CINXE.COM

<!DOCTYPE html> <html class="client-nojs vector-feature-language-in-header-enabled vector-feature-language-in-main-page-header-disabled vector-feature-sticky-header-disabled vector-feature-page-tools-pinned-disabled vector-feature-toc-pinned-clientpref-1 vector-feature-main-menu-pinned-disabled vector-feature-limited-width-clientpref-1 vector-feature-limited-width-content-enabled vector-feature-custom-font-size-clientpref-1 vector-feature-appearance-pinned-clientpref-1 vector-feature-night-mode-enabled skin-theme-clientpref-day vector-toc-available" lang="en" dir="ltr"> <head> <meta charset="UTF-8"> <title>Voice over IP - Wikipedia</title> <script>(function(){var className="client-js vector-feature-language-in-header-enabled vector-feature-language-in-main-page-header-disabled vector-feature-sticky-header-disabled vector-feature-page-tools-pinned-disabled vector-feature-toc-pinned-clientpref-1 vector-feature-main-menu-pinned-disabled vector-feature-limited-width-clientpref-1 vector-feature-limited-width-content-enabled vector-feature-custom-font-size-clientpref-1 vector-feature-appearance-pinned-clientpref-1 vector-feature-night-mode-enabled skin-theme-clientpref-day vector-toc-available";var cookie=document.cookie.match(/(?:^|; )enwikimwclientpreferences=([^;]+)/);if(cookie){cookie[1].split('%2C').forEach(function(pref){className=className.replace(new RegExp('(^| )'+pref.replace(/-clientpref-\w+$|[^\w-]+/g,'')+'-clientpref-\\w+( |$)'),'$1'+pref+'$2');});}document.documentElement.className=className;}());RLCONF={"wgBreakFrames":false,"wgSeparatorTransformTable":["",""],"wgDigitTransformTable":["",""],"wgDefaultDateFormat":"dmy", "wgMonthNames":["","January","February","March","April","May","June","July","August","September","October","November","December"],"wgRequestId":"30348ee8-0ad9-483a-909a-3859924e0c5a","wgCanonicalNamespace":"","wgCanonicalSpecialPageName":false,"wgNamespaceNumber":0,"wgPageName":"Voice_over_IP","wgTitle":"Voice over IP","wgCurRevisionId":1263667331,"wgRevisionId":1263667331,"wgArticleId":75028,"wgIsArticle":true,"wgIsRedirect":false,"wgAction":"view","wgUserName":null,"wgUserGroups":["*"],"wgCategories":["CS1 maint: unfit URL","CS1 maint: bot: original URL status unknown","Webarchive template wayback links","Articles with short description","Short description is different from Wikidata","Use mdy dates from August 2021","Use American English from October 2023","All Wikipedia articles written in American English","Articles needing additional references from November 2019","All articles needing additional references","Wikipedia articles in need of updating from April 2022", "All Wikipedia articles in need of updating","All articles with unsourced statements","Articles with unsourced statements from April 2022","Articles with unsourced statements from September 2013","Articles with unsourced statements from June 2022","Wikipedia articles needing clarification from December 2019","Articles with unsourced statements from March 2024","Articles needing more detailed references","Articles with unsourced statements from July 2023","Voice over IP","Broadband","Videotelephony","Audio network protocols","Office equipment"],"wgPageViewLanguage":"en","wgPageContentLanguage":"en","wgPageContentModel":"wikitext","wgRelevantPageName":"Voice_over_IP","wgRelevantArticleId":75028,"wgIsProbablyEditable":true,"wgRelevantPageIsProbablyEditable":true,"wgRestrictionEdit":[],"wgRestrictionMove":[],"wgNoticeProject":"wikipedia","wgCiteReferencePreviewsActive":false,"wgFlaggedRevsParams":{"tags":{"status":{"levels":1}}},"wgMediaViewerOnClick":true,"wgMediaViewerEnabledByDefault": true,"wgPopupsFlags":0,"wgVisualEditor":{"pageLanguageCode":"en","pageLanguageDir":"ltr","pageVariantFallbacks":"en"},"wgMFDisplayWikibaseDescriptions":{"search":true,"watchlist":true,"tagline":false,"nearby":true},"wgWMESchemaEditAttemptStepOversample":false,"wgWMEPageLength":90000,"wgRelatedArticlesCompat":[],"wgEditSubmitButtonLabelPublish":true,"wgULSPosition":"interlanguage","wgULSisCompactLinksEnabled":false,"wgVector2022LanguageInHeader":true,"wgULSisLanguageSelectorEmpty":false,"wgWikibaseItemId":"Q81945","wgCheckUserClientHintsHeadersJsApi":["brands","architecture","bitness","fullVersionList","mobile","model","platform","platformVersion"],"GEHomepageSuggestedEditsEnableTopics":true,"wgGETopicsMatchModeEnabled":false,"wgGEStructuredTaskRejectionReasonTextInputEnabled":false,"wgGELevelingUpEnabledForUser":false};RLSTATE={"ext.globalCssJs.user.styles":"ready","site.styles":"ready","user.styles":"ready","ext.globalCssJs.user":"ready","user":"ready","user.options":"loading", "ext.cite.styles":"ready","skins.vector.search.codex.styles":"ready","skins.vector.styles":"ready","skins.vector.icons":"ready","jquery.makeCollapsible.styles":"ready","ext.wikimediamessages.styles":"ready","ext.visualEditor.desktopArticleTarget.noscript":"ready","ext.uls.interlanguage":"ready","wikibase.client.init":"ready","ext.wikimediaBadges":"ready"};RLPAGEMODULES=["ext.cite.ux-enhancements","mediawiki.page.media","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.6"> <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="Voice over IP - 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/Voice_over_IP"> <link rel="alternate" type="application/x-wiki" title="Edit this page" href="/w/index.php?title=Voice_over_IP&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/Voice_over_IP"> <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-Voice_over_IP rootpage-Voice_over_IP skin-vector-2022 action-view"><a class="mw-jump-link" href="#bodyContent">Jump to content</a> <div class="vector-header-container"> <header class="vector-header mw-header"> <div class="vector-header-start"> <nav class="vector-main-menu-landmark" aria-label="Site"> <div id="vector-main-menu-dropdown" class="vector-dropdown vector-main-menu-dropdown vector-button-flush-left vector-button-flush-right" > <input type="checkbox" id="vector-main-menu-dropdown-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-main-menu-dropdown" class="vector-dropdown-checkbox " aria-label="Main menu" > <label id="vector-main-menu-dropdown-label" for="vector-main-menu-dropdown-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" > Main menu </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">Main page</a></li><li id="n-contents" class="mw-list-item"><a href="/wiki/Wikipedia:Contents" title="Guides to browsing Wikipedia">Contents</a></li><li id="n-currentevents" class="mw-list-item"><a href="/wiki/Portal:Current_events" title="Articles related to current events">Current events</a></li><li id="n-randompage" class="mw-list-item"><a href="/wiki/Special:Random" title="Visit a randomly selected article [x]" accesskey="x">Random article</a></li><li id="n-aboutsite" class="mw-list-item"><a href="/wiki/Wikipedia:About" title="Learn about Wikipedia and how it works">About Wikipedia</a></li><li id="n-contactpage" class="mw-list-item"><a href="//en.wikipedia.org/wiki/Wikipedia:Contact_us" title="How to contact Wikipedia">Contact us</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">Help</a></li><li id="n-introduction" class="mw-list-item"><a href="/wiki/Help:Introduction" title="Learn how to edit Wikipedia">Learn to edit</a></li><li id="n-portal" class="mw-list-item"><a href="/wiki/Wikipedia:Community_portal" title="The hub for editors">Community portal</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">Recent changes</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">Upload file</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"> <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;"> </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"> Search </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" > </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" > Appearance </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="">Donate</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=Voice+over+IP" title="You are encouraged to create an account and log in; however, it is not mandatory" class="">Create account</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=Voice+over+IP" title="You're encouraged to log in; however, it's not mandatory. [o]" accesskey="o" class="">Log in</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" > Personal tools </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">Donate</a></li><li id="pt-createaccount" class="user-links-collapsible-item mw-list-item"><a href="/w/index.php?title=Special:CreateAccount&returnto=Voice+over+IP" title="You are encouraged to create an account and log in; however, it is not mandatory"> Create account</a></li><li id="pt-login" class="user-links-collapsible-item mw-list-item"><a href="/w/index.php?title=Special:UserLogin&returnto=Voice+over+IP" title="You're encouraged to log in; however, it's not mandatory. [o]" accesskey="o"> Log in</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">learn more</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">Contributions</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">Talk</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-Overview" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Overview"> <div class="vector-toc-text"> 1 Overview </div> </a> <button aria-controls="toc-Overview-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> Toggle Overview subsection </button> <ul id="toc-Overview-sublist" class="vector-toc-list"> <li id="toc-Integration_of_VoIP_in_Mobile_Networks" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Integration_of_VoIP_in_Mobile_Networks"> <div class="vector-toc-text"> 1.1 Integration of VoIP in Mobile Networks </div> </a> <ul id="toc-Integration_of_VoIP_in_Mobile_Networks-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Protocols" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Protocols"> <div class="vector-toc-text"> 2 Protocols </div> </a> <ul id="toc-Protocols-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Adoption" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Adoption"> <div class="vector-toc-text"> 3 Adoption </div> </a> <button aria-controls="toc-Adoption-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> Toggle Adoption subsection </button> <ul id="toc-Adoption-sublist" class="vector-toc-list"> <li id="toc-Consumer_market" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Consumer_market"> <div class="vector-toc-text"> 3.1 Consumer market </div> </a> <ul id="toc-Consumer_market-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-PSTN_and_mobile_network_providers" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#PSTN_and_mobile_network_providers"> <div class="vector-toc-text"> 3.2 PSTN and mobile network providers </div> </a> <ul id="toc-PSTN_and_mobile_network_providers-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Corporate_use" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Corporate_use"> <div class="vector-toc-text"> 3.3 Corporate use </div> </a> <ul id="toc-Corporate_use-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Delivery_mechanisms" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Delivery_mechanisms"> <div class="vector-toc-text"> 4 Delivery mechanisms </div> </a> <button aria-controls="toc-Delivery_mechanisms-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> Toggle Delivery mechanisms subsection </button> <ul id="toc-Delivery_mechanisms-sublist" class="vector-toc-list"> <li id="toc-Hosted_VoIP_systems" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Hosted_VoIP_systems"> <div class="vector-toc-text"> 4.1 Hosted VoIP systems </div> </a> <ul id="toc-Hosted_VoIP_systems-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Private_VoIP_systems" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Private_VoIP_systems"> <div class="vector-toc-text"> 4.2 Private VoIP systems </div> </a> <ul id="toc-Private_VoIP_systems-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Quality_of_service" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Quality_of_service"> <div class="vector-toc-text"> 5 Quality of service </div> </a> <button aria-controls="toc-Quality_of_service-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> Toggle Quality of service subsection </button> <ul id="toc-Quality_of_service-sublist" class="vector-toc-list"> <li id="toc-DSL_and_ATM" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#DSL_and_ATM"> <div class="vector-toc-text"> 5.1 DSL and ATM </div> </a> <ul id="toc-DSL_and_ATM-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Layer_2" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Layer_2"> <div class="vector-toc-text"> 5.2 Layer 2 </div> </a> <ul id="toc-Layer_2-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Performance_metrics" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Performance_metrics"> <div class="vector-toc-text"> 6 Performance metrics </div> </a> <ul id="toc-Performance_metrics-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-PSTN_integration" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#PSTN_integration"> <div class="vector-toc-text"> 7 PSTN integration </div> </a> <button aria-controls="toc-PSTN_integration-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> Toggle PSTN integration subsection </button> <ul id="toc-PSTN_integration-sublist" class="vector-toc-list"> <li id="toc-Number_portability" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Number_portability"> <div class="vector-toc-text"> 7.1 Number portability </div> </a> <ul id="toc-Number_portability-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Emergency_calls" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Emergency_calls"> <div class="vector-toc-text"> 7.2 Emergency calls </div> </a> <ul id="toc-Emergency_calls-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-Fax_support" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Fax_support"> <div class="vector-toc-text"> 8 Fax support </div> </a> <ul id="toc-Fax_support-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Power_requirements" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Power_requirements"> <div class="vector-toc-text"> 9 Power requirements </div> </a> <ul id="toc-Power_requirements-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Security" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Security"> <div class="vector-toc-text"> 10 Security </div> </a> <ul id="toc-Security-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Caller_ID" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Caller_ID"> <div class="vector-toc-text"> 11 Caller ID </div> </a> <ul id="toc-Caller_ID-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Hearing_aid_compatibility" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Hearing_aid_compatibility"> <div class="vector-toc-text"> 12 Hearing aid compatibility </div> </a> <ul id="toc-Hearing_aid_compatibility-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Operational_cost" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Operational_cost"> <div class="vector-toc-text"> 13 Operational cost </div> </a> <ul id="toc-Operational_cost-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Regulatory_and_legal_issues" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Regulatory_and_legal_issues"> <div class="vector-toc-text"> 14 Regulatory and legal issues </div> </a> <button aria-controls="toc-Regulatory_and_legal_issues-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> Toggle Regulatory and legal issues subsection </button> <ul id="toc-Regulatory_and_legal_issues-sublist" class="vector-toc-list"> <li id="toc-Canada" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Canada"> <div class="vector-toc-text"> 14.1 Canada </div> </a> <ul id="toc-Canada-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-European_Union" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#European_Union"> <div class="vector-toc-text"> 14.2 European Union </div> </a> <ul id="toc-European_Union-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Arab_states_of_the_GCC" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Arab_states_of_the_GCC"> <div class="vector-toc-text"> 14.3 Arab states of the GCC </div> </a> <ul id="toc-Arab_states_of_the_GCC-sublist" class="vector-toc-list"> <li id="toc-Oman" class="vector-toc-list-item vector-toc-level-3"> <a class="vector-toc-link" href="#Oman"> <div class="vector-toc-text"> 14.3.1 Oman </div> </a> <ul id="toc-Oman-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Saudi_Arabia" class="vector-toc-list-item vector-toc-level-3"> <a class="vector-toc-link" href="#Saudi_Arabia"> <div class="vector-toc-text"> 14.3.2 Saudi Arabia </div> </a> <ul id="toc-Saudi_Arabia-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-United_Arab_Emirates" class="vector-toc-list-item vector-toc-level-3"> <a