.37.241</span> <span class="go">10.32.37.128/26 Intra Network IP 101 ge-0/0/1.0 10.32.37.241</span> <span class="gp"># </span>show<span class="w"> </span>route<span class="w"> </span>advertising-protocol<span class="w"> </span>bgp<span class="w"> </span><span class="m">10</span>.32.94.169 <span class="go"> Prefix Nexthop MED Lclpref AS path</span> <span class="go">* 10.32.37.0/24 Self 16777215 I</span> <span class="go">* 10.32.37.0/26 Self 101 I</span> <span class="go">* 10.32.37.64/26 Self 102 I</span> <span class="go">* 10.32.37.128/26 Self 101 I</span> </pre></div> <div class="mw-heading mw-heading2"><h2 id="Packet_format">Packet format</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Border_Gateway_Protocol&action=edit&section=9" title="Edit section: Packet format"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <div class="mw-heading mw-heading3"><h3 id="Message_header_format">Message header format</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Border_Gateway_Protocol&action=edit&section=10" title="Edit section: Message header format"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <table class="wikitable" style="text-align:center; border:none; background:none;"> <caption>BGP version 4 message header format<sup id="cite_ref-" class="reference"><a href="#cite_note-"><span class="cite-bracket">[</span>24<span class="cite-bracket">]</span></a></sup> </caption> <tbody><tr> <th style="width:4%;">bit offset </th> <th colspan="16" style="width:50%;">0–15 </th> <th colspan="8" style="width:25%;">16–23 </th> <th colspan="8" style="width:25%;">24–31 </th></tr> <tr> <th>0 </th> <td rowspan="4" colspan="32">Marker (always: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff) </td></tr> <tr> <th>32 </th></tr> <tr> <th>64 </th></tr> <tr> <th>96 </th></tr> <tr> <th>128 </th> <td colspan="16">Length </td> <td colspan="8">Type </td> <td colspan="8" style="border: none; background:none;"> </td></tr></tbody></table> <ul><li><b>Marker</b>: Included for compatibility, must be set to all ones.</li> <li><b>Length</b>: Total length of the message in <a href="/wiki/Octet_(computing)" title="Octet (computing)">octets</a>, including the header.</li> <li><b>Type</b>: Type of BGP message. The following values are defined: <ul><li>Open (1)</li> <li>Update (2)</li> <li>Notification (3)</li> <li>KeepAlive (4)</li> <li>Route-Refresh (5)</li></ul></li></ul> <p>note: "Marker" and "Length" is omitted from the examples. </p> <div class="mw-heading mw-heading3"><h3 id="Open_Packet">Open Packet</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Border_Gateway_Protocol&action=edit&section=11" title="Edit section: Open Packet"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <dl><dt>Version (8bit)</dt> <dd>Version of BGP used.</dd> <dt>My AS (16bit)</dt> <dd>Senders <a href="/wiki/Autonomous_system_(Internet)" title="Autonomous system (Internet)">autonomous system</a> number.</dd> <dt>Hold Time (16bit)</dt> <dd>Timeout timer, used to calculate KeepAlive messages. Default 90 seconds.</dd> <dt>BGP Identifier (32bit)</dt> <dd>IP-address of sender.</dd> <dd>Optional Parameters Length (8 bit): total length of the Optional parameters field.</dd></dl> <p><b>Example of Open Message</b> </p> <pre>Type: Open Message (1) Version: 4 My AS: 64496 Hold Time: 90 BGP Identifier: <i><span class="ipaddr"><span style="padding-right: 1px;">192.0.2.254</span></span></i> Optional Parameters Length: 16 Optional Parameters: Capability: Multiprotocol extensions capability (1) Capability: Route refresh capability (2) Capability: Route refresh capability (Cisco) (128) </pre> <div class="mw-heading mw-heading3"><h3 id="Update_Packet">Update Packet</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Border_Gateway_Protocol&action=edit&section=12" title="Edit section: Update Packet"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Only changes are sent, after initial exchange, only difference (add/change/removed) are sent. </p><p><b>Example of UPDATE Message</b> </p> <pre>Type: UPDATE Message (2) Withdrawn Routes Length: 0 Total Path Attribute Length: 25 Path attributes ORIGIN: IGP AS_PATH: 64500 NEXT_HOP: 192.0.2.254 MULTI_EXIT_DISC: 0 Network Layer Reachability Information (NLRI) <i><span class="ipaddr"><span style="padding-right: 1px;">192.0.2.0/27</span></span></i> <i><span class="ipaddr"><span style="padding-right: 1px;">192.0.2.32/27</span></span></i> <i><span class="ipaddr"><span style="padding-right: 1px;">192.0.2.64/27</span></span></i> </pre> <div class="mw-heading mw-heading3"><h3 id="Notification">Notification</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Border_Gateway_Protocol&action=edit&section=13" title="Edit section: Notification"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>If there is an error it is because one of the fields in the OPEN or UPDATE message does not match between the peers, e.g., BGP version mismatch, the peering router expects a different My AS, etc. The router then sends a Notification message to the peer indicating why the error occurred. </p> <table class="wikitable mw-collapsible mw-collapsed" style="margin: 0 auto; text-align:center"> <caption>Error Codes </caption> <tbody><tr> <th rowspan="2">Error Code</th> <th rowspan="2">Name</th> <th colspan="2">subcodes </th></tr> <tr> <td>Code</td> <td>Name </td></tr> <tr> <td rowspan="3">1</td> <td rowspan="3">Message Header Error</td> <td>1</td> <td style="text-align:left">Connection Not Synchronized </td></tr> <tr> <td>2</td> <td style="text-align:left">Bad Message Length </td></tr> <tr> <td>3</td> <td style="text-align:left">Bad Message Type </td></tr> <tr> <td rowspan="6">2</td> <td rowspan="6">OPEN Message Error</td> <td>1</td> <td style="text-align:left">Unsupported Version Number. </td></tr> <tr> <td>2</td> <td style="text-align:left">Bad Peer AS. </td></tr> <tr> <td>3</td> <td style="text-align:left">Bad BGP Identifier. </td></tr> <tr> <td>4</td> <td style="text-align:left">Unsupported Authentication Code. </td></tr> <tr> <td>5</td> <td style="text-align:left">Authentication Failure. </td></tr> <tr> <td>6</td> <td style="text-align:left">Unacceptable Hold Time. </td></tr> <tr> <td rowspan="11">3</td> <td rowspan="11" style="text-align:left">UPDATE Message Error</td> <td>1</td> <td style="text-align:left">Malformed Attribute List. </td></tr> <tr> <td>2</td> <td style="text-align:left">Unrecognized Well-known Attribute. </td></tr> <tr> <td>3</td> <td style="text-align:left">Missing Well-known Attribute. </td></tr> <tr> <td>4</td> <td style="text-align:left">Attribute Flags Error. </td></tr> <tr> <td>5</td> <td style="text-align:left">Attribute Length Error. </td></tr> <tr> <td>6</td> <td style="text-align:left">Invalid ORIGIN Attribute </td></tr> <tr> <td>7</td> <td style="text-align:left">AS Routing Loop. </td></tr> <tr> <td>8</td> <td style="text-align:left">Invalid NEXT_HOP Attribute. </td></tr> <tr> <td>9</td> <td style="text-align:left">Optional Attribute Error. </td></tr> <tr> <td>10</td> <td style="text-align:left">Invalid Network Field. </td></tr> <tr> <td>11</td> <td style="text-align:left">Malformed AS_PATH. </td></tr> <tr> <td>4</td> <td colspan="3">Hold Timer Expired </td></tr> <tr> <td>5</td> <td colspan="3">Finite State Machine Error </td></tr> <tr> <td>6</td> <td colspan="3">Cease </td></tr></tbody></table> <p><b>Example of NOTIFICATION Message</b> </p> <pre>Type: NOTIFICATION Message (3) Major error Code: OPEN Message Error (2) Minor error Code (Open Message): Bad Peer AS (2) Bad Peer AS: 65200 </pre> <div class="mw-heading mw-heading3"><h3 id="KeepAlive">KeepAlive</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Border_Gateway_Protocol&action=edit&section=14" title="Edit section: KeepAlive"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>KeepAlive messages are sent periodically, to verify that remote peer is still alive. keepalives should be sent at intervals of one third the <code>holdtime</code>. </p><p><b>Example of KEEPALIVE Message</b> </p> <pre>Type: KEEPALIVE Message (4) </pre> <div class="mw-heading mw-heading3"><h3 id="Route-Refresh">Route-Refresh</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Border_Gateway_Protocol&action=edit&section=15" title="Edit section: Route-Refresh"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Defined in RFC<link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc7313">7313</a>. </p><p>Allows for soft updating of <code>Adj-RIB-in</code>, without resetting connection. </p><p><b>Example of ROUTE-REFRESH Message</b> </p> <pre>Type: ROUTE-REFRESH Message (5) Address family identifier (AFI): IPv4 (1) Subtype: Normal route refresh request [RFC2918] with/without ORF [RFC5291] (0) Subsequent address family identifier (SAFI): Unicast (1) </pre> <div class="mw-heading mw-heading2"><h2 id="Internal_scalability">Internal scalability</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Border_Gateway_Protocol&action=edit&section=16" title="Edit section: Internal scalability"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>BGP is "the most scalable of all routing protocols."