CINXE.COM

<!DOCTYPE html> <html class="client-nojs vector-feature-language-in-header-enabled vector-feature-language-in-main-page-header-disabled vector-feature-page-tools-pinned-disabled vector-feature-toc-pinned-clientpref-1 vector-feature-main-menu-pinned-disabled vector-feature-limited-width-clientpref-1 vector-feature-limited-width-content-enabled vector-feature-custom-font-size-clientpref-1 vector-feature-appearance-pinned-clientpref-1 vector-feature-night-mode-enabled skin-theme-clientpref-day vector-sticky-header-enabled vector-toc-available" lang="en" dir="ltr"> <head> <meta charset="UTF-8"> <title>Network switching subsystem - Wikipedia</title> <script>(function(){var className="client-js vector-feature-language-in-header-enabled vector-feature-language-in-main-page-header-disabled vector-feature-page-tools-pinned-disabled vector-feature-toc-pinned-clientpref-1 vector-feature-main-menu-pinned-disabled vector-feature-limited-width-clientpref-1 vector-feature-limited-width-content-enabled vector-feature-custom-font-size-clientpref-1 vector-feature-appearance-pinned-clientpref-1 vector-feature-night-mode-enabled skin-theme-clientpref-day vector-sticky-header-enabled vector-toc-available";var cookie=document.cookie.match(/(?:^|; )enwikimwclientpreferences=([^;]+)/);if(cookie){cookie[1].split('%2C').forEach(function(pref){className=className.replace(new RegExp('(^| )'+pref.replace(/-clientpref-\w+$|[^\w-]+/g,'')+'-clientpref-\\w+( |$)'),'$1'+pref+'$2');});}document.documentElement.className=className;}());RLCONF={"wgBreakFrames":false,"wgSeparatorTransformTable":["",""],"wgDigitTransformTable":["",""],"wgDefaultDateFormat":"dmy", "wgMonthNames":["","January","February","March","April","May","June","July","August","September","October","November","December"],"wgRequestId":"ef4c1a53-220d-4f90-9410-88347ad97f53","wgCanonicalNamespace":"","wgCanonicalSpecialPageName":false,"wgNamespaceNumber":0,"wgPageName":"Network_switching_subsystem","wgTitle":"Network switching subsystem","wgCurRevisionId":1276807664,"wgRevisionId":1276807664,"wgArticleId":664022,"wgIsArticle":true,"wgIsRedirect":false,"wgAction":"view","wgUserName":null,"wgUserGroups":["*"],"wgCategories":["Articles with short description","Short description matches Wikidata","Use American English from March 2019","All Wikipedia articles written in American English","Articles lacking in-text citations from March 2019","All articles lacking in-text citations","Articles needing additional references from March 2009","All articles needing additional references","Articles with multiple maintenance issues","Pages with broken anchors","GSM standard", "Telecommunications infrastructure"],"wgPageViewLanguage":"en","wgPageContentLanguage":"en","wgPageContentModel":"wikitext","wgRelevantPageName":"Network_switching_subsystem","wgRelevantArticleId":664022,"wgIsProbablyEditable":true,"wgRelevantPageIsProbablyEditable":true,"wgRestrictionEdit":[],"wgRestrictionMove":[],"wgRedirectedFrom":"Visitor_Location_Registers","wgNoticeProject":"wikipedia","wgCiteReferencePreviewsActive":false,"wgFlaggedRevsParams":{"tags":{"status":{"levels":1}}},"wgMediaViewerOnClick":true,"wgMediaViewerEnabledByDefault":true,"wgPopupsFlags":0,"wgVisualEditor":{"pageLanguageCode":"en","pageLanguageDir":"ltr","pageVariantFallbacks":"en"},"wgMFDisplayWikibaseDescriptions":{"search":true,"watchlist":true,"tagline":false,"nearby":true},"wgWMESchemaEditAttemptStepOversample":false,"wgWMEPageLength":20000,"wgInternalRedirectTargetUrl":"/wiki/Network_switching_subsystem#Visitor_location_register_(VLR)","wgEditSubmitButtonLabelPublish":true,"wgULSPosition":"interlanguage" ,"wgULSisCompactLinksEnabled":false,"wgVector2022LanguageInHeader":true,"wgULSisLanguageSelectorEmpty":false,"wgWikibaseItemId":"Q779475","wgCheckUserClientHintsHeadersJsApi":["brands","architecture","bitness","fullVersionList","mobile","model","platform","platformVersion"],"GEHomepageSuggestedEditsEnableTopics":true,"wgGETopicsMatchModeEnabled":false,"wgGEStructuredTaskRejectionReasonTextInputEnabled":false,"wgGELevelingUpEnabledForUser":false};RLSTATE={"ext.globalCssJs.user.styles":"ready","site.styles":"ready","user.styles":"ready","ext.globalCssJs.user":"ready","user":"ready","user.options":"loading","ext.cite.styles":"ready","skins.vector.search.codex.styles":"ready","skins.vector.styles":"ready","skins.vector.icons":"ready","jquery.makeCollapsible.styles":"ready","ext.wikimediamessages.styles":"ready","ext.visualEditor.desktopArticleTarget.noscript":"ready","ext.uls.interlanguage":"ready","wikibase.client.init":"ready","ext.wikimediaBadges":"ready"};RLPAGEMODULES=[ "mediawiki.action.view.redirect","ext.cite.ux-enhancements","ext.scribunto.logs","site","mediawiki.page.ready","jquery.makeCollapsible","mediawiki.toc","skins.vector.js","ext.centralNotice.geoIP","ext.centralNotice.startUp","ext.gadget.ReferenceTooltips","ext.gadget.switcher","ext.urlShortener.toolbar","ext.centralauth.centralautologin","mmv.bootstrap","ext.popups","ext.visualEditor.desktopArticleTarget.init","ext.visualEditor.targetLoader","ext.echo.centralauth","ext.eventLogging","ext.wikimediaEvents","ext.navigationTiming","ext.uls.interface","ext.cx.eventlogging.campaigns","ext.cx.uls.quick.actions","wikibase.client.vector-2022","ext.checkUser.clientHints","ext.growthExperiments.SuggestedEditSession"];</script> <script>(RLQ=window.RLQ||[]).push(function(){mw.loader.impl(function(){return["user.options@12s5i",function($,jQuery,require,module){mw.user.tokens.set({"patrolToken":"+\\","watchToken":"+\\","csrfToken":"+\\"}); }];});});</script> <link rel="stylesheet" href="/w/load.php?lang=en&modules=ext.cite.styles%7Cext.uls.interlanguage%7Cext.visualEditor.desktopArticleTarget.noscript%7Cext.wikimediaBadges%7Cext.wikimediamessages.styles%7Cjquery.makeCollapsible.styles%7Cskins.vector.icons%2Cstyles%7Cskins.vector.search.codex.styles%7Cwikibase.client.init&only=styles&skin=vector-2022"> <script async="" src="/w/load.php?lang=en&modules=startup&only=scripts&raw=1&skin=vector-2022"></script> <meta name="ResourceLoaderDynamicStyles" content=""> <link rel="stylesheet" href="/w/load.php?lang=en&modules=site.styles&only=styles&skin=vector-2022"> <meta name="generator" content="MediaWiki 1.44.0-wmf.17"> <meta name="referrer" content="origin"> <meta name="referrer" content="origin-when-cross-origin"> <meta name="robots" content="max-image-preview:standard"> <meta name="format-detection" content="telephone=no"> <meta name="viewport" content="width=1120"> <meta property="og:title" content="Network switching subsystem - Wikipedia"> <meta property="og:type" content="website"> <link rel="preconnect" href="//upload.wikimedia.org"> <link rel="alternate" media="only screen and (max-width: 640px)" href="//en.m.wikipedia.org/wiki/Network_switching_subsystem#Visitor_location_register_(VLR)"> <link rel="alternate" type="application/x-wiki" title="Edit this page" href="/w/index.php?title=Network_switching_subsystem&action=edit"> <link rel="apple-touch-icon" href="/static/apple-touch/wikipedia.png"> <link rel="icon" href="/static/favicon/wikipedia.ico"> <link rel="search" type="application/opensearchdescription+xml" href="/w/rest.php/v1/search" title="Wikipedia (en)"> <link rel="EditURI" type="application/rsd+xml" href="//en.wikipedia.org/w/api.php?action=rsd"> <link rel="canonical" href="https://en.wikipedia.org/wiki/Network_switching_subsystem#Visitor_location_register_(VLR)"> <link rel="license" href="https://creativecommons.org/licenses/by-sa/4.0/deed.en"> <link rel="alternate" type="application/atom+xml" title="Wikipedia Atom feed" href="/w/index.php?title=Special:RecentChanges&feed=atom"> <link rel="dns-prefetch" href="//meta.wikimedia.org" /> <link rel="dns-prefetch" href="login.wikimedia.org"> </head> <body class="skin--responsive skin-vector skin-vector-search-vue mediawiki ltr sitedir-ltr mw-hide-empty-elt ns-0 ns-subject mw-editable page-Network_switching_subsystem rootpage-Network_switching_subsystem skin-vector-2022 action-view"><a class="mw-jump-link" href="#bodyContent">Jump to content</a> <div class="vector-header-container"> <header class="vector-header mw-header"> <div class="vector-header-start"> <nav class="vector-main-menu-landmark" aria-label="Site"> <div id="vector-main-menu-dropdown" class="vector-dropdown vector-main-menu-dropdown vector-button-flush-left vector-button-flush-right" title="Main menu" > <input type="checkbox" id="vector-main-menu-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-main-menu-dropdown" class="vector-dropdown-checkbox " aria-label="Main menu" > <label id="vector-main-menu-dropdown-label" for="vector-main-menu-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-menu mw-ui-icon-wikimedia-menu"></span> <span class="vector-dropdown-label-text">Main menu</span> </label> <div class="vector-dropdown-content"> <div id="vector-main-menu-unpinned-container" class="vector-unpinned-container"> <div id="vector-main-menu" class="vector-main-menu vector-pinnable-element"> <div class="vector-pinnable-header vector-main-menu-pinnable-header vector-pinnable-header-unpinned" data-feature-name="main-menu-pinned" data-pinnable-element-id="vector-main-menu" data-pinned-container-id="vector-main-menu-pinned-container" data-unpinned-container-id="vector-main-menu-unpinned-container" > <div class="vector-pinnable-header-label">Main menu</div> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-main-menu.pin">move to sidebar</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-main-menu.unpin">hide</button> </div> <div id="p-navigation" class="vector-menu mw-portlet mw-portlet-navigation" > <div class="vector-menu-heading"> Navigation </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="n-mainpage-description" class="mw-list-item"><a href="/wiki/Main_Page" title="Visit the main page [z]" accesskey="z"><span>Main page</span></a></li><li id="n-contents" class="mw-list-item"><a href="/wiki/Wikipedia:Contents" title="Guides to browsing Wikipedia"><span>Contents</span></a></li><li id="n-currentevents" class="mw-list-item"><a href="/wiki/Portal:Current_events" title="Articles related to current events"><span>Current events</span></a></li><li id="n-randompage" class="mw-list-item"><a href="/wiki/Special:Random" title="Visit a randomly selected article [x]" accesskey="x"><span>Random article</span></a></li><li id="n-aboutsite" class="mw-list-item"><a href="/wiki/Wikipedia:About" title="Learn about Wikipedia and how it works"><span>About Wikipedia</span></a></li><li id="n-contactpage" class="mw-list-item"><a href="//en.wikipedia.org/wiki/Wikipedia:Contact_us" title="How to contact Wikipedia"><span>Contact us</span></a></li> </ul> </div> </div> <div id="p-interaction" class="vector-menu mw-portlet mw-portlet-interaction" > <div class="vector-menu-heading"> Contribute </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="n-help" class="mw-list-item"><a href="/wiki/Help:Contents" title="Guidance on how to use and edit Wikipedia"><span>Help</span></a></li><li id="n-introduction" class="mw-list-item"><a href="/wiki/Help:Introduction" title="Learn how to edit Wikipedia"><span>Learn to edit</span></a></li><li id="n-portal" class="mw-list-item"><a href="/wiki/Wikipedia:Community_portal" title="The hub for editors"><span>Community portal</span></a></li><li id="n-recentchanges" class="mw-list-item"><a href="/wiki/Special:RecentChanges" title="A list of recent changes to Wikipedia [r]" accesskey="r"><span>Recent changes</span></a></li><li id="n-upload" class="mw-list-item"><a href="/wiki/Wikipedia:File_upload_wizard" title="Add images or other media for use on Wikipedia"><span>Upload file</span></a></li><li id="n-specialpages" class="mw-list-item"><a href="/wiki/Special:SpecialPages"><span>Special pages</span></a></li> </ul> </div> </div> </div> </div> </div> </div> </nav> <a href="/wiki/Main_Page" class="mw-logo"> <img class="mw-logo-icon" src="/static/images/icons/wikipedia.png" alt="" aria-hidden="true" height="50" width="50"> <span class="mw-logo-container skin-invert"> <img class="mw-logo-wordmark" alt="Wikipedia" src="/static/images/mobile/copyright/wikipedia-wordmark-en.svg" style="width: 7.5em; height: 1.125em;"> <img class="mw-logo-tagline" alt="The Free Encyclopedia" src="/static/images/mobile/copyright/wikipedia-tagline-en.svg" width="117" height="13" style="width: 7.3125em; height: 0.8125em;"> </span> </a> </div> <div class="vector-header-end"> <div id="p-search" role="search" class="vector-search-box-vue vector-search-box-collapses vector-search-box-show-thumbnail vector-search-box-auto-expand-width vector-search-box"> <a href="/wiki/Special:Search" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only search-toggle" title="Search Wikipedia [f]" accesskey="f"><span class="vector-icon mw-ui-icon-search mw-ui-icon-wikimedia-search"></span> <span>Search</span> </a> <div class="vector-typeahead-search-container"> <div class="cdx-typeahead-search cdx-typeahead-search--show-thumbnail cdx-typeahead-search--auto-expand-width"> <form action="/w/index.php" id="searchform" class="cdx-search-input cdx-search-input--has-end-button"> <div id="simpleSearch" class="cdx-search-input__input-wrapper" data-search-loc="header-moved"> <div class="cdx-text-input cdx-text-input--has-start-icon"> <input class="cdx-text-input__input" type="search" name="search" placeholder="Search Wikipedia" aria-label="Search Wikipedia" autocapitalize="sentences" title="Search Wikipedia [f]" accesskey="f" id="searchInput" > <span class="cdx-text-input__icon cdx-text-input__start-icon"></span> </div> <input type="hidden" name="title" value="Special:Search"> </div> <button class="cdx-button cdx-search-input__end-button">Search</button> </form> </div> </div> </div> <nav class="vector-user-links vector-user-links-wide" aria-label="Personal tools"> <div class="vector-user-links-main"> <div id="p-vector-user-menu-preferences" class="vector-menu mw-portlet emptyPortlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> </ul> </div> </div> <div id="p-vector-user-menu-userpage" class="vector-menu mw-portlet emptyPortlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> </ul> </div> </div> <nav class="vector-appearance-landmark" aria-label="Appearance"> <div id="vector-appearance-dropdown" class="vector-dropdown " title="Change the appearance of the page's font size, width, and color" > <input type="checkbox" id="vector-appearance-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-appearance-dropdown" class="vector-dropdown-checkbox " aria-label="Appearance" > <label id="vector-appearance-dropdown-label" for="vector-appearance-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-appearance mw-ui-icon-wikimedia-appearance"></span> <span class="vector-dropdown-label-text">Appearance</span> </label> <div class="vector-dropdown-content"> <div id="vector-appearance-unpinned-container" class="vector-unpinned-container"> </div> </div> </div> </nav> <div id="p-vector-user-menu-notifications" class="vector-menu mw-portlet emptyPortlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> </ul> </div> </div> <div id="p-vector-user-menu-overflow" class="vector-menu mw-portlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="pt-sitesupport-2" class="user-links-collapsible-item mw-list-item user-links-collapsible-item"><a data-mw="interface" href="https://donate.wikimedia.org/?wmf_source=donate&wmf_medium=sidebar&wmf_campaign=en.wikipedia.org&uselang=en" class=""><span>Donate</span></a> </li> <li id="pt-createaccount-2" class="user-links-collapsible-item mw-list-item user-links-collapsible-item"><a data-mw="interface" href="/w/index.php?title=Special:CreateAccount&returnto=Network+switching+subsystem" title="You