class="vector-toc-link" href="#United_Arab_Emirates"> <div class="vector-toc-text"> 14.3.3 United Arab Emirates </div> </a> <ul id="toc-United_Arab_Emirates-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-India" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#India"> <div class="vector-toc-text"> 14.4 India </div> </a> <ul id="toc-India-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-South_Korea" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#South_Korea"> <div class="vector-toc-text"> 14.5 South Korea </div> </a> <ul id="toc-South_Korea-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-United_States" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#United_States"> <div class="vector-toc-text"> 14.6 United States </div> </a> <ul id="toc-United_States-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-History" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#History"> <div class="vector-toc-text"> 15 History </div> </a> <button aria-controls="toc-History-sublist" class="cdx-button cdx-button--weight-quiet cdx-button--icon-only vector-toc-toggle"> Toggle History subsection </button> <ul id="toc-History-sublist" class="vector-toc-list"> <li id="toc-Milestones" class="vector-toc-list-item vector-toc-level-2"> <a class="vector-toc-link" href="#Milestones"> <div class="vector-toc-text"> 15.1 Milestones </div> </a> <ul id="toc-Milestones-sublist" class="vector-toc-list"> </ul> </li> </ul> </li> <li id="toc-See_also" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#See_also"> <div class="vector-toc-text"> 16 See also </div> </a> <ul id="toc-See_also-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-Notes" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#Notes"> <div class="vector-toc-text"> 17 Notes </div> </a> <ul id="toc-Notes-sublist" class="vector-toc-list"> </ul> </li> <li id="toc-References" class="vector-toc-list-item vector-toc-level-1"> <a class="vector-toc-link" href="#References"> <div class="vector-toc-text"> 18 References </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"> <a class="vector-toc-link" href="#External_links"> <div class="vector-toc-text"> 19 External links </div> </a> <ul id="toc-External_links-sublist" class="vector-toc-list"> </ul> </li> </ul> </div> </div> </nav> </div> </div> <div class="mw-content-container"> <main id="content" class="mw-body"> <header class="mw-body-header vector-page-titlebar"> <nav aria-label="Contents" class="vector-toc-landmark"> <div id="vector-page-titlebar-toc" class="vector-dropdown vector-page-titlebar-toc vector-button-flush-left" > <input type="checkbox" id="vector-page-titlebar-toc-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-vector-page-titlebar-toc" class="vector-dropdown-checkbox " aria-label="Toggle the table of contents" > <label id="vector-page-titlebar-toc-label" for="vector-page-titlebar-toc-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" > Toggle the table of contents </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">Voice over IP</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 73 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-73" aria-hidden="true" > 73 languages </label> <div class="vector-dropdown-content"> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li class="interlanguage-link interwiki-af mw-list-item"><a href="https://af.wikipedia.org/wiki/Stem_oor_IP" title="Stem oor IP – Afrikaans" lang="af" hreflang="af" data-title="Stem oor IP" data-language-autonym="Afrikaans" data-language-local-name="Afrikaans" class="interlanguage-link-target">Afrikaans</a></li><li class="interlanguage-link interwiki-ar mw-list-item"><a href="https://ar.wikipedia.org/wiki/%D9%86%D9%82%D9%84_%D8%A7%D9%84%D8%B5%D9%88%D8%AA_%D8%A8%D8%A7%D8%B3%D8%AA%D8%B9%D9%85%D8%A7%D9%84_%D8%A8%D8%B1%D9%88%D8%AA%D9%88%D9%83%D9%88%D9%84_%D8%A7%D9%84%D8%A5%D9%86%D8%AA%D8%B1%D9%86%D8%AA" title="نقل الصوت باستعمال بروتوكول الإنترنت – Arabic" lang="ar" hreflang="ar" data-title="نقل الصوت باستعمال بروتوكول الإنترنت" data-language-autonym="العربية" data-language-local-name="Arabic" class="interlanguage-link-target">العربية</a></li><li class="interlanguage-link interwiki-ast mw-list-item"><a href="https://ast.wikipedia.org/wiki/Voz_sobre_protocolu_d%27internet" title="Voz sobre protocolu d'internet – Asturian" lang="ast" hreflang="ast" data-title="Voz sobre protocolu d'internet" data-language-autonym="Asturianu" data-language-local-name="Asturian" class="interlanguage-link-target">Asturianu</a></li><li class="interlanguage-link interwiki-az mw-list-item"><a href="https://az.wikipedia.org/wiki/IP-telefoniya" title="IP-telefoniya – Azerbaijani" lang="az" hreflang="az" data-title="IP-telefoniya" data-language-autonym="Azərbaycanca" data-language-local-name="Azerbaijani" class="interlanguage-link-target">Azərbaycanca</a></li><li class="interlanguage-link interwiki-bn mw-list-item"><a href="https://bn.wikipedia.org/wiki/%E0%A6%AD%E0%A6%AF%E0%A6%BC%E0%A7%87%E0%A6%B8_%E0%A6%93%E0%A6%AD%E0%A6%BE%E0%A6%B0_%E0%A6%87%E0%A6%A8%E0%A7%8D%E0%A6%9F%E0%A6%BE%E0%A6%B0%E0%A6%A8%E0%A7%87%E0%A6%9F_%E0%A6%AA%E0%A7%8D%E0%A6%B0%E0%A7%8B%E0%A6%9F%E0%A7%8B%E0%A6%95%E0%A6%B2" title="ভয়েস ওভার ইন্টারনেট প্রোটোকল – Bangla" lang="bn" hreflang="bn" data-title="ভয়েস ওভার ইন্টারনেট প্রোটোকল" data-language-autonym="বাংলা" data-language-local-name="Bangla" class="interlanguage-link-target">বাংলা</a></li><li class="interlanguage-link interwiki-zh-min-nan mw-list-item"><a href="https://zh-min-nan.wikipedia.org/wiki/VoIP" title="VoIP – Minnan" lang="nan" hreflang="nan" data-title="VoIP" data-language-autonym="閩南語 / Bân-lâm-gú" data-language-local-name="Minnan" class="interlanguage-link-target">閩南語 / Bân-lâm-gú</a></li><li class="interlanguage-link interwiki-ba mw-list-item"><a href="https://ba.wikipedia.org/wiki/IP-%D1%82%D0%B5%D0%BB%D0%B5%D1%84%D0%BE%D0%BD%D0%B8%D1%8F" title="IP-телефония – Bashkir" lang="ba" hreflang="ba" data-title="IP-телефония" data-language-autonym="Башҡортса" data-language-local-name="Bashkir" class="interlanguage-link-target">Башҡортса</a></li><li class="interlanguage-link interwiki-be mw-list-item"><a href="https://be.wikipedia.org/wiki/VoIP" title="VoIP – Belarusian" lang="be" hreflang="be" data-title="VoIP" data-language-autonym="Беларуская" data-language-local-name="Belarusian" class="interlanguage-link-target">Беларуская</a></li><li class="interlanguage-link interwiki-bg mw-list-item"><a href="https://bg.wikipedia.org/wiki/%D0%98%D0%BD%D1%82%D0%B5%D1%80%D0%BD%D0%B5%D1%82_%D1%82%D0%B5%D0%BB%D0%B5%D1%84%D0%BE%D0%BD%D0%B8%D1%8F" title="Интернет телефония – Bulgarian" lang="bg" hreflang="bg" data-title="Интернет телефония" data-language-autonym="Български" data-language-local-name="Bulgarian" class="interlanguage-link-target">Български</a></li><li class="interlanguage-link interwiki-bs mw-list-item"><a href="https://bs.wikipedia.org/wiki/Voice_over_Internet_Protocol" title="Voice over Internet Protocol – Bosnian" lang="bs" hreflang="bs" data-title="Voice over Internet Protocol" data-language-autonym="Bosanski" data-language-local-name="Bosnian" class="interlanguage-link-target">Bosanski</a></li><li class="interlanguage-link interwiki-ca mw-list-item"><a href="https://ca.wikipedia.org/wiki/Veu_per_IP" title="Veu per IP – Catalan" lang="ca" hreflang="ca" data-title="Veu per IP" data-language-autonym="Català" data-language-local-name="Catalan" class="interlanguage-link-target">Català</a></li><li class="interlanguage-link interwiki-cs mw-list-item"><a href="https://cs.wikipedia.org/wiki/Voice_over_Internet_Protocol" title="Voice over Internet Protocol – Czech" lang="cs" hreflang="cs" data-title="Voice over Internet Protocol" data-language-autonym="Čeština" data-language-local-name="Czech" class="interlanguage-link-target">Čeština</a></li><li class="interlanguage-link interwiki-da mw-list-item"><a href="https://da.wikipedia.org/wiki/VoIP" title="VoIP – Danish" lang="da" hreflang="da" data-title="VoIP" data-language-autonym="Dansk" data-language-local-name="Danish" class="interlanguage-link-target">Dansk</a></li><li class="interlanguage-link interwiki-de mw-list-item"><a href="https://de.wikipedia.org/wiki/IP-Telefonie" title="IP-Telefonie – German" lang="de" hreflang="de" data-title="IP-Telefonie" data-language-autonym="Deutsch" data-language-local-name="German" class="interlanguage-link-target">Deutsch</a></li><li class="interlanguage-link interwiki-et mw-list-item"><a href="https://et.wikipedia.org/wiki/Internetitelefon" title="Internetitelefon – Estonian" lang="et" hreflang="et" data-title="Internetitelefon" data-language-autonym="Eesti" data-language-local-name="Estonian" class="interlanguage-link-target">Eesti</a></li><li class="interlanguage-link interwiki-el mw-list-item"><a href="https://el.wikipedia.org/wiki/VoIP" title="VoIP – Greek" lang="el" hreflang="el" data-title="VoIP" data-language-autonym="Ελληνικά" data-language-local-name="Greek" class="interlanguage-link-target">Ελληνικά</a></li><li class="interlanguage-link interwiki-es mw-list-item"><a href="https://es.wikipedia.org/wiki/Voz_sobre_protocolo_de_internet" title="Voz sobre protocolo de internet – Spanish" lang="es" hreflang="es" data-title="Voz sobre protocolo de internet" data-language-autonym="Español" data-language-local-name="Spanish" class="interlanguage-link-target">Español</a></li><li class="interlanguage-link interwiki-eo mw-list-item"><a href="https://eo.wikipedia.org/wiki/Interreta_telefono" title="Interreta telefono – Esperanto" lang="eo" hreflang="eo" data-title="Interreta telefono" data-language-autonym="Esperanto" data-language-local-name="Esperanto" class="interlanguage-link-target">Esperanto</a></li><li class="interlanguage-link interwiki-eu mw-list-item"><a href="https://eu.wikipedia.org/wiki/VoIP" title="VoIP – Basque" lang="eu" hreflang="eu" data-title="VoIP" data-language-autonym="Euskara" data-language-local-name="Basque" class="interlanguage-link-target">Euskara</a></li><li class="interlanguage-link interwiki-fa mw-list-item"><a href="https://fa.wikipedia.org/wiki/%D8%B5%D8%AF%D8%A7_%D8%B1%D9%88%DB%8C_%D9%BE%D8%B1%D9%88%D8%AA%DA%A9%D9%84_%D8%A7%DB%8C%D9%86%D8%AA%D8%B1%D9%86%D8%AA" title="صدا روی پروتکل اینترنت – Persian" lang="fa" hreflang="fa" data-title="صدا روی پروتکل اینترنت" data-language-autonym="فارسی" data-language-local-name="Persian" class="interlanguage-link-target">فارسی</a></li><li class="interlanguage-link interwiki-fr mw-list-item"><a href="https://fr.wikipedia.org/wiki/Voix_sur_IP" title="Voix sur IP – French" lang="fr" hreflang="fr" data-title="Voix sur IP" data-language-autonym="Français" data-language-local-name="French" class="interlanguage-link-target">Français</a></li><li class="interlanguage-link interwiki-ga mw-list-item"><a href="https://ga.wikipedia.org/wiki/VoIP" title="VoIP – Irish" lang="ga" hreflang="ga" data-title="VoIP" data-language-autonym="Gaeilge" data-language-local-name="Irish" class="interlanguage-link-target">Gaeilge</a></li><li class="interlanguage-link interwiki-gl mw-list-item"><a href="https://gl.wikipedia.org/wiki/VoIP" title="VoIP – Galician" lang="gl" hreflang="gl" data-title="VoIP" data-language-autonym="Galego" data-language-local-name="Galician" class="interlanguage-link-target">Galego</a></li><li class="interlanguage-link interwiki-ko mw-list-item"><a href="https://ko.wikipedia.org/wiki/%EC%9D%8C%EC%84%B1_%EC%9D%B8%ED%84%B0%EB%84%B7_%ED%94%84%EB%A1%9C%ED%86%A0%EC%BD%9C" title="음성 인터넷 프로토콜 – Korean" lang="ko" hreflang="ko" data-title="음성 인터넷 프로토콜" data-language-autonym="한국어" data-language-local-name="Korean" class="interlanguage-link-target">한국어</a></li><li class="interlanguage-link interwiki-hi mw-list-item"><a href="https://hi.wikipedia.org/wiki/%E0%A4%B5%E0%A5%89%E0%A4%87%E0%A4%B8_%E0%A4%93%E0%A4%B5%E0%A4%B0_%E0%A4%87%E0%A4%A3%E0%A5%8D%E0%A4%9F%E0%A4%B0%E0%A4%A8%E0%A5%87%E0%A4%9F_%E0%A4%AA%E0%A5%8D%E0%A4%B0%E0%A5%8B%E0%A4%9F%E0%A5%8B%E0%A4%95%E0%A5%89%E0%A4%B2" title="वॉइस ओवर इण्टरनेट प्रोटोकॉल – Hindi" lang="hi" hreflang="hi" data-title="वॉइस ओवर इण्टरनेट प्रोटोकॉल" data-language-autonym="हिन्दी" data-language-local-name="Hindi" class="interlanguage-link-target">हिन्दी</a></li><li class="interlanguage-link interwiki-hr mw-list-item"><a href="https://hr.wikipedia.org/wiki/VoIP" title="VoIP – Croatian" lang="hr" hreflang="hr" data-title="VoIP" data-language-autonym="Hrvatski" data-language-local-name="Croatian" class="interlanguage-link-target">Hrvatski</a></li><li class="interlanguage-link interwiki-io mw-list-item"><a href="https://io.wikipedia.org/wiki/IP-telefonado" title="IP-telefonado – Ido" lang="io" hreflang="io" data-title="IP-telefonado" data-language-autonym="Ido" data-language-local-name="Ido" class="interlanguage-link-target">Ido</a></li><li class="interlanguage-link interwiki-id mw-list-item"><a href="https://id.wikipedia.org/wiki/Voice_over_IP" title="Voice over IP – Indonesian" lang="id" hreflang="id" data-title="Voice over IP" data-language-autonym="Bahasa Indonesia" data-language-local-name="Indonesian" class="interlanguage-link-target">Bahasa Indonesia</a></li><li class="interlanguage-link interwiki-xh mw-list-item"><a href="https://xh.wikipedia.org/wiki/Ilizwi_nge-IP" title="Ilizwi nge-IP – Xhosa" lang="xh" hreflang="xh" data-title="Ilizwi nge-IP" data-language-autonym="IsiXhosa" data-language-local-name="Xhosa" class="interlanguage-link-target">IsiXhosa</a></li><li class="interlanguage-link interwiki-it mw-list-item"><a href="https://it.wikipedia.org/wiki/Voice_over_IP" title="Voice over IP – Italian" lang="it" hreflang="it" data-title="Voice over IP" data-language-autonym="Italiano" data-language-local-name="Italian" class="interlanguage-link-target">Italiano</a></li><li class="interlanguage-link interwiki-he mw-list-item"><a href="https://he.wikipedia.org/wiki/VoIP" title="VoIP – Hebrew" lang="he" hreflang="he" data-title="VoIP" data-language-autonym="עברית" data-language-local-name="Hebrew" class="interlanguage-link-target">עברית</a></li><li class="interlanguage-link interwiki-kn mw-list-item"><a href="https://kn.wikipedia.org/wiki/%E0%B2%85%E0%B2%82%E0%B2%A4%E0%B2%B0%E0%B2%9C%E0%B2%BE%E0%B2%B2_%E0%B2%86%E0%B2%A7%E0%B2%BE%E0%B2%B0%E0%B2%BF%E0%B2%A4_%E0%B2%95%E0%B2%B0%E0%B3%86_%E0%B2%AA%E0%B3%8D%E0%B2%B0%E0%B3%8B%E0%B2%9F%E0%B3%8B%E0%B2%95%E0%B2%BE%E0%B2%B2%E0%B3%8D%E2%80%8C" title="ಅಂತರಜಾಲ ಆಧಾರಿತ ಕರೆ ಪ್ರೋಟೋಕಾಲ್‌ – Kannada" lang="kn" hreflang="kn" data-title="ಅಂತರಜಾಲ ಆಧಾರಿತ ಕರೆ ಪ್ರೋಟೋಕಾಲ್‌" data-language-autonym="ಕನ್ನಡ" data-language-local-name="Kannada" class="interlanguage-link-target">ಕನ್ನಡ</a></li><li class="interlanguage-link interwiki-kk mw-list-item"><a href="https://kk.wikipedia.org/wiki/IP-%D1%82%D0%B5%D0%BB%D0%B5%D1%84%D0%BE%D0%BD%D0%B8%D1%8F" title="IP-телефония – Kazakh" lang="kk" hreflang="kk" data-title="IP-телефония" data-language-autonym="Қазақша" data-language-local-name="Kazakh" class="interlanguage-link-target">Қазақша</a></li><li class="interlanguage-link interwiki-lo mw-list-item"><a href="https://lo.wikipedia.org/wiki/VoIP" title="VoIP – Lao" lang="lo" hreflang="lo" data-title="VoIP" data-language-autonym="ລາວ" data-language-local-name="Lao" class="interlanguage-link-target">ລາວ</a></li><li class="interlanguage-link interwiki-lv mw-list-item"><a href="https://lv.wikipedia.org/wiki/IP_balss_p%C4%81rraide" title="IP balss pārraide – Latvian" lang="lv" hreflang="lv" data-title="IP balss pārraide" data-language-autonym="Latviešu" data-language-local-name="Latvian" class="interlanguage-link-target">Latviešu</a></li><li class="interlanguage-link interwiki-lt mw-list-item"><a href="https://lt.wikipedia.org/wiki/IP_telefonija" title="IP telefonija – Lithuanian" lang="lt" hreflang="lt" data-title="IP telefonija" data-language-autonym="Lietuvių" data-language-local-name="Lithuanian" class="interlanguage-link-target">Lietuvių</a></li><li class="interlanguage-link interwiki-lmo mw-list-item"><a href="https://lmo.wikipedia.org/wiki/Vus_sura_IP" title="Vus sura IP – Lombard" lang="lmo" hreflang="lmo" data-title="Vus sura IP" data-language-autonym="Lombard" data-language-local-name="Lombard" class="interlanguage-link-target">Lombard</a></li><li class="interlanguage-link interwiki-hu mw-list-item"><a href="https://hu.wikipedia.org/wiki/Voice_over_IP" title="Voice over IP – Hungarian" lang="hu" hreflang="hu" data-title="Voice over IP" data-language-autonym="Magyar" data-language-local-name="Hungarian" class="interlanguage-link-target">Magyar</a></li><li class="interlanguage-link interwiki-mk mw-list-item"><a href="https://mk.wikipedia.org/wiki/Voice_over_IP" title="Voice over IP – Macedonian" lang="mk" hreflang="mk" data-title="Voice over IP" data-language-autonym="Македонски" data-language-local-name="Macedonian" class="interlanguage-link-target">Македонски</a></li><li class="interlanguage-link interwiki-ml mw-list-item"><a