<sup id="cite_ref-25" class="reference"><a href="#cite_note-25"><span class="cite-bracket">[</span>25<span class="cite-bracket">]</span></a></sup> </p><p>An autonomous system with internal BGP (iBGP) must have all of its iBGP peers connect to each other in a <a href="/wiki/Complete_graph" title="Complete graph">full mesh</a> (where everyone speaks to everyone directly). This full-mesh configuration requires that each router maintain a session with every other router. In large networks, this number of sessions may degrade the performance of routers, due to either a lack of memory, or high CPU process requirements. </p> <div class="mw-heading mw-heading3"><h3 id="Route_reflectors">Route reflectors</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Border_Gateway_Protocol&action=edit&section=17" title="Edit section: Route reflectors"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p><b>Route reflectors</b> (RRs) reduce the number of connections required in an AS. A single router (or two for redundancy) can be made an RR: other routers in the AS need only be configured as peers to them. An RR offers an alternative to the logical full-mesh requirement of iBGP. The purpose of the RR is concentration. Multiple BGP routers can peer with a central point, the RR –  acting as an RR server –  rather than peer with every other router in a full mesh. All the other iBGP routers become RR clients.<sup id="cite_ref-26" class="reference"><a href="#cite_note-26"><span class="cite-bracket">[</span>26<span class="cite-bracket">]</span></a></sup> </p><p>This approach, similar to <a href="/wiki/OSPF" class="mw-redirect" title="OSPF">OSPF</a>'s DR/BDR feature, provides large networks with added iBGP scalability. In a fully meshed iBGP network of 10 routers, 90 individual CLI statements (spread throughout all routers in the topology) are needed just to define the remote-AS of each peer: this quickly becomes a headache to manage. An RR topology can cut these 90 statements down to 18, offering a viable solution for the larger networks administered by ISPs. </p><p>An RR is a <a href="/wiki/Single_point_of_failure" title="Single point of failure">single point of failure</a>, therefore at least a second RR may be configured in order to provide redundancy. As it is an additional peer for the other 10 routers, it approximately doubles the number of CLI statements, requiring an additional <span class="nowrap">11 × 2 − 2 = 20</span> statements in this case. In a BGP multipath environment the additional RR also can benefit the network by adding local routing throughput if the RRs are acting as traditional routers instead of just a dedicated RR server role. </p><p>RRs and confederations both reduce the number of iBGP peers to each router and thus reduce processing overhead. RRs are a pure performance-enhancing technique, while confederations also can be used to implement more fine-grained policy. </p> <div class="mw-heading mw-heading4"><h4 id="Rules">Rules</h4><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Border_Gateway_Protocol&action=edit&section=18" title="Edit section: Rules"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure typeof="mw:File/Thumb"><a href="/wiki/File:RR_BGP.svg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/6/6e/RR_BGP.svg/300px-RR_BGP.svg.png" decoding="async" width="300" height="212" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/6/6e/RR_BGP.svg/450px-RR_BGP.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/6/6e/RR_BGP.svg/600px-RR_BGP.svg.png 2x" data-file-width="1052" data-file-height="744" /></a><figcaption>A typical configuration of BGP RR deployment, as proposed by Section 6, RFC 4456.</figcaption></figure> <p>RR servers propagate routes inside the AS based on the following rules: </p> <ul><li>Routes are always reflected to eBGP peers.</li> <li>Routes are never reflected to the originator of the route.</li> <li>If a route is received from a non-client peer, reflect to client peers.</li> <li>If a route is received from a client peer, reflect to client and non-client peers.</li></ul> <div class="mw-heading mw-heading4"><h4 id="Cluster">Cluster</h4><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Border_Gateway_Protocol&action=edit&section=19" title="Edit section: Cluster"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>An RR and its clients form a <i>cluster</i>. The <i>cluster ID</i> is then attached to every route advertised by the RR to its client or nonclient peers. A cluster ID is a cumulative, non-transitive BGP attribute, and every RR must prepend the local cluster ID to the cluster list to avoid routing loops. </p> <div class="mw-heading mw-heading3"><h3 id="Confederation">Confederation</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Border_Gateway_Protocol&action=edit&section=20" title="Edit section: Confederation"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Confederations are sets of autonomous systems. In common practice,<sup id="cite_ref-27" class="reference"><a href="#cite_note-27"><span class="cite-bracket">[</span>27<span class="cite-bracket">]</span></a></sup> only one of the confederation AS numbers is seen by the Internet as a whole. Confederations are used in very large networks where a large AS can be configured to encompass smaller more manageable internal ASs. </p><p>The confederated AS is composed of multiple ASs. Each confederated AS alone has iBGP fully meshed and has connections to other ASs inside the confederation. Even though these ASs have eBGP peers to ASs within the confederation, the ASs exchange routing as if they used iBGP. In this way, the confederation preserves next hop, metric, and local preference information. To the outside world, the confederation appears to be a single AS. With this solution, iBGP transit AS problems can be resolved as iBGP requires a full mesh between all BGP routers: large number of TCP sessions and unnecessary duplication of routing traffic.<sup class="noprint Inline-Template" style="margin-left:0.1em; white-space:nowrap;">[<i><a href="/wiki/Wikipedia:Please_clarify" title="Wikipedia:Please clarify"><span title="My guess is this is trying to say that using eBGP within a confederation avoids scaling issues that would exist if iBGP were used instead. (October 2022)">clarification needed</span></a></i>]</sup> </p><p>Confederations can be used in conjunction with route reflectors. Both confederations and route reflectors can be subject to persistent oscillation unless specific design rules, affecting both BGP and the interior routing protocol, are followed.<sup id="cite_ref-28" class="reference"><a href="#cite_note-28"><span class="cite-bracket">[</span>28<span class="cite-bracket">]</span></a></sup> </p><p>These alternatives can introduce problems of their own, including the following: </p> <ul><li>route oscillation</li> <li>sub-optimal routing</li> <li>increase of BGP convergence time<sup id="cite_ref-29" class="reference"><a href="#cite_note-29"><span class="cite-bracket">[</span>29<span class="cite-bracket">]</span></a></sup></li></ul> <p>Additionally, route reflectors and BGP confederations were not designed to ease BGP router configuration. Nevertheless, these are common tools for experienced BGP network architects. These tools may be combined, for example, as a hierarchy of route reflectors. </p> <div class="mw-heading mw-heading2"><h2 id="Stability">Stability</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Border_Gateway_Protocol&action=edit&section=21" title="Edit section: Stability"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The routing tables managed by a BGP implementation are adjusted continually to reflect actual changes in the network, such as links or routers going down and coming back up. In the network as a whole, it is normal for these changes to happen almost continuously, but for any particular router or link, changes are expected to be relatively infrequent. If a router is misconfigured or mismanaged then it may get into a rapid cycle between down and up states. This pattern of repeated withdrawal and re-announcement known as <a href="/wiki/Route_flapping" title="Route flapping">route flapping</a> can cause excessive activity in all the other routers that know about the cycling entity, as the same route is continually injected and withdrawn from the routing tables. The BGP design is such that delivery of traffic may not function while routes are being updated. On the Internet, a BGP routing change may cause outages for several minutes. </p><p>A feature known as <i>route flap damping</i> (<link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><a href="/wiki/RFC_(identifier)" class="mw-redirect" title="RFC (identifier)">RFC</a> <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc2439">2439</a>) is built into many BGP implementations in an attempt to mitigate the effects of route flapping. Without damping, the excessive activity can cause a heavy processing load on routers, which may in turn delay updates on other