are encouraged to create an account and log in; however, it is not mandatory" class=""><span>Create account</span></a> </li> <li id="pt-login-2" class="user-links-collapsible-item mw-list-item user-links-collapsible-item"><a data-mw="interface" href="/w/index.php?title=Special:UserLogin&returnto=Network+switching+subsystem" title="You're encouraged to log in; however, it's not mandatory. [o]" accesskey="o" class=""><span>Log in</span></a> </li> </ul> </div> </div> </div> <div id="vector-user-links-dropdown" class="vector-dropdown vector-user-menu vector-button-flush-right vector-user-menu-logged-out" title="Log in and more options" > <input type="checkbox" id="vector-user-links-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-user-links-dropdown" class="vector-dropdown-checkbox " aria-label="Personal tools" > <label id="vector-user-links-dropdown-label" for="vector-user-links-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-ellipsis mw-ui-icon-wikimedia-ellipsis"></span> <span class="vector-dropdown-label-text">Personal tools</span> </label> <div class="vector-dropdown-content"> <div id="p-personal" class="vector-menu mw-portlet mw-portlet-personal user-links-collapsible-item" title="User menu" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="pt-sitesupport" class="user-links-collapsible-item mw-list-item"><a href="https://donate.wikimedia.org/?wmf_source=donate&wmf_medium=sidebar&wmf_campaign=en.wikipedia.org&uselang=en"><span>Donate</span></a></li><li id="pt-createaccount" class="user-links-collapsible-item mw-list-item"><a href="/w/index.php?title=Special:CreateAccount&returnto=Network+switching+subsystem" title="You are encouraged to create an account and log in; however, it is not mandatory"><span class="vector-icon mw-ui-icon-userAdd mw-ui-icon-wikimedia-userAdd"></span> <span>Create account</span></a></li><li id="pt-login" class="user-links-collapsible-item mw-list-item"><a href="/w/index.php?title=Special:UserLogin&returnto=Network+switching+subsystem" title="You're encouraged to log in; however, it's not mandatory. [o]" accesskey="o"><span class="vector-icon mw-ui-icon-logIn mw-ui-icon-wikimedia-logIn"></span> <span>Log in</span></a></li> </ul> </div> </div> <div id="p-user-menu-anon-editor" class="vector-menu mw-portlet mw-portlet-user-menu-anon-editor" > <div class="vector-menu-heading"> Pages for logged out editors <a href="/wiki/Help:Introduction" aria-label="Learn more about editing"><span>learn more</span></a> </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="pt-anoncontribs" class="mw-list-item"><a href="/wiki/Special:MyContributions" title="A list of edits made from this IP address [y]" accesskey="y"><span>Contributions</span></a></li><li id="pt-anontalk" class="mw-list-item"><a href="/wiki/Special:MyTalk" title="Discussion about edits from this IP address [n]" accesskey="n"><span>Talk</span></a></li> </ul> </div> </div> </div> </div> </nav> </div> </header> </div> <div class="mw-page-container"> <div class="mw-page-container-inner"> <div class="vector-sitenotice-container"> <div id="siteNotice"></div> </div> <div class="vector-column-start"> <div class="vector-main-menu-container"> <div id="mw-navigation"> <nav id="mw-panel" class="vector-main-menu-landmark" aria-label="Site"> <div id="vector-main-menu-pinned-container" class="vector-pinned-container"> </div> </nav> </div> </div> <div class="vector-sticky-pinned-container"> <nav id="mw-panel-toc" aria-label="Contents" data-event-name="ui.sidebar-toc" class="mw-table-of-contents-container vector-toc-landmark"> <div id="vector-toc-pinned-container" class="vector-pinned-container"> <div id="vector-toc" class="vector-toc vector-pinnable-element"> <div class="vector-pinnable-header vector-toc-pinnable-header vector-pinnable-header-pinned" data-feature-name="toc-pinned" data-pinnable-element-id="vector-toc" > <h2 class="vector-pinnable-header-label">Contents</h2> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-toc.pin">move to sidebar</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-toc.unpin">hide</button> </div> <ul class="vector-toc-contents" id="mw-panel-toc-list"> <li id="toc-mw-content-text" class="vector-toc-list-item vector-toc-level-1"> <a href="#" class="vector-toc-link"> <div class="vector-toc-text">(Top)</div> </a> </li> <li id="toc-Mobile_switching_center_(MSC)" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Mobile_switching_center_(MSC)"> <div class="vector-toc-text"> <span class="vector-toc-numb">1</span> <span>Mobile switching center (MSC)</span> </div> </a> <button aria-controls="toc-Mobile_switching_center_(MSC)-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 Mobile switching center (MSC) subsection</span> </button> <ul id="toc-Mobile_switching_center_(MSC)-sublist" class="vector-toc-list"> <li id="toc-Description" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Description"> <div class="vector-toc-text"> <span class="vector-toc-numb">1.1</span> <span>Description</span> </div> </a> <ul id="toc-Description-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Mobile_switching_center_server_(MSC-Server,_MSCS_or_MSS)" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Mobile_switching_center_server_(MSC-Server,_MSCS_or_MSS)"> <div class="vector-toc-text"> <span class="vector-toc-numb">1.2</span> <span>Mobile switching center server (MSC-Server, MSCS or MSS)</span> </div> </a> <ul id="toc-Mobile_switching_center_server_(MSC-Server,_MSCS_or_MSS)-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Other_GSM_core_network_elements_connected_to_the_MSC" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Other_GSM_core_network_elements_connected_to_the_MSC"> <div class="vector-toc-text"> <span class="vector-toc-numb">1.3</span> <span>Other GSM core network elements connected to the MSC</span> </div> </a> <ul id="toc-Other_GSM_core_network_elements_connected_to_the_MSC-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Procedures_implemented" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Procedures_implemented"> <div class="vector-toc-text"> <span class="vector-toc-numb">1.4</span> <span>Procedures implemented</span> </div> </a> <ul id="toc-Procedures_implemented-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Home_location_register_(HLR)" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Home_location_register_(HLR)"> <div class="vector-toc-text"> <span class="vector-toc-numb">2</span> <span>Home location register (HLR)</span> </div> </a> <button aria-controls="toc-Home_location_register_(HLR)-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 Home location register (HLR) subsection</span> </button> <ul id="toc-Home_location_register_(HLR)-sublist" class="vector-toc-list"> <li id="toc-Other_GSM_core_network_elements_connected_to_the_HLR" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Other_GSM_core_network_elements_connected_to_the_HLR"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.1</span> <span>Other GSM core network elements connected to the HLR</span> </div> </a> <ul id="toc-Other_GSM_core_network_elements_connected_to_the_HLR-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Procedures_implemented_2" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Procedures_implemented_2"> <div class="vector-toc-text"> <span class="vector-toc-numb">2.2</span> <span>Procedures implemented</span> </div> </a> <ul id="toc-Procedures_implemented_2-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Authentication_center_(AuC)" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Authentication_center_(AuC)"> <div class="vector-toc-text"> <span class="vector-toc-numb">3</span> <span>Authentication center (AuC)</span> </div> </a> <button aria-controls="toc-Authentication_center_(AuC)-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 Authentication center (AuC) subsection</span> </button> <ul id="toc-Authentication_center_(AuC)-sublist" class="vector-toc-list"> <li id="toc-Description_2" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Description_2"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.1</span> <span>Description</span> </div> </a> <ul id="toc-Description_2-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Other_GSM_core_network_elements_connected_to_the_AuC" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Other_GSM_core_network_elements_connected_to_the_AuC"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.2</span> <span>Other GSM core network elements connected to the AuC</span> </div> </a> <ul id="toc-Other_GSM_core_network_elements_connected_to_the_AuC-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Procedures_implemented_3" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Procedures_implemented_3"> <div class="vector-toc-text"> <span class="vector-toc-numb">3.3</span> <span>Procedures implemented</span> </div> </a> <ul id="toc-Procedures_implemented_3-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Visitor_location_register_(VLR)" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Visitor_location_register_(VLR)"> <div class="vector-toc-text"> <span class="vector-toc-numb">4</span> <span>Visitor location register (VLR)</span> </div> </a> <button aria-controls="toc-Visitor_location_register_(VLR)-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 Visitor location register (VLR) subsection</span> </button> <ul id="toc-Visitor_location_register_(VLR)-sublist" class="vector-toc-list"> <li id="toc-Description_3" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Description_3"> <div class="vector-toc-text"> <span class="vector-toc-numb">4.1</span> <span>Description</span> </div> </a> <ul id="toc-Description_3-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Procedures_implemented_4" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Procedures_implemented_4"> <div class="vector-toc-text"> <span class="vector-toc-numb">4.2</span> <span>Procedures implemented</span> </div> </a> <ul id="toc-Procedures_implemented_4-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Equipment_identity_register_(EIR)" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Equipment_identity_register_(EIR)"> <div class="vector-toc-text"> <span class="vector-toc-numb">5</span> <span>Equipment identity register (EIR)</span> </div> </a> <ul id="toc-Equipment_identity_register_(EIR)-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Other_support_functions" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#Other_support_functions"> <div class="vector-toc-text"> <span class="vector-toc-numb">6</span> <span>Other support functions</span> </div> </a> <button aria-controls="toc-Other_support_functions-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 Other support functions subsection</span> </button> <ul id="toc-Other_support_functions-sublist" class="vector-toc-list"> <li id="toc-Billing_center_(BC)" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Billing_center_(BC)"> <div class="vector-toc-text"> <span class="vector-toc-numb">6.1</span> <span>Billing center (BC)</span> </div> </a> <ul id="toc-Billing_center_(BC)-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Multimedia_messaging_service_center_(MMSC)" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Multimedia_messaging_service_center_(MMSC)"> <div class="vector-toc-text"> <span class="vector-toc-numb">6.2</span> <span>Multimedia messaging service center (MMSC)</span> </div> </a> <ul id="toc-Multimedia_messaging_service_center_(MMSC)-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Voicemail_system_(VMS)" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Voicemail_system_(VMS)"> <div class="vector-toc-text"> <span class="vector-toc-numb">6.3</span> <span>Voicemail system (VMS)</span> </div> </a> <ul id="toc-Voicemail_system_(VMS)-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Lawful_interception_functions" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Lawful_interception_functions"> <div class="vector-toc-text"> <span class="vector-toc-numb">6.4</span> <span>Lawful interception functions</span> </div> </a> <ul id="toc-Lawful_interception_functions-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-See_also" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#See_also"> <div class="vector-toc-text"> <span class="vector-toc-numb">7</span> <span>See also</span> </div> </a> <ul id="toc-See_also-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-References" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#References"> <div class="vector-toc-text"> <span class="vector-toc-numb">8</span> <span>References</span> </div> </a> <ul id="toc-References-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-External_links" class="vector-toc-list-item vector-toc-level-1 vector-toc-list-item-expanded"> <a class="vector-toc-link" href="#External_links"> <div class="vector-toc-text"> <span class="vector-toc-numb">9</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">Network switching subsystem</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 14 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-14" 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">14 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%A3%D8%B3%D8%A7%D8%B3%D9%8A%D8%A7%D8%AA_%D8%AA%D8%A8%D8%A7%D8%AF%D9%84_%D8%A7%D9%84%D8%A8%D9%8A%D8%A7%D9%86%D8%A7%D8%AA_%D8%B9%D8%A8%D8%B1_%D8%B4%D8%A8%D9%83%D8%A9_%D8%A7%D9%84%D8%A7%D8%AA%D8%B5%D8%A7%D9%84" title="أساسيات تبادل البيانات عبر شبكة الاتصال – Arabic" lang="ar" hreflang="ar" data-title="أساسيات تبادل البيانات عبر شبكة الاتصال" data-language-autonym="العربية" data-language-local-name="Arabic" class="interlanguage-link-target"><span>العربية</span></a></li><li class="interlanguage-link interwiki-ca mw-list-item"><a href="https://ca.wikipedia.org/wiki/Subsistema_de_commutaci%C3%B3_de_xarxa" title="Subsistema de commutació de xarxa – Catalan" lang="ca" hreflang="ca" data-title="Subsistema de commutació de xarxa" 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/S%C3%AD%C5%A5ov%C3%BD_spojovac%C3%AD_subsyst%C3%A9m" title="Síťový spojovací subsystém – Czech" lang="cs" hreflang="cs" data-title="Síťový spojovací subsystém" 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/Network_Switching_Subsystem" title="Network Switching Subsystem – German" lang="de" hreflang="de" data-title="Network Switching Subsystem" data-language-autonym="Deutsch" data-language-local-name="German" class="interlanguage-link-target"><span>Deutsch</span></a></li><li class="interlanguage-link interwiki-es mw-list-item"><a href="https://es.wikipedia.org/wiki/NSS" title="NSS – Spanish" lang="es" hreflang="es" data-title="NSS" data-language-autonym="Español" data-language-local-name="Spanish" class="interlanguage-link-target"><span>Español</span></a></li><li class="interlanguage-link interwiki-fr mw-list-item"><a href="https://fr.wikipedia.org/wiki/GMSC" title="GMSC – French" lang="fr" hreflang="fr" data-title="GMSC" data-language-autonym="Français" data-language-local-name="French" class="interlanguage-link-target"><span>Français</span></a></li><li class="interlanguage-link interwiki-ko mw-list-item"><a href="https://ko.wikipedia.org/wiki/%EB%84%A4%ED%8A%B8%EC%9B%8C%ED%81%AC_%EC%8A%A4%EC%9C%84%EC%B9%AD_%EC%84%9C%EB%B8%8C%EC%8B%9C%EC%8A%A4%ED%85%9C" title="네트워크 스위칭 서브시스템 – Korean" lang="ko" hreflang="ko" data-title="네트워크 스위칭 서브시스템" data-language-autonym="한국어" data-language-local-name="Korean" class="interlanguage-link-target"><span>한국어</span></a></li><li class="interlanguage-link interwiki-id mw-list-item"><a href="https://id.wikipedia.org/wiki/Authentication_Center" title="Authentication Center – Indonesian" lang="id" hreflang="id" data-title="Authentication