href="https://ml.wikipedia.org/wiki/%E0%B4%B5%E0%B5%8B%E0%B4%AF%E0%B4%BF%E0%B4%B8%E0%B5%8D_%E0%B4%93%E0%B4%B5%E0%B5%BC_%E0%B4%87%E0%B4%A8%E0%B5%8D%E0%B4%B1%E0%B5%BC%E0%B4%A8%E0%B5%86%E0%B4%B1%E0%B5%8D%E0%B4%B1%E0%B5%8D_%E0%B4%AA%E0%B5%8D%E0%B4%B0%E0%B5%8B%E0%B4%9F%E0%B5%8D%E0%B4%9F%E0%B5%8B%E0%B4%95%E0%B5%8D%E0%B4%95%E0%B5%8B%E0%B5%BE" title="വോയിസ് ഓവർ ഇന്റർനെറ്റ് പ്രോട്ടോക്കോൾ – Malayalam" lang="ml" hreflang="ml" data-title="വോയിസ് ഓവർ ഇന്റർനെറ്റ് പ്രോട്ടോക്കോൾ" data-language-autonym="മലയാളം" data-language-local-name="Malayalam" class="interlanguage-link-target">മലയാളം</a></li><li class="interlanguage-link interwiki-ms mw-list-item"><a href="https://ms.wikipedia.org/wiki/Suara_melalui_Protokol_Internet" title="Suara melalui Protokol Internet – Malay" lang="ms" hreflang="ms" data-title="Suara melalui Protokol Internet" data-language-autonym="Bahasa Melayu" data-language-local-name="Malay" class="interlanguage-link-target">Bahasa Melayu</a></li><li class="interlanguage-link interwiki-my mw-list-item"><a href="https://my.wikipedia.org/wiki/%E1%80%97%E1%80%BD%E1%80%AE%E1%80%A1%E1%80%AD%E1%80%AF%E1%80%A1%E1%80%AD%E1%80%AF%E1%80%84%E1%80%BA%E1%80%95%E1%80%AE" title="ဗွီအိုအိုင်ပီ – Burmese" lang="my" hreflang="my" data-title="ဗွီအိုအိုင်ပီ" data-language-autonym="မြန်မာဘာသာ" data-language-local-name="Burmese" class="interlanguage-link-target">မြန်မာဘာသာ</a></li><li class="interlanguage-link interwiki-nl mw-list-item"><a href="https://nl.wikipedia.org/wiki/IP-telefonie" title="IP-telefonie – Dutch" lang="nl" hreflang="nl" data-title="IP-telefonie" data-language-autonym="Nederlands" data-language-local-name="Dutch" class="interlanguage-link-target">Nederlands</a></li><li class="interlanguage-link interwiki-ja mw-list-item"><a href="https://ja.wikipedia.org/wiki/VoIP" title="VoIP – Japanese" lang="ja" hreflang="ja" data-title="VoIP" data-language-autonym="日本語" data-language-local-name="Japanese" class="interlanguage-link-target">日本語</a></li><li class="interlanguage-link interwiki-nn mw-list-item"><a href="https://nn.wikipedia.org/wiki/IP-telefoni" title="IP-telefoni – Norwegian Nynorsk" lang="nn" hreflang="nn" data-title="IP-telefoni" data-language-autonym="Norsk nynorsk" data-language-local-name="Norwegian Nynorsk" class="interlanguage-link-target">Norsk nynorsk</a></li><li class="interlanguage-link interwiki-pms mw-list-item"><a href="https://pms.wikipedia.org/wiki/Telefon%C3%ACa_IP" title="Telefonìa IP – Piedmontese" lang="pms" hreflang="pms" data-title="Telefonìa IP" data-language-autonym="Piemontèis" data-language-local-name="Piedmontese" class="interlanguage-link-target">Piemontèis</a></li><li class="interlanguage-link interwiki-pl mw-list-item"><a href="https://pl.wikipedia.org/wiki/Voice_over_Internet_Protocol" title="Voice over Internet Protocol – Polish" lang="pl" hreflang="pl" data-title="Voice over Internet Protocol" data-language-autonym="Polski" data-language-local-name="Polish" class="interlanguage-link-target">Polski</a></li><li class="interlanguage-link interwiki-pt mw-list-item"><a href="https://pt.wikipedia.org/wiki/Voz_sobre_IP" title="Voz sobre IP – Portuguese" lang="pt" hreflang="pt" data-title="Voz sobre IP" data-language-autonym="Português" data-language-local-name="Portuguese" class="interlanguage-link-target">Português</a></li><li class="interlanguage-link interwiki-ro mw-list-item"><a href="https://ro.wikipedia.org/wiki/Voce_peste_IP" title="Voce peste IP – Romanian" lang="ro" hreflang="ro" data-title="Voce peste IP" data-language-autonym="Română" data-language-local-name="Romanian" class="interlanguage-link-target">Română</a></li><li class="interlanguage-link interwiki-qu mw-list-item"><a href="https://qu.wikipedia.org/wiki/IP_patapi_kunka" title="IP patapi kunka – Quechua" lang="qu" hreflang="qu" data-title="IP patapi kunka" data-language-autonym="Runa Simi" data-language-local-name="Quechua" class="interlanguage-link-target">Runa Simi</a></li><li class="interlanguage-link interwiki-ru mw-list-item"><a href="https://ru.wikipedia.org/wiki/IP-%D1%82%D0%B5%D0%BB%D0%B5%D1%84%D0%BE%D0%BD%D0%B8%D1%8F" title="IP-телефония – Russian" lang="ru" hreflang="ru" data-title="IP-телефония" data-language-autonym="Русский" data-language-local-name="Russian" class="interlanguage-link-target">Русский</a></li><li class="interlanguage-link interwiki-sq mw-list-item"><a href="https://sq.wikipedia.org/wiki/Z%C3%ABri_p%C3%ABrmes_IP" title="Zëri përmes IP – Albanian" lang="sq" hreflang="sq" data-title="Zëri përmes IP" data-language-autonym="Shqip" data-language-local-name="Albanian" class="interlanguage-link-target">Shqip</a></li><li class="interlanguage-link interwiki-si mw-list-item"><a href="https://si.wikipedia.org/wiki/%E0%B6%85%E0%B6%B1%E0%B7%8A%E0%B6%AD%E0%B6%BB%E0%B7%8A%E0%B6%A2%E0%B7%8F%E0%B6%BD_%E0%B6%B4%E0%B7%8A%E2%80%8D%E0%B6%BB%E0%B7%9C%E0%B6%A7%E0%B7%9D%E0%B6%9A%E0%B7%9D%E0%B6%BD%E0%B6%BA_%E0%B7%84%E0%B6%BB%E0%B7%84%E0%B7%8F_%E0%B6%9A%E0%B6%A7%E0%B7%84%E0%B6%AC" title="අන්තර්ජාල ප්‍රොටෝකෝලය හරහා කටහඬ – Sinhala" lang="si" hreflang="si" data-title="අන්තර්ජාල ප්‍රොටෝකෝලය හරහා කටහඬ" data-language-autonym="සිංහල" data-language-local-name="Sinhala" class="interlanguage-link-target">සිංහල</a></li><li class="interlanguage-link interwiki-simple mw-list-item"><a href="https://simple.wikipedia.org/wiki/Voice_over_Internet_Protocol" title="Voice over Internet Protocol – Simple English" lang="en-simple" hreflang="en-simple" data-title="Voice over Internet Protocol" data-language-autonym="Simple English" data-language-local-name="Simple English" class="interlanguage-link-target">Simple English</a></li><li class="interlanguage-link interwiki-sk mw-list-item"><a href="https://sk.wikipedia.org/wiki/Prenos_hlasu_internetov%C3%BDm_protokolom" title="Prenos hlasu internetovým protokolom – Slovak" lang="sk" hreflang="sk" data-title="Prenos hlasu internetovým protokolom" data-language-autonym="Slovenčina" data-language-local-name="Slovak" class="interlanguage-link-target">Slovenčina</a></li><li class="interlanguage-link interwiki-sl mw-list-item"><a href="https://sl.wikipedia.org/wiki/VoIP_telefonija" title="VoIP telefonija – Slovenian" lang="sl" hreflang="sl" data-title="VoIP telefonija" data-language-autonym="Slovenščina" data-language-local-name="Slovenian" class="interlanguage-link-target">Slovenščina</a></li><li class="interlanguage-link interwiki-so mw-list-item"><a href="https://so.wikipedia.org/wiki/VOIP" title="VOIP – Somali" lang="so" hreflang="so" data-title="VOIP" data-language-autonym="Soomaaliga" data-language-local-name="Somali" class="interlanguage-link-target">Soomaaliga</a></li><li class="interlanguage-link interwiki-sr mw-list-item"><a href="https://sr.wikipedia.org/wiki/%D0%98%D0%BD%D1%82%D0%B5%D1%80%D0%BD%D0%B5%D1%82_%D1%82%D0%B5%D0%BB%D0%B5%D1%84%D0%BE%D0%BD%D0%B8%D1%98%D0%B0" title="Интернет телефонија – Serbian" lang="sr" hreflang="sr" data-title="Интернет телефонија" data-language-autonym="Српски / srpski" data-language-local-name="Serbian" class="interlanguage-link-target">Српски / srpski</a></li><li class="interlanguage-link interwiki-su mw-list-item"><a href="https://su.wikipedia.org/wiki/Voice_over_Internet_Protocol" title="Voice over Internet Protocol – Sundanese" lang="su" hreflang="su" data-title="Voice over Internet Protocol" data-language-autonym="Sunda" data-language-local-name="Sundanese" class="interlanguage-link-target">Sunda</a></li><li class="interlanguage-link interwiki-fi mw-list-item"><a href="https://fi.wikipedia.org/wiki/VoIP" title="VoIP – Finnish" lang="fi" hreflang="fi" data-title="VoIP" data-language-autonym="Suomi" data-language-local-name="Finnish" class="interlanguage-link-target">Suomi</a></li><li class="interlanguage-link interwiki-sv mw-list-item"><a href="https://sv.wikipedia.org/wiki/IP-telefoni" title="IP-telefoni – Swedish" lang="sv" hreflang="sv" data-title="IP-telefoni" data-language-autonym="Svenska" data-language-local-name="Swedish" class="interlanguage-link-target">Svenska</a></li><li class="interlanguage-link interwiki-ta mw-list-item"><a href="https://ta.wikipedia.org/wiki/%E0%AE%87%E0%AE%A3%E0%AF%88%E0%AE%AF%E0%AE%B5%E0%AE%B4%E0%AE%BF_%E0%AE%92%E0%AE%B2%E0%AE%BF_%E0%AE%AA%E0%AE%B0%E0%AE%BF%E0%AE%AE%E0%AE%BE%E0%AE%B1%E0%AF%8D%E0%AE%B1%E0%AE%AE%E0%AF%8D" title="இணையவழி ஒலி பரிமாற்றம் – Tamil" lang="ta" hreflang="ta" data-title="இணையவழி ஒலி பரிமாற்றம்" data-language-autonym="தமிழ்" data-language-local-name="Tamil" class="interlanguage-link-target">தமிழ்</a></li><li class="interlanguage-link interwiki-th mw-list-item"><a href="https://th.wikipedia.org/wiki/%E0%B8%A7%E0%B8%AD%E0%B8%A2%E0%B8%8B%E0%B9%8C%E0%B9%82%E0%B8%AD%E0%B9%80%E0%B8%A7%E0%B8%AD%E0%B8%A3%E0%B9%8C%E0%B9%84%E0%B8%AD%E0%B8%9E%E0%B8%B5" title="วอยซ์โอเวอร์ไอพี – Thai" lang="th" hreflang="th" data-title="วอยซ์โอเวอร์ไอพี" data-language-autonym="ไทย" data-language-local-name="Thai" class="interlanguage-link-target">ไทย</a></li><li class="interlanguage-link interwiki-tg mw-list-item"><a href="https://tg.wikipedia.org/wiki/IP-%D1%82%D0%B5%D0%BB%D0%B5%D1%84%D0%BE%D0%BD%D0%B8%D1%8F" title="IP-телефония – Tajik" lang="tg" hreflang="tg" data-title="IP-телефония" data-language-autonym="Тоҷикӣ" data-language-local-name="Tajik" class="interlanguage-link-target">Тоҷикӣ</a></li><li class="interlanguage-link interwiki-tr mw-list-item"><a href="https://tr.wikipedia.org/wiki/VoIP" title="VoIP – Turkish" lang="tr" hreflang="tr" data-title="VoIP" data-language-autonym="Türkçe" data-language-local-name="Turkish" class="interlanguage-link-target">Türkçe</a></li><li class="interlanguage-link interwiki-uk mw-list-item"><a href="https://uk.wikipedia.org/wiki/VoIP" title="VoIP – Ukrainian" lang="uk" hreflang="uk" data-title="VoIP" data-language-autonym="Українська" data-language-local-name="Ukrainian" class="interlanguage-link-target">Українська</a></li><li class="interlanguage-link interwiki-ur mw-list-item"><a href="https://ur.wikipedia.org/wiki/%D8%A2%D9%88%D8%A7%D8%B2_%D8%A8%D8%AF%D9%88%D8%B4_%D8%A2%D8%A6%DB%8C_%D9%BE%DB%8C" title="آواز بدوش آئی پی – Urdu" lang="ur" hreflang="ur" data-title="آواز بدوش آئی پی" data-language-autonym="اردو" data-language-local-name="Urdu" class="interlanguage-link-target">اردو</a></li><li class="interlanguage-link interwiki-vec mw-list-item"><a href="https://vec.wikipedia.org/wiki/Te%C5%82efono_VoIP" title="Tełefono VoIP – Venetian" lang="vec" hreflang="vec" data-title="Tełefono VoIP" data-language-autonym="Vèneto" data-language-local-name="Venetian" class="interlanguage-link-target">Vèneto</a></li><li class="interlanguage-link interwiki-vi mw-list-item"><a href="https://vi.wikipedia.org/wiki/VoIP" title="VoIP – Vietnamese" lang="vi" hreflang="vi" data-title="VoIP" data-language-autonym="Tiếng Việt" data-language-local-name="Vietnamese" class="interlanguage-link-target">Tiếng Việt</a></li><li class="interlanguage-link interwiki-wa mw-list-item"><a href="https://wa.wikipedia.org/wiki/Telefoneye_pal_Daegntoele" title="Telefoneye pal Daegntoele – Walloon" lang="wa" hreflang="wa" data-title="Telefoneye pal Daegntoele" data-language-autonym="Walon" data-language-local-name="Walloon" class="interlanguage-link-target">Walon</a></li><li class="interlanguage-link interwiki-wuu mw-list-item"><a href="https://wuu.wikipedia.org/wiki/VoIP" title="VoIP – Wu" lang="wuu" hreflang="wuu" data-title="VoIP" data-language-autonym="吴语" data-language-local-name="Wu" class="interlanguage-link-target">吴语</a></li><li class="interlanguage-link interwiki-yi mw-list-item"><a href="https://yi.wikipedia.org/wiki/VoIP" title="VoIP – Yiddish" lang="yi" hreflang="yi" data-title="VoIP" data-language-autonym="ייִדיש" data-language-local-name="Yiddish" class="interlanguage-link-target">ייִדיש</a></li><li class="interlanguage-link interwiki-zh mw-list-item"><a href="https://zh.wikipedia.org/wiki/VoIP" title="VoIP – Chinese" lang="zh" hreflang="zh" data-title="VoIP" data-language-autonym="中文" data-language-local-name="Chinese" class="interlanguage-link-target">中文</a></li> </ul> <div class="after-portlet after-portlet-lang"><a href="https://www.wikidata.org/wiki/Special:EntityPage/Q81945#sitelinks-wikipedia" title="Edit interlanguage links" class="wbc-editpage">Edit links</a></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/Voice_over_IP" title="View the content page [c]" accesskey="c">Article</a></li><li id="ca-talk" class="vector-tab-noicon mw-list-item"><a href="/wiki/Talk:Voice_over_IP" rel="discussion" title="Discuss improvements to the content page [t]" accesskey="t">Talk</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" >English </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/Voice_over_IP">Read</a></li><li id="ca-edit" class="vector-tab-noicon mw-list-item"><a href="/w/index.php?title=Voice_over_IP&action=edit" title="Edit this page [e]" accesskey="e">Edit</a></li><li id="ca-history" class="vector-tab-noicon mw-list-item"><a href="/w/index.php?title=Voice_over_IP&action=history" title="Past revisions of this page [h]" accesskey="h">View history</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" >Tools </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/Voice_over_IP">Read</a></li><li id="ca-more-edit" class="vector-more-collapsible-item mw-list-item"><a href="/w/index.php?title=Voice_over_IP&action=edit" title="Edit this page [e]" accesskey="e">Edit</a></li><li id="ca-more-history" class="vector-more-collapsible-item mw-list-item"><a href="/w/index.php?title=Voice_over_IP&action=history">View history</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/Voice_over_IP" title="List of all English Wikipedia pages containing links to this page [j]" accesskey="j">What links here</a></li><li id="t-recentchangeslinked" class="mw-list-item"><a href="/wiki/Special:RecentChangesLinked/Voice_over_IP" rel="nofollow" title="Recent changes in pages linked from this page [k]" accesskey="k">Related changes</a></li><li id="t-upload" class="mw-list-item"><a href="/wiki/Wikipedia:File_Upload_Wizard" title="Upload files [u]" accesskey="u">Upload file</a></li><li id="t-specialpages" class="mw-list-item"><a href="/wiki/Special:SpecialPages" title="A list of all special pages [q]" accesskey="q">Special pages</a></li><li id="t-permalink" class="mw-list-item"><a href="/w/index.php?title=Voice_over_IP&oldid=1263667331" title="Permanent link to this revision of this page">Permanent link</a></li><li id="t-info" class="mw-list-item"><a href="/w/index.php?title=Voice_over_IP&action=info" title="More information about this page">Page information</a></li><li id="t-cite" class="mw-list-item"><a href="/w/index.php?title=Special:CiteThisPage&page=Voice_over_IP&id=1263667331&wpFormIdentifier=titleform" title="Information on how to cite this page">Cite this page</a></li><li id="t-urlshortener" class="mw-list-item"><a href="/w/index.php?title=Special:UrlQ%C4%B1sald%C4%B1c%C4%B1s%C4%B1&url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FVoice_over_IP">Get shortened URL</a></li><li id="t-urlshortener-qrcode" class="mw-list-item"><a href="/w/index.php?title=Special:QrKodu&url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FVoice_over_IP">Download QR code</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=Voice_over_IP&action=show-download-screen" title="Download this page as a PDF file">Download as PDF</a></li><li id="t-print" class="mw-list-item"><a href="/w/index.php?title=Voice_over_IP&printable=yes" title="Printable version of this page [p]" accesskey="p">Printable version</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 class="wb-otherproject-link wb-otherproject-commons mw-list-item"><a href="https://commons.wikimedia.org/wiki/Category:VoIP" hreflang="en">Wikimedia Commons</a></li><li class="wb-otherproject-link wb-otherproject-wikiversity mw-list-item"><a href="https://en.wikiversity.org/wiki/VoIP" hreflang="en">Wikiversity</a></li><li class="wb-otherproject-link wb-otherproject-wikivoyage badge-Q17559452 badge-recommendedarticle mw-list-item" title="recommended article"><a href="https://en.wikivoyage.org/wiki/Internet_telephony" hreflang="en">Wikivoyage</a></li><li id="t-wikibase" class="wb-otherproject-link wb-otherproject-wikibase-dataitem mw-list-item"><a href="https://www.wikidata.org/wiki/Special:EntityPage/Q81945" title="Structured data on this page hosted by Wikidata [g]" accesskey="g">Wikidata item</a></li> </ul> </div> </div> </div> </div> </div> </div> </nav> </div> </div> </div> <div class="vector-column-end"> <div class="vector-sticky-pinned-container"> <nav class="vector-page-tools-landmark" aria-label="Page tools"> <div id="vector-page-tools-pinned-container" class="vector-pinned-container"> </div> </nav> <nav class="vector-appearance-landmark" aria-label="Appearance"> <div id="vector-appearance-pinned-container" class="vector-pinned-container"> <div id="vector-appearance" class="vector-appearance vector-pinnable-element"> <div class="vector-pinnable-header vector-appearance-pinnable-header vector-pinnable-header-pinned" data-feature-name="appearance-pinned" data-pinnable-element-id="vector-appearance" data-pinned-container-id="vector-appearance-pinned-container" data-unpinned-container-id="vector-appearance-unpinned-container" > <div class="vector-pinnable-header-label">Appearance</div> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-pin-button" data-event-name="pinnable-header.vector-appearance.pin">move to sidebar</button> <button class="vector-pinnable-header-toggle-button vector-pinnable-header-unpin-button" data-event-name="pinnable-header.vector-appearance.unpin">hide</button> </div> </div> </div> </nav> </div> </div> <div id="bodyContent" class="vector-body" aria-labelledby="firstHeading" data-mw-ve-target-container> <div class="vector-body-before-content"> <div class="mw-indicators"> </div> <div id="siteSub" class="noprint">From Wikipedia, the free encyclopedia</div> </div> <div id="contentSub"><div id="mw-content-subtitle"></div></div> <div id="mw-content-text" class="mw-body-content"><div class="mw-content-ltr mw-parser-output" lang="en" dir="ltr"><div class="shortdescription nomobile noexcerpt noprint searchaux" style="display:none">Methods of delivering voice communications and multimedia over IP networks</div> Voice over Internet Protocol (VoIP),<a href="#cite_note-2">[a]</a> also known as IP telephony, refers to a set of technologies used for voice communication sessions over <a href="/wiki/Internet_Protocol" title="Internet Protocol">Internet Protocol</a> (IP) networks, such as the <a href="/wiki/Internet" title="Internet">Internet</a>.