routes, and so affect overall routing stability. With damping, a route's flapping is <a href="/wiki/Exponential_decay" title="Exponential decay">exponentially decayed</a>. At the first instance when a route becomes unavailable and quickly reappears, damping does not take effect, so as to maintain the normal fail-over times of BGP. At the second occurrence, BGP shuns that prefix for a certain length of time; subsequent occurrences are ignored exponentially longer. After the abnormalities have ceased and a suitable length of time has passed for the offending route, prefixes can be reinstated with a clean slate. Damping can also mitigate <a href="/wiki/Denial-of-service_attack" title="Denial-of-service attack">denial-of-service attacks</a>. </p><p>It is also suggested in RFC 2439<sup class="reference nowrap"><span title="Page / location: Section 4">: Section 4 </span></sup> that route flap damping is a feature more desirable if implemented to Exterior Border Gateway Protocol Sessions (eBGP sessions or simply called exterior peers) and not on Interior Border Gateway Protocol Sessions (iBGP sessions or simply called internal peers). With this approach when a route flaps inside an autonomous system, it is not propagated to the external ASs –  flapping a route to an eBGP will cause a chain of flapping for the particular route throughout the backbone. This method also successfully avoids the overhead of route flap damping for iBGP sessions. </p><p>Subsequent research has shown that flap damping can actually lengthen convergence times in some cases, and can cause interruptions in connectivity even when links are not flapping.<sup id="cite_ref-30" class="reference"><a href="#cite_note-30"><span class="cite-bracket">[</span>30<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-31" class="reference"><a href="#cite_note-31"><span class="cite-bracket">[</span>31<span class="cite-bracket">]</span></a></sup> Moreover, as backbone links and router processors have become faster, some network architects have suggested that flap damping may not be as important as it used to be, since changes to the routing table can be handled much faster by routers.<sup id="cite_ref-32" class="reference"><a href="#cite_note-32"><span class="cite-bracket">[</span>32<span class="cite-bracket">]</span></a></sup> This has led the RIPE Routing Working Group to write, "With the current implementations of BGP flap damping, the application of flap damping in ISP networks is NOT recommended. ... If flap damping is implemented, the ISP operating that network will cause side-effects to their customers and the Internet users of their customers' content and services ... . These side-effects would quite likely be worse than the impact caused by simply not running flap damping at all."<sup id="cite_ref-33" class="reference"><a href="#cite_note-33"><span class="cite-bracket">[</span>33<span class="cite-bracket">]</span></a></sup> Improving stability without the problems of flap damping is the subject of current research.<sup id="cite_ref-34" class="reference"><a href="#cite_note-34"><span class="cite-bracket">[</span>34<span class="cite-bracket">]</span></a></sup><sup class="noprint Inline-Template" style="white-space:nowrap;">[<i><a href="/wiki/Wikipedia:Manual_of_Style/Dates_and_numbers#Chronological_items" title="Wikipedia:Manual of Style/Dates and numbers"><span title="Ref indicates research was in progress in 2011. (December 2022)">needs update</span></a></i>]</sup> </p> <div class="mw-heading mw-heading2"><h2 id="Routing_table_growth">Routing table growth</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Border_Gateway_Protocol&action=edit&section=22" title="Edit section: Routing table growth"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:BGP_Table_growth.svg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/c/ce/BGP_Table_growth.svg/220px-BGP_Table_growth.svg.png" decoding="async" width="220" height="176" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/c/ce/BGP_Table_growth.svg/330px-BGP_Table_growth.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/c/ce/BGP_Table_growth.svg/440px-BGP_Table_growth.svg.png 2x" data-file-width="600" data-file-height="480" /></a><figcaption>BGP table growth on the Internet</figcaption></figure> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Internet_AS.svg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/c/cf/Internet_AS.svg/220px-Internet_AS.svg.png" decoding="async" width="220" height="176" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/c/cf/Internet_AS.svg/330px-Internet_AS.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/c/cf/Internet_AS.svg/440px-Internet_AS.svg.png 2x" data-file-width="600" data-file-height="480" /></a><figcaption>Number of AS on the Internet vs number of registered AS</figcaption></figure> <p>One of the largest problems faced by BGP, and indeed the Internet infrastructure as a whole, is the growth of the Internet routing table. If the global routing table grows to the point where some older, less capable routers cannot cope with the memory requirements or the CPU load of maintaining the table, these routers will cease to be effective gateways between the parts of the Internet they connect. In addition, and perhaps even more importantly, larger routing tables take longer to stabilize after a major connectivity change, leaving network service unreliable, or even unavailable, in the interim. </p><p>Until late 2001, the global routing table was <a href="/wiki/Exponential_growth" title="Exponential growth">growing exponentially</a>, threatening an eventual widespread breakdown of connectivity. In an attempt to prevent this, ISPs cooperated in keeping the global routing table as small as possible, by using <a href="/wiki/Classless_Inter-Domain_Routing" title="Classless Inter-Domain Routing">Classless Inter-Domain Routing</a> (CIDR) and <a href="/wiki/Route_aggregation" class="mw-redirect" title="Route aggregation">route aggregation</a>. While this slowed the growth of the routing table to a linear process for several years, with the expanded demand for <a href="/wiki/Multihoming" title="Multihoming">multihoming</a> by end-user networks the growth was once again superlinear by the middle of 2004. </p> <div class="mw-heading mw-heading3"><h3 id="512k_day">512k day</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Border_Gateway_Protocol&action=edit&section=23" title="Edit section: 512k day"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>A <a href="/wiki/Year_2000_problem" title="Year 2000 problem">Y2K</a>-like overflow triggered in 2014 for those models that were not appropriately updated. </p><p>While a full IPv4 BGP table as of August 2014<sup class="plainlinks noexcerpt noprint asof-tag update" style="display:none;"><a class="external text" href="https://en.wikipedia.org/w/index.php?title=Border_Gateway_Protocol&action=edit">[update]</a></sup> (512k day)<sup id="cite_ref-35" class="reference"><a href="#cite_note-35"><span class="cite-bracket">[</span>35<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-36" class="reference"><a href="#cite_note-36"><span class="cite-bracket">[</span>36<span class="cite-bracket">]</span></a></sup> was in excess of 512,000 prefixes,<sup id="cite_ref-Potaroo_—_BGP_Table_data_37-0" class="reference"><a href="#cite_note-Potaroo_—_BGP_Table_data-37"><span class="cite-bracket">[</span>37<span class="cite-bracket">]</span></a></sup> many older routers had a limit of 512k (512,000–524,288)<sup id="cite_ref-38" class="reference"><a href="#cite_note-38"><span class="cite-bracket">[</span>38<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-39" class="reference"><a href="#cite_note-39"><span class="cite-bracket">[</span>39<span class="cite-bracket">]</span></a></sup> routing table entries. On August 12, 2014, outages resulting from full tables hit <a href="/wiki/EBay" title="EBay">eBay</a>, <a href="/wiki/LastPass" title="LastPass">LastPass</a> and <a href="/wiki/Microsoft_Azure" title="Microsoft Azure">Microsoft Azure</a> among others.<sup id="cite_ref-40" class="reference"><a href="#cite_note-40"><span class="cite-bracket">[</span>40<span class="cite-bracket">]</span></a></sup> A number of Cisco routers commonly in use had <a href="/wiki/Ternary_Content-Addressable_Memory" class="mw-redirect" title="Ternary Content-Addressable Memory">TCAM</a>, a form of high-speed <a href="/wiki/Content-addressable_memory" title="Content-addressable memory">content-addressable memory</a>, for storing BGP advertised routes. On impacted routers, the TCAM was by default allocated as 512k IPv4 routes and 256k IPv6 routes. While the reported number of IPv6 advertised routes was only about 20k, the number of advertised IPv4 routes reached the default limit, causing a <a href="/wiki/Spillover_effect" class="mw-redirect" title="Spillover effect">spillover effect</a> as routers attempted to compensate for the issue by using slow software routing (as opposed to fast hardware routing via TCAM). The main method for dealing with this issue involves operators changing the TCAM allocation to allow more IPv4 entries, by reallocating some of the TCAM reserved for IPv6 routes, which requires a reboot on most routers. The 512k problem was predicted by a number of IT professionals.