Center" 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/Network_Switching_Subsystem" title="Network Switching Subsystem – Italian" lang="it" hreflang="it" data-title="Network Switching Subsystem" data-language-autonym="Italiano" data-language-local-name="Italian" class="interlanguage-link-target"><span>Italiano</span></a></li><li class="interlanguage-link interwiki-ru mw-list-item"><a href="https://ru.wikipedia.org/wiki/%D0%9E%D0%BF%D0%BE%D1%80%D0%BD%D0%B0%D1%8F_%D1%81%D0%B5%D1%82%D1%8C_GSM" title="Опорная сеть GSM – Russian" lang="ru" hreflang="ru" data-title="Опорная сеть GSM" data-language-autonym="Русский" data-language-local-name="Russian" class="interlanguage-link-target"><span>Русский</span></a></li><li class="interlanguage-link interwiki-sr mw-list-item"><a href="https://sr.wikipedia.org/wiki/%D0%9C%D1%80%D0%B5%D0%B6%D0%BD%D0%B8_%D0%BA%D0%BE%D0%BC%D1%83%D1%82%D0%B0%D1%82%D0%BE%D1%80%D1%81%D0%BA%D0%B8_%D0%BF%D0%BE%D0%B4%D1%81%D0%B8%D1%81%D1%82%D0%B5%D0%BC" title="Мрежни комутаторски подсистем – Serbian" lang="sr" hreflang="sr" data-title="Мрежни комутаторски подсистем" data-language-autonym="Српски / srpski" data-language-local-name="Serbian" class="interlanguage-link-target"><span>Српски / srpski</span></a></li><li class="interlanguage-link interwiki-uk mw-list-item"><a href="https://uk.wikipedia.org/wiki/GSM_Core_network" title="GSM Core network – Ukrainian" lang="uk" hreflang="uk" data-title="GSM Core network" 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/Network_switching_subsystem" title="Network switching subsystem – Vietnamese" lang="vi" hreflang="vi" data-title="Network switching subsystem" data-language-autonym="Tiếng Việt" data-language-local-name="Vietnamese" class="interlanguage-link-target"><span>Tiếng Việt</span></a></li><li class="interlanguage-link interwiki-zh mw-list-item"><a href="https://zh.wikipedia.org/wiki/%E7%BD%91%E7%BB%9C%E4%BA%A4%E6%8D%A2%E5%AD%90%E7%B3%BB%E7%BB%9F" title="网络交换子系统 – Chinese" lang="zh" hreflang="zh" data-title="网络交换子系统" data-language-autonym="中文" data-language-local-name="Chinese" class="interlanguage-link-target"><span>中文</span></a></li> </ul> <div class="after-portlet after-portlet-lang"><span class="wb-langlinks-edit wb-langlinks-link"><a href="https://www.wikidata.org/wiki/Special:EntityPage/Q779475#sitelinks-wikipedia" title="Edit interlanguage links" class="wbc-editpage">Edit links</a></span></div> </div> </div> </div> </header> <div class="vector-page-toolbar"> <div class="vector-page-toolbar-container"> <div id="left-navigation"> <nav aria-label="Namespaces"> <div id="p-associated-pages" class="vector-menu vector-menu-tabs mw-portlet mw-portlet-associated-pages" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="ca-nstab-main" class="selected vector-tab-noicon mw-list-item"><a href="/wiki/Network_switching_subsystem" title="View the content page [c]" accesskey="c"><span>Article</span></a></li><li id="ca-talk" class="vector-tab-noicon mw-list-item"><a href="/wiki/Talk:Network_switching_subsystem" rel="discussion" title="Discuss improvements to the content page [t]" accesskey="t"><span>Talk</span></a></li> </ul> </div> </div> <div id="vector-variants-dropdown" class="vector-dropdown emptyPortlet" > <input type="checkbox" id="vector-variants-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-variants-dropdown" class="vector-dropdown-checkbox " aria-label="Change language variant" > <label id="vector-variants-dropdown-label" for="vector-variants-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet" aria-hidden="true" ><span class="vector-dropdown-label-text">English</span> </label> <div class="vector-dropdown-content"> <div id="p-variants" class="vector-menu mw-portlet mw-portlet-variants emptyPortlet" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> </ul> </div> </div> </div> </div> </nav> </div> <div id="right-navigation" class="vector-collapsible"> <nav aria-label="Views"> <div id="p-views" class="vector-menu vector-menu-tabs mw-portlet mw-portlet-views" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="ca-view" class="selected vector-tab-noicon mw-list-item"><a href="/wiki/Network_switching_subsystem"><span>Read</span></a></li><li id="ca-edit" class="vector-tab-noicon mw-list-item"><a href="/w/index.php?title=Network_switching_subsystem&action=edit" title="Edit this page [e]" accesskey="e"><span>Edit</span></a></li><li id="ca-history" class="vector-tab-noicon mw-list-item"><a href="/w/index.php?title=Network_switching_subsystem&action=history" title="Past revisions of this page [h]" accesskey="h"><span>View history</span></a></li> </ul> </div> </div> </nav> <nav class="vector-page-tools-landmark" aria-label="Page tools"> <div id="vector-page-tools-dropdown" class="vector-dropdown vector-page-tools-dropdown" > <input type="checkbox" id="vector-page-tools-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-page-tools-dropdown" class="vector-dropdown-checkbox " aria-label="Tools" > <label id="vector-page-tools-dropdown-label" for="vector-page-tools-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet" aria-hidden="true" ><span class="vector-dropdown-label-text">Tools</span> </label> <div class="vector-dropdown-content"> <div id="vector-page-tools-unpinned-container" class="vector-unpinned-container"> <div id="vector-page-tools" class="vector-page-tools vector-pinnable-element"> <div class="vector-pinnable-header vector-page-tools-pinnable-header vector-pinnable-header-unpinned" data-feature-name="page-tools-pinned" data-pinnable-element-id="vector-page-tools" data-pinned-container-id="vector-page-tools-pinned-container" data-unpinned-container-id="vector-page-tools-unpinned-container" > <div class="vector-pinnable-header-label">Tools</div> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-page-tools.pin">move to sidebar</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-page-tools.unpin">hide</button> </div> <div id="p-cactions" class="vector-menu mw-portlet mw-portlet-cactions emptyPortlet vector-has-collapsible-items" title="More options" > <div class="vector-menu-heading"> Actions </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="ca-more-view" class="selected vector-more-collapsible-item mw-list-item"><a href="/wiki/Network_switching_subsystem"><span>Read</span></a></li><li id="ca-more-edit" class="vector-more-collapsible-item mw-list-item"><a href="/w/index.php?title=Network_switching_subsystem&action=edit" title="Edit this page [e]" accesskey="e"><span>Edit</span></a></li><li id="ca-more-history" class="vector-more-collapsible-item mw-list-item"><a href="/w/index.php?title=Network_switching_subsystem&action=history"><span>View history</span></a></li> </ul> </div> </div> <div id="p-tb" class="vector-menu mw-portlet mw-portlet-tb" > <div class="vector-menu-heading"> General </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="t-whatlinkshere" class="mw-list-item"><a href="/wiki/Special:WhatLinksHere/Network_switching_subsystem" title="List of all English Wikipedia pages containing links to this page [j]" accesskey="j"><span>What links here</span></a></li><li id="t-recentchangeslinked" class="mw-list-item"><a href="/wiki/Special:RecentChangesLinked/Network_switching_subsystem" rel="nofollow" title="Recent changes in pages linked from this page [k]" accesskey="k"><span>Related changes</span></a></li><li id="t-upload" class="mw-list-item"><a href="//en.wikipedia.org/wiki/Wikipedia:File_Upload_Wizard" title="Upload files [u]" accesskey="u"><span>Upload file</span></a></li><li id="t-permalink" class="mw-list-item"><a href="/w/index.php?title=Network_switching_subsystem&oldid=1276807664" title="Permanent link to this revision of this page"><span>Permanent link</span></a></li><li id="t-info" class="mw-list-item"><a href="/w/index.php?title=Network_switching_subsystem&action=info" title="More information about this page"><span>Page information</span></a></li><li id="t-cite" class="mw-list-item"><a href="/w/index.php?title=Special:CiteThisPage&page=Network_switching_subsystem&id=1276807664&wpFormIdentifier=titleform" title="Information on how to cite this page"><span>Cite this page</span></a></li><li id="t-urlshortener" class="mw-list-item"><a href="/w/index.php?title=Special:UrlShortener&url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FNetwork_switching_subsystem%23Visitor_location_register_%28VLR%29"><span>Get shortened URL</span></a></li><li id="t-urlshortener-qrcode" class="mw-list-item"><a href="/w/index.php?title=Special:QrCode&url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FNetwork_switching_subsystem%23Visitor_location_register_%28VLR%29"><span>Download QR code</span></a></li> </ul> </div> </div> <div id="p-coll-print_export" class="vector-menu mw-portlet mw-portlet-coll-print_export" > <div class="vector-menu-heading"> Print/export </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="coll-download-as-rl" class="mw-list-item"><a href="/w/index.php?title=Special:DownloadAsPdf&page=Network_switching_subsystem&action=show-download-screen" title="Download this page as a PDF file"><span>Download as PDF</span></a></li><li id="t-print" class="mw-list-item"><a href="/w/index.php?title=Network_switching_subsystem&printable=yes" title="Printable version of this page [p]" accesskey="p"><span>Printable version</span></a></li> </ul> </div> </div> <div id="p-wikibase-otherprojects" class="vector-menu mw-portlet mw-portlet-wikibase-otherprojects" > <div class="vector-menu-heading"> In other projects </div> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="t-wikibase" class="wb-otherproject-link wb-otherproject-wikibase-dataitem mw-list-item"><a href="https://www.wikidata.org/wiki/Special:EntityPage/Q779475" title="Structured data on this page hosted by Wikidata [g]" accesskey="g"><span>Wikidata item</span></a></li> </ul> </div> </div> </div> </div> </div> </div> </nav> </div> </div> </div> <div class="vector-column-end"> <div class="vector-sticky-pinned-container"> <nav class="vector-page-tools-landmark" aria-label="Page tools"> <div id="vector-page-tools-pinned-container" class="vector-pinned-container"> </div> </nav> <nav class="vector-appearance-landmark" aria-label="Appearance"> <div id="vector-appearance-pinned-container" class="vector-pinned-container"> <div id="vector-appearance" class="vector-appearance vector-pinnable-element"> <div class="vector-pinnable-header vector-appearance-pinnable-header vector-pinnable-header-pinned" data-feature-name="appearance-pinned" data-pinnable-element-id="vector-appearance" data-pinned-container-id="vector-appearance-pinned-container" data-unpinned-container-id="vector-appearance-unpinned-container" > <div class="vector-pinnable-header-label">Appearance</div> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-appearance.pin">move to sidebar</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-appearance.unpin">hide</button> </div> </div> </div> </nav> </div> </div> <div id="bodyContent" class="vector-body" aria-labelledby="firstHeading" data-mw-ve-target-container> <div class="vector-body-before-content"> <div class="mw-indicators"> </div> <div id="siteSub" class="noprint">From Wikipedia, the free encyclopedia</div> </div> <div id="contentSub"><div id="mw-content-subtitle"><span class="mw-redirectedfrom">(Redirected from <a href="/w/index.php?title=Visitor_Location_Registers&redirect=no" class="mw-redirect" title="Visitor Location Registers">Visitor Location Registers</a>)</span></div></div> <div id="mw-content-text" class="mw-body-content"><div class="mw-content-ltr mw-parser-output" lang="en" dir="ltr"><div class="shortdescription nomobile noexcerpt noprint searchaux" style="display:none">Component of the Global System for Mobile Communications (GSM)</div> <p class="mw-empty-elt"> </p> <style data-mw-deduplicate="TemplateStyles:r1251242444">.mw-parser-output .ambox{border:1px solid #a2a9b1;border-left:10px solid #36c;background-color:#fbfbfb;box-sizing:border-box}.mw-parser-output .ambox+link+.ambox,.mw-parser-output .ambox+link+style+.ambox,.mw-parser-output .ambox+link+link+.ambox,.mw-parser-output .ambox+.mw-empty-elt+link+.ambox,.mw-parser-output .ambox+.mw-empty-elt+link+style+.ambox,.mw-parser-output .ambox+.mw-empty-elt+link+link+.ambox{margin-top:-1px}html body.mediawiki .mw-parser-output .ambox.mbox-small-left{margin:4px 1em 4px 0;overflow:hidden;width:238px;border-collapse:collapse;font-size:88%;line-height:1.25em}.mw-parser-output .ambox-speedy{border-left:10px solid #b32424;background-color:#fee7e6}.mw-parser-output .ambox-delete{border-left:10px solid #b32424}.mw-parser-output .ambox-content{border-left:10px solid #f28500}.mw-parser-output .ambox-style{border-left:10px solid #fc3}.mw-parser-output .ambox-move{border-left:10px solid #9932cc}.mw-parser-output .ambox-protection{border-left:10px solid #a2a9b1}.mw-parser-output .ambox .mbox-text{border:none;padding:0.25em 0.5em;width:100%}.mw-parser-output .ambox .mbox-image{border:none;padding:2px 0 2px 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><style data-mw-deduplicate="TemplateStyles:r1248332772">.mw-parser-output .multiple-issues-text{width:95%;margin:0.2em 0}.mw-parser-output .multiple-issues-text>.mw-collapsible-content{margin-top:0.3em}.mw-parser-output .compact-ambox .ambox{border:none;border-collapse:collapse;background-color:transparent;margin:0 0 0 1.6em!important;padding:0!important;width:auto;display:block}body.mediawiki .mw-parser-output .compact-ambox .ambox.mbox-small-left{font-size:100%;width:auto;margin:0}.mw-parser-output .compact-ambox .ambox .mbox-text{padding:0!important;margin:0!important}.mw-parser-output .compact-ambox .ambox .mbox-text-span{display:list-item;line-height:1.5em;list-style-type:disc}body.skin-minerva .mw-parser-output .multiple-issues-text>.mw-collapsible-toggle,.mw-parser-output .compact-ambox .ambox .mbox-image,.mw-parser-output .compact-ambox .ambox .mbox-imageright,.mw-parser-output .compact-ambox .ambox .mbox-empty-cell,.mw-parser-output .compact-ambox .hide-when-compact{display:none}</style><table class="box-Multiple_issues plainlinks metadata ambox ambox-content ambox-multiple_issues compact-ambox" 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/b/b4/Ambox_important.svg/40px-Ambox_important.svg.png" decoding="async" width="40" height="40" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/b/b4/Ambox_important.svg/60px-Ambox_important.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/b/b4/Ambox_important.svg/80px-Ambox_important.svg.png 2x" data-file-width="40" data-file-height="40" /></span></span></div></td><td class="mbox-text"><div class="mbox-text-span"><div class="multiple-issues-text mw-collapsible"><b>This article has multiple issues.</b> Please help <b><a href="/wiki/Special:EditPage/Network_switching_subsystem" title="Special:EditPage/Network switching subsystem">improve it</a></b> or discuss these issues on the <b><a href="/wiki/Talk:Network_switching_subsystem" title="Talk:Network switching subsystem">talk page</a></b>. <small><i>(<a href="/wiki/Help:Maintenance_template_removal" title="Help:Maintenance template removal">Learn how and when to remove these messages</a>)</i></small> <div class="mw-collapsible-content"> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1251242444"><table class="box-No_footnotes plainlinks metadata ambox ambox-style ambox-No_footnotes" 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/commons/thumb/a/a4/Text_document_with_red_question_mark.svg/40px-Text_document_with_red_question_mark.svg.png" decoding="async" width="40" height="40" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/a/a4/Text_document_with_red_question_mark.svg/60px-Text_document_with_red_question_mark.