<a href="#cite_note-Arora_2023_t525-3">[2]</a> VoIP enables <a href="/wiki/Voice_call" class="mw-redirect" title="Voice call">voice calls</a> to be transmitted as data packets, facilitating various methods of <a href="/wiki/Voice_communication" class="mw-redirect" title="Voice communication">voice communication</a>, including traditional applications like Skype, Microsoft Teams, Google Voice, and <a href="/wiki/VoIP_phone" title="VoIP phone">VoIP phones</a>. Regular telephones can also be used for VoIP by connecting them to the Internet via <a href="/wiki/Analog_telephone_adapter" title="Analog telephone adapter">analog telephone adapters</a> (ATAs), which convert traditional telephone signals into digital data packets that can be transmitted over IP networks. The broader terms Internet telephony, broadband telephony, and broadband phone service specifically refer to the delivery of voice and other communication services, such as <a href="/wiki/Fax" title="Fax">fax</a>, <a href="/wiki/SMS" title="SMS">SMS</a>, and <a href="/wiki/Voice_messaging" class="mw-redirect" title="Voice messaging">voice messaging</a>, over the Internet, in contrast to the traditional <a href="/wiki/Public_switched_telephone_network" title="Public switched telephone network">public switched telephone network</a> (PSTN), commonly known as <a href="/wiki/Plain_old_telephone_service" title="Plain old telephone service">plain old telephone service</a> (POTS). VoIP technology has evolved to integrate with <a href="/wiki/Mobile_telephony" title="Mobile telephony">mobile telephony</a>, including Voice over LTE (<a href="/wiki/VoLTE" class="mw-redirect" title="VoLTE">VoLTE</a>) and Voice over 5G (<a href="/wiki/Vo5G" class="mw-redirect" title="Vo5G">Vo5G</a>), enabling seamless voice communication over <a href="/wiki/Cellular_network" title="Cellular network">mobile data networks</a>. These advancements have extended VoIP's role beyond its traditional use in internet-based applications. It has become a key component of modern mobile infrastructure, as <a href="/wiki/4G" title="4G">4G</a> and <a href="/wiki/5G" title="5G">5G</a> networks rely entirely on this technology for voice transmission. <meta property="mw:PageProp/toc" /> <div class="mw-heading mw-heading2"><h2 id="Overview">Overview</h2>[<a href="/w/index.php?title=Voice_over_IP&action=edit&section=1" title="Edit section: Overview">edit</a>]</div> The steps and principles involved in originating VoIP telephone calls are similar to traditional digital <a href="/wiki/Telephony" title="Telephony">telephony</a> and involve signaling, channel setup, digitization of the analog voice signals, and encoding. Instead of being transmitted over a <a href="/wiki/Circuit-switched_network" class="mw-redirect" title="Circuit-switched network">circuit-switched network</a>, the digital information is packetized and transmission occurs as IP packets over a <a href="/wiki/Packet-switched_network" class="mw-redirect" title="Packet-switched network">packet-switched network</a>. They transport media streams using special media delivery protocols that encode audio and video with <a href="/wiki/Audio_codec" title="Audio codec">audio codecs</a> and <a href="/wiki/Video_codec" title="Video codec">video codecs</a>. Various codecs exist that optimize the media stream based on application requirements and network bandwidth; some implementations rely on <a href="/wiki/Narrowband" title="Narrowband">narrowband</a> and <a href="/wiki/Speech_coding" title="Speech coding">compressed speech</a>, while others support <a href="/wiki/High-fidelity" class="mw-redirect" title="High-fidelity">high-fidelity</a> stereo codecs. The most widely used <a href="/wiki/Speech_coding" title="Speech coding">speech coding</a> standards in VoIP are based on the <a href="/wiki/Linear_predictive_coding" title="Linear predictive coding">linear predictive coding</a> (LPC) and <a href="/wiki/Modified_discrete_cosine_transform" title="Modified discrete cosine transform">modified discrete cosine transform</a> (MDCT) compression methods. Popular codecs include the MDCT-based <a href="/wiki/AAC-LD" title="AAC-LD">AAC-LD</a> (used in <a href="/wiki/FaceTime" title="FaceTime">FaceTime</a>), the LPC/MDCT-based <a href="/wiki/Opus_(audio_format)" title="Opus (audio format)">Opus</a> (used in <a href="/wiki/WhatsApp" title="WhatsApp">WhatsApp</a>), the LPC-based <a href="/wiki/SILK" title="SILK">SILK</a> (used in <a href="/wiki/Skype" title="Skype">Skype</a>), <a href="/wiki/%CE%9C-law" class="mw-redirect" title="Μ-law">μ-law</a> and <a href="/wiki/A-law" class="mw-redirect" title="A-law">A-law</a> versions of <a href="/wiki/G.711" title="G.711">G.711</a>, <a href="/wiki/G.722" title="G.722">G.722</a>, and an <a href="/wiki/Open-source_license" title="Open-source license">open source</a> voice codec known as <a href="/wiki/ILBC" class="mw-redirect" title="ILBC">iLBC</a>, a codec that uses only 8 kbit/s each way called <a href="/wiki/G.729" title="G.729">G.729</a>. Early providers of voice-over-IP services used business models and offered technical solutions that mirrored the architecture of the legacy telephone network. Second-generation providers, such as <a href="/wiki/Skype" title="Skype">Skype</a>, built closed networks for private user bases, offering the benefit of free calls and convenience while potentially charging for access to other communication networks, such as the PSTN. This limited the freedom of users to mix-and-match third-party hardware and software. Third-generation providers, such as <a href="/wiki/Google_Talk" title="Google Talk">Google Talk</a>, adopted the concept of <a href="/wiki/Federated_VoIP" title="Federated VoIP">federated VoIP</a>.<a href="#cite_note-4">[3]</a> These solutions typically allow dynamic interconnection between users in any two domains of the Internet, when a user wishes to place a call. In addition to <a href="/wiki/VoIP_phone" title="VoIP phone">VoIP phones</a>, VoIP is also available on many personal computers and other Internet access devices. Calls and SMS text messages may be sent via <a href="/wiki/Wi-Fi" title="Wi-Fi">Wi-Fi</a> or the carrier's <a href="/wiki/Mobile_data" class="mw-redirect" title="Mobile data">mobile data</a> network.<a href="#cite_note-EBSCOhost-5">[4]</a> VoIP provides a framework for consolidation of all modern communications technologies using a single <a href="/wiki/Unified_communications" title="Unified communications">unified communications</a> system. <div class="mw-heading mw-heading3"><h3 id="Integration_of_VoIP_in_Mobile_Networks">Integration of VoIP in Mobile Networks</h3>[<a href="/w/index.php?title=Voice_over_IP&action=edit&section=2" title="Edit section: Integration of VoIP in Mobile Networks">edit</a>]</div> VoIP technology has been adapted for use in <a href="/wiki/Cellular_network" title="Cellular network">mobile networks</a>, leading to the development of advanced systems designed to support voice communication over modern data infrastructures. Among these are Voice over LTE (<a href="/wiki/VoLTE" class="mw-redirect" title="VoLTE">VoLTE</a>) and Voice over 5G (<a href="/wiki/Vo5G" class="mw-redirect" title="Vo5G">Vo5G</a>), which enable voice communication over IP-based mobile infrastructures. In contrast to traditional VoIP services, which often function independently of global telephone numbering systems, VoLTE and Vo5G are directly connected to <a href="/wiki/Mobile_operator" class="mw-redirect" title="Mobile operator">mobile operators</a>' infrastructures, providing seamless connectivity to the international telephone network.<a href="#cite_note-6">[5]</a><a href="#cite_note-7">[6]</a> VoLTE, introduced as part of <a href="/wiki/4G" title="4G">4G</a> <a href="/wiki/LTE_(telecommunication)" title="LTE (telecommunication)">LTE</a> networks, enables voice communication over an IP-based infrastructure initially developed for data transmission. It offers features such as high-definition voice (<a href="/wiki/HD_Voice" class="mw-redirect" title="HD Voice">HD Voice</a>) and faster call setup times compared to <a href="/wiki/Circuit-switched_network" class="mw-redirect" title="Circuit-switched network">circuit-switched networks</a>.<a href="#cite_note-8">[7]</a> Vo5G, the <a href="/wiki/5G" title="5G">5G</a> equivalent of VoLTE, utilizes the increased speed, reduced latency, and greater capacity of 5G networks to further enhance these capabilities.<a href="#cite_note-9">[8]</a> Both VoLTE and Vo5G maintain compatibility with traditional <a href="/wiki/Public_switched_telephone_network" title="Public switched telephone network">public switched telephone networks</a> (PSTNs), allowing users to make and receive calls to and from any <a href="/wiki/Telephone_number" title="Telephone number">telephone number</a> worldwide. These technologies differ from standalone VoIP services by being fully integrated with mobile network operators. This integration ensures additional features such as <a href="/wiki/Emergency_call" class="mw-redirect" title="Emergency call">emergency call</a> support and <a href="/wiki/Quality-of-service" class="mw-redirect" title="Quality-of-service">quality-of-service</a> guarantees, making them a central part of modern mobile telecommunication systems. <div class="mw-heading mw-heading2"><h2 id="Protocols">Protocols</h2>[<a href="/w/index.php?title=Voice_over_IP&action=edit&section=3" title="Edit section: Protocols">edit</a>]</div> Voice over IP has been implemented with <a href="/wiki/Proprietary_protocol" title="Proprietary protocol">proprietary protocols</a> and protocols based on <a href="/wiki/Open_standard#Protocols" title="Open standard">open standards</a> in applications such as VoIP phones, mobile applications, and <a href="/wiki/Web-based_VoIP" title="Web-based VoIP">web-based communications</a>. A variety of functions are needed to implement VoIP communication. Some protocols perform multiple functions, while others perform only a few and must be used in concert. These functions include: <ul><li>Network and transport – Creating reliable transmission over unreliable protocols, which may involve acknowledging receipt of data and retransmitting data that wasn't received.</li> <li>Session management – Creating and managing a <a href="/wiki/Session_(computer_science)" title="Session (computer science)">session</a> (sometimes glossed as simply a "call"), which is a connection between two or more peers that provides a context for further communication.</li> <li><a href="/wiki/Signaling_(telecommunications)" title="Signaling (telecommunications)">Signaling</a> – Performing registration (advertising one's presence and contact information) and discovery (locating someone and obtaining their contact information), dialing (including reporting <a href="/wiki/Call-progress_tone" title="Call-progress tone">call progress</a>), negotiating capabilities, and call control (such as hold, mute, transfer/forwarding, dialing DTMF keys during a call [e.g. to interact with an <a href="/wiki/Automated_attendant" title="Automated attendant">automated attendant</a> or <a href="/wiki/IVR" class="mw-redirect" title="IVR">IVR</a>], etc.).</li> <li>Media description – Determining what type of media to send (audio, video, etc.), how to encode/decode it, and how to send/receive it (IP addresses, ports, etc.).</li> <li>Media – Transferring the actual media in the call, such as audio, video, text messages, files, etc.</li> <li>Quality of service – Providing out-of-band content or feedback about the media such as <a href="/wiki/Lip_sync" title="Lip sync">synchronization</a>, statistics, etc.</li> <li>Security – Implementing access control, verifying the identity of other participants (computers or people), and encrypting data to protect the privacy and integrity of the media contents and/or the control messages.</li></ul> VoIP protocols include: <ul><li><a href="/wiki/Matrix_(protocol)" title="Matrix (protocol)">Matrix</a>, open standard for <a href="/wiki/Online_chat" title="Online chat">online chat</a>, voice over IP, and <a href="/wiki/Videotelephony" title="Videotelephony">videotelephony</a></li> <li><a href="/wiki/Session_Initiation_Protocol" title="Session Initiation Protocol">Session Initiation Protocol</a> (SIP),<a href="#cite_note-10">[9]</a> connection management protocol developed by the IETF</li> <li><a href="/wiki/H.323" title="H.323">H.323</a>, one of the first VoIP call signaling and control protocols that found widespread implementation.<a href="#cite_note-11">[10]</a> Since the development of newer, less complex protocols such as MGCP and SIP, H.323 deployments are increasingly limited to carrying existing long-haul network traffic.<a href="#cite_note-12">[11]</a></li> <li><a href="/wiki/Media_Gateway_Control_Protocol" title="Media Gateway Control Protocol">Media Gateway Control Protocol</a> (MGCP), connection management for media gateways</li> <li><a href="/wiki/H.248" title="H.248">H.248</a>, control protocol for media gateways across a converged internetwork consisting of the traditional PSTN and modern packet networks</li> <li><a href="/wiki/Real-time_Transport_Protocol" title="Real-time Transport Protocol">Real-time Transport Protocol</a> (RTP), transport protocol for real-time audio and video data</li> <li><a href="/wiki/Real-time_Transport_Control_Protocol" class="mw-redirect" title="Real-time Transport Control Protocol">Real-time Transport Control Protocol</a> (RTCP), sister protocol for RTP providing stream statistics and status information</li> <li><a href="/wiki/Secure_Real-time_Transport_Protocol" title="Secure Real-time Transport Protocol">Secure Real-time Transport Protocol</a> (SRTP), encrypted version of RTP</li> <li><a href="/wiki/Session_Description_Protocol" title="Session Description Protocol">Session Description Protocol</a> (SDP), a syntax for session initiation and announcement for multi-media communications and <a href="/wiki/WebSocket" title="WebSocket">WebSocket</a> transports.</li> <li><a href="/wiki/Inter-Asterisk_eXchange" title="Inter-Asterisk eXchange">Inter-Asterisk eXchange</a> (IAX), protocol used between <a href="/wiki/Asterisk_PBX" class="mw-redirect" title="Asterisk PBX">Asterisk PBX</a> instances</li> <li><a href="/wiki/Extensible_Messaging_and_Presence_Protocol" class="mw-redirect" title="Extensible Messaging and Presence Protocol">Extensible Messaging and Presence Protocol</a> (XMPP), instant messaging, presence information, and contact list maintenance</li> <li><a href="/wiki/Jingle_(protocol)" title="Jingle (protocol)">Jingle</a>, for peer-to-peer session control in XMPP</li> <li><a href="/wiki/Skype_protocol" title="Skype protocol">Skype protocol</a>, proprietary Internet telephony protocol suite based on peer-to-peer architecture</li></ul> <div class="mw-heading mw-heading2"><h2 id="Adoption">Adoption</h2>[<a href="/w/index.php?title=Voice_over_IP&action=edit&section=4" title="Edit section: Adoption">edit</a>]</div> <div class="mw-heading mw-heading3"><h3 id="Consumer_market">Consumer market</h3>[<a href="/w/index.php?title=Voice_over_IP&action=edit&section=5" title="Edit section: Consumer market">edit</a>]</div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Voip-typical.gif" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/4/44/Voip-typical.gif/220px-Voip-typical.gif" decoding="async" width="220" height="221" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/4/44/Voip-typical.gif 1.5x" data-file-width="300" data-file-height="302" /></a><figcaption>Example of residential network including VoIP</figcaption></figure> Mass-market VoIP services use existing <a href="/wiki/Broadband_Internet_access" class="mw-redirect" title="Broadband Internet access">broadband Internet access</a>, by which subscribers place and receive telephone calls in much the same manner as they would via the PSTN. Full-service VoIP phone companies provide inbound and outbound service with <a href="/wiki/Direct_inbound_dialing" class="mw-redirect" title="Direct inbound dialing">direct inbound dialing</a>. Many offer unlimited domestic calling and sometimes international calls for a flat monthly subscription fee. Phone calls between subscribers of the same provider are usually free when flat-fee service is not available.