<sup id="cite_ref-41" class="reference"><a href="#cite_note-41"><span class="cite-bracket">[</span>41<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-42" class="reference"><a href="#cite_note-42"><span class="cite-bracket">[</span>42<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-43" class="reference"><a href="#cite_note-43"><span class="cite-bracket">[</span>43<span class="cite-bracket">]</span></a></sup> </p><p>The actual allocations which pushed the number of routes above 512k was the announcement of about 15,000 new routes in short order, starting at 07:48 UTC. Almost all of these routes were to <a href="/wiki/Verizon" title="Verizon">Verizon</a> <a href="/wiki/Autonomous_system_(Internet)" title="Autonomous system (Internet)">Autonomous Systems</a> 701 and 705, created as a result of deaggregation of larger blocks, introducing thousands of new <i><span class="ipaddr"><span style="padding-right: 1px;">/</span><span style="padding-right: 1px;">24</span></span></i> routes, and making the routing table reach 515,000 entries. The new routes appear to have been reaggregated within 5 minutes, but instability across the Internet apparently continued for a number of hours.<sup id="cite_ref-44" class="reference"><a href="#cite_note-44"><span class="cite-bracket">[</span>44<span class="cite-bracket">]</span></a></sup> Even if Verizon had not caused the routing table to exceed 512k entries in the short spike, it would have soon happened through natural growth. </p><p><a href="/wiki/Route_summarization" class="mw-redirect" title="Route summarization">Route summarization</a> is often used to improve aggregation of the BGP global routing table, thereby reducing the necessary table size in routers of an AS. Consider AS1 has been allocated the big address space of <i><span class="ipaddr"><span style="padding-right: 1px;">172.16.0.0</span><span style="padding-right: 1px;">/</span><span style="padding-right: 1px;">16</span></span></i>, this would be counted as one route in the table, but due to customer requirements or traffic engineering purposes, AS1 wants to announce smaller, more specific routes of <i><span class="ipaddr"><span style="padding-right: 1px;">172.16.0.0</span><span style="padding-right: 1px;">/</span><span style="padding-right: 1px;">18</span></span></i>, <i><span class="ipaddr"><span style="padding-right: 1px;">172.16.64.0</span><span style="padding-right: 1px;">/</span><span style="padding-right: 1px;">18</span></span></i>, and <i><span class="ipaddr"><span style="padding-right: 1px;">172.16.128.0</span><span style="padding-right: 1px;">/</span><span style="padding-right: 1px;">18</span></span></i>. The prefix <i><span class="ipaddr"><span style="padding-right: 1px;">172.16.192.0</span><span style="padding-right: 1px;">/</span><span style="padding-right: 1px;">18</span></span></i> does not have any hosts so AS1 does not announce a specific route <i><span class="ipaddr"><span style="padding-right: 1px;">172.16.192.0</span><span style="padding-right: 1px;">/</span><span style="padding-right: 1px;">18</span></span></i>. This all counts as AS1 announcing four routes. </p><p>AS2 will see the four routes from AS1 (<i><span class="ipaddr"><span style="padding-right: 1px;">172.16.0.0</span><span style="padding-right: 1px;">/</span><span style="padding-right: 1px;">16</span></span></i>, <i><span class="ipaddr"><span style="padding-right: 1px;">172.16.0.0</span><span style="padding-right: 1px;">/</span><span style="padding-right: 1px;">18</span></span></i>, <i><span class="ipaddr"><span style="padding-right: 1px;">172.16.64.0</span><span style="padding-right: 1px;">/</span><span style="padding-right: 1px;">18</span></span></i>, and <i><span class="ipaddr"><span style="padding-right: 1px;">172.16.128.0</span><span style="padding-right: 1px;">/</span><span style="padding-right: 1px;">18</span></span></i>) and it is up to the routing policy of AS2 to decide whether or not to take a copy of the four routes or, as <i><span class="ipaddr"><span style="padding-right: 1px;">172.16.0.0</span><span style="padding-right: 1px;">/</span><span style="padding-right: 1px;">16</span></span></i> overlaps all the other specific routes, to just store the summary, <i><span class="ipaddr"><span style="padding-right: 1px;">172.16.0.0</span><span style="padding-right: 1px;">/</span><span style="padding-right: 1px;">16</span></span></i>. </p><p>If AS2 wants to send data to prefix <i><span class="ipaddr"><span style="padding-right: 1px;">172.16.192.0</span><span style="padding-right: 1px;">/</span><span style="padding-right: 1px;">18</span></span></i>, it will be sent to the routers of AS1 on route <i><span class="ipaddr"><span style="padding-right: 1px;">172.16.0.0</span><span style="padding-right: 1px;">/</span><span style="padding-right: 1px;">16</span></span></i>. At AS1, it will either be dropped or a destination unreachable <a href="/wiki/ICMP" class="mw-redirect" title="ICMP">ICMP</a> message will be sent back, depending on the configuration of AS1's routers. </p><p>If AS1 later decides to drop the route <i><span class="ipaddr"><span style="padding-right: 1px;">172.16.0.0</span><span style="padding-right: 1px;">/</span><span style="padding-right: 1px;">16</span></span></i>, leaving <i><span class="ipaddr"><span style="padding-right: 1px;">172.16.0.0</span><span style="padding-right: 1px;">/</span><span style="padding-right: 1px;">18</span></span></i>, <i><span class="ipaddr"><span style="padding-right: 1px;">172.16.64.0</span><span style="padding-right: 1px;">/</span><span style="padding-right: 1px;">18</span></span></i>, and <i><span class="ipaddr"><span style="padding-right: 1px;">172.16.128.0</span><span style="padding-right: 1px;">/</span><span style="padding-right: 1px;">18</span></span></i>, the number of routes AS1 announces drops to three. Depending on the routing policy of AS2, it will store a copy of the three routes, or aggregate <i><span class="ipaddr"><span style="padding-right: 1px;">172.16.0.0</span><span style="padding-right: 1px;">/</span><span style="padding-right: 1px;">18</span></span></i> and <i><span class="ipaddr"><span style="padding-right: 1px;">172.16.64.0</span><span style="padding-right: 1px;">/</span><span style="padding-right: 1px;">18</span></span></i> to <i><span class="ipaddr"><span style="padding-right: 1px;">172.16.0.0</span><span style="padding-right: 1px;">/</span><span style="padding-right: 1px;">17</span></span></i>, thereby reducing the number of routes AS2 stores to two (<i><span class="ipaddr"><span style="padding-right: 1px;">172.16.0.0</span><span style="padding-right: 1px;">/</span><span style="padding-right: 1px;">17</span></span></i> and <i><span class="ipaddr"><span style="padding-right: 1px;">172.16.128.0</span><span style="padding-right: 1px;">/</span><span style="padding-right: 1px;">18</span></span></i>). </p><p>If AS2 now wants to send data to prefix <i><span class="ipaddr"><span style="padding-right: 1px;">172.16.192.0</span><span style="padding-right: 1px;">/</span><span style="padding-right: 1px;">18</span></span></i>, it will be dropped or a destination unreachable ICMP message will be sent back at the routers of AS2 (not AS1 as before), because <i><span class="ipaddr"><span style="padding-right: 1px;">172.16.192.0</span><span style="padding-right: 1px;">/</span><span style="padding-right: 1px;">18</span></span></i> is not in the routing table. </p> <div class="mw-heading mw-heading3"><h3 id="AS_number_depletion_and_32-bit_ASNs">AS number depletion and 32-bit ASNs<span class="anchor" id="AS23456"></span></h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Border_Gateway_Protocol&action=edit&section=24" title="Edit section: AS number depletion and 32-bit ASNs"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The RFC 1771 BGP-4 specification coded AS numbers on 16 bits, for 64,510 possible public AS numbers.<sup id="cite_ref-45" class="reference"><a href="#cite_note-45"><span class="cite-bracket">[</span>a<span class="cite-bracket">]</span></a></sup> In 2011, only 15,000 AS numbers were still available, and projections<sup id="cite_ref-46" class="reference"><a href="#cite_note-46"><span class="cite-bracket">[</span>45<span class="cite-bracket">]</span></a></sup> were envisioning a complete depletion of available AS numbers in September 2013. </p><p>RFC 6793 extends AS coding from 16 to 32 bits,<sup id="cite_ref-47" class="reference"><a href="#cite_note-47"><span class="cite-bracket">[</span>b<span class="cite-bracket">]</span></a></sup> which now allows up to 4 billion available AS. An additional private AS range is also defined in RFC 6996.