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/a/a4/Text_document_with_red_question_mark.svg/80px-Text_document_with_red_question_mark.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 includes a <a href="/wiki/Wikipedia:Citing_sources" title="Wikipedia:Citing sources">list of references</a>, <a href="/wiki/Wikipedia:Further_reading" title="Wikipedia:Further reading">related reading</a>, or <a href="/wiki/Wikipedia:External_links" title="Wikipedia:External links">external links</a>, <b>but its sources remain unclear because it lacks <a href="/wiki/Wikipedia:Citing_sources#Inline_citations" title="Wikipedia:Citing sources">inline citations</a></b>.<span class="hide-when-compact"> Please help <a href="/wiki/Wikipedia:WikiProject_Fact_and_Reference_Check" class="mw-redirect" title="Wikipedia:WikiProject Fact and Reference Check">improve</a> this article by <a href="/wiki/Wikipedia:When_to_cite" title="Wikipedia:When to cite">introducing</a> more precise citations.</span> <span class="date-container"><i>(<span class="date">March 2019</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> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1251242444"><table class="box-More_citations_needed plainlinks metadata ambox ambox-content ambox-Refimprove" role="presentation"><tbody><tr><td class="mbox-image"><div class="mbox-image-div"><span typeof="mw:File"><a href="/wiki/File:Question_book-new.svg" class="mw-file-description"><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/9/99/Question_book-new.svg/50px-Question_book-new.svg.png" decoding="async" width="50" height="39" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/9/99/Question_book-new.svg/75px-Question_book-new.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/9/99/Question_book-new.svg/100px-Question_book-new.svg.png 2x" data-file-width="512" data-file-height="399" /></a></span></div></td><td class="mbox-text"><div class="mbox-text-span">This article <b>needs additional citations for <a href="/wiki/Wikipedia:Verifiability" title="Wikipedia:Verifiability">verification</a></b>.<span class="hide-when-compact"> Please help <a href="/wiki/Special:EditPage/Network_switching_subsystem" title="Special:EditPage/Network switching subsystem">improve this article</a> by <a href="/wiki/Help:Referencing_for_beginners" title="Help:Referencing for beginners">adding citations to reliable sources</a>. Unsourced material may be challenged and removed.<br /><small><span class="plainlinks"><i>Find sources:</i> <a rel="nofollow" class="external text" href="https://www.google.com/search?as_eq=wikipedia&q=%22Network+switching+subsystem%22">"Network switching subsystem"</a> – <a rel="nofollow" class="external text" href="https://www.google.com/search?tbm=nws&q=%22Network+switching+subsystem%22+-wikipedia&tbs=ar:1">news</a> <b>·</b> <a rel="nofollow" class="external text" href="https://www.google.com/search?&q=%22Network+switching+subsystem%22&tbs=bkt:s&tbm=bks">newspapers</a> <b>·</b> <a rel="nofollow" class="external text" href="https://www.google.com/search?tbs=bks:1&q=%22Network+switching+subsystem%22+-wikipedia">books</a> <b>·</b> <a rel="nofollow" class="external text" href="https://scholar.google.com/scholar?q=%22Network+switching+subsystem%22">scholar</a> <b>·</b> <a rel="nofollow" class="external text" href="https://www.jstor.org/action/doBasicSearch?Query=%22Network+switching+subsystem%22&acc=on&wc=on">JSTOR</a></span></small></span> <span class="date-container"><i>(<span class="date">March 2009</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> </div> </div><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><b>Network switching subsystem</b> (<b>NSS</b>) (or <b>GSM core network</b>) is the component of a <a href="/wiki/GSM" title="GSM">GSM</a> system that carries out <a href="/wiki/Telephone_exchange" title="Telephone exchange">call out</a> and <a href="/wiki/Mobility_management" title="Mobility management">mobility management</a> functions for <a href="/wiki/Mobile_phones" class="mw-redirect" title="Mobile phones">mobile phones</a> <a href="/wiki/Roaming" title="Roaming">roaming</a> on the <a href="/wiki/Base_Station_subsystem" class="mw-redirect" title="Base Station subsystem">network of base stations</a>. It is owned and deployed by <a href="/wiki/Mobile_phone_operator" title="Mobile phone operator">mobile phone operators</a> and allows mobile devices to communicate with each other and <a href="/wiki/Telephone" title="Telephone">telephones</a> in the wider <a href="/wiki/Public_switched_telephone_network" title="Public switched telephone network">public switched telephone network</a> (PSTN). The architecture contains specific features and functions which are needed because the phones are not fixed in one location. </p><p>The NSS originally consisted of the circuit-switched <a href="/wiki/Core_network" class="mw-redirect" title="Core network">core network</a>, used for traditional <a href="/wiki/GSM_services" title="GSM services">GSM services</a> such as voice calls, <a href="/wiki/Short_message_service" class="mw-redirect" title="Short message service">SMS</a>, and <a href="/wiki/Circuit_Switched_Data" title="Circuit Switched Data">circuit switched data</a> calls. It was extended with an overlay architecture to provide packet-switched data services known as the <a href="/wiki/GPRS_core_network" title="GPRS core network">GPRS core network</a>. This allows mobile phones to have access to services such as <a href="/wiki/Wireless_Application_Protocol" title="Wireless Application Protocol">WAP</a>, <a href="/wiki/Multimedia_Messaging_Service" title="Multimedia Messaging Service">MMS</a> and the <a href="/wiki/Internet" title="Internet">Internet</a>. </p> <meta property="mw:PageProp/toc" /> <div class="mw-heading mw-heading2"><h2 id="Mobile_switching_center_(MSC)"><span id="Mobile_switching_center_.28MSC.29"></span>Mobile switching center (MSC)</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Network_switching_subsystem&action=edit&section=1" title="Edit section: Mobile switching center (MSC)"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <div class="mw-heading mw-heading3"><h3 id="Description">Description</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Network_switching_subsystem&action=edit&section=2" title="Edit section: Description"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The <b>mobile switching center</b> (MSC) is the primary service delivery node for GSM/CDMA, responsible for <a href="/wiki/Routing_in_the_PSTN" title="Routing in the PSTN">routing</a> voice calls and SMS as well as other services (such as conference calls, FAX, and circuit-switched data). </p><p>The MSC sets up and releases the <b>end-to-end connection</b>, handles mobility and hand-over requirements during the call and takes care of charging and real-time prepaid account monitoring. </p><p>In the GSM mobile phone system, in contrast with earlier analogue services, fax and data information is sent digitally encoded directly to the MSC. Only at the MSC is this re-coded into an "analogue" signal (although actually this will almost certainly mean sound is encoded digitally as a <a href="/wiki/Pulse-code_modulation" title="Pulse-code modulation">pulse-code modulation</a> (PCM) signal in a 64-kbit/s timeslot, known as a <a href="/wiki/DS0" class="mw-redirect" title="DS0">DS0</a> in America). </p><p>There are various different names for MSCs in different contexts which reflects their complex role in the network, all of these terms though could refer to the same MSC, but doing different things at different times. </p><p>The <b>gateway MSC</b> (G-MSC) is the MSC that determines which "visited MSC" (V-MSC) the subscriber who is being called is currently located at. It also interfaces with the PSTN. All mobile to mobile calls and PSTN to mobile calls are routed through a G-MSC. The term is only valid in the context of one call, since any MSC may provide both the gateway function and the visited MSC function. However, some manufacturers design dedicated high capacity MSCs which do not have any <a href="/wiki/Base_station_subsystem" title="Base station subsystem">base station subsystems</a> (BSS) connected to them. These MSCs will then be the gateway MSC for many of the calls they handle. </p><p>The <b>visited MSC</b> (V-MSC) is the MSC where a customer is currently located. The <a class="mw-selflink-fragment" href="#Visitor_location_register_(VLR)">visitor location register</a> (VLR) associated with this MSC will have the subscriber's data in it. </p><p>The <b>anchor MSC</b> is the MSC from which a <a href="/wiki/Handover" title="Handover">handover</a> has been initiated. The <b>target MSC</b> is the MSC toward which a handover should take place. A <a href="/wiki/Mobile_switching_center_server" class="mw-redirect" title="Mobile switching center server">mobile switching center server</a> is a part of the redesigned MSC concept starting from <a href="/wiki/3GPP#Standards" title="3GPP">3GPP Release 4</a>. </p> <div class="mw-heading mw-heading3"><h3 id="Mobile_switching_center_server_(MSC-Server,_MSCS_or_MSS)"><span id="Mobile_switching_center_server_.28MSC-Server.2C_MSCS_or_MSS.29"></span>Mobile switching center server (MSC-Server, MSCS or MSS)</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Network_switching_subsystem&action=edit&section=3" title="Edit section: Mobile switching center server (MSC-Server, MSCS or MSS)"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></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">Main article: <a href="/wiki/Mobile_switching_centre_server" title="Mobile switching centre server">Mobile switching centre server</a></div> <p>The <b>mobile switching center server</b> is a soft-switch variant (therefore it may be referred to as mobile soft switch, MSS) of the mobile switching center, which provides circuit-switched calling mobility management, and GSM services to the mobile phones <a href="/wiki/Roaming" title="Roaming">roaming</a> within the area that it serves. The functionality enables split control between (signaling ) and user plane (bearer in network element called as media gateway/MG), which guarantees better placement of network elements within the network. </p><p>MSS and <a href="/wiki/Media_Gateway" class="mw-redirect" title="Media Gateway">media gateway</a> (MGW) makes it possible to cross-connect circuit-switched calls switched by using IP, ATM AAL2 as well as <a href="/wiki/Time-division_multiplexing" title="Time-division multiplexing">TDM</a>. More information is available in 3GPP TS 23.205. </p><p>The term <a href="/wiki/Circuit_switching" title="Circuit switching">Circuit switching</a> (CS) used here originates from traditional telecommunications systems. However, modern MSS and MGW devices mostly use generic <a href="/wiki/Internet" title="Internet">Internet</a> technologies and form <a href="/wiki/Next-generation_network" title="Next-generation network">next-generation telecommunication networks</a>. MSS software may run on generic computers or <a href="/wiki/Virtual_machine" title="Virtual machine">virtual machines</a> in <a href="/wiki/Cloud_computing" title="Cloud computing">cloud</a> environment. </p> <div class="mw-heading mw-heading3"><h3 id="Other_GSM_core_network_elements_connected_to_the_MSC">Other GSM core network elements connected to the MSC</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Network_switching_subsystem&action=edit&section=4" title="Edit section: Other GSM core network elements connected to the MSC"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The MSC connects to the following elements: </p> <ul><li>The <a class="mw-selflink-fragment" href="#Home_location_register_(HLR)">home location register</a> (HLR) for obtaining data about the <a href="/wiki/Subscriber_Identity_Module" class="mw-redirect" title="Subscriber Identity Module">SIM</a> and <a href="/wiki/MSISDN" title="MSISDN">mobile services ISDN</a> number (MSISDN; i.e., the telephone number).</li> <li>The <a href="/wiki/Base_Station_Subsystem" class="mw-redirect" title="Base Station Subsystem">base station subsystems</a> (BSS) which handles the radio communication with <a href="/wiki/2G" title="2G">2G</a> and <a href="/wiki/2.5G" class="mw-redirect" title="2.5G">2.5G</a> mobile phones.</li> <li>The <a href="/wiki/UTRAN" class="mw-redirect" title="UTRAN">UMTS terrestrial radio access network</a> (UTRAN) which handles the radio communication with <a href="/wiki/3G" title="3G">3G</a> mobile phones.</li> <li>The <a class="mw-selflink-fragment" href="#Visitor_location_register_(VLR)">visitor location register</a> (VLR) provides subscriber information when the subscriber is outside its home network.</li> <li>Other MSCs for procedures such as <a href="/wiki/Handoff" class="mw-redirect" title="Handoff">hand over</a>.</li></ul> <div class="mw-heading mw-heading3"><h3 id="Procedures_implemented">Procedures implemented</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Network_switching_subsystem&action=edit&section=5" title="Edit section: Procedures implemented"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Tasks of the MSC include: </p> <ul><li><a href="/wiki/GSM_services#Call_set_up_process_for_incoming_calls" title="GSM services">Delivering calls to subscribers</a><sup class="noprint Inline-Template" style="white-space:nowrap;">[<i><a href="/wiki/MOS:BROKENSECTIONLINKS" class="mw-redirect" title="MOS:BROKENSECTIONLINKS"><span title="The anchor (Call set up process for incoming calls) has been deleted. (2024-07-22)">broken anchor</span></a></i>]</sup> as they arrive based on information from the VLR.</li> <li>Connecting outgoing calls to other mobile subscribers or the PSTN.</li> <li>Delivering SMSs from subscribers to the <a href="/wiki/Short_message_service_center" class="mw-redirect" title="Short message service center">short message service center</a> (SMSC) and vice versa.</li> <li>Arranging handovers from BSC to BSC.</li> <li>Carrying out handovers from this MSC to another.</li> <li>Supporting <a href="/w/index.php?title=Supplementary_services&action=edit&redlink=1" class="new" title="Supplementary services (page does not exist)">supplementary services</a> such as conference calls or call hold.</li> <li>Generating billing information.</li></ul> <div class="mw-heading mw-heading2"><h2 id="Home_location_register_(HLR)"><span id="Home_location_register_.28HLR.29"></span>Home location register (HLR) <span class="anchor" id="HLR"></span></h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Network_switching_subsystem&action=edit&section=6" title="Edit section: Home location register (HLR)"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The <b>home location register</b> (HLR) is a central database that contains details of each mobile phone subscriber that is authorized to use the GSM core network. There can be several logical, and physical, HLRs per <a href="/wiki/Public_Land_Mobile_Network" class="mw-redirect" title="Public Land Mobile Network">public land mobile network</a> (PLMN), though one <a href="/wiki/International_mobile_subscriber_identity" title="International mobile subscriber identity">international mobile subscriber identity</a> (IMSI)/MSISDN pair can be associated with only one logical HLR (which can span several physical nodes) at a time. </p><p>The HLRs store details of every <a href="/wiki/SIM_card" title="SIM card">SIM card</a> issued by the mobile phone operator. Each SIM has a unique identifier called an IMSI which is the <a href="/wiki/Primary_key" title="Primary key">primary key</a> to each HLR record. </p><p>Another important item of data associated with the SIM are the MSISDNs, which are the <a href="/wiki/Telephone_number" title="Telephone number">telephone numbers</a> used by mobile phones to make and receive calls. The primary MSISDN is the number used for making and receiving voice calls and SMS, but it is possible for a SIM to have other secondary MSISDNs associated with it for <a href="/wiki/Fax" title="Fax">fax</a> and data calls. Each MSISDN is also a <a href="/wiki/Unique_key" title="Unique key">unique key</a> to the HLR record. The HLR data is stored for as long as a subscriber remains with the mobile phone operator. </p><p>Examples of other data stored in the HLR against an IMSI record is: </p> <ul><li>GSM services that the subscriber has requested or been given.