<a href="#cite_note-13">[12]</a> A VoIP phone is necessary to connect to a VoIP service provider. This can be implemented in several ways: <ul><li>Dedicated VoIP phones connect directly to the IP network using technologies such as wired <a href="/wiki/Ethernet" title="Ethernet">Ethernet</a> or <a href="/wiki/Wi-Fi" title="Wi-Fi">Wi-Fi</a>. These are typically designed in the style of traditional digital business telephones.</li> <li>An <a href="/wiki/Analog_telephone_adapter" title="Analog telephone adapter">analog telephone adapter</a> connects to the network and implements the electronics and firmware to operate a conventional analog telephone attached through a modular phone jack. Some residential Internet gateways and <a href="/wiki/Cable_modem" title="Cable modem">cable modems</a> have this function built in.</li> <li><a href="/wiki/Softphone" title="Softphone">Softphone</a> application software installed on a networked computer that is equipped with a microphone and speaker, or headset. The application typically presents a dial pad and display field to the user to operate the application by mouse clicks or keyboard input.<a href="#cite_note-14">[13]</a></li></ul> <div class="mw-heading mw-heading3"><h3 id="PSTN_and_mobile_network_providers">PSTN and mobile network providers</h3>[<a href="/w/index.php?title=Voice_over_IP&action=edit&section=6" title="Edit section: PSTN and mobile network providers">edit</a>]</div> It is increasingly common for telecommunications providers to use VoIP telephony over dedicated and public IP networks as a <a href="/wiki/Backhaul_(telecommunications)" title="Backhaul (telecommunications)">backhaul</a> to connect switching centers and to interconnect with other telephony network providers; this is often referred to as IP backhaul.<a href="#cite_note-15">[14]</a><a href="#cite_note-16">[15]</a> <a href="/wiki/Smartphones" class="mw-redirect" title="Smartphones">Smartphones</a> may have SIP clients built into the firmware or available as an application download.<a href="#cite_note-17">[16]</a><a href="#cite_note-18">[17]</a> <div class="mw-heading mw-heading3"><h3 id="Corporate_use">Corporate use</h3>[<a href="/w/index.php?title=Voice_over_IP&action=edit&section=7" title="Edit section: Corporate use">edit</a>]</div> Because of the bandwidth efficiency and low costs that VoIP technology can provide, businesses are migrating from traditional copper-wire telephone systems to VoIP systems to reduce their monthly phone costs. In 2008, 80% of all new <a href="/wiki/Private_branch_exchange" class="mw-redirect" title="Private branch exchange">Private branch exchange</a> (PBX) lines installed internationally were VoIP.<a href="#cite_note-19">[18]</a> For example, in the United States, the <a href="/wiki/Social_Security_Administration" title="Social Security Administration">Social Security Administration</a> is converting its field offices of 63,000 workers from traditional phone installations to a VoIP infrastructure carried over its existing data network.<a href="#cite_note-20">[19]</a><a href="#cite_note-21">[20]</a> VoIP allows both voice and data communications to be run over a single network, which can significantly reduce infrastructure costs. The prices of extensions on VoIP are lower than for PBX and key systems. VoIP switches may run on commodity hardware, such as <a href="/wiki/Personal_computer" title="Personal computer">personal computers</a>. Rather than closed architectures, these devices rely on standard interfaces.<a href="#cite_note-Korzeniowski-22">[21]</a> VoIP devices have simple, intuitive user interfaces, so users can often make simple system configuration changes. Dual-mode phones enable users to continue their conversations as they move between an outside cellular service and an internal <a href="/wiki/Wi-Fi" title="Wi-Fi">Wi-Fi</a> network, so that it is no longer necessary to carry both a desktop phone and a cell phone. Maintenance becomes simpler as there are fewer devices to oversee.<a href="#cite_note-Korzeniowski-22">[21]</a> VoIP solutions aimed at businesses have evolved into <a href="/wiki/Unified_communications" title="Unified communications">unified communications</a> services that treat all communications—phone calls, faxes, voice mail, e-mail, web conferences, and more—as discrete units that can all be delivered via any means and to any handset, including cellphones. Two kinds of service providers are operating in this space: one set is focused on VoIP for medium to large enterprises, while another is targeting the small-to-medium business (SMB) market.<a href="#cite_note-23">[22]</a> <a href="/wiki/Skype" title="Skype">Skype</a>, which originally marketed itself as a service among friends, has begun to cater to businesses, providing free-of-charge connections between any users on the Skype network and connecting to and from ordinary PSTN telephones for a charge.<a href="#cite_note-24">[23]</a> <div class="mw-heading mw-heading2"><h2 id="Delivery_mechanisms">Delivery mechanisms</h2>[<a href="/w/index.php?title=Voice_over_IP&action=edit&section=8" title="Edit section: Delivery mechanisms">edit</a>]</div> In general, the provision of VoIP telephony systems to organizational or individual users can be divided into two primary delivery methods: private or on-premises solutions, or externally hosted solutions delivered by third-party providers. On-premises delivery methods are more akin to the classic PBX deployment model for connecting an office to local PSTN networks. While many use cases still remain for private or on-premises VoIP systems, the wider market has been gradually shifting toward Cloud or Hosted VoIP solutions. Hosted systems are also generally better suited to smaller or personal use VoIP deployments, where a private system may not be viable for these scenarios. <div class="mw-heading mw-heading3"><h3 id="Hosted_VoIP_systems">Hosted VoIP systems</h3>[<a href="/w/index.php?title=Voice_over_IP&action=edit&section=9" title="Edit section: Hosted VoIP systems">edit</a>]</div> Hosted or Cloud VoIP solutions involve a service provider or telecommunications carrier hosting the telephone system as a software solution within their own infrastructure. Typically this will be one or more <a href="/wiki/Data_center" title="Data center">data centers</a> with geographic relevance to the end-user(s) of the system. This infrastructure is external to the user of the system and is deployed and maintained by the service provider. Endpoints, such as VoIP telephones or softphone applications (apps running on a computer or mobile device), will connect to the VoIP service remotely. These connections typically take place over public internet links, such as local fixed WAN breakout or mobile carrier service. <div class="mw-heading mw-heading3"><h3 id="Private_VoIP_systems">Private VoIP systems</h3>[<a href="/w/index.php?title=Voice_over_IP&action=edit&section=10" title="Edit section: Private VoIP systems">edit</a>]</div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Gigabyte_BRIX_as_Asterisk-based_PBX.jpg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/5/52/Gigabyte_BRIX_as_Asterisk-based_PBX.jpg/220px-Gigabyte_BRIX_as_Asterisk-based_PBX.jpg" decoding="async" width="220" height="165" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/5/52/Gigabyte_BRIX_as_Asterisk-based_PBX.jpg/330px-Gigabyte_BRIX_as_Asterisk-based_PBX.jpg 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/5/52/Gigabyte_BRIX_as_Asterisk-based_PBX.jpg/440px-Gigabyte_BRIX_as_Asterisk-based_PBX.jpg 2x" data-file-width="4128" data-file-height="3096" /></a><figcaption><a href="/wiki/Asterisk_(PBX)" title="Asterisk (PBX)">Asterisk</a>-based PBX for small business</figcaption></figure> In the case of a private VoIP system, the primary telephony system itself is located within the private infrastructure of the end-user organization. Usually, the system will be deployed on-premises at a site within the direct control of the organization. This can provide numerous benefits in terms of QoS control (see <a class="mw-selflink-fragment" href="#Quality_of_service">below</a>), cost scalability, and ensuring privacy and security of communications traffic. However, the responsibility for ensuring that the VoIP system remains performant and resilient is predominantly vested in the end-user organization. This is not the case with a Hosted VoIP solution. Private VoIP systems can be physical hardware PBX appliances, converged with other infrastructure, or they can be deployed as software applications. Generally, the latter two options will be in the form of a separate virtualized appliance. However, in some scenarios, these systems are deployed on bare metal infrastructure or IoT devices. With some solutions, such as 3CX, companies can attempt to blend the benefits of hosted and private on-premises systems by implementing their own private solution but within an external environment. Examples can include data center collocation services, public cloud, or private cloud locations. For on-premises systems, local endpoints within the same location typically connect directly over the <a href="/wiki/LAN" class="mw-redirect" title="LAN">LAN</a>. For remote and external endpoints, available connectivity options mirror those of Hosted or Cloud VoIP solutions. However, VoIP traffic to and from the on-premises systems can often also be sent over secure private links. Examples include personal VPN, <a href="/wiki/VPN#Types" class="mw-redirect" title="VPN">site-to-site VPN</a>, private networks such as MPLS and SD-WAN, or via private SBCs (Session Border Controllers). While exceptions and private peering options do exist, it is generally uncommon for those private connectivity methods to be provided by Hosted or Cloud VoIP providers. <div class="mw-heading mw-heading2"><h2 id="Quality_of_service">Quality of service</h2>[<a href="/w/index.php?title=Voice_over_IP&action=edit&section=11" title="Edit section: Quality of service">edit</a>]</div> Communication on the IP network is perceived as less reliable in contrast to the circuit-switched public telephone network because it does not provide a network-based mechanism to ensure that data packets are not lost, and are delivered in sequential order. It is a best-effort network without fundamental <a href="/wiki/Quality_of_service" title="Quality of service">quality of service</a> (QoS) guarantees. Voice, and all other data, travels in packets over IP networks with fixed maximum capacity. This system may be more prone to data loss in the presence of congestion<a href="#cite_note-26">[b]</a> than traditional <a href="/wiki/Circuit_switched" class="mw-redirect" title="Circuit switched">circuit switched</a> systems; a circuit switched system of insufficient capacity will refuse new connections while carrying the remainder without impairment, while the quality of real-time data such as telephone conversations on packet-switched networks degrades dramatically.<a href="#cite_note-cisco-27">[25]</a> Therefore, VoIP implementations may face problems with <a href="/wiki/Network_latency" class="mw-redirect" title="Network latency">latency</a>, packet loss, and <a href="/wiki/Jitter" title="Jitter">jitter</a>.<a href="#cite_note-cisco-27">[25]</a><a href="#cite_note-28">[26]</a> By default, network routers handle traffic on a first-come, first-served basis. Fixed delays cannot be controlled as they are caused by the physical distance the packets travel. They are especially problematic when satellite circuits are involved because of the long distance to a <a href="/wiki/Geosynchronous_satellite" title="Geosynchronous satellite">geostationary satellite</a> and back; delays of 400–600 ms are typical. Latency can be minimized by marking voice packets as being delay-sensitive with QoS methods such as <a href="/wiki/DiffServ" class="mw-redirect" title="DiffServ">DiffServ</a>.<a href="#cite_note-cisco-27">[25]</a> Network routers on high volume traffic links may introduce latency that exceeds permissible thresholds for VoIP. Excessive load on a link can cause congestion and associated <a href="/wiki/Queueing_delay" class="mw-redirect" title="Queueing delay">queueing delays</a> and <a href="/wiki/Packet_loss" title="Packet loss">packet loss</a>. This signals a transport protocol like <a href="/wiki/Transmission_Control_Protocol" title="Transmission Control Protocol">TCP</a> to reduce its transmission rate to alleviate the congestion. But VoIP usually uses <a href="/wiki/User_Datagram_Protocol" title="User Datagram Protocol">UDP</a> not TCP because recovering from congestion through retransmission usually entails too much latency.<a href="#cite_note-cisco-27">[25]</a> So QoS mechanisms can avoid the undesirable loss of VoIP packets by immediately transmitting them ahead of any queued bulk traffic on the same link, even when the link is congested by bulk traffic. VoIP endpoints usually have to wait for the completion of transmission of previous packets before new data may be sent. Although it is possible to preempt (abort) a less important packet in mid-transmission, this is not commonly done, especially on high-speed links where transmission times are short even for maximum-sized packets.<a href="#cite_note-ciscoPacket-29">[27]</a> An alternative to preemption on slower links, such as dialup and <a href="/wiki/Digital_subscriber_line" title="Digital subscriber line">digital subscriber line</a> (DSL), is to reduce the maximum transmission time by reducing the <a href="/wiki/Maximum_transmission_unit" title="Maximum transmission unit">maximum transmission unit</a>. But since every packet must contain protocol headers, this increases relative header overhead on every link traversed.<a href="#cite_note-ciscoPacket-29">[27]</a> The receiver must resequence IP packets that arrive out of order and recover gracefully when packets arrive too late or not at all. <a href="/wiki/Packet_delay_variation" title="Packet delay variation">Packet delay variation</a> results from changes in <a href="/wiki/Queuing_delay" title="Queuing delay">queuing delay</a> along a given network path due to competition from other users for the same transmission links. VoIP receivers accommodate this variation by storing incoming packets briefly in a <a href="/wiki/Playout_buffer" class="mw-redirect" title="Playout buffer">playout buffer</a>, deliberately increasing latency to improve the chance that each packet will be on hand when it is time for the <a href="/wiki/Voice_engine" title="Voice engine">voice engine</a> to play it. The added delay is thus a compromise between excessive latency and excessive <a href="/wiki/Dropout_(communications)" title="Dropout (communications)">dropout</a>, i.e. momentary audio interruptions. Although jitter is a random variable, it is the sum of several other random variables that are at least somewhat independent: the individual queuing delays of the routers along the Internet path in question. Motivated by the <a href="/wiki/Central_limit_theorem" title="Central limit theorem">central limit theorem</a>, jitter can be modeled as a <a href="/wiki/Gaussian_random_variable" class="mw-redirect" title="Gaussian random variable">Gaussian random variable</a>. This suggests continually estimating the mean delay and its standard deviation and setting the playout delay so that only packets delayed more than several standard deviations above the mean will arrive too late to be useful. In practice, the variance in latency of many Internet paths is dominated by a small number (often one) of relatively slow and congested <a href="/wiki/Internet_bottleneck" title="Internet bottleneck">bottleneck links</a>. Most Internet backbone links are now so fast (e.g. 10 Gbit/s) that their delays are dominated by the <a href="/wiki/Signal_transmission" title="Signal transmission">transmission</a> medium (e.g. optical fiber) and the routers driving them do not have enough buffering for queuing delays to be significant.