<sup id="cite_ref-48" class="reference"><a href="#cite_note-48"><span class="cite-bracket">[</span>c<span class="cite-bracket">]</span></a></sup> To allow the traversal of router groups not able to manage those new ASNs, the new attribute <b>AS4_PATH</b> (optional transitive) and the special 16-bit ASN <b>AS_TRANS</b> (AS23456) is used.<sup id="cite_ref-49" class="reference"><a href="#cite_note-49"><span class="cite-bracket">[</span>46<span class="cite-bracket">]</span></a></sup> 32-bit ASN assignments started in 2007. </p> <div class="mw-heading mw-heading3"><h3 id="Load_balancing">Load balancing</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Border_Gateway_Protocol&action=edit&section=25" title="Edit section: Load balancing"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Another factor contributing to the growth of the routing table is the need for load balancing of <a href="/wiki/Multi-homed" class="mw-redirect" title="Multi-homed">multi-homed</a> networks. It is not a trivial task to balance the inbound traffic to a multi-homed network across its multiple inbound paths, due to limitation of the BGP route selection process. For a multi-homed network, if it announces the same network blocks across all of its BGP peers, the result may be that one or several of its inbound links become congested while the other links remain under-utilized, because external networks all picked that set of congested paths as optimal. Like most other routing protocols, BGP does not detect congestion. </p><p>To work around this problem, BGP administrators of that multihomed network may divide a large contiguous IP address block into smaller blocks and tweak the route announcement to make different blocks look optimal on different paths, so that external networks will choose a different path to reach different blocks of that multi-homed network. Such cases will increase the number of routes as seen on the global BGP table. </p><p>One method to address the routing table issue associated with load balancing is to deploy <a href="/wiki/Locator/Identifier_Separation_Protocol" title="Locator/Identifier Separation Protocol">Locator/Identifier Separation Protocol</a> (BGP/LISP) gateways within an <a href="/wiki/Internet_exchange_point" title="Internet exchange point">Internet exchange point</a> to allow ingress traffic engineering across multiple links. This technique does not increase the number of routes seen on the global BGP table. </p> <div class="mw-heading mw-heading2"><h2 id="Security">Security</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Border_Gateway_Protocol&action=edit&section=26" title="Edit section: Security"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>By design, routers running BGP accept advertised routes from other BGP routers by default. This allows for automatic and decentralized routing of traffic across the Internet, but it also leaves the Internet potentially vulnerable to accidental or malicious disruption, known as <a href="/wiki/BGP_hijacking" title="BGP hijacking">BGP hijacking</a>. Due to the extent to which BGP is embedded in the core systems of the Internet, and the number of different networks operated by many different organizations which collectively make up the Internet, correcting this vulnerability (such as by introducing the use of cryptographic keys to verify the identity of BGP routers) is a technically and economically challenging problem.<sup id="cite_ref-50" class="reference"><a href="#cite_note-50"><span class="cite-bracket">[</span>47<span class="cite-bracket">]</span></a></sup> </p> <div class="mw-heading mw-heading2"><h2 id="Extensions">Extensions</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Border_Gateway_Protocol&action=edit&section=27" title="Edit section: Extensions"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Multiprotocol Extensions for BGP (MBGP), sometimes referred to as Multiprotocol BGP or Multicast BGP and defined in <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><a href="/wiki/RFC_(identifier)" class="mw-redirect" title="RFC (identifier)">RFC</a> <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc4760">4760</a>, is an extension to BGP that allows different types of addresses (known as address families) to be distributed in parallel. Whereas standard BGP supports only IPv4 unicast addresses, Multiprotocol BGP supports IPv4 and IPv6 addresses and it supports unicast and multicast variants of each. Multiprotocol BGP allows information about the topology of IP multicast-capable routers to be exchanged separately from the topology of normal IPv4 unicast routers. Thus, it allows a multicast routing topology different from the unicast routing topology. Although MBGP enables the exchange of inter-domain multicast routing information, other protocols such as the Protocol Independent Multicast family are needed to build trees and forward multicast traffic. </p><p>Multiprotocol BGP is also widely deployed in case of <a href="/wiki/MPLS" class="mw-redirect" title="MPLS">MPLS</a> L3 VPN, to exchange VPN labels learned for the routes from the customer sites over the MPLS network, in order to distinguish between different customer sites when the traffic from the other customer sites comes to the <a href="/wiki/Provider_edge_router" title="Provider edge router">provider edge router</a> for routing. </p><p>Another extension to BGP is <a href="/wiki/Multipath_routing" title="Multipath routing">multipath routing</a>. This typically requires identical MED, weight, origin, and AS-path although some implementations provide the ability to relax the AS-path checking to only expect an equal path length rather than the actual AS numbers in the path being expected to match too. This can then be extended further with features like Cisco's dmzlink-bw which enables a ratio of traffic sharing based on bandwidth values configured on individual links. </p> <div class="mw-heading mw-heading2"><h2 id="Uses">Uses</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Border_Gateway_Protocol&action=edit&section=28" title="Edit section: Uses"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>BGP4 is standard for Internet routing and required of most <a href="/wiki/Internet_service_provider" title="Internet service provider">Internet service providers</a> (ISPs) to establish routing between one another. Very large private <a href="/wiki/IP_network" class="mw-redirect" title="IP network">IP networks</a> use BGP internally. An example use case is the joining of a number of large <a href="/wiki/Open_Shortest_Path_First" title="Open Shortest Path First">Open Shortest Path First</a> (OSPF) networks when OSPF by itself does not scale to the size required. Another reason to use BGP is multihoming a network for better redundancy, either to multiple access points to a single ISP or to multiple ISPs. </p> <div class="mw-heading mw-heading2"><h2 id="Implementations">Implementations</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Border_Gateway_Protocol&action=edit&section=29" title="Edit section: Implementations"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Routers, especially small ones intended for <a href="/wiki/Small_office/home_office" title="Small office/home office">small office/home office</a> (SOHO) use, may not include BGP capability. Other commercial routers may need a specific software executable image that supports BGP, or a license that enables it. Devices marketed as <a href="/wiki/Layer-3_switch" class="mw-redirect" title="Layer-3 switch">layer-3 switches</a> are less likely to support BGP than devices marketed as <a href="/wiki/Router_(computing)" title="Router (computing)">routers</a>, but many high-end layer-3 switches can run BGP. </p><p>Products marketed as switches may have a size limitation on BGP tables that is far smaller than a full Internet table plus internal routes. These devices may be perfectly reasonable and useful when used for BGP routing of some smaller part of the network, such as a <a href="/w/index.php?title=Confederation-AS&action=edit&redlink=1" class="new" title="Confederation-AS (page does not exist)">confederation-AS</a> representing one of several smaller enterprises that are linked, by a BGP <a href="/w/index.php?title=Backbone_of_backbones&action=edit&redlink=1" class="new" title="Backbone of backbones (page does not exist)">backbone of backbones</a>, or a small enterprise that announces routes to an ISP but only accepts a <a href="/wiki/Default_route" title="Default route">default route</a> and perhaps a small number of aggregated routes. </p><p>A BGP router used only for a network with a single point of entry to the Internet may have a much smaller routing table size (and hence RAM and CPU requirement) than a multihomed network. Even simple multihoming can have modest routing table size. The actual amount of memory required in a BGP router depends on the amount of BGP information exchanged with other BGP speakers and the way in which the particular router stores BGP information. The router may have to keep more than one copy of a route, so it can manage different policies for route advertising and acceptance to a specific neighboring AS. The term <i>view</i> is often used for these different policy relationships on a running router. </p><p>If one router implementation takes more memory per route than another implementation, this may be a legitimate design choice, trading processing speed against memory. A full IPv4 BGP table as of August 2015<sup class="plainlinks noexcerpt noprint asof-tag update" style="display:none;"><a class="external text" href="https://en.wikipedia.org/w/index.php?title=Border_Gateway_Protocol&action=edit">[update]</a></sup> is in excess of 590,000 prefixes.