</li> <li><a href="/wiki/General_Packet_Radio_Service" title="General Packet Radio Service">General Packet Radio Service</a> (GPRS) settings to allow the subscriber to access packet services.</li> <li>Current location of subscriber (VLR and <a href="/wiki/SGSN" class="mw-redirect" title="SGSN">serving GPRS support node</a>/SGSN).</li> <li><a href="/wiki/Call_forwarding" title="Call forwarding">Call divert</a> settings applicable for each associated MSISDN.</li></ul> <p>The HLR is a system which directly receives and processes <a href="/wiki/Mobile_Application_Part" title="Mobile Application Part">MAP</a> transactions and messages from elements in the GSM network, for example, the location update messages received as mobile phones roam around. </p> <div class="mw-heading mw-heading3"><h3 id="Other_GSM_core_network_elements_connected_to_the_HLR">Other GSM core network elements connected to the HLR</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Network_switching_subsystem&action=edit&section=7" title="Edit section: Other GSM core network elements connected to the HLR"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The HLR connects to the following elements: </p> <ul><li>The G-MSC for handling incoming calls</li> <li>The VLR for handling requests from mobile phones to attach to the network</li> <li>The SMSC for handling incoming SMSs</li> <li>The <span lang="id">voice mail</span> system for delivering notifications to the mobile phone that a message is waiting</li> <li>The AuC for authentication and ciphering and exchange of data (triplets)</li></ul> <div class="mw-heading mw-heading3"><h3 id="Procedures_implemented_2">Procedures implemented</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Network_switching_subsystem&action=edit&section=8" title="Edit section: Procedures implemented"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The main function of the HLR is to manage the fact that SIMs and phones move around a lot. The following procedures are implemented to deal with this: </p> <ul><li>Manage the mobility of subscribers by means of updating their position in administrative areas called 'location areas', which are identified with a LAC. The action of a user of moving from one LA to another is followed by the HLR with a Location area update procedure.</li> <li>Send the subscriber data to a VLR or SGSN when a subscriber first roams there.</li> <li>Broker between the G-MSC or SMSC and the subscriber's current VLR in order to allow <a href="/wiki/GSM_services#Call_set_up_process_for_incoming_calls" title="GSM services">incoming calls or text messages to be delivered</a><sup class="noprint Inline-Template" style="white-space:nowrap;">[<i><a href="/wiki/MOS:BROKENSECTIONLINKS" class="mw-redirect" title="MOS:BROKENSECTIONLINKS"><span title="The anchor (Call set up process for incoming calls) has been deleted. (2024-07-22)">broken anchor</span></a></i>]</sup>.</li> <li>Remove subscriber data from the previous VLR when a subscriber has roamed away from it.</li> <li>Responsible for all SRI related queries (i.e. for invoke SRI, HLR should give sack SRI or SRI reply).</li></ul> <div class="mw-heading mw-heading2"><h2 id="Authentication_center_(AuC)"><span id="Authentication_center_.28AuC.29"></span><span class="anchor" id="AuC"></span> Authentication center (AuC)</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Network_switching_subsystem&action=edit&section=9" title="Edit section: Authentication center (AuC)"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <div class="mw-heading mw-heading3"><h3 id="Description_2">Description</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Network_switching_subsystem&action=edit&section=10" title="Edit section: Description"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The <b>authentication center</b> (AuC) is a function to <a href="/wiki/Authentication" title="Authentication">authenticate</a> each <a href="/wiki/SIM_card" title="SIM card">SIM card</a> that attempts to connect to the <b>gsm</b> core network (typically when the phone is powered on). Once the authentication is successful, the HLR is allowed to manage the SIM and services described above. An <a href="/wiki/Encryption_key" class="mw-redirect" title="Encryption key">encryption key</a> is also generated that is subsequently used to encrypt all wireless communications (voice, SMS, etc.) between the mobile phone and the GSM core network. </p><p>If the authentication fails, then no services are possible from that particular combination of SIM card and mobile phone operator attempted. There is an additional form of identification check performed on the serial number of the mobile phone described in the EIR section below, but this is not relevant to the AuC processing. </p><p>Proper implementation of security in and around the AuC is a key part of an operator's strategy to avoid <a href="/wiki/SIM_cloning" class="mw-redirect" title="SIM cloning">SIM cloning</a>. </p><p>The AuC does not engage directly in the authentication process, but instead generates data known as <i>triplets</i> for the MSC to use during the procedure. The security of the process depends upon a <a href="/wiki/Shared_secret" title="Shared secret">shared secret</a> between the AuC and the SIM called the <i>K<sub>i</sub></i>. The <i>K<sub>i</sub></i> is securely burned into the SIM during manufacture and is also securely replicated onto the AuC. This <i>K<sub>i</sub></i> is never transmitted between the AuC and SIM, but is combined with the IMSI to produce a <a href="/wiki/Challenge%E2%80%93response_authentication" title="Challenge–response authentication">challenge/response</a> for identification purposes and an encryption key called <i>K<sub>c</sub></i> for use in over the air communications. </p> <div class="mw-heading mw-heading3"><h3 id="Other_GSM_core_network_elements_connected_to_the_AuC">Other GSM core network elements connected to the AuC</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Network_switching_subsystem&action=edit&section=11" title="Edit section: Other GSM core network elements connected to the AuC"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The AuC connects to the following elements: </p> <ul><li>The MSC which requests a new batch of triplet data for an IMSI after the previous data have been used. This ensures that same keys and challenge responses are not used twice for a particular mobile.</li></ul> <div class="mw-heading mw-heading3"><h3 id="Procedures_implemented_3">Procedures implemented</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Network_switching_subsystem&action=edit&section=12" title="Edit section: Procedures implemented"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The AuC stores the following data for each IMSI: </p> <ul><li>the <i>K<sub>i</sub></i></li> <li>Algorithm id. (the standard algorithms are called A3 or A8, but an operator may choose a proprietary one).</li></ul> <p>When the MSC asks the AuC for a new set of triplets for a particular IMSI, the AuC first generates a random number known as <i>RAND</i>. This <i>RAND</i> is then combined with the <i>K<sub>i</sub></i> to produce two numbers as follows: </p> <ul><li>The <i>K<sub>i</sub></i> and <i>RAND</i> are fed into the A3 algorithm and the signed response (SRES) is calculated.</li> <li>The <i>K<sub>i</sub></i> and <i>RAND</i> are fed into the A8 algorithm and a session key called <i>K<sub>c</sub></i> is calculated.</li></ul> <p>The numbers (<i>RAND</i>, SRES, <i>K<sub>c</sub></i>) form the triplet sent back to the MSC. When a particular IMSI requests access to the GSM core network, the MSC sends the <i>RAND</i> part of the triplet to the SIM. The SIM then feeds this number and the <i>K<sub>i</sub></i> (which is burned onto the SIM) into the A3 algorithm as appropriate and an SRES is calculated and sent back to the MSC. If this SRES matches with the SRES in the triplet (which it should if it is a valid SIM), then the mobile is allowed to attach and proceed with GSM services. </p><p>After successful authentication, the MSC sends the encryption key <i>K<sub>c</sub></i> to the <a href="/wiki/Base_Station_Subsystem#Base_station_controller" class="mw-redirect" title="Base Station Subsystem">base station controller</a> (BSC) so that all communications can be encrypted and decrypted. Of course, the mobile phone can generate the <i>K<sub>c</sub></i> itself by feeding the same RAND supplied during authentication and the <i>K<sub>i</sub></i> into the A8 algorithm. </p><p>The AuC is usually collocated with the HLR, although this is not necessary. Whilst the procedure is secure for most everyday use, it is by no means hack proof. Therefore, a new set of security methods was designed for 3G phones. </p><p>In practice, A3 and A8 algorithms are generally implemented together (known as A3/A8, see <a href="/wiki/COMP128" title="COMP128">COMP128</a>). An A3/A8 algorithm is implemented in Subscriber Identity Module (SIM) cards and in GSM network Authentication Centers. It is used to authenticate the customer and generate a key for encrypting voice and data traffic, as defined in 3GPP TS 43.020 (03.20 before Rel-4). Development of A3 and A8 algorithms is considered a matter for individual GSM network operators, although example implementations are available. To encrypt Global System for Mobile Communications (GSM) cellular communications A5 algorithm is used.<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> </p> <div class="mw-heading mw-heading2"><h2 id="Visitor_location_register_(VLR)"><span id="Visitor_location_register_.28VLR.29"></span>Visitor location register (VLR)</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Network_switching_subsystem&action=edit&section=13" title="Edit section: Visitor location register (VLR)"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <div class="mw-heading mw-heading3"><h3 id="Description_3">Description</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Network_switching_subsystem&action=edit&section=14" title="Edit section: Description"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The <b>Visitor Location Register (VLR)</b> is a database of the MSs (<a href="/wiki/Mobile_station" title="Mobile station">Mobile stations</a>) that have roamed into the jurisdiction of the Mobile Switching Center (MSC) which it serves. Each main <a href="/wiki/Base_Transceiver_Station" class="mw-redirect" title="Base Transceiver Station">base transceiver station</a> in the network is served by exactly one VLR (one <a href="/wiki/Base_transceiver_station" title="Base transceiver station">BTS</a> may be served by many MSCs in case of MSC in pool), hence a subscriber cannot be present in more than one VLR at a time. </p><p>The data stored in the VLR has either been received from the <a class="mw-selflink-fragment" href="#Home_location_register_.28HLR.29"><b>Home Location Register (HLR)</b></a>, or collected from the MS. In practice, for performance reasons, most vendors integrate the VLR directly to the V-MSC and, where this is not done, the VLR is very tightly linked with the MSC via a proprietary interface. Whenever an MSC detects a new MS in its network, in addition to creating a new record in the VLR, it also updates the HLR of the mobile subscriber, apprising it of the new location of that MS. If VLR data is corrupted it can lead to serious issues with text messaging and call services. </p><p>Data stored include: </p> <ul><li><a href="/wiki/International_mobile_subscriber_identity" title="International mobile subscriber identity">IMSI</a> (the subscriber's identity number).</li> <li>Authentication data.</li> <li>MSISDN (the subscriber's phone number).</li> <li>GSM services that the subscriber is allowed to access.</li> <li><a href="/w/index.php?title=GPRS_Access_Points&action=edit&redlink=1" class="new" title="GPRS Access Points (page does not exist)">access point (GPRS)</a> subscribed.</li> <li>The HLR address of the subscriber.</li> <li>SCP Address(For Prepaid Subscriber).</li></ul> <div class="mw-heading mw-heading3"><h3 id="Procedures_implemented_4">Procedures implemented</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Network_switching_subsystem&action=edit&section=15" title="Edit section: Procedures implemented"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The primary functions of the VLR are: </p> <ul><li>To inform the HLR that a subscriber has arrived in the particular area covered by the VLR.</li> <li>To track where the subscriber is within the VLR area (location area) when no call is ongoing.</li> <li>To allow or disallow which services the subscriber may use.</li> <li>To allocate roaming numbers during the processing of incoming calls.</li> <li>To purge the subscriber record if a subscriber becomes inactive whilst in the area of a VLR. The VLR deletes the subscriber's data after a fixed time period of inactivity and informs the HLR (e.g., when the phone has been switched off and left off or when the subscriber has moved to an area with no coverage for a long time).</li> <li>To delete the subscriber record when a subscriber explicitly moves to another, as instructed by the HLR.</li></ul> <div class="mw-heading mw-heading2"><h2 id="Equipment_identity_register_(EIR)"><span id="Equipment_identity_register_.28EIR.29"></span>Equipment identity register (EIR)</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Network_switching_subsystem&action=edit&section=16" title="Edit section: Equipment identity register (EIR)"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p><b>EIR</b> is a system that handles real-time requests to check the <a href="/wiki/International_Mobile_Equipment_Identity" title="International Mobile Equipment Identity">IMEI</a> (checkIMEI) of mobile devices that come from the switching equipment (MSC, <a href="/wiki/SGSN" class="mw-redirect" title="SGSN">SGSN</a>, <a href="/wiki/Mobility_Management_Entity" class="mw-redirect" title="Mobility Management Entity">MME</a>). The answer contains the result of the check: </p> <ul><li>whitelisted – the device is allowed to register on the network.</li> <li>blacklisted – the device is prohibited from registering on the network.</li> <li>greylisted – the device is allowed to register on the network temporarily.</li> <li>An error ‘unknown equipment’ may also be returned.