<a href="#cite_note-30">[28]</a> A number of protocols have been defined to support the reporting of <a href="/wiki/Quality_of_service" title="Quality of service">quality of service</a> (QoS) and <a href="/wiki/Quality_of_experience" title="Quality of experience">quality of experience</a> (QoE) for VoIP calls. These include <a href="/wiki/RTP_Control_Protocol" title="RTP Control Protocol">RTP Control Protocol</a> (RTCP) extended reports,<a href="#cite_note-:1-31">[29]</a> SIP RTCP summary reports, H.460.9 Annex B (for <a href="/wiki/H.323" title="H.323">H.323</a>), <a href="/wiki/H.248" title="H.248">H.248</a>.30 and MGCP extensions. The RTCP extended report VoIP metrics block specified by <style data-mw-deduplicate="TemplateStyles:r1238218222">.mw-parser-output cite.citation{font-style:inherit;word-wrap:break-word}.mw-parser-output .citation q{quotes:"\"""\"""'""'"}.mw-parser-output .citation:target{background-color:rgba(0,127,255,0.133)}.mw-parser-output .id-lock-free.id-lock-free a{background:url("//upload.wikimedia.org/wikipedia/commons/6/65/Lock-green.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-limited.id-lock-limited a,.mw-parser-output .id-lock-registration.id-lock-registration a{background:url("//upload.wikimedia.org/wikipedia/commons/d/d6/Lock-gray-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-subscription.id-lock-subscription a{background:url("//upload.wikimedia.org/wikipedia/commons/a/aa/Lock-red-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .cs1-ws-icon a{background:url("//upload.wikimedia.org/wikipedia/commons/4/4c/Wikisource-logo.svg")right 0.1em center/12px no-repeat}body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-free a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-limited a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-registration a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-subscription a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .cs1-ws-icon a{background-size:contain;padding:0 1em 0 0}.mw-parser-output .cs1-code{color:inherit;background:inherit;border:none;padding:inherit}.mw-parser-output .cs1-hidden-error{display:none;color:var(--color-error,#d33)}.mw-parser-output .cs1-visible-error{color:var(--color-error,#d33)}.mw-parser-output .cs1-maint{display:none;color:#085;margin-left:0.3em}.mw-parser-output .cs1-kern-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right{padding-right:0.2em}.mw-parser-output .citation .mw-selflink{font-weight:inherit}@media screen{.mw-parser-output .cs1-format{font-size:95%}html.skin-theme-clientpref-night .mw-parser-output .cs1-maint{color:#18911f}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .cs1-maint{color:#18911f}}</style><a href="/wiki/RFC_(identifier)" class="mw-redirect" title="RFC (identifier)">RFC</a> <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc3611">3611</a> is generated by an VoIP phone or gateway during a live call and contains information on packet loss rate, packet discard rate (because of jitter), packet loss/discard burst metrics (burst length/density, gap length/density), network delay, end system delay, signal/noise/echo level, <a href="/wiki/Mean_opinion_score" title="Mean opinion score">mean opinion scores</a> (MOS) and R factors and configuration information related to the jitter buffer. VoIP metrics reports are exchanged between IP endpoints on an occasional basis during a call, and an end of call message sent via SIP RTCP summary report or one of the other signaling protocol extensions. VoIP metrics reports are intended to support real-time feedback related to QoS problems, the exchange of information between the endpoints for improved call quality calculation and a variety of other applications. <div class="mw-heading mw-heading3"><h3 id="DSL_and_ATM">DSL and ATM</h3>[<a href="/w/index.php?title=Voice_over_IP&action=edit&section=12" title="Edit section: DSL and ATM">edit</a>]</div> DSL modems typically provide Ethernet connections to local equipment, but inside they may actually be <a href="/wiki/Asynchronous_Transfer_Mode" title="Asynchronous Transfer Mode">Asynchronous Transfer Mode</a> (ATM) modems.<a href="#cite_note-32">[c]</a> They use <a href="/wiki/ATM_Adaptation_Layer_5" title="ATM Adaptation Layer 5">ATM Adaptation Layer 5</a> (AAL5) to segment each Ethernet packet into a series of 53-byte ATM cells for transmission, reassembling them back into Ethernet frames at the receiving end. Using a separate <a href="/wiki/Virtual_circuit_identifier" class="mw-redirect" title="Virtual circuit identifier">virtual circuit identifier</a> (VCI) for voice over IP has the potential to reduce latency on shared connections. ATM's potential for latency reduction is greatest on slow links because worst-case latency decreases with increasing link speed. A full-size (1500 byte) Ethernet frame takes 94 ms to transmit at 128 kbit/s but only 8 ms at 1.5 Mbit/s. If this is the bottleneck link, this latency is probably small enough to ensure good VoIP performance without MTU reductions or multiple ATM VCs. The latest generations of DSL, <a href="/wiki/VDSL" title="VDSL">VDSL</a> and <a href="/wiki/VDSL2" class="mw-redirect" title="VDSL2">VDSL2</a>, carry Ethernet without intermediate ATM/AAL5 layers, and they generally support <a href="/wiki/IEEE_802.1p" class="mw-redirect" title="IEEE 802.1p">IEEE 802.1p</a> priority tagging so that VoIP can be queued ahead of less time-critical traffic.<a href="#cite_note-cisco-27">[25]</a> ATM has substantial header overhead: 5/53 = 9.4%, roughly twice the total header overhead of a 1500 byte Ethernet frame. This "ATM tax" is incurred by every DSL user whether or not they take advantage of multiple virtual circuits – and few can.<a href="#cite_note-cisco-27">[25]</a> <div class="mw-heading mw-heading3"><h3 id="Layer_2">Layer 2</h3>[<a href="/w/index.php?title=Voice_over_IP&action=edit&section=13" title="Edit section: Layer 2">edit</a>]</div> Several protocols are used in the <a href="/wiki/Data_link_layer" title="Data link layer">data link layer</a> and <a href="/wiki/Physical_layer" title="Physical layer">physical layer</a> for quality-of-service mechanisms that help VoIP applications work well even in the presence of <a href="/wiki/Network_congestion" title="Network congestion">network congestion</a>. Some examples include: <ul><li><a href="/wiki/IEEE_802.11e" class="mw-redirect" title="IEEE 802.11e">IEEE 802.11e</a> is an approved amendment to the <a href="/wiki/IEEE_802.11" title="IEEE 802.11">IEEE 802.11</a> standard that defines a set of quality-of-service enhancements for wireless LAN applications through modifications to the <a href="/wiki/Media_access_control" class="mw-redirect" title="Media access control">media access control</a> (MAC) layer. The standard is considered of critical importance for delay-sensitive applications, such as voice over wireless IP.</li> <li><a href="/wiki/IEEE_802.1p" class="mw-redirect" title="IEEE 802.1p">IEEE 802.1p</a> defines 8 different classes of service (including one dedicated to voice) for traffic on layer-2 wired <a href="/wiki/Ethernet" title="Ethernet">Ethernet</a>.</li> <li>The <a href="/wiki/ITU-T" title="ITU-T">ITU-T</a> <a href="/wiki/G.hn" title="G.hn">G.hn</a> standard, which provides a way to create a high-speed (up to 1 gigabit per second) <a href="/wiki/Local_area_network" title="Local area network">Local area network</a> (LAN) using existing home wiring (<a href="/wiki/Power_line_communication" class="mw-redirect" title="Power line communication">power lines</a>, phone lines and <a href="/wiki/Ethernet_over_coax" title="Ethernet over coax">coaxial cables</a>). G.hn provides QoS by means of Contention-Free Transmission Opportunities (CFTXOPs) which are allocated to flows (such as a VoIP call) that require QoS and which have negotiated a contract with the network controllers.</li></ul> <div class="mw-heading mw-heading2"><h2 id="Performance_metrics">Performance metrics</h2>[<a href="/w/index.php?title=Voice_over_IP&action=edit&section=14" title="Edit section: Performance metrics">edit</a>]</div> The quality of voice transmission is characterized by several metrics that may be monitored by network elements and by the user agent hardware or software. Such metrics include network <a href="/wiki/Packet_loss" title="Packet loss">packet loss</a>, packet <a href="/wiki/Jitter" title="Jitter">jitter</a>, packet <a href="/wiki/Round-trip_delay_time" class="mw-redirect" title="Round-trip delay time">latency</a> (delay), post-dial delay, and echo. The metrics are determined by VoIP performance testing and monitoring.<a href="#cite_note-33">[30]</a><a href="#cite_note-34">[31]</a><a href="#cite_note-35">[32]</a><a href="#cite_note-36">[33]</a><a href="#cite_note-37">[34]</a><a href="#cite_note-38">[35]</a> <div class="mw-heading mw-heading2"><h2 id="PSTN_integration">PSTN integration</h2>[<a href="/w/index.php?title=Voice_over_IP&action=edit&section=15" title="Edit section: PSTN integration">edit</a>]</div> <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><table class="box-More_citations_needed_section plainlinks metadata ambox ambox-content ambox-Refimprove" role="presentation"><tbody><tr><td class="mbox-image"><div class="mbox-image-div"><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></div></td><td class="mbox-text"><div class="mbox-text-span">This section needs additional citations for <a href="/wiki/Wikipedia:Verifiability" title="Wikipedia:Verifiability">verification</a>. Please help <a href="/wiki/Special:EditPage/Voice_over_IP" title="Special:EditPage/Voice over IP">improve this article</a> by <a href="/wiki/Help:Referencing_for_beginners" title="Help:Referencing for beginners">adding citations to reliable sources</a> in this section. Unsourced material may be challenged and removed. (November 2019) (<a href="/wiki/Help:Maintenance_template_removal" title="Help:Maintenance template removal">Learn how and when to remove this message</a>)</div></td></tr></tbody></table> A VoIP media gateway controller (aka <a href="/wiki/Class-5_telephone_switch" title="Class-5 telephone switch">Class 5</a> Softswitch) works in cooperation with a media gateway (aka IP Business Gateway) and connects the digital media stream, so as to complete the path for voice and data. Gateways include interfaces for connecting to standard PSTN networks. Ethernet interfaces are also included in the modern systems which are specially designed to link calls that are passed via VoIP.<a href="#cite_note-39">[36]</a> <a href="/wiki/E.164" title="E.164">E.164</a> is a global numbering standard for both the PSTN and <a href="/wiki/Public_land_mobile_network" title="Public land mobile network">public land mobile network</a> (PLMN). Most VoIP implementations support <a href="/wiki/E.164" title="E.164">E.164</a> to allow calls to be routed to and from VoIP subscribers and the PSTN/PLMN.<a href="#cite_note-40">[37]</a> VoIP implementations can also allow other identification techniques to be used. For example, <a href="/wiki/Skype_Technologies" title="Skype Technologies">Skype</a> allows subscribers to choose Skype names (usernames)<a href="#cite_note-41">[38]</a> whereas SIP implementations can use <a href="/wiki/Uniform_Resource_Identifier" title="Uniform Resource Identifier">Uniform Resource Identifier</a> (URIs) similar to <a href="/wiki/Email_address" title="Email address">email addresses</a>.<a href="#cite_note-42">[39]</a> Often VoIP implementations employ methods of translating non-E.164 identifiers to E.164 numbers and vice versa, such as the Skype-In service provided by Skype<a href="#cite_note-43">[40]</a> and the <a href="/wiki/E.164_number_to_URI_mapping" class="mw-redirect" title="E.164 number to URI mapping">E.164 number to URI mapping</a> (ENUM) service in IMS and SIP.<a href="#cite_note-44">[41]</a> Echo can also be an issue for PSTN integration.<a href="#cite_note-45">[42]</a> Common causes of echo include <a href="/wiki/Impedance_matching" title="Impedance matching">impedance mismatches</a> in analog circuitry and an acoustic path from the receive to transmit signal at the receiving end. <div class="mw-heading mw-heading3"><h3 id="Number_portability">Number portability</h3>[<a href="/w/index.php?title=Voice_over_IP&action=edit&section=16" title="Edit section: Number portability">edit</a>]</div> <a href="/wiki/Local_number_portability" title="Local number portability">Local number portability</a> (LNP) and <a href="/wiki/Mobile_number_portability" title="Mobile number portability">mobile number portability</a> (MNP) also impact VoIP business. Number portability is a service that allows a subscriber to select a new telephone carrier without requiring a new number to be issued. Typically, it is the responsibility of the former carrier to "map" the old number to the undisclosed number assigned by the new carrier. This is achieved by maintaining a database of numbers. A dialed number is initially received by the original carrier and quickly rerouted to the new carrier. Multiple porting references must be maintained even if the subscriber returns to the original carrier. The <a href="/wiki/Federal_Communications_Commission" title="Federal Communications Commission">Federal Communications Commission</a> (FCC) mandates carrier compliance with these consumer-protection stipulations. In November 2007, the FCC in the United States released an order extending number portability obligations to interconnected VoIP providers and carriers that support VoIP providers.<a href="#cite_note-46">[43]</a> A voice call originating in the VoIP environment also faces <a href="/wiki/Least-cost_routing" title="Least-cost routing">least-cost routing</a> (LCR) challenges to reach its destination if the number is routed to a mobile phone number on a traditional mobile carrier. LCR is based on checking the destination of each telephone call as it is made, and then sending the call via the network that will cost the customer the least. This rating is subject to some debate given the complexity of call routing created by number portability. With MNP in place, LCR providers can no longer rely on using the network root prefix to determine how to route a call. Instead, they must now determine the actual network of every number before routing the call.<a href="#cite_note-47">[44]</a> Therefore, VoIP solutions also need to handle MNP when routing a voice call. In countries without a central database, like the UK, it may be necessary to query the mobile network about which home network a mobile phone number belongs to. As the popularity of VoIP increases in the enterprise markets because of LCR options, VoIP needs to provide a certain level of reliability when handling calls. <div class="mw-heading mw-heading3"><h3 id="Emergency_calls">Emergency calls</h3>[<a href="/w/index.php?title=Voice_over_IP&action=edit&section=17" title="Edit section: Emergency calls">edit</a>]</div> A telephone connected to a <a href="/wiki/Land_line" class="mw-redirect" title="Land line">land line</a> has a direct relationship between a telephone number and a physical location, which is maintained by the telephone company and available to emergency responders via the national emergency response service centers in form of emergency subscriber lists. When an emergency call is received by a center the location is automatically determined from its databases and displayed on the operator console. In IP telephony, no such direct link between location and communications end point exists. Even a provider having wired infrastructure, such as a DSL provider, may know only the approximate location of the device, based on the <a href="/wiki/IP_address" title="IP address">IP address</a> allocated to the network router and the known service address. Some ISPs do not track the automatic assignment of IP addresses to customer equipment.