<sup id="cite_ref-Potaroo_—_BGP_Table_data_37-1" class="reference"><a href="#cite_note-Potaroo_—_BGP_Table_data-37"><span class="cite-bracket">[</span>37<span class="cite-bracket">]</span></a></sup> Large ISPs may add another 50% for internal and customer routes. Again depending on implementation, separate tables may be kept for each view of a different peer AS. </p><p>Notable free and open-source implementations of BGP include: </p> <ul><li><a href="/wiki/Bird_Internet_routing_daemon" title="Bird Internet routing daemon">BIRD</a>, a <a href="/wiki/GPL" class="mw-redirect" title="GPL">GPL</a> routing package for Unix-like systems.</li> <li><a href="/wiki/FRRouting" title="FRRouting">FRRouting</a>, a fork of Quagga for <a href="/wiki/Unix-like" title="Unix-like">Unix-like</a> systems; and its ancestors: <ul><li><a href="/wiki/Quagga_(software)" title="Quagga (software)">Quagga</a>, a fork of GNU Zebra for <a href="/wiki/Unix-like" title="Unix-like">Unix-like</a> systems (no longer developed).</li> <li><a href="/wiki/GNU_Zebra" title="GNU Zebra">GNU Zebra</a>, a GPL routing suite supporting BGP4 (decommissioned).<sup id="cite_ref-51" class="reference"><a href="#cite_note-51"><span class="cite-bracket">[</span>48<span class="cite-bracket">]</span></a></sup></li></ul></li> <li><a href="/wiki/OpenBGPD" title="OpenBGPD">OpenBGPD</a>, a <a href="/wiki/BSD_licence" class="mw-redirect" title="BSD licence">BSD-licensed</a> implementation by the <a href="/wiki/OpenBSD" title="OpenBSD">OpenBSD</a> team.</li> <li><a href="/wiki/XORP" title="XORP">XORP</a>, the eXtensible Open Router Platform, a BSD-licensed suite of routing protocols.</li></ul> <p>Systems for testing BGP conformance, load or stress performance come from vendors such as: </p> <ul><li><a href="/wiki/Agilent_Technologies" title="Agilent Technologies">Agilent Technologies</a></li> <li><a href="/wiki/GNS3" class="mw-redirect" title="GNS3">GNS3</a> open source <a href="/wiki/Network_simulator" class="mw-redirect" title="Network simulator">network simulator</a></li> <li><a href="/wiki/Ixia_(company)" title="Ixia (company)">Ixia</a></li> <li><a href="/wiki/Spirent" title="Spirent">Spirent</a></li></ul> <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=Border_Gateway_Protocol&action=edit&section=30" title="Edit section: See also"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><a href="/wiki/2021_Facebook_outage" title="2021 Facebook outage">2021 Facebook outage</a> – Outage affecting all Facebook operated services</li> <li><a href="/wiki/AS_7007_incident" title="AS 7007 incident">AS 7007 incident</a> – Major disruption of the Internet on April 25, 1997</li> <li><a href="/wiki/Internet_Assigned_Numbers_Authority" title="Internet Assigned Numbers Authority">Internet Assigned Numbers Authority</a> – Standards organization overseeing IP addresses</li> <li><a href="/wiki/Packet_forwarding" title="Packet forwarding">Packet forwarding</a> – Relaying of packets from one network segment to another</li> <li><a href="/wiki/Private_IP" title="Private IP">Private IP</a></li> <li><a href="/wiki/QPPB" title="QPPB">QPPB</a> – Traffic engineering mechanism</li> <li><a href="/wiki/Regional_Internet_registry" title="Regional Internet registry">Regional Internet registry</a> – Organization responsible for managing network numbering</li> <li><a href="/wiki/Resource_Public_Key_Infrastructure" title="Resource Public Key Infrastructure">Resource Public Key Infrastructure</a> – Internet routing security framework</li> <li><a href="/wiki/Route_filtering" title="Route filtering">Route filtering</a> – Process of excluding certain networking routes</li> <li><a href="/wiki/Routing_Assets_Database" title="Routing Assets Database">Routing Assets Database</a> – Routing registry for Internet networks</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=Border_Gateway_Protocol&action=edit&section=31" 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-45"><span class="mw-cite-backlink"><b><a href="#cite_ref-45">^</a></b></span> <span class="reference-text">ASN 64512 to 65534 were reserved for private use and 0 and 65535 are forbidden.</span> </li> <li id="cite_note-47"><span class="mw-cite-backlink"><b><a href="#cite_ref-47">^</a></b></span> <span class="reference-text">The 16-bit AS range 0 to 65535 and its reserved AS numbers are retained.</span> </li> <li id="cite_note-48"><span class="mw-cite-backlink"><b><a href="#cite_ref-48">^</a></b></span> <span class="reference-text">ASN 4200000000 to 4294967294 are private and 4294967295 is forbidden by RFC 7300.</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=Border_Gateway_Protocol&action=edit&section=32" 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"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/rfc1105/history/">"History for rfc1105"</a>. <a href="/wiki/IETF" class="mw-redirect" title="IETF">IETF</a>. June 1989<span class="reference-accessdate">. Retrieved <span class="nowrap">1 December</span> 2023</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=History+for+rfc1105&rft.pub=IETF&rft.date=1989-06&rft_id=https%3A%2F%2Fdatatracker.ietf.org%2Fdoc%2Frfc1105%2Fhistory%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3ABorder+Gateway+Protocol" class="Z3988"></span></span> </li> <li id="cite_note-orbit-2"><span class="mw-cite-backlink"><b><a href="#cite_ref-orbit_2-0">^</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/20130928115120/http://www.orbit-computer-solutions.com/BGP.php">"BGP: Border Gateway Protocol Explained"</a>. <i>Orbit-Computer Solutions.Com</i>. 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Retrieved <span class="nowrap">March 16,</span> 2018</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Network+Routing+with+Path+Vector+Protocols%3A+Theory+and+Applications&rft.date=2003&rft.aulast=Sobrinho&rft.aufirst=Jo%C3%A3o+Lu%C3%ADs&rft_id=https%3A%2F%2Fconferences.sigcomm.org%2Fsigcomm%2F2003%2Fpapers%2Fp49-sobrinho.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3ABorder+Gateway+Protocol" class="Z3988"></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="CITEREFCHM2015" class="citation web cs1">Jabloner, Paula (2015-03-04). <a rel="nofollow" class="external text" href="https://computerhistory.org/blog/the-two-napkin-protocol/?key=the-two-napkin-protocol">"The Two-Napkin Protocol"</a>. <i>Computer History Museum</i><span class="reference-accessdate">. Retrieved <span class="nowrap">2024-10-01</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=Computer+History+Museum&rft.atitle=The+Two-Napkin+Protocol&rft.date=2015-03-04&rft.aulast=Jabloner&rft.aufirst=Paula&rft_id=https%3A%2F%2Fcomputerhistory.org%2Fblog%2Fthe-two-napkin-protocol%2F%3Fkey%3Dthe-two-napkin-protocol&rfr_id=info%3Asid%2Fen.wikipedia.org%3ABorder+Gateway+Protocol" 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 id="CITEREFJabloner2020" class="citation web cs1">Jabloner, Paula (2020-07-02). <a rel="nofollow" class="external text" href="https://weare.cisco.com/c/r/weare/amazing-stories/amazing-things/two-napkin.html">"The Two-Napkin Protocol #WeAreCisco"</a>. <i>Cisco</i><span class="reference-accessdate">. Retrieved <span class="nowrap">2024-10-01</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=Cisco&rft.atitle=The+Two-Napkin+Protocol+%23WeAreCisco&rft.date=2020-07-02&rft.aulast=Jabloner&rft.aufirst=Paula&rft_id=https%3A%2F%2Fweare.cisco.com%2Fc%2Fr%2Fweare%2Famazing-stories%2Famazing-things%2Ftwo-napkin.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3ABorder+Gateway+Protocol" class="Z3988"></span></span> </li> <li id="cite_note-6"><span class="mw-cite-backlink"><b><a href="#cite_ref-6">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation journal cs1"><a rel="nofollow" class="external text" href="https://weare.cisco.com/c/dam/r/weare/assets/files/packet-winter89.pdf">"BGP - A Tale of Two Napkins"</a> <span class="cs1-format">(PDF)</span>. <i>The Packet</i>. <b>1</b> (2). Cisco Systems. 1989<span class="reference-accessdate">. Retrieved <span class="nowrap">2024-10-01</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=The+Packet&rft.atitle=BGP+-+A+Tale+of+Two+Napkins&rft.volume=1&rft.issue=2&rft.date=1989&rft_id=https%3A%2F%2Fweare.cisco.com%2Fc%2Fdam%2Fr%2Fweare%2Fassets%2Ffiles%2Fpacket-winter89.