</li></ul> <p>The switching equipment must use the EIR response to determine whether or not to allow the device to register or re-register on the network. Since the response of switching equipment to ‘greylisted’ and ‘unknown equipment’ responses is not clearly described in the standard, they are most often not used. </p><p>Most often, EIR uses the IMEI blacklist feature, which contains the IMEI of the devices that need to be banned from the network. As a rule, these are stolen or lost devices. Mobile operators rarely use EIR capabilities to block devices on their own. Usually blocking begins when there is a law in the country, which obliges all cellular operators of the country to do so. Therefore, in the delivery of the basic components of the network switching subsystem (core network) is often already present EIR with basic functionality, which includes a ‘whitelisted’ response to all CheckIMEI and the ability to fill IMEI blacklist, which will be given a ‘blacklisted’ response. </p><p>When the legislative framework for blocking registration of devices in cellular networks appears in the country, the telecommunications regulator usually has a Central EIR (<a href="/wiki/Central_Equipment_Identity_Register" title="Central Equipment Identity Register">CEIR</a>) system, which is integrated with the EIR of all operators and transmits to them the actual lists of identifiers that must be used when processing CheckIMEI requests. In doing so, there may be many new requirements for EIR systems that are not present in the legacy EIR: </p> <ul><li>Synchronizing lists with CEIR. CEIR systems are not described by a standard, so the protocols and exchange mode may differ from country to country.</li> <li>Supporting additional lists – IMEI white list, IMEI grey list, list of allocated <a href="/wiki/Type_Allocation_Code" title="Type Allocation Code">TACs</a>, etc.</li> <li>Support in lists not only IMEI but also bindings – IMEI-IMSI, IMEI-MSISDN, IMEI-<a href="/wiki/International_mobile_subscriber_identity" title="International mobile subscriber identity">IMSI</a>-<a href="/wiki/MSISDN" title="MSISDN">MSISDN</a>.</li> <li>Supporting the customized logic of lists applying.</li> <li>Automatic adding the item to a list in separate scenarios.</li> <li>Sending <a href="/wiki/SMS" title="SMS">SMS</a> notifications to subscribers in separate scenarios.</li> <li>Integration with the billing system to receive IMSI-MSISDN bundles.</li> <li>Accumulating the subscribers’ profiles (history of device changing).</li> <li>Long-term storage of processing of all CheckIMEI requests.</li></ul> <p>Other functions may be required in individual cases. For example, Kazakhstan has introduced mandatory registration of devices and their binding to subscribers. But when a subscriber appears in the network with a new device, the network operation is not blocked completely, and the subscriber is allowed to register the device. To do this, there are blocked all services, except the following: calls to a specific service number, sending SMS to a specific service number, and all Internet traffic is redirected to a specific landing page. This is achieved by the fact that EIR can send commands to several MNO systems (HLR, <a href="/wiki/Policy_and_charging_rules_function" title="Policy and charging rules function">PCRF</a>, <a href="/wiki/Short_Message_service_center" title="Short Message service center">SMSC</a>, etc.). </p><p>The most common suppliers of individual EIR systems (not as part of a complex solution) are the companies BroadForward, Mahindra Comviva, Mavenir, Nokia, Eastwind. </p> <div class="mw-heading mw-heading2"><h2 id="Other_support_functions">Other support functions</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Network_switching_subsystem&action=edit&section=17" title="Edit section: Other support functions"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>Connected more or less directly to the GSM core network are many other functions. </p> <div class="mw-heading mw-heading3"><h3 id="Billing_center_(BC)"><span id="Billing_center_.28BC.29"></span>Billing center (BC)</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Network_switching_subsystem&action=edit&section=18" title="Edit section: Billing center (BC)"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The <b>billing center</b> is responsible for processing the toll tickets generated by the VLRs and HLRs and generating a bill for each subscriber. It is also responsible for generating billing data of roaming subscriber. </p> <div class="mw-heading mw-heading3"><h3 id="Multimedia_messaging_service_center_(MMSC)"><span id="Multimedia_messaging_service_center_.28MMSC.29"></span>Multimedia messaging service center (MMSC)</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Network_switching_subsystem&action=edit&section=19" title="Edit section: Multimedia messaging service center (MMSC)"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The <b><a href="/wiki/Multimedia_messaging_service" class="mw-redirect" title="Multimedia messaging service">multimedia messaging service</a> center</b> supports the sending of multimedia messages (e.g., images, <a href="/wiki/Sound" title="Sound">audio</a>, <a href="/wiki/Video" title="Video">video</a> and their combinations) to (or from) MMS-bluetooth. </p> <div class="mw-heading mw-heading3"><h3 id="Voicemail_system_(VMS)"><span id="Voicemail_system_.28VMS.29"></span>Voicemail system (VMS)</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Network_switching_subsystem&action=edit&section=20" title="Edit section: Voicemail system (VMS)"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>The <b><a href="/wiki/Voicemail" title="Voicemail">voicemail</a> system</b> records and stores voicemail. </p> <div class="mw-heading mw-heading3"><h3 id="Lawful_interception_functions">Lawful interception functions</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Network_switching_subsystem&action=edit&section=21" title="Edit section: Lawful interception functions"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236090951"><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="/wiki/Lawful_interception" title="Lawful interception">Lawful interception</a></div> <p>According to U.S. law, which has also been copied into many other countries, especially in Europe, all telecommunications equipment must provide facilities for monitoring the calls of selected users. There must be some level of support for this built into any of the different elements. The concept of <i>lawful interception</i> is also known, following the relevant U.S. law, as <a href="/wiki/Communications_Assistance_for_Law_Enforcement_Act" title="Communications Assistance for Law Enforcement Act">CALEA</a>. Generally, lawful Interception implementation is similar to the implementation of conference call. While A and B are talking with each other, C can join the call and listen silently. </p> <div class="mw-heading mw-heading2"><h2 id="See_also">See also</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Network_switching_subsystem&action=edit&section=22" title="Edit section: See also"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li>The GSM core network.</li> <li><a href="/wiki/Base_station_subsystem" title="Base station subsystem">Base station subsystem</a></li> <li><a href="/wiki/COMP128" title="COMP128">COMP128</a></li> <li><a href="/w/index.php?title=4GLET&action=edit&redlink=1" class="new" title="4GLET (page does not exist)">4GLET</a></li></ul> <div class="mw-heading mw-heading2"><h2 id="References">References</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Network_switching_subsystem&action=edit&section=23" title="Edit section: References"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <style data-mw-deduplicate="TemplateStyles:r1239543626">.mw-parser-output .reflist{margin-bottom:0.5em;list-style-type:decimal}@media screen{.mw-parser-output .reflist{font-size:90%}}.mw-parser-output .reflist .references{font-size:100%;margin-bottom:0;list-style-type:inherit}.mw-parser-output .reflist-columns-2{column-width:30em}.mw-parser-output .reflist-columns-3{column-width:25em}.mw-parser-output .reflist-columns{margin-top:0.3em}.mw-parser-output .reflist-columns ol{margin-top:0}.mw-parser-output .reflist-columns li{page-break-inside:avoid;break-inside:avoid-column}.mw-parser-output .reflist-upper-alpha{list-style-type:upper-alpha}.mw-parser-output .reflist-upper-roman{list-style-type:upper-roman}.mw-parser-output .reflist-lower-alpha{list-style-type:lower-alpha}.mw-parser-output .reflist-lower-greek{list-style-type:lower-greek}.mw-parser-output .reflist-lower-roman{list-style-type:lower-roman}</style><div class="reflist"> <div class="mw-references-wrap"><ol class="references"> <li id="cite_note-1"><span class="mw-cite-backlink"><b><a href="#cite_ref-1">^</a></b></span> <span class="reference-text"><style data-mw-deduplicate="TemplateStyles:r1238218222">.mw-parser-output cite.citation{font-style:inherit;word-wrap:break-word}.mw-parser-output .citation q{quotes:"\"""\"""'""'"}.mw-parser-output .citation:target{background-color:rgba(0,127,255,0.133)}.mw-parser-output .id-lock-free.id-lock-free a{background:url("//upload.wikimedia.org/wikipedia/commons/6/65/Lock-green.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-limited.id-lock-limited a,.mw-parser-output .id-lock-registration.id-lock-registration a{background:url("//upload.wikimedia.org/wikipedia/commons/d/d6/Lock-gray-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-subscription.id-lock-subscription a{background:url("//upload.wikimedia.org/wikipedia/commons/a/aa/Lock-red-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .cs1-ws-icon a{background:url("//upload.wikimedia.org/wikipedia/commons/4/4c/Wikisource-logo.svg")right 0.1em center/12px no-repeat}body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-free a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-limited a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-registration a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-subscription a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .cs1-ws-icon a{background-size:contain;padding:0 1em 0 0}.mw-parser-output .cs1-code{color:inherit;background:inherit;border:none;padding:inherit}.mw-parser-output .cs1-hidden-error{display:none;color:var(--color-error,#d33)}.mw-parser-output .cs1-visible-error{color:var(--color-error,#d33)}.mw-parser-output .cs1-maint{display:none;color:#085;margin-left:0.3em}.mw-parser-output .cs1-kern-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right{padding-right:0.2em}.mw-parser-output .citation .mw-selflink{font-weight:inherit}@media screen{.mw-parser-output .cs1-format{font-size:95%}html.skin-theme-clientpref-night .mw-parser-output .cs1-maint{color:#18911f}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .cs1-maint{color:#18911f}}</style><cite id="CITEREFShahabuddinRahamanRehmanAhmad2018" class="citation book cs1">Shahabuddin, Shahria; Rahaman, Sadiqur; Rehman, Faisal; Ahmad, Ijaz; Khan, Zaheer (2018). <i>A Comprehensive Guide to 5G Security</i>. John Wiley & Sons Ltd. p. 12.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=A+Comprehensive+Guide+to+5G+Security&rft.pages=12&rft.pub=John+Wiley+%26+Sons+Ltd.&rft.date=2018&rft.aulast=Shahabuddin&rft.aufirst=Shahria&rft.au=Rahaman%2C+Sadiqur&rft.au=Rehman%2C+Faisal&rft.au=Ahmad%2C+Ijaz&rft.au=Khan%2C+Zaheer&rfr_id=info%3Asid%2Fen.wikipedia.org%3ANetwork+switching+subsystem" class="Z3988"></span></span> </li> </ol></div></div> <div class="mw-heading mw-heading2"><h2 id="External_links">External links</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Network_switching_subsystem&action=edit&section=24" title="Edit section: External links"><span>edit</span></a><span class="mw-editsection-bracket">]</span></span></div> <ul><li>4GLET - the standardisation body for GSM and UMTS</li> <li><a rel="nofollow" class="external text" href="http://www.elektroda.pl/rtvforum/download.php?id=338749">UMTS Networks: Protocols, Terminology and Implementation</a> - a PDF eBook by Gunnar Heine</li></ul> <div class="navbox-styles"><style data-mw-deduplicate="TemplateStyles:r1129693374">.mw-parser-output .hlist dl,.mw-parser-output .hlist ol,.mw-parser-output .hlist ul{margin:0;padding:0}.mw-parser-output .hlist dd,.mw-parser-output .hlist dt,.mw-parser-output .hlist li{margin:0;display:inline}.mw-parser-output .hlist.inline,.mw-parser-output .hlist.inline dl,.mw-parser-output .hlist.inline ol,.mw-parser-output .hlist.inline ul,.mw-parser-output .hlist dl dl,.mw-parser-output .hlist dl ol,.mw-parser-output .hlist dl ul,.mw-parser-output .hlist ol dl,.mw-parser-output .hlist ol ol,.mw-parser-output .hlist ol ul,.mw-parser-output .hlist ul dl,.mw-parser-output .hlist ul ol,.mw-parser-output .hlist ul ul{display:inline}.mw-parser-output .hlist .mw-empty-li{display:none}.mw-parser-output .hlist dt::after{content:": "}.mw-parser-output .hlist dd::after,.mw-parser-output .hlist li::after{content:" · ";font-weight:bold}.mw-parser-output .hlist dd:last-child::after,.mw-parser-output .hlist dt:last-child::after,.mw-parser-output .hlist li:last-child::after{content:none}.mw-parser-output .hlist dd dd:first-child::before,.mw-parser-output .hlist dd dt:first-child::before,.mw-parser-output .hlist dd li:first-child::before,.mw-parser-output .hlist dt dd:first-child::before,.mw-parser-output .hlist dt dt:first-child::before,.mw-parser-output .hlist dt li:first-child::before,.mw-parser-output .hlist li dd:first-child::before,.mw-parser-output .hlist li dt:first-child::before,.mw-parser-output .hlist li li:first-child::before{content:" (";font-weight:normal}.mw-parser-output .hlist dd dd:last-child::after,.mw-parser-output .hlist dd dt:last-child::after,.mw-parser-output .hlist dd li:last-child::after,.mw-parser-output .hlist dt dd:last-child::after,.mw-parser-output .hlist dt dt:last-child::after,.mw-parser-output .hlist dt li:last-child::after,.mw-parser-output .hlist li dd:last-child::after,.mw-parser-output .hlist li dt:last-child::after,.mw-parser-output .hlist li li:last-child::after{content:")";font-weight:normal}.mw-parser-output .hlist ol{counter-reset:listitem}.mw-parser-output .hlist ol>li{counter-increment:listitem}.mw-parser-output .hlist ol>li::before{content:" "counter(listitem)"\a0 "}.mw-parser-output .hlist dd ol>li:first-child::before,.mw-parser-output .hlist dt ol>li:first-child::before,.mw-parser-output .hlist li ol>li:first-child::before{content:" ("counter(listitem)"\a0 "}</style><style data-mw-deduplicate="TemplateStyles:r1236075235">.mw-parser-output .navbox{box-sizing:border-box;border:1px solid #a2a9b1;width:100%;clear:both;font-size:88%;text-align:center;padding:1px;margin:1em auto 0}.mw-parser-output .navbox .navbox{margin-top:0}.mw-parser-output .navbox+.navbox,.mw-parser-output .navbox+.navbox-styles+.navbox{margin-top:-1px}.mw-parser-output .navbox-inner,.mw-parser-output .navbox-subgroup{width:100%}.mw-parser-output .navbox-group,.mw-parser-output .navbox-title,.mw-parser-output .navbox-abovebelow{padding:0.25em 1em;line-height:1.5em;text-align:center}.mw-parser-output .navbox-group{white-space:nowrap;text-align:right}.mw-parser-output .navbox,.mw-parser-output .navbox-subgroup{background-color:#fdfdfd}.mw-parser-output .navbox-list{line-height:1.5em;border-color:#fdfdfd}.mw-parser-output .navbox-list-with-group{text-align:left;border-left-width:2px;border-left-style:solid}.mw-parser-output tr+tr>.navbox-abovebelow,.mw-parser-output tr+tr>.navbox-group,.mw-parser-output tr+tr>.navbox-image,.mw-parser-output tr+tr>.navbox-list{border-top:2px solid #fdfdfd}.mw-parser-output .navbox-title{background-color:#ccf}.mw-parser-output .navbox-abovebelow,.mw-parser-output .navbox-group,.mw-parser-output .navbox-subgroup .navbox-title{background-color:#ddf}.mw-parser-output .navbox-subgroup .navbox-group,.mw-parser-output .navbox-subgroup .navbox-abovebelow{background-color:#e6e6ff}.mw-parser-output .navbox-even{background-color:#f7f7f7}.mw-parser-output .navbox-odd{background-color:transparent}.mw-parser-output .navbox .hlist td dl,.mw-parser-output .navbox .hlist td ol,.mw-parser-output .navbox .hlist td ul,.mw-parser-output .navbox