<a href="#cite_note-fcc-48">[45]</a> IP communication provides for device mobility. For example, a residential broadband connection may be used as a link to a <a href="/wiki/Virtual_private_network" title="Virtual private network">virtual private network</a> of a corporate entity, in which case the IP address being used for customer communications may belong to the enterprise, not the residential ISP. Such <a href="/wiki/Off-premises_extension" title="Off-premises extension">off-premises extensions</a> may appear as part of an upstream IP PBX. On mobile devices, e.g., a 3G handset or USB wireless broadband adapter, the IP address has no relationship with any physical location known to the telephony service provider, since a mobile user could be anywhere in a region with network coverage, even roaming via another cellular company. At the VoIP level, a phone or gateway may identify itself by its account credentials with a <a href="/wiki/Session_Initiation_Protocol" title="Session Initiation Protocol">Session Initiation Protocol</a> (SIP) registrar. In such cases, the <a href="/wiki/Internet_telephony_service_provider" title="Internet telephony service provider">Internet telephony service provider</a> (ITSP) knows only that a particular user's equipment is active. Service providers often provide emergency response services by agreement with the user who registers a physical location and agrees that, if an emergency number is called from the IP device, emergency services are provided to that address only. Such emergency services are provided by VoIP vendors in the United States by a system called <a href="/wiki/Enhanced_911" title="Enhanced 911">Enhanced 911</a> (E911), based on the <a href="/wiki/Wireless_Communications_and_Public_Safety_Act" title="Wireless Communications and Public Safety Act">Wireless Communications and Public Safety Act</a>. The VoIP E911 emergency-calling system associates a physical address with the calling party's telephone number. All VoIP providers that provide access to the public switched telephone network are required to implement E911, a service for which the subscriber may be charged. "VoIP providers may not allow customers to opt-out of 911 service."<a href="#cite_note-fcc-48">[45]</a> The <a href="/wiki/VoIP_E911" class="mw-redirect" title="VoIP E911">VoIP E911</a> system is based on a static table lookup. Unlike in cellular phones, where the location of an E911 call can be traced using <a href="/wiki/Assisted_GPS" class="mw-redirect" title="Assisted GPS">assisted GPS</a> or other methods, the VoIP E911 information is accurate only if subscribers keep their emergency address information current.<a href="#cite_note-49">[46]</a> <div class="mw-heading mw-heading2"><h2 id="Fax_support">Fax support</h2>[<a href="/w/index.php?title=Voice_over_IP&action=edit&section=18" title="Edit section: Fax support">edit</a>]</div> Sending <a href="/wiki/Fax" title="Fax">faxes</a> over VoIP networks is sometimes referred to as Fax over IP (FoIP). Transmission of fax documents was problematic in early VoIP implementations, as most voice digitization and compression <a href="/wiki/Codec" title="Codec">codecs</a> are optimized for the representation of the human voice and the proper timing of the modem signals cannot be guaranteed in a packet-based, connectionless network. A standards-based solution for reliably delivering fax-over-IP is the <a href="/wiki/T.38" title="T.38">T.38</a> protocol. The T.38 protocol is designed to compensate for the differences between traditional packet-less communications over analog lines and packet-based transmissions which are the basis for IP communications. The fax machine may be a standard device connected to an <a href="/wiki/Analog_telephone_adapter" title="Analog telephone adapter">analog telephone adapter</a> (ATA), or it may be a software application or dedicated network device operating via an Ethernet interface.<a href="#cite_note-50">[47]</a> Originally, T.38 was designed to use UDP or TCP transmission methods across an IP network. Some newer high-end fax machines have built-in T.38 capabilities which are connected directly to a network switch or router. In T.38 each packet contains a portion of the data stream sent in the previous packet. Two successive packets have to be lost to actually lose <a href="/wiki/Data_integrity" title="Data integrity">data integrity</a>. <div class="mw-heading mw-heading2"><h2 id="Power_requirements">Power requirements</h2>[<a href="/w/index.php?title=Voice_over_IP&action=edit&section=19" title="Edit section: Power requirements">edit</a>]</div> Telephones for traditional residential analog service are usually connected directly to telephone company <a href="/wiki/Phone_line" class="mw-redirect" title="Phone line">phone lines</a> which provide direct current to power most basic analog handsets independently of locally available electrical power. The susceptibility of phone service to power failures is a common problem even with traditional analog service where customers purchase telephone units that operate with wireless handsets to a base station, or that have other modern phone features, such as built-in voicemail or phone book features. VoIP phones and VoIP telephone adapters connect to <a href="/wiki/Network_router" class="mw-redirect" title="Network router">routers</a> or <a href="/wiki/Cable_modem" title="Cable modem">cable modems</a> which typically depend on the availability of <a href="/wiki/Mains_electricity" title="Mains electricity">mains electricity</a> or locally generated power.<a href="#cite_note-51">[48]</a> Some VoIP service providers use customer premises equipment (e.g., cable modems) with battery-backed power supplies to assure uninterrupted service for up to several hours in case of local power failures. Such battery-backed devices typically are designed for use with analog handsets. Some VoIP service providers implement services to route calls to other telephone services of the subscriber, such a cellular phone, in the event that the customer's network device is inaccessible to terminate the call. <div class="mw-heading mw-heading2"><h2 id="Security">Security</h2>[<a href="/w/index.php?title=Voice_over_IP&action=edit&section=20" title="Edit section: Security">edit</a>]</div> Secure calls are possible using standardized protocols such as <a href="/wiki/Secure_Real-time_Transport_Protocol" title="Secure Real-time Transport Protocol">Secure Real-time Transport Protocol</a>. Most of the facilities of creating a <a href="/wiki/Secure_telephone" title="Secure telephone">secure telephone</a> connection over traditional phone lines, such as digitizing and digital transmission, are already in place with VoIP. It is necessary only to <a href="/wiki/Encrypt" class="mw-redirect" title="Encrypt">encrypt</a> and <a href="/wiki/Authenticate" class="mw-redirect" title="Authenticate">authenticate</a> the existing data stream. Automated software, such as a <a href="/wiki/Business_telephone_system#Current_trends" title="Business telephone system">virtual PBX</a>, may eliminate the need for personnel to greet and switch incoming calls. The security concerns for VoIP telephone systems are similar to those of other Internet-connected devices. This means that <a href="/wiki/Hacker" title="Hacker">hackers</a> with knowledge of <a href="/wiki/VoIP_vulnerabilities" title="VoIP vulnerabilities">VoIP vulnerabilities</a> can perform <a href="/wiki/Denial-of-service" class="mw-redirect" title="Denial-of-service">denial-of-service</a> attacks, harvest customer data, record conversations, and compromise voicemail messages. Compromised VoIP user account or session credentials may enable an attacker to incur substantial charges from third-party services, such as long-distance or international calling. The technical details of many VoIP protocols create challenges in routing VoIP traffic through <a href="/wiki/Firewall_(networking)" class="mw-redirect" title="Firewall (networking)">firewalls</a> and <a href="/wiki/Network_address_translator" class="mw-redirect" title="Network address translator">network address translators</a>, used to interconnect to transit networks or the Internet. Private <a href="/wiki/Session_border_controller" title="Session border controller">session border controllers</a> are often employed to enable VoIP calls to and from protected networks. Other methods to <a href="/wiki/NAT_traversal" title="NAT traversal">traverse NAT</a> devices involve assistive protocols such as <a href="/wiki/STUN" title="STUN">STUN</a> and <a href="/wiki/Interactive_Connectivity_Establishment" title="Interactive Connectivity Establishment">Interactive Connectivity Establishment</a> (ICE). Standards for securing VoIP are available in the <a href="/wiki/Secure_Real-time_Transport_Protocol" title="Secure Real-time Transport Protocol">Secure Real-time Transport Protocol</a> (SRTP) and the <a href="/wiki/ZRTP" title="ZRTP">ZRTP</a> protocol for <a href="/wiki/Analog_telephony_adapter" class="mw-redirect" title="Analog telephony adapter">analog telephony adapters</a>, as well as for some <a href="/wiki/Softphone" title="Softphone">softphones</a>. <a href="/wiki/IPsec" title="IPsec">IPsec</a> is available to secure <a href="/wiki/Point-to-point_(telecommunications)" title="Point-to-point (telecommunications)">point-to-point</a> VoIP at the transport level by using <a href="/wiki/Opportunistic_encryption" title="Opportunistic encryption">opportunistic encryption</a>. Though many consumer VoIP solutions do not support encryption of the signaling path or the media, securing a VoIP phone is conceptually easier to implement using VoIP than on traditional telephone circuits. A result of the lack of widespread support for encryption is that it is relatively easy to eavesdrop on VoIP calls when access to the data network is possible.<a href="#cite_note-52">[49]</a> Free open-source solutions, such as <a href="/wiki/Wireshark" title="Wireshark">Wireshark</a>, facilitate capturing VoIP conversations. Government and military organizations use various security measures to protect VoIP traffic, such as voice over secure IP (VoSIP), secure voice over IP (SVoIP), and secure voice over secure IP (SVoSIP).<a href="#cite_note-53">[50]</a> The distinction lies in whether encryption is applied in the telephone endpoint or in the network.<a href="#cite_note-54">[51]</a> Secure voice over secure IP may be implemented by encrypting the media with protocols such as <a href="/wiki/Secure_Real-time_Transport_Protocol" title="Secure Real-time Transport Protocol">SRTP</a> and <a href="/wiki/ZRTP" title="ZRTP">ZRTP</a>. Secure voice over IP uses <a href="/wiki/Type_1_encryption" class="mw-redirect" title="Type 1 encryption">Type 1 encryption</a> on a classified network, such as <a href="/wiki/SIPRNet" title="SIPRNet">SIPRNet</a>.<a href="#cite_note-55">[52]</a><a href="#cite_note-56">[53]</a><a href="#cite_note-57">[54]</a><a href="#cite_note-58">[55]</a> Public Secure VoIP is also available with free GNU software and in many popular commercial VoIP programs via libraries, such as ZRTP.<a href="#cite_note-59">[56]</a> In June 2021, the <a href="/wiki/National_Security_Agency" title="National Security Agency">National Security Agency</a> (NSA) released comprehensive documents describing the four attack planes of a communications system – the network, perimeter, session controllers and <a href="/wiki/Communication_endpoint" title="Communication endpoint">endpoints</a> – and explaining security risks and mitigation techniques for each of them.<a href="#cite_note-60">[57]</a><a href="#cite_note-61">[58]</a> <div class="mw-heading mw-heading2"><h2 id="Caller_ID">Caller ID</h2>[<a href="/w/index.php?title=Voice_over_IP&action=edit&section=21" title="Edit section: Caller ID">edit</a>]</div> Voice over IP protocols and equipment provide <a href="/wiki/Caller_ID" title="Caller ID">caller ID</a> support that is compatible with the PSTN. Many VoIP service providers also allow callers to configure custom caller ID information.<a href="#cite_note-62">[59]</a> <div class="mw-heading mw-heading2"><h2 id="Hearing_aid_compatibility">Hearing aid compatibility</h2>[<a href="/w/index.php?title=Voice_over_IP&action=edit&section=22" title="Edit section: Hearing aid compatibility">edit</a>]</div> Wireline telephones which are manufactured in, imported to, or intended to be used in the US with Voice over IP service, on or after February 28, 2020, are required to meet the <a href="/wiki/Hearing_aid" title="Hearing aid">hearing aid</a> compatibility requirements set forth by the <a href="/wiki/Federal_Communications_Commission" title="Federal Communications Commission">Federal Communications Commission</a>.<a href="#cite_note-63">[60]</a> <div class="mw-heading mw-heading2"><h2 id="Operational_cost">Operational cost</h2>[<a href="/w/index.php?title=Voice_over_IP&action=edit&section=23" title="Edit section: Operational cost">edit</a>]</div> VoIP has drastically reduced the cost of communication by sharing network infrastructure between data and voice.<a href="#cite_note-64">[61]</a><a href="#cite_note-65">[62]</a> A single broadband connection has the ability to transmit multiple telephone calls. <div class="mw-heading mw-heading2"><h2 id="Regulatory_and_legal_issues">Regulatory and legal issues</h2>[<a href="/w/index.php?title=Voice_over_IP&action=edit&section=24" title="Edit section: Regulatory and legal issues">edit</a>]</div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1251242444"><table class="box-Update plainlinks metadata ambox ambox-content ambox-Update" role="presentation"><tbody><tr><td class="mbox-image"><div class="mbox-image-div"><img alt="" src="//upload.wikimedia.org/wikipedia/commons/thumb/b/bd/Ambox_current_red_Asia_Australia.svg/42px-Ambox_current_red_Asia_Australia.svg.png" decoding="async" width="42" height="34" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/b/bd/Ambox_current_red_Asia_Australia.svg/63px-Ambox_current_red_Asia_Australia.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/b/bd/Ambox_current_red_Asia_Australia.svg/84px-Ambox_current_red_Asia_Australia.svg.png 2x" data-file-width="360" data-file-height="290" /></div></td><td class="mbox-text"><div class="mbox-text-span">This section needs to be updated. Please help update this article to reflect recent events or newly available information. (April 2022)</div></td></tr></tbody></table> As the popularity of VoIP grows, governments are becoming more interested in regulating VoIP in a manner similar to PSTN services.<a href="#cite_note-66">[63]</a> Throughout the developing world, particularly in countries where regulation is weak or <a href="/wiki/Regulatory_capture" title="Regulatory capture">captured</a> by the dominant operator, restrictions on the use of VoIP are often imposed, including in <a href="/wiki/Panama" title="Panama">Panama</a> where VoIP is taxed, Guyana where VoIP is prohibited.<a href="#cite_note-67">[64]</a> In <a href="/wiki/Ethiopia" title="Ethiopia">Ethiopia</a>, where the government is nationalizing telecommunication service, it is a criminal offense to offer services using VoIP. The country has installed firewalls to prevent international calls from being made using VoIP. These measures were taken after the popularity of VoIP reduced the income generated by the state-owned <a href="/wiki/Telecommunications_company" title="Telecommunications company">telecommunications company</a>.[<a href="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed">citation needed</a>]<a href="#cite_note-68">[65]</a> <div class="mw-heading mw-heading3"><h3 id="Canada">Canada</h3>[<a href="/w/index.php?title=Voice_over_IP&action=edit&section=25" title="Edit section: Canada">edit</a>]</div> In <a href="/wiki/Canada" title="Canada">Canada</a>, the <a href="/wiki/Canadian_Radio-television_and_Telecommunications_Commission" title="Canadian Radio-television and Telecommunications Commission">Canadian Radio-television and Telecommunications Commission</a> regulates telephone service, including VoIP telephony service. VoIP services operating in Canada are required to provide <a href="/wiki/9-1-1" class="mw-redirect" title="9-1-1">9-1-1</a> emergency service.<a href="#cite_note-69">[66]</a> <div class="mw-heading mw-heading3"><h3 id="European_Union">European Union</h3>[<a href="/w/index.php?title=Voice_over_IP&action=edit&section=26" title="Edit section: European Union">edit</a>]</div> In the <a href="/wiki/European_Union" title="European Union">European Union</a>, the treatment of VoIP service providers is a decision for each national telecommunications regulator, which must use competition law to define relevant national markets and then determine whether any service provider on those national markets has "significant market power" (and so should be subject to certain obligations). A general distinction is usually made between VoIP services that function over managed networks (via broadband connections) and VoIP services that function over unmanaged networks (essentially, the Internet).[<a href="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed">citation needed</a>] The relevant EU Directive is not clearly drafted concerning obligations that can exist independently of market power (e.g., the obligation to offer access to emergency calls), and it is impossible to say definitively whether VoIP service providers of either type are bound by them.