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3ABorder+Gateway+Protocol" class="Z3988"></span></span> </li> <li id="cite_note-7"><span class="mw-cite-backlink"><b><a href="#cite_ref-7">^</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/20201029233343/https://datapath.io/resources/blog/the-history-of-border-gateway-protocol/">"The History of Border Gateway Protocol"</a>. <i>blog.datapath.io</i>. Archived from <a rel="nofollow" class="external text" href="https://datapath.io/resources/blog/the-history-of-border-gateway-protocol/">the original</a> on 29 October 2020.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=blog.datapath.io&rft.atitle=The+History+of+Border+Gateway+Protocol&rft_id=https%3A%2F%2Fdatapath.io%2Fresources%2Fblog%2Fthe-history-of-border-gateway-protocol%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3ABorder+Gateway+Protocol" 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 cs1"><i>A Border Gateway Protocol 4 (BGP-4)</i>. <a href="/wiki/RFC_(identifier)" class="mw-redirect" title="RFC (identifier)">RFC</a> <span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://tools.ietf.org/html/rfc4271">4271</a></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=A+Border+Gateway+Protocol+4+%28BGP-4%29&rft_id=https%3A%2F%2Ftools.ietf.org%2Fhtml%2Frfc4271%23id-name%3DRFC&rfr_id=info%3Asid%2Fen.wikipedia.org%3ABorder+Gateway+Protocol" 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">RFC 4274</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="CITEREFR._ChandraJ._Scudder2000" class="citation cs1">R. Chandra; J. Scudder (May 2000). <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc2842"><i>Capabilities Advertisement with BGP-4</i></a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://doi.org/10.17487%2FRFC2842">10.17487/RFC2842</a></span>. <a href="/wiki/Request_for_Comments" title="Request for Comments">RFC</a> <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc2842">2842</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Capabilities+Advertisement+with+BGP-4&rft.date=2000-05&rft_id=info%3Adoi%2F10.17487%2FRFC2842&rft.au=R.+Chandra&rft.au=J.+Scudder&rft_id=https%3A%2F%2Fdatatracker.ietf.org%2Fdoc%2Fhtml%2Frfc2842&rfr_id=info%3Asid%2Fen.wikipedia.org%3ABorder+Gateway+Protocol" 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 id="CITEREFT._Bates2000" class="citation cs1">T. 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Archived from <a rel="nofollow" class="external text" href="http://www.renesys.com/2014/08/internet-512k-global-routes">the original</a> on 13 August 2014.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=renesys.com&rft.atitle=Internet+Touches+Half+Million+Routes%3A+Outages+Possible+Next+Week&rft.date=2014-08-13&rft.aulast=Cowie&rft.aufirst=Jim&rft_id=http%3A%2F%2Fwww.renesys.com%2F2014%2F08%2Finternet-512k-global-routes&rfr_id=info%3Asid%2Fen.wikipedia.org%3ABorder+Gateway+Protocol" class="Z3988"></span></span> </li> <li id="cite_note-Potaroo_—_BGP_Table_data-37"><span class="mw-cite-backlink">^ <a href="#cite_ref-Potaroo_—_BGP_Table_data_37-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Potaroo_—_BGP_Table_data_37-1"><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 class="citation web cs1"><a rel="nofollow" class="external text" href="http://bgp.potaroo.net/index-bgp.html">"BGP Reports"</a>. <i>potaroo.net</i>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=potaroo.net&rft.atitle=BGP+Reports&rft_id=http%3A%2F%2Fbgp.potaroo.net%2Findex-bgp.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3ABorder+Gateway+Protocol" class="Z3988"></span></span> </li> <li id="cite_note-38"><span class="mw-cite-backlink"><b><a href="#cite_ref-38">^</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/c/en/us/support/docs/switches/catalyst-6500-series-switches/117712-problemsolution-cat6500-00.html#.U-okMKwClYO.twitter">"CAT 6500 and 7600 Series Routers and Switches TCAM Allocation Adjustment Procedures"</a>. <i>Cisco</i>. 9 March 2015.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=Cisco&rft.atitle=CAT+6500+and+7600+Series+Routers+and+Switches+TCAM+Allocation+Adjustment+Procedures&rft.date=2015-03-09&rft_id=http%3A%2F%2Fwww.cisco.com%2Fc%2Fen%2Fus%2Fsupport%2Fdocs%2Fswitches%2Fcatalyst-6500-series-switches%2F117712-problemsolution-cat6500-00.html%23.U-okMKwClYO.twitter&rfr_id=info%3Asid%2Fen.wikipedia.org%3ABorder+Gateway+Protocol" class="Z3988"></span></span> </li> <li id="cite_note-39"><span class="mw-cite-backlink"><b><a href="#cite_ref-39">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFJim_Cowie" class="citation web cs1">Jim Cowie. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20140817205028/http://www.renesys.com/2014/08/internet-512k-global-routes/">"Internet Touches Half Million Routes: Outages Possible Next Week"</a>. <i>Dyn Research</i>. Archived from <a rel="nofollow" class="external text" href="http://www.renesys.com/2014/08/internet-512k-global-routes/">the original</a> on 2014-08-17<span class="reference-accessdate">. Retrieved <span class="nowrap">2015-01-02</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=Dyn+Research&rft.atitle=Internet+Touches+Half+Million+Routes%3A+Outages+Possible+Next+Week&rft.au=Jim+Cowie&rft_id=http%3A%2F%2Fwww.renesys.com%2F2014%2F08%2Finternet-512k-global-routes%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3ABorder+Gateway+Protocol" class="Z3988"></span></span> </li> <li id="cite_note-40"><span class="mw-cite-backlink"><b><a href="#cite_ref-40">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFGarsideGibbs2014" class="citation news cs1">Garside, Juliette; Gibbs, Samuel (14 August 2014). <a rel="nofollow" class="external text" href="https://www.theguardian.com/technology/2014/aug/14/internet-infrastructure-needs-updating-more-blackouts-will-happen">"Internet infrastructure 'needs updating or more blackouts will happen'<span class="cs1-kern-right"></span>"</a>. <i>The Guardian</i><span class="reference-accessdate">. Retrieved <span class="nowrap">15 Aug</span> 2014</span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=The+Guardian&rft.atitle=Internet+infrastructure+%27needs+updating+or+more+blackouts+will+happen%27&rft.date=2014-08-14&rft.aulast=Garside&rft.aufirst=Juliette&rft.au=Gibbs%2C+Samuel&rft_id=https%3A%2F%2Fwww.theguardian.com%2Ftechnology%2F2014%2Faug%2F14%2Finternet-infrastructure-needs-updating-more-blackouts-will-happen&rfr_id=info%3Asid%2Fen.wikipedia.org%3ABorder+Gateway+Protocol" class="Z3988"></span></span> </li> <li id="cite_note-41"><span class="mw-cite-backlink"><b><a href="#cite_ref-41">^</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://www.nanog.org/meetings/nanog39/presentations/bof-report.pdf">"BOF report"</a> <span class="cs1-format">(PDF)</span>. www.nanog.org. <a rel="nofollow" class="external text" href="https://ghostarchive.org/archive/20221009/https://www.nanog.org/meetings/nanog39/presentations/bof-report.pdf">Archived</a> <span class="cs1-format">(PDF)</span> from the original on 2022-10-09<span class="reference-accessdate">. Retrieved <span class="nowrap">2019-12-17</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=BOF+report&rft.pub=www.nanog.org&rft_id=https%3A%2F%2Fwww.nanog.org%2Fmeetings%2Fnanog39%2Fpresentations%2Fbof-report.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3ABorder+Gateway+Protocol" class="Z3988"></span></span> </li> <li id="cite_note-42"><span class="mw-cite-backlink"><b><a href="#cite_ref-42">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFGreg_Ferro2011" class="citation web cs1">Greg Ferro (26 January 2011). <a rel="nofollow" class="external text" href="http://etherealmind.com/tcam-detail-review/">"TCAM — a Deeper Look and the impact of IPv6"</a>. <i>EtherealMind</i>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=EtherealMind&rft.atitle=TCAM+%E2%80%94+a+Deeper+Look+and+the+impact+of+IPv6&rft.date=2011-01-26&rft.au=Greg+Ferro&rft_id=http%3A%2F%2Fetherealmind.com%2Ftcam-detail-review%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3ABorder+Gateway+Protocol" class="Z3988"></span></span> </li> <li id="cite_note-43"><span class="mw-cite-backlink"><b><a href="#cite_ref-43">^</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.ipv4depletion.com/?p=672">"The IPv4 Depletion site"</a>. <i>ipv4depletion.com</i>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=ipv4depletion.com&rft.atitle=The+IPv4+Depletion+site&rft_id=http%3A%2F%2Fwww.ipv4depletion.com%2F%3Fp%3D672&rfr_id=info%3Asid%2Fen.wikipedia.org%3ABorder+Gateway+Protocol" class="Z3988"></span></span> </li> <li id="cite_note-44"><span class="mw-cite-backlink"><b><a href="#cite_ref-44">^</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://www.bgpmon.net/what-caused-todays-internet-hiccup/">"What caused today's Internet hiccup"</a>. <i>bgpmon.net</i>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=bgpmon.net&rft.atitle=What+caused+today%27s+Internet+hiccup&rft_id=https%3A%2F%2Fwww.bgpmon.net%2Fwhat-caused-todays-internet-hiccup%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3ABorder+Gateway+Protocol" class="Z3988"></span></span> </li> <li id="cite_note-46"><span class="mw-cite-backlink"><b><a href="#cite_ref-46">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="http://www.potaroo.net/tools/asn16/"><i>16-bit