td.hlist dl,.mw-parser-output .navbox td.hlist ol,.mw-parser-output .navbox td.hlist ul{padding:0.125em 0}.mw-parser-output .navbox .navbar{display:block;font-size:100%}.mw-parser-output .navbox-title .navbar{float:left;text-align:left;margin-right:0.5em}body.skin--responsive .mw-parser-output .navbox-image img{max-width:none!important}@media print{body.ns-0 .mw-parser-output .navbox{display:none!important}}</style></div><div role="navigation" class="navbox" aria-labelledby="Cellular_network_standards736" style="padding:3px"><table class="nowraplinks mw-collapsible autocollapse navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="2"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><style data-mw-deduplicate="TemplateStyles:r1239400231">.mw-parser-output .navbar{display:inline;font-size:88%;font-weight:normal}.mw-parser-output .navbar-collapse{float:left;text-align:left}.mw-parser-output .navbar-boxtext{word-spacing:0}.mw-parser-output .navbar ul{display:inline-block;white-space:nowrap;line-height:inherit}.mw-parser-output .navbar-brackets::before{margin-right:-0.125em;content:"[ "}.mw-parser-output .navbar-brackets::after{margin-left:-0.125em;content:" ]"}.mw-parser-output .navbar li{word-spacing:-0.125em}.mw-parser-output .navbar a>span,.mw-parser-output .navbar a>abbr{text-decoration:inherit}.mw-parser-output .navbar-mini abbr{font-variant:small-caps;border-bottom:none;text-decoration:none;cursor:inherit}.mw-parser-output .navbar-ct-full{font-size:114%;margin:0 7em}.mw-parser-output .navbar-ct-mini{font-size:114%;margin:0 4em}html.skin-theme-clientpref-night .mw-parser-output .navbar li a abbr{color:var(--color-base)!important}@media(prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .navbar li a abbr{color:var(--color-base)!important}}@media print{.mw-parser-output .navbar{display:none!important}}</style><div class="navbar plainlinks hlist navbar-mini"><ul><li class="nv-view"><a href="/wiki/Template:Cellular_network_standards" title="Template:Cellular network standards"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Cellular_network_standards" title="Template talk:Cellular network standards"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Cellular_network_standards" title="Special:EditPage/Template:Cellular network standards"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="Cellular_network_standards736" style="font-size:114%;margin:0 4em"><a href="/wiki/Cellular_network" title="Cellular network">Cellular network</a> standards</div></th></tr><tr><td class="navbox-abovebelow" colspan="2"><div><a href="/wiki/List_of_mobile_phone_generations" class="mw-redirect" title="List of mobile phone generations">List of mobile phone generations</a></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Mobile_radio_telephone" title="Mobile radio telephone">0G</a> <a href="/wiki/Radiotelephone" title="Radiotelephone">radio telephones</a> (1946)</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Mobile_Telephone_Service" title="Mobile Telephone Service">MTS</a></li> <li><a href="/wiki/Improved_Mobile_Telephone_Service" title="Improved Mobile Telephone Service">IMTS</a></li> <li><a href="/wiki/Altai_(mobile_telephone_system)" title="Altai (mobile telephone system)">Altai</a></li> <li><a href="/wiki/OLT_(mobile_network)" title="OLT (mobile network)">OLT</a></li> <li><a href="/wiki/MTD_(mobile_network)" title="MTD (mobile network)">MTA - MTB - MTC - MTD</a></li> <li><a href="/w/index.php?title=Mobile_TeleSeratout&action=edit&redlink=1" class="new" title="Mobile TeleSeratout (page does not exist)">Mobile TeleSeratout</a></li> <li><a href="/wiki/Advanced_Mobile_Telephone_System" title="Advanced Mobile Telephone System">AMTS</a></li> <li><a href="/wiki/Autotel" title="Autotel">Autotel (PALM)</a></li> <li><a href="/wiki/Autoradiopuhelin" title="Autoradiopuhelin">ARP</a></li> <li><a href="/wiki/B-Netz" title="B-Netz">B-Netz</a></li> <li><a href="/wiki/AMR_radiotelephone_network_(Czechoslovakia)" title="AMR radiotelephone network (Czechoslovakia)">AMR</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/1G" title="1G">1G</a> (1979)</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:10em"><a href="/wiki/Advanced_Mobile_Phone_System" title="Advanced Mobile Phone System">AMPS</a> family</th><td class="navbox-list-with-group navbox-list navbox-even" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Advanced_Mobile_Phone_System" title="Advanced Mobile Phone System">AMPS - N-AMPS</a></li> <li><a href="/wiki/Total_Access_Communication_System" title="Total Access Communication System">TACS - ETACS</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:10em">Other</th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Nordic_Mobile_Telephone" title="Nordic Mobile Telephone">NMT</a></li> <li><a href="/wiki/C-Netz" title="C-Netz">C-450</a></li> <li><a href="/wiki/Hicap" title="Hicap">Hicap</a></li> <li><a href="/wiki/Mobitex" title="Mobitex">Mobitex</a></li> <li><a href="/wiki/DataTAC" title="DataTAC">DataTAC</a></li> <li><a href="/wiki/CT1" title="CT1">CT1</a></li> <li><a href="/wiki/RTMI" title="RTMI">RTMI</a></li></ul> </div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/2G" title="2G">2G</a> (1991)</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:10em"><a href="/wiki/GSM" title="GSM">GSM</a>/<a href="/wiki/3GPP" title="3GPP">3GPP</a> family</th><td class="navbox-list-with-group navbox-list navbox-even" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/GSM" title="GSM">GSM</a></li> <li><a href="/wiki/Circuit_Switched_Data" title="Circuit Switched Data">CSD - HSCSD</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:10em"><a href="/wiki/3rd_Generation_Partnership_Project_2" title="3rd Generation Partnership Project 2">3GPP2</a> family</th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/CdmaOne" title="CdmaOne">cdmaOne (IS-95)</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:10em"><a href="/wiki/Advanced_Mobile_Phone_System" title="Advanced Mobile Phone System">AMPS</a> family</th><td class="navbox-list-with-group navbox-list navbox-even" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Digital_AMPS" title="Digital AMPS">D-AMPS (IS-54 and IS-136)</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:10em">Other</th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Cellular_digital_packet_data" title="Cellular digital packet data">CDPD</a></li> <li><a href="/wiki/IDEN" title="IDEN">iDEN</a></li> <li><a href="/wiki/Personal_Digital_Cellular" title="Personal Digital Cellular">PDC</a></li> <li><a href="/wiki/Personal_Handy-phone_System" title="Personal Handy-phone System">PHS</a></li> <li><a href="/wiki/CT2" title="CT2">CT2</a></li></ul> </div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/2G#Evolution" title="2G">2G transitional<br />(2.5G, 2.75G, 2.9G)</a></th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:10em"><a href="/wiki/GSM" title="GSM">GSM</a>/3GPP family</th><td class="navbox-list-with-group navbox-list navbox-even" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/General_Packet_Radio_Service" title="General Packet Radio Service">GPRS</a></li> <li><a href="/wiki/Enhanced_Data_rates_for_GSM_Evolution" title="Enhanced Data rates for GSM Evolution">EDGE/EGPRS - Evolved EDGE</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:10em">3GPP2 family</th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/CDMA2000#1X" title="CDMA2000">CDMA2000 1X</a> (TIA/EIA/IS-2000)</li> <li><a href="/wiki/CDMA2000#1X_Advanced" title="CDMA2000">CDMA2000 1X Advanced</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:10em">Other</th><td class="navbox-list-with-group navbox-list navbox-even" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/WiDEN" class="mw-redirect" title="WiDEN">WiDEN</a></li> <li><a href="/wiki/Digital_enhanced_cordless_telecommunications" class="mw-redirect" title="Digital enhanced cordless telecommunications">DECT</a></li></ul> </div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/3G" title="3G">3G</a> (1998)<br /><a href="/wiki/IMT-2000" title="IMT-2000">IMT-2000</a> (2001)</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:10em">3GPP family</th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/UMTS" title="UMTS">UMTS</a> <ul><li><a href="/wiki/W-CDMA" class="mw-redirect" title="W-CDMA">UTRA-FDD / W-CDMA</a> <ul><li><a href="/wiki/Freedom_of_Mobile_Multimedia_Access" title="Freedom of Mobile Multimedia Access">FOMA</a></li></ul></li> <li><a href="/wiki/TD-SCDMA" class="mw-redirect" title="TD-SCDMA">UTRA-TDD LCR / TD-SCDMA</a></li> <li><a href="/wiki/TD-CDMA" class="mw-redirect" title="TD-CDMA">UTRA-TDD HCR / TD-CDMA</a></li></ul></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:10em">3GPP2 family</th><td class="navbox-list-with-group navbox-list navbox-even" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Evolution-Data_Optimized" title="Evolution-Data Optimized">CDMA2000 1xEV-DO Release 0</a> (TIA/IS-856)</li></ul> </div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/3G#Evolution" title="3G">3G transitional<br />(3.5G, 3.75G, 3.9G)</a></th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:10em">3GPP family</th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/High_Speed_Packet_Access" title="High Speed Packet Access">HSPA</a> <ul><li><a href="/wiki/High_Speed_Downlink_Packet_Access" class="mw-redirect" title="High Speed Downlink Packet Access">HSDPA</a></li> <li><a href="/wiki/High_Speed_Uplink_Packet_Access" class="mw-redirect" title="High Speed Uplink Packet Access">HSUPA</a></li></ul></li> <li><a href="/wiki/Evolved_High_Speed_Packet_Access" title="Evolved High Speed Packet Access">HSPA+</a> <ul><li><a href="/wiki/DC-HSDPA" class="mw-redirect" title="DC-HSDPA">DC-HSDPA</a></li></ul></li> <li><a href="/wiki/LTE_(telecommunication)" title="LTE (telecommunication)">LTE</a> (<a href="/wiki/E-UTRA" title="E-UTRA">E-UTRA</a>)</li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:10em">3GPP2 family</th><td class="navbox-list-with-group navbox-list navbox-even" style="padding:0"><div style="padding:0 0.25em"> <ul><li>CDMA2000 <a href="/wiki/Evolution-Data_Optimized" title="Evolution-Data Optimized">1xEV-DO Revision A</a> (TIA/EIA/IS-856-A)</li> <li><a href="/wiki/Evolution-Data_Optimized" title="Evolution-Data Optimized">EV-DO Revision B</a> (TIA/EIA/IS-856-B)</li> <li><a href="/wiki/Evolution-Data_Optimized" title="Evolution-Data Optimized">EV-DO Revision C</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:10em"><a href="/wiki/Institute_of_Electrical_and_Electronics_Engineers" title="Institute of Electrical and Electronics Engineers">IEEE</a> family</th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/WiMAX" title="WiMAX">Mobile WiMAX</a> <ul><li><a href="/wiki/IEEE_802.16" title="IEEE 802.16">IEEE 802.16e</a></li></ul></li> <li><a href="/wiki/Orthogonal_frequency-division_multiplexing#FLASH-OFDM" title="Orthogonal frequency-division multiplexing">Flash-OFDM</a></li> <li><a href="/wiki/IEEE_802.20" title="IEEE 802.20">iBurst (IEEE 802.20)</a></li> <li><a href="/wiki/WiBro" title="WiBro">WiBro</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:10em"><a href="/wiki/ETSI" class="mw-redirect" title="ETSI">ETSI</a> family</th><td class="navbox-list-with-group navbox-list navbox-even" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/HiperMAN" title="HiperMAN">HiperMAN</a></li></ul> </div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/4G" title="4G">4G</a> (2009)<br /><a href="/wiki/IMT_Advanced" title="IMT Advanced">IMT Advanced</a> (2013)</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:10em">3GPP family</th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/LTE_Advanced" title="LTE Advanced">LTE Advanced</a> (<a href="/wiki/E-UTRA" title="E-UTRA">E-UTRA</a>)</li> <li><a href="/wiki/LTE_Advanced_Pro" class="mw-redirect" title="LTE Advanced Pro">LTE Advanced Pro</a> (4.5G/4.9G)</li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:10em">IEEE family</th><td class="navbox-list-with-group navbox-list navbox-even" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/WiMAX" title="WiMAX">WiMAX</a> (<a href="/wiki/IEEE_802.16" title="IEEE 802.16">IEEE 802.16m</a>) <ul><li>WiMax 2.1</li> <li><a href="/wiki/WiBro" title="WiBro">WiBro</a></li></ul></li></ul> </div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/5G" title="5G">5G</a> (2018)<br /><a href="/wiki/IMT-2020" title="IMT-2020">IMT-2020</a> (2021)</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:10em">3GPP family</th><td class="navbox-list-with-group navbox-list navbox-odd" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/5G_NR" title="5G NR">5G NR</a></li> <li><a href="/wiki/5G-Advanced" class="mw-redirect" title="5G-Advanced">5G-Advanced</a> (5.5G)</li> <li><a href="/w/index.php?title=NR-IIoT&action=edit&redlink=1" class="new" title="NR-IIoT (page does not exist)">NR-IIoT</a></li> <li><a href="/wiki/LTE-M" title="LTE-M">LTE-M</a></li> <li><a href="/wiki/Narrowband_IoT" title="Narrowband IoT">NB-IoT</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:10em">Other</th><td class="navbox-list-with-group navbox-list navbox-even" style="padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/w/index.php?title=DECT-5G&action=edit&redlink=1" class="new" title="DECT-5G (page does not exist)">DECT-5G</a></li></ul> </div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Related articles</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Cellular_network" title="Cellular network">Cellular networks</a></li> <li><a href="/wiki/Mobile_telephony" title="Mobile telephony">Mobile telephony</a></li> <li><a href="/wiki/History_of_mobile_phones" title="History of mobile phones">History</a></li> <li><a href="/wiki/Comparison_of_mobile_phone_standards" title="Comparison of mobile phone standards">Comparison of standards</a></li> <li><a href="/wiki/Channel_access_method" title="Channel access method">Channel access methods</a> <ul><li><a href="/wiki/Frequency-division_multiple_access" title="Frequency-division multiple access">FDMA</a> <ul><li><a href="/wiki/Orthogonal_frequency-division_multiple_access" title="Orthogonal frequency-division multiple access">OFDMA</a></li></ul></li> <li><a href="/wiki/Time-division_multiple_access" title="Time-division multiple access">TDMA</a> <ul><li><a href="/wiki/Self-organized_time-division_multiple_access" title="Self-organized time-division multiple access">STDMA</a></li></ul></li> <li><a href="/wiki/Spread_spectrum" title="Spread spectrum">SSMA</a> <ul><li><a href="/wiki/Code-division_multiple_access" title="Code-division multiple access">CDMA</a></li></ul></li> <li><a href="/wiki/Space-division_multiple_access" title="Space-division multiple access">SDMA</a></li></ul></li> <li><a href="/wiki/Spectral_efficiency#Comparison_table" title="Spectral efficiency">Spectral efficiency comparison table</a></li> <li><a href="/wiki/Cellular_frequencies" title="Cellular frequencies">Frequency bands</a> <ul><li><a href="/wiki/GSM_frequency_bands" title="GSM frequency bands">GSM</a></li> <li><a href="/wiki/UMTS_frequency_bands" title="UMTS frequency bands">UMTS</a></li> <li><a href="/wiki/LTE_frequency_bands" title="LTE frequency bands">LTE</a></li> <li><a href="/wiki/5G_NR_frequency_bands" title="5G NR frequency bands">5G NR</a></li> <li><a href="/wiki/CDMA_frequency_bands" title="CDMA frequency bands">CDMA</a></li></ul></li> <li><a href="/wiki/Mobile_broadband" title="Mobile broadband">Mobile broadband</a></li> <li><a href="/wiki/Multimedia_Broadcast_Multicast_Service" title="Multimedia Broadcast Multicast Service">Multimedia Broadcast Multicast Service</a></li> <li><a href="/wiki/Next_Generation_Mobile_Networks" title="Next Generation Mobile Networks">NGMN Alliance</a></li> <li><a href="/wiki/Push-to-talk" title="Push-to-talk">Push-to-talk</a></li> <li><a href="/wiki/MIMO" title="MIMO">MIMO</a></li> <li><a href="/wiki/IP_Multimedia_Subsystem" title="IP Multimedia Subsystem">IMS</a> <ul><li><a href="/wiki/Voice_over_LTE" title="Voice over LTE">VoLTE</a></li> <li><a href="/wiki/Video_over_LTE" title="Video over LTE">ViLTE</a></li> <li><a href="/wiki/Voice_over_NR" title="Voice over NR">VoNR</a></li> <li><a href="/w/index.php?title=Video_over_NR&action=edit&redlink=1" class="new" title="Video over NR (page does not exist)">ViNR</a></li> <li><a href="/wiki/Generic_Access_Network" class="mw-redirect" title="Generic Access Network">Wi-Fi Calling</a></li></ul></li> <li><a href="/wiki/Osmocom" title="Osmocom">Osmocom</a></li></ul> </div></td></tr><tr><td class="navbox-abovebelow" colspan="2"><div><span class="nowrap"><span class="noviewer" typeof="mw:File"><span><img alt="" src="//upload.wikimedia.org/wikipedia/commons/thumb/4/4e/Telecom-icon.svg/28px-Telecom-icon.svg.png" decoding="async" width="28" height="28" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/4/4e/Telecom-icon.svg/42px-Telecom-icon.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/4/4e/Telecom-icon.svg/56px-Telecom-icon.svg.png 2x" data-file-width="500" data-file-height="500" /></span></span> </span><a href="/wiki/Portal:Telecommunication" title="Portal:Telecommunication">Telecommunication portal</a>   <span class="nowrap"><span class="noviewer" typeof="mw:File"><span><img alt="telephone icon" src="//upload.wikimedia.org/wikipedia/commons/thumb/b/b8/Telephone_icon_blue_gradient.svg/28px-Telephone_icon_blue_gradient.svg.png" decoding="async" width="28" height="28" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/b/b8/Telephone_icon_blue_gradient.svg/42px-Telephone_icon_blue_gradient.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/b/b8/Telephone_icon_blue_gradient.svg/56px-Telephone_icon_blue_gradient.svg.png 2x" data-file-width="722" data-file-height="722" /></span></span> </span><a href="/wiki/Portal:Telephones" title="Portal:Telephones">Telephones portal</a></div></td></tr></tbody></table></div>    </div><noscript><img src="https://login.wikimedia.org/wiki/Special:CentralAutoLogin/start?useformat=desktop&type=1x1&usesul3=0" alt="" width="1" height="1" style="border: none; position: absolute;"></noscript> <div class="printfooter" data-nosnippet="">Retrieved from "<a dir="ltr" href="https://en.wikipedia.org/w/index.php?title=Network_switching_subsystem&oldid=1276807664#Visitor_location_register_(VLR)">https://en.wikipedia.org/w/index.php?title=Network_switching_subsystem&oldid=1276807664#Visitor_location_register_(VLR)</a>"</div></div> <div id="catlinks" class="catlinks" data-mw="interface"><div id="mw-normal-catlinks" class="mw-normal-catlinks"><a href="/wiki/Help:Category" title="Help:Category">Categories</a>: <ul><li><a href="/wiki/Category:GSM_standard" title="Category:GSM standard">GSM standard</a></li><li><a href="/wiki/Category:Telecommunications_infrastructure" title="Category:Telecommunications infrastructure">Telecommunications infrastructure</a></li></ul></div><div id="mw-hidden-catlinks" class="mw-hidden-catlinks mw-hidden-cats-hidden">Hidden categories: <ul><li><a href="/wiki/Category:Articles_with_short_description" title="Category:Articles with short description">Articles with short description</a></li><li><a href="/wiki/Category:Short_description_matches_Wikidata" title="Category:Short description matches Wikidata">Short description matches Wikidata</a></li><li><a href="/wiki/Category:Use_American_English_from_March_2019" title="Category:Use American English from March 2019">Use American English from March 2019</a></li><li><a href="/wiki/Category:All_Wikipedia_articles_written_in_American_English" title="Category:All Wikipedia articles written in American English">All Wikipedia articles written in American English</a></li><li><a href="/wiki/Category:Articles_lacking_in-text_citations_from_March_2019" title="Category:Articles lacking in-text citations from March 2019">Articles lacking in-text citations from March 2019</a></li><li><a href="/wiki/Category:All_articles_lacking_in-text_citations" title="Category:All articles lacking in-text citations">All articles lacking in-text citations</a></li><li><a href="/wiki/Category:Articles_needing_additional_references_from_March_2009" title="Category:Articles needing additional references from March 2009">Articles needing additional references from March 2009</a></li><li><a href="/wiki/Category:All_articles_needing_additional_references" title="Category:All articles needing additional references">All articles needing additional references</a></li><li><a href="/wiki/Category:Articles_with_multiple_maintenance_issues" title="Category:Articles with multiple maintenance issues">Articles with multiple maintenance issues</a></li><li><a href="/wiki/Category:Pages_with_broken_anchors" title="Category:Pages with broken anchors">Pages with broken anchors</a></li></ul></div></div> </div> </main> </div> <div class="mw-footer-container"> <footer id="footer" class="mw-footer" > <ul id="footer-info"> <li id="footer-info-lastmod"> This page was last edited on 20 February 2025, at 21:44<span class="anonymous-show"> (UTC)</span>.</li> <li id="footer-info-copyright">Text is available under the <a href="/wiki/Wikipedia:Text_of_the_Creative_Commons_Attribution-ShareAlike_4.0_International_License" title="Wikipedia:Text of the Creative Commons Attribution-ShareAlike 4.0 International License">Creative Commons Attribution-ShareAlike 4.0 License</a>; additional terms may apply. By using this site, you agree to the <a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Terms_of_Use" class="extiw" title="foundation:Special:MyLanguage/Policy:Terms of Use">Terms of Use</a> and <a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Privacy_policy" class="extiw" title="foundation:Special:MyLanguage/Policy:Privacy policy">Privacy Policy</a>. Wikipedia® is a registered trademark of the <a rel="nofollow" class="external text" href="https://wikimediafoundation.org/">Wikimedia Foundation, Inc.</a>, a non-profit organization.</li> </ul> <ul id="footer-places"> <li id="footer-places-privacy"><a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Privacy_policy">Privacy policy</a></li> <li id="footer-places-about"><a href="/wiki/Wikipedia:About">About Wikipedia</a></li> <li id="footer-places-disclaimers"><a href="/wiki/Wikipedia:General_disclaimer">Disclaimers</a></li> <li id="footer-places-contact"><a href="//en.wikipedia.org/wiki/Wikipedia:Contact_us">Contact Wikipedia</a></li> <li id="footer-places-wm-codeofconduct"><a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Universal_Code_of_Conduct">Code of Conduct</a></li> <li id="footer-places-developers"><a href="https://developer.wikimedia.org">Developers</a></li> <li id="footer-places-statslink"><a href="https://stats.wikimedia.org/#/en.wikipedia.org">Statistics</a></li> <li id="footer-places-cookiestatement"><a href="https://foundation.wikimedia.org/wiki/Special:MyLanguage/Policy:Cookie_statement">Cookie statement</a></li> <li id="footer-places-mobileview"><a href="//en.m.wikipedia.org/w/index.php?title=Network_switching_subsystem&mobileaction=toggle_view_mobile#Visitor_location_register_(VLR)" class="noprint stopMobileRedirectToggle">Mobile view</a></li> </ul> <ul id="footer-icons" class="noprint"> <li id="footer-copyrightico"><a href="https://wikimediafoundation.org/" class="cdx-button cdx-button--fake-button cdx-button--size-large cdx-button--fake-button--enabled"><picture><source media="(min-width: 500px)" srcset="/static/images/footer/wikimedia-button.svg" width="84" height="29"><img src="/static/images/footer/wikimedia.svg" width="25" height="25" alt="Wikimedia Foundation" lang="en" loading="lazy"></picture></a></li> <li id="footer-poweredbyico"><a href="https://www.mediawiki.org/" class="cdx-button cdx-button--fake-button cdx-button--size-large cdx-button--fake-button--enabled"><picture><source media="(min-width: 500px)" srcset="/w/resources/assets/poweredby_mediawiki.svg" width="88" height="31"><img src="/w/resources/assets/mediawiki_compact.svg" alt="Powered by MediaWiki" width="25" height="25" loading="lazy"></picture></a></li> </ul> </footer> </div> </div> </div> <div class="vector-header-container vector-sticky-header-container"> <div id="vector-sticky-header" class="vector-sticky-header"> <div class="vector-sticky-header-start"> <div class="vector-sticky-header-icon-start vector-button-flush-left vector-button-flush-right" aria-hidden="true"> <button class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-sticky-header-search-toggle" tabindex="-1" data-event-name="ui.vector-sticky-search-form.icon"><span class="vector-icon mw-ui-icon-search mw-ui-icon-wikimedia-search"></span> <span>Search</span> </button> </div> <div role="search" class="vector-search-box-vue vector-search-box-show-thumbnail vector-search-box"> <div class="vector-typeahead-search-container"> <div class="cdx-typeahead-search cdx-typeahead-search--show-thumbnail"> <form action="/w/index.php" id="vector-sticky-search-form" class="cdx-search-input cdx-search-input--has-end-button"> <div class="cdx-search-input__input-wrapper" data-search-loc="header-moved"> <div class="cdx-text-input cdx-text-input--has-start-icon"> <input class="cdx-text-input__input" type="search" name="search" placeholder="Search Wikipedia"> <span class="cdx-text-input__icon cdx-text-input__start-icon"></span> </div> <input type="hidden" name="title" value="Special:Search"> </div> <button class="cdx-button cdx-search-input__end-button">Search</button> </form> </div> </div> </div> <div class="vector-sticky-header-context-bar"> <nav aria-label="Contents" class="vector-toc-landmark"> <div id="vector-sticky-header-toc" class="vector-dropdown mw-portlet mw-portlet-sticky-header-toc vector-sticky-header-toc vector-button-flush-left" > <input type="checkbox" id="vector-sticky-header-toc-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-sticky-header-toc" class="vector-dropdown-checkbox " aria-label="Toggle the table of contents" > <label id="vector-sticky-header-toc-label" for="vector-sticky-header-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-sticky-header-toc-unpinned-container" class="vector-unpinned-container"> </div> </div> </div> </nav> <div class="vector-sticky-header-context-bar-primary" aria-hidden="true" ><span class="mw-page-title-main">Network switching subsystem</span></div> </div> </div> <div class="vector-sticky-header-end" aria-hidden="true"> <div class="vector-sticky-header-icons"> <a href="#" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only" id="ca-talk-sticky-header" tabindex="-1" data-event-name="talk-sticky-header"><span class="vector-icon mw-ui-icon-speechBubbles mw-ui-icon-wikimedia-speechBubbles"></span> <span></span> </a> <a href="#" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only" id="ca-subject-sticky-header" tabindex="-1" data-event-name="subject-sticky-header"><span class="vector-icon mw-ui-icon-article mw-ui-icon-wikimedia-article"></span> <span></span> </a> <a href="#" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only" id="ca-history-sticky-header" tabindex="-1" data-event-name="history-sticky-header"><span class="vector-icon mw-ui-icon-wikimedia-history mw-ui-icon-wikimedia-wikimedia-history"></span> <span></span> </a> <a href="#" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only mw-watchlink" id="ca-watchstar-sticky-header" tabindex="-1" data-event-name="watch-sticky-header"><span class="vector-icon mw-ui-icon-wikimedia-star mw-ui-icon-wikimedia-wikimedia-star"></span> <span></span> </a> <a href="#" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only" id="ca-edit-sticky-header" tabindex="-1" data-event-name="wikitext-edit-sticky-header"><span class="vector-icon mw-ui-icon-wikimedia-wikiText mw-ui-icon-wikimedia-wikimedia-wikiText"></span> <span></span> </a> <a href="#" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only" id="ca-ve-edit-sticky-header" tabindex="-1" data-event-name="ve-edit-sticky-header"><span class="vector-icon mw-ui-icon-wikimedia-edit mw-ui-icon-wikimedia-wikimedia-edit"></span> <span></span> </a> <a href="#" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only" id="ca-viewsource-sticky-header" tabindex="-1" data-event-name="ve-edit-protected-sticky-header"><span class="vector-icon mw-ui-icon-wikimedia-editLock mw-ui-icon-wikimedia-wikimedia-editLock"></span> <span></span> </a> </div> <div class="vector-sticky-header-buttons"> <button class="cdx-button cdx-button--weight-quiet mw-interlanguage-selector" id="p-lang-btn-sticky-header" tabindex="-1" data-event-name="ui.dropdown-p-lang-btn-sticky-header"><span class="vector-icon mw-ui-icon-wikimedia-language mw-ui-icon-wikimedia-wikimedia-language"></span> <span>14 languages</span> </button> <a href="#" class="cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--action-progressive" id="ca-addsection-sticky-header" tabindex="-1" data-event-name="addsection-sticky-header"><span class="vector-icon mw-ui-icon-speechBubbleAdd-progressive mw-ui-icon-wikimedia-speechBubbleAdd-progressive"></span> <span>Add topic</span> </a> </div> <div class="vector-sticky-header-icon-end"> <div class="vector-user-links"> </div> </div> </div> </div> </div> <div class="vector-settings" id="p-dock-bottom"> <ul></ul> </div><script>(RLQ=window.RLQ||[]).push(function(){mw.config.set({"wgHostname":"mw-web.codfw.main-5c66dc9bfb-ltxhq","wgBackendResponseTime":125,"wgPageParseReport":{"limitreport":{"cputime":"0.397","walltime":"0.544","ppvisitednodes":{"value":1571,"limit":1000000},"postexpandincludesize":{"value":89826,"limit":2097152},"templateargumentsize":{"value":10998,"limit":2097152},"expansiondepth":{"value":18,"limit":100},"expensivefunctioncount":{"value":8,"limit":500},"unstrip-depth":{"value":1,"limit":20},"unstrip-size":{"value":19291,"limit":5000000},"entityaccesscount":{"value":0,"limit":400},"timingprofile":["100.00% 467.095 1 -total"," 23.87% 111.492 8 Template:Navbox"," 23.25% 108.580 1 Template:Mobile_telecommunications_standards"," 20.16% 94.160 1 Template:Reflist"," 19.94% 93.149 1 Template:Multiple_issues"," 18.71% 87.383 1 Template:Short_description"," 17.45% 81.487 1 Template:Cite_book"," 13.10% 61.174 2 Template:Ambox"," 10.76% 50.268 1 Template:No_footnotes"," 9.98% 46.598 2 Template:Pagetype"]},"scribunto":{"limitreport-timeusage":{"value":"0.242","limit":"10.000"},"limitreport-memusage":{"value":5304224,"limit":52428800},"limitreport-logs":"table#1 {\n [\"size\"] = \"small\",\n}\ntable#1 {\n [\"size\"] = \"small\",\n}\n"},"cachereport":{"origin":"mw-api-ext.codfw.main-6b8dbdfc56-km5f7","timestamp":"20250220214455","ttl":2592000,"transientcontent":false}}});});</script> <script type="application/ld+json">{"@context":"https:\/\/schema.org","@type":"Article","name":"Network switching subsystem","url":"https:\/\/en.wikipedia.org\/wiki\/Network_switching_subsystem#Visitor_location_register_(VLR)","sameAs":"http:\/\/www.wikidata.org\/entity\/Q779475","mainEntity":"http:\/\/www.wikidata.org\/entity\/Q779475","author":{"@type":"Organization","name":"Contributors to Wikimedia projects"},"publisher":{"@type":"Organization","name":"Wikimedia Foundation, Inc.","logo":{"@type":"ImageObject","url":"https:\/\/www.wikimedia.org\/static\/images\/wmf-hor-googpub.png"}},"datePublished":"2004-05-18T22:15:28Z","dateModified":"2025-02-20T21:44:55Z","headline":"component of the Global System for Mobile Communications (GSM)"}</script> </body> </html>