[<a href="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed">citation needed</a>]<a href="#cite_note-70">[67]</a> <div class="mw-heading mw-heading3"><h3 id="Arab_states_of_the_GCC">Arab states of the <a href="/wiki/Gulf_Cooperation_Council" title="Gulf Cooperation Council">GCC</a></h3>[<a href="/w/index.php?title=Voice_over_IP&action=edit&section=27" title="Edit section: Arab states of the GCC">edit</a>]</div> <div class="mw-heading mw-heading4"><h4 id="Oman">Oman</h4>[<a href="/w/index.php?title=Voice_over_IP&action=edit&section=28" title="Edit section: Oman">edit</a>]</div> In <a href="/wiki/Oman" title="Oman">Oman</a>, it is illegal to provide or use unauthorized VoIP services, to the extent that web sites of unlicensed VoIP providers have been blocked.[<a href="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed">citation needed</a>] Violations may be punished with fines of 50,000 Omani Rial (about 130,317 US dollars), a two-year prison sentence or both. In 2009, police raided 121 Internet cafes throughout the country and arrested 212 people for using or providing VoIP services.<a href="#cite_note-71">[68]</a> <div class="mw-heading mw-heading4"><h4 id="Saudi_Arabia">Saudi Arabia</h4>[<a href="/w/index.php?title=Voice_over_IP&action=edit&section=29" title="Edit section: Saudi Arabia">edit</a>]</div> In September 2017, <a href="/wiki/Saudi_Arabia" title="Saudi Arabia">Saudi Arabia</a> lifted the ban on VoIPs, in an attempt to reduce operational costs and spur digital entrepreneurship.<a href="#cite_note-72">[69]</a><a href="#cite_note-73">[70]</a> <div class="mw-heading mw-heading4"><h4 id="United_Arab_Emirates">United Arab Emirates</h4>[<a href="/w/index.php?title=Voice_over_IP&action=edit&section=30" title="Edit section: United Arab Emirates">edit</a>]</div> In the <a href="/wiki/United_Arab_Emirates" title="United Arab Emirates">United Arab Emirates</a> (UAE), it is illegal to provide or use unauthorized VoIP services. Web sites of unlicensed VoIP providers have been blocked. Some VoIP services such as <a href="/wiki/Skype" title="Skype">Skype</a> were allowed.<a href="#cite_note-74">[71]</a> In January 2018, internet service providers in UAE blocked all VoIP apps, including Skype, but permitting only 2 government-approved VoIP apps (C’ME and BOTIM).<a href="#cite_note-75">[72]</a><a href="#cite_note-76">[73]</a> In opposition, a petition on Change.org garnered over 5000 signatures, in response to which the website was blocked in UAE.<a href="#cite_note-77">[74]</a> On March 24, 2020, the United Arab Emirates loosened restriction on VoIP services earlier prohibited in the country, to ease communication during the <a href="/wiki/COVID-19_pandemic" title="COVID-19 pandemic">COVID-19 pandemic</a>. However, popular instant messaging applications like <a href="/wiki/WhatsApp" title="WhatsApp">WhatsApp</a>, <a href="/wiki/Skype" title="Skype">Skype</a>, and <a href="/wiki/FaceTime" title="FaceTime">FaceTime</a> remained blocked from being used for voice and video calls, constricting residents to use paid services from the country's state-owned telecom providers.<a href="#cite_note-78">[75]</a> <div class="mw-heading mw-heading3"><h3 id="India">India</h3>[<a href="/w/index.php?title=Voice_over_IP&action=edit&section=31" title="Edit section: India">edit</a>]</div> In <a href="/wiki/India" title="India">India</a>, it is legal to use VoIP, but it is illegal to have <a href="/wiki/VoIP_gateway" class="mw-redirect" title="VoIP gateway">VoIP gateways</a> inside India.<a href="#cite_note-TRAI-voip-gateway-79">[76]</a> This effectively means that people who have PCs can use them to make a VoIP call to other computers but not to a normal phone number. Foreign-based VoIP server services are illegal to use in India.<a href="#cite_note-TRAI-voip-gateway-79">[76]</a> Internet telephony is permitted to the ISP with restrictions. The following services are permitted:<a href="#cite_note-80">[77]</a> <ol><li>PC to PC; within or outside India</li> <li>PC / a device / Adapter conforming to the standard of any international agencies like- ITU or IETF etc. in India to PSTN/PLMN abroad.</li> <li>Any device / Adapter conforming to standards of International agencies like ITU, IETF etc. connected to ISP node with static IP address to similar device / Adapter; within or outside India.</li> <li>Except whatever is described in condition (ii) above[<a href="/wiki/Wikipedia:Please_clarify" title="Wikipedia:Please clarify">clarification needed</a>], no other form of Internet Telephony is permitted.</li> <li>In India no Separate Numbering Scheme is provided to the Internet Telephony. Presently the 10 digit Numbering allocation based on E.164 is permitted to the Fixed Telephony, GSM, CDMA wireless service. For Internet Telephony, the numbering scheme shall only conform to IP addressing Scheme of <a href="/wiki/Internet_Assigned_Numbers_Authority" title="Internet Assigned Numbers Authority">Internet Assigned Numbers Authority</a> (IANA). Translation of E.164 number / private number to IP address allotted to any device and vice versa, by ISP to show compliance with IANA numbering scheme is not permitted.</li> <li>The Internet Service Licensee is not permitted to have PSTN/PLMN connectivity. Voice communication to and from a telephone connected to PSTN/PLMN and following E.164 numbering is prohibited in India.</li></ol> <div class="mw-heading mw-heading3"><h3 id="South_Korea">South Korea</h3>[<a href="/w/index.php?title=Voice_over_IP&action=edit&section=32" title="Edit section: South Korea">edit</a>]</div> In <a href="/wiki/South_Korea" title="South Korea">South Korea</a>, only providers registered with the government are authorized to offer VoIP services. Unlike many VoIP providers, most of whom offer flat rates, Korean VoIP services are generally metered and charged at rates similar to terrestrial calling. Foreign VoIP providers encounter high barriers to government registration. This issue came to a head in 2006 when <a href="/wiki/Internet_service_providers" class="mw-redirect" title="Internet service providers">Internet service providers</a> providing personal Internet services by contract to <a href="/wiki/United_States_Forces_Korea" title="United States Forces Korea">United States Forces Korea</a> (USFK) members residing on USFK bases threatened to block off access to VoIP services used by USFK members as an economical way to keep in contact with their families in the United States, on the grounds that the service members' VoIP providers were not registered. A compromise was reached between USFK and Korean telecommunications officials in January 2007, wherein USFK service members arriving in Korea before June 1, 2007, and subscribing to the ISP services provided on base could continue to use their US-based VoIP subscription, but later arrivals are required to use a Korean-based VoIP provider, which by contract will offer pricing similar to the flat rates offered by US VoIP providers.<a href="#cite_note-81">[78]</a> <div class="mw-heading mw-heading3"><h3 id="United_States">United States</h3>[<a href="/w/index.php?title=Voice_over_IP&action=edit&section=33" title="Edit section: United States">edit</a>]</div> In the United States, the FCC requires all interconnected VoIP service providers to comply with requirements comparable to those for traditional telecommunications service providers.<a href="#cite_note-82">[79]</a> VoIP operators in the US are required to support <a href="/wiki/Local_number_portability" title="Local number portability">local number portability</a>; make service accessible to people with disabilities; pay regulatory fees, <a href="/wiki/Universal_service" title="Universal service">universal service</a> contributions, and other mandated payments; and enable law enforcement authorities to conduct surveillance pursuant to the <a href="/wiki/Communications_Assistance_for_Law_Enforcement_Act" title="Communications Assistance for Law Enforcement Act">Communications Assistance for Law Enforcement Act</a> (CALEA). Operators of Interconnected VoIP (fully connected to the PSTN) are mandated to provide <a href="/wiki/Enhanced_911" title="Enhanced 911">Enhanced 911</a> service without special request, provide for customer location updates, clearly disclose any limitations on their E-911 functionality to their consumers, obtain affirmative acknowledgements of these disclosures from all consumers,<a href="#cite_note-83">[80]</a> and may not allow their customers to opt-out of 911 service.<a href="#cite_note-FCC-VoIP-911-84">[81]</a> VoIP operators also receive the benefit of certain US telecommunications regulations, including an entitlement to <a href="/wiki/Interconnection" title="Interconnection">interconnection</a> and exchange of traffic with <a href="/wiki/Incumbent_local_exchange_carrier" title="Incumbent local exchange carrier">incumbent local exchange carriers</a> via wholesale carriers. Providers of nomadic VoIP service—those who are unable to determine the location of their users—are exempt from state telecommunications regulation.<a href="#cite_note-85">[82]</a> Another legal issue that the <a href="/wiki/US_Congress" class="mw-redirect" title="US Congress">US Congress</a> is debating concerns changes to the <a href="/wiki/Foreign_Intelligence_Surveillance_Act" title="Foreign Intelligence Surveillance Act">Foreign Intelligence Surveillance Act</a>. The issue in question is calls between Americans and foreigners. The NSA is not authorized to tap Americans' conversations without a warrant—but the Internet, and specifically VoIP does not draw as clear a line to the location of a caller or a call's recipient as the traditional phone system does. As VoIP's low cost and flexibility convinces more and more organizations to adopt the technology, surveillance for law enforcement agencies becomes more difficult. VoIP technology has also increased federal security concerns because VoIP and similar technologies have made it more difficult for the government to determine where a target is physically located when communications are being intercepted, and that creates a whole set of new legal challenges.<a href="#cite_note-Greenberg-86">[83]</a> <div class="mw-heading mw-heading2"><h2 id="History">History</h2>[<a href="/w/index.php?title=Voice_over_IP&action=edit&section=34" title="Edit section: History">edit</a>]</div> The early developments of <a href="/wiki/Packet_network" class="mw-redirect" title="Packet network">packet network</a> designs by <a href="/wiki/Paul_Baran" title="Paul Baran">Paul Baran</a> and other researchers were motivated by a desire for a higher degree of circuit redundancy and network availability in the face of infrastructure failures than was possible in the circuit-switched networks in <a href="/wiki/Telecommunications" title="Telecommunications">telecommunications</a> of the mid-twentieth century. <a href="/wiki/Danny_Cohen_(engineer)" class="mw-redirect" title="Danny Cohen (engineer)">Danny Cohen</a> first demonstrated a form of <a href="/wiki/Packet_telephony" title="Packet telephony">packet voice</a> in 1973 which was developed into <a href="/wiki/Network_Voice_Protocol" title="Network Voice Protocol">Network Voice Protocol</a> which operated across the early <a href="/wiki/ARPANET" title="ARPANET">ARPANET</a>.<a href="#cite_note-87">[84]</a><a href="#cite_note-88">[85]</a> On the early ARPANET, real-time voice communication was not possible with uncompressed <a href="/wiki/Pulse-code_modulation" title="Pulse-code modulation">pulse-code modulation</a> (PCM) <a href="/wiki/Digital_audio" title="Digital audio">digital speech</a> packets, which had a <a href="/wiki/Bit_rate" title="Bit rate">bit rate</a> of 64 kbps, much greater than the 2.4 kbps <a href="/wiki/Internet_bandwidth" class="mw-redirect" title="Internet bandwidth">bandwidth</a> of early <a href="/wiki/Modems" class="mw-redirect" title="Modems">modems</a>. The solution to this problem was <a href="/wiki/Linear_predictive_coding" title="Linear predictive coding">linear predictive coding</a> (LPC), a <a href="/wiki/Speech_coding" title="Speech coding">speech coding</a> <a href="/wiki/Data_compression" title="Data compression">data compression</a> algorithm that was first proposed by <a href="/wiki/Fumitada_Itakura" title="Fumitada Itakura">Fumitada Itakura</a> of <a href="/wiki/Nagoya_University" title="Nagoya University">Nagoya University</a> and Shuzo Saito of <a href="/wiki/Nippon_Telegraph_and_Telephone" title="Nippon Telegraph and Telephone">Nippon Telegraph and Telephone</a> (NTT) in 1966. LPC was capable of speech compression down to 2.4 kbps, leading to the first successful real-time conversation over ARPANET in 1974, between Culler-Harrison Incorporated in <a href="/wiki/Goleta,_California" title="Goleta, California">Goleta, California</a>, and <a href="/wiki/MIT_Lincoln_Laboratory" title="MIT Lincoln Laboratory">MIT Lincoln Laboratory</a> in <a href="/wiki/Lexington,_Massachusetts" title="Lexington, Massachusetts">Lexington, Massachusetts</a>.<a href="#cite_note-Gray-89">[86]</a> LPC has since been the most widely used speech coding method.<a href="#cite_note-90">[87]</a> <a href="/wiki/Code-excited_linear_prediction" title="Code-excited linear prediction">Code-excited linear prediction</a> (CELP), a type of LPC algorithm, was developed by <a href="/wiki/Manfred_R._Schroeder" title="Manfred R. Schroeder">Manfred R. Schroeder</a> and <a href="/wiki/Bishnu_S._Atal" title="Bishnu S. Atal">Bishnu S. Atal</a> in 1985.<a href="#cite_note-Schroeder-91">[88]</a> LPC algorithms remain an <a href="/wiki/Audio_coding_standard" class="mw-redirect" title="Audio coding standard">audio coding standard</a> in modern VoIP technology.<a href="#cite_note-Gray-89">[86]</a> In the two decades following the 1974 demo, various forms of packet telephony were developed and industry interest groups formed to support the new technologies. Following the termination of the ARPANET project, and expansion of the <a href="/wiki/Internet" title="Internet">Internet</a> for commercial traffic, IP telephony was tested and deemed infeasible for commercial use until the introduction of VocalChat in the early 1990s and then in Feb 1995 the official release of Internet Phone (or iPhone for short) commercial software by <a href="/wiki/VocalTec" title="VocalTec">VocalTec</a>, based on a patent by <a href="/wiki/Lior_Haramaty" title="Lior Haramaty">Lior Haramaty</a> and <a href="/wiki/Alon_Cohen" title="Alon Cohen">Alon Cohen</a>,<a href="#cite_note-92">[89]</a> and followed by other VoIP infrastructure components such as telephony gateways and switching servers. Soon after it became an established area of interest in commercial labs of the major IT concerns, notably at AT&T, where <a href="/wiki/Marian_Croak" title="Marian Croak">Marian Croak</a> and her team filed many patents related to the technology.[<a href="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed">citation needed</a>] By the late 1990s, the first <a href="/wiki/Softswitch" title="Softswitch">softswitches</a> became available, and new protocols, such as <a href="/wiki/H.323" title="H.323">H.323</a>, MGCP and <a href="/wiki/Session_Initiation_Protocol" title="Session Initiation Protocol">Session Initiation Protocol</a> (SIP) gained widespread attention. In the early 2000s, the proliferation of high-bandwidth always-on Internet connections to residential dwellings and businesses, spawned an industry of Internet telephony service providers (ITSPs). The development of open-source telephony software, such as <a href="/wiki/Asterisk_PBX" class="mw-redirect" title="Asterisk PBX">Asterisk PBX</a>, fueled widespread interest and entrepreneurship in voice-over-IP services, applying new Internet technology paradigms, such as <a href="/wiki/Cloud_service" class="mw-redirect" title="Cloud service">cloud services</a> to telephony. <div class="mw-heading mw-heading3"><h3 id="Milestones">Milestones</h3>[<a href="/w/index.php?title=Voice_over_IP&action=edit&section=35" title="Edit section: Milestones">edit</a>]</div> <ul><li>1966: <a href="/wiki/Linear_predictive_coding" title="Linear predictive coding">Linear predictive coding</a> (LPC) proposed by <a href="/wiki/Fumitada_Itakura" title="Fumitada Itakura">Fumitada Itakura</a> of <a href="/wiki/Nagoya_University" title="Nagoya University">Nagoya University</a> and Shuzo Saito of <a href="/wiki/Nippon_Telegraph_and_Telephone" title="Nippon Telegraph and Telephone">Nippon Telegraph and Telephone</a> (NTT).<a href="#cite_note-Gray-89">[86]</a></li> <li>1973: <a href="/wiki/Packet_telephony" title="Packet telephony">Packet voice</a> application by <a href="/wiki/Danny_Cohen_(engineer)" class="mw-redirect" title="Danny Cohen (engineer)">Danny Cohen</a>.</li> <li>1974: The <a href="/wiki/Institute_of_Electrical_and_Electronics_Engineers" title="Institute of Electrical and Electronics Engineers">Institute of Electrical and Electronics Engineers</a> (IEEE) publishes a paper entitled "