Autonomous System Report</i></a>, Geoff Huston 2011 (original archived at <a rel="nofollow" class="external free" href="https://web.archive.org/web/20110906085724/http://www.potaroo.net/tools/asn16/">https://web.archive.org/web/20110906085724/http://www.potaroo.net/tools/asn16/</a>)</span> </li> <li id="cite_note-49"><span class="mw-cite-backlink"><b><a href="#cite_ref-49">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFVohraChen2007" class="citation cs1">Vohra, Quaizar; Chen, Enke (May 2007). <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc4893"><i>BGP Support for Four-octet AS Number Space</i></a>. <a href="/wiki/IETF" class="mw-redirect" title="IETF">IETF</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://doi.org/10.17487%2FRFC4893">10.17487/RFC4893</a></span>. <a href="/wiki/Request_for_Comments" title="Request for Comments">RFC</a> <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc4893">4893</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=BGP+Support+for+Four-octet+AS+Number+Space&rft.pub=IETF&rft.date=2007-05&rft_id=info%3Adoi%2F10.17487%2FRFC4893&rft.aulast=Vohra&rft.aufirst=Quaizar&rft.au=Chen%2C+Enke&rft_id=https%3A%2F%2Fdatatracker.ietf.org%2Fdoc%2Fhtml%2Frfc4893&rfr_id=info%3Asid%2Fen.wikipedia.org%3ABorder+Gateway+Protocol" class="Z3988"></span></span> </li> <li id="cite_note-50"><span class="mw-cite-backlink"><b><a href="#cite_ref-50">^</a></b></span> <span class="reference-text"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFCraig_Timberg2015" class="citation news cs1">Craig Timberg (2015-05-31). <a rel="nofollow" class="external text" href="https://www.washingtonpost.com/sf/business/2015/05/31/net-of-insecurity-part-2/">"Quick fix for an early Internet problem lives on a quarter-century later"</a>. <i>The Washington Post</i><span class="reference-accessdate">. Retrieved <span class="nowrap">2015-06-01</span></span>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=The+Washington+Post&rft.atitle=Quick+fix+for+an+early+Internet+problem+lives+on+a+quarter-century+later&rft.date=2015-05-31&rft.au=Craig+Timberg&rft_id=https%3A%2F%2Fwww.washingtonpost.com%2Fsf%2Fbusiness%2F2015%2F05%2F31%2Fnet-of-insecurity-part-2%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3ABorder+Gateway+Protocol" class="Z3988"></span></span> </li> <li id="cite_note-51"><span class="mw-cite-backlink"><b><a href="#cite_ref-51">^</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://www.gnu.org/software/zebra/">"Zebra - GNU Project - Free Software Foundation"</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Zebra+-+GNU+Project+-+Free+Software+Foundation&rft_id=https%3A%2F%2Fwww.gnu.org%2Fsoftware%2Fzebra%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3ABorder+Gateway+Protocol" class="Z3988"></span></span> </li> </ol></div></div> <div class="mw-heading mw-heading2"><h2 id="Further_reading">Further reading</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Border_Gateway_Protocol&action=edit&section=33" title="Edit section: Further reading"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation cs2"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20110708155259/http://docwiki.cisco.com/wiki/Border_Gateway_Protocol">"Border Gateway Protocol (BGP)"</a>, <i>IOS Technology Handbook</i>, <a href="/wiki/Cisco_Systems" class="mw-redirect" title="Cisco Systems">Cisco Systems</a>, archived from <a rel="nofollow" class="external text" href="http://docwiki.cisco.com/wiki/Border_Gateway_Protocol">the original</a> on 2011-07-08</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=IOS+Technology+Handbook&rft.atitle=Border+Gateway+Protocol+%28BGP%29&rft_id=http%3A%2F%2Fdocwiki.cisco.com%2Fwiki%2FBorder_Gateway_Protocol&rfr_id=info%3Asid%2Fen.wikipedia.org%3ABorder+Gateway+Protocol" class="Z3988"></span></li></ul> <div class="mw-heading mw-heading3"><h3 id="Standards_documents">Standards documents</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Border_Gateway_Protocol&action=edit&section=34" title="Edit section: Standards documents"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc1772">1772</a>, Application of the Border Gateway Protocol in the Internet Protocol (BGP-4) using SMIv2</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc1997">1997</a>, BGP Communities Attribute</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc2439">2439</a>, BGP Route Flap Damping</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc2918">2918</a>, Route Refresh Capability for BGP-4</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc3765">3765</a>, NOPEER Community for Border Gateway Protocol (BGP) Route Scope Control</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc4271">4271</a>, A Border Gateway Protocol 4 (BGP-4)</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc4272">4272</a>, BGP Security Vulnerabilities Analysis</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc4273">4273</a>, Definitions of Managed Objects for BGP-4</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc4274">4274</a>, BGP-4 Protocol Analysis</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc4275">4275</a>, BGP-4 MIB Implementation Survey</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc4276">4276</a>, BGP-4 Implementation Report</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc4277">4277</a>, Experience with the BGP-4 Protocol</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc4278">4278</a>, Standards Maturity Variance Regarding the TCP MD5 Signature Option (RFC 2385) and the BGP-4 Specification</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc4360">4360</a>, BGP Extended Communities Attribute</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc4456">4456</a>, BGP Route Reflection – An Alternative to Full Mesh Internal BGP (iBGP)</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc4724">4724</a>, Graceful Restart Mechanism for BGP</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc4760">4760</a>, Multiprotocol Extensions for BGP-4</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc5065">5065</a>, Autonomous System Confederations for BGP</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc5492">5492</a>, Capabilities Advertisement with BGP-4</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc5701">5701</a>, IPv6 Address Specific BGP Extended Community Attribute</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc6793">6793</a>, BGP Support for Four-Octet Autonomous System (AS) Number Space</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc7153">7153</a>, IANA Registries for BGP Extended Communities</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc7606">7606</a>, Revised Error Handling for BGP UPDATE Messages</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc7911">7911</a>, Advertisement of Multiple Paths in BGP</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc8092">8092</a>, BGP Large Communities Attribute</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc8195">8195</a>, Use of BGP Large Communities</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc8642">8642</a>, Policy Behavior for Well-Known BGP Communities</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc8955">8955</a>, Dissemination of Flow Specification Rules</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc9552">9552</a>, Distribution of Link-State and Traffic Engineering Information Using BGP</li> <li><a rel="nofollow" class="external text" href="https://tools.ietf.org/html/draft-ietf-idr-custom-decision-08">BGP Custom Decision Process</a>, IETF draft, February 3, 2017</li> <li><a rel="nofollow" class="external text" href="https://tools.ietf.org/html/draft-utgikar-serr-00">Selective Route Refresh for BGP</a>, IETF draft, November 7, 2015</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc1105">1105</a>, Obsolete – Border Gateway Protocol (BGP)</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc1654">1654</a>, Obsolete – A Border Gateway Protocol 4 (BGP-4)</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc1655">1655</a>, Obsolete – Application of the Border Gateway Protocol in the Internet</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc1657">1657</a>, Obsolete – Definitions of Managed Objects for the Fourth Version of the Border Gateway</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc1771">1771</a>, Obsolete – A Border Gateway Protocol 4 (BGP-4)</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc1965">1965</a>, Obsolete – Autonomous System Confederations for BGP</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc2796">2796</a>, Obsolete – BGP Route Reflection –  An Alternative to Full Mesh iBGP</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc2858">2858</a>, Obsolete – Multiprotocol Extensions for BGP-4</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc3065">3065</a>, Obsolete – Autonomous System Confederations for BGP</li> <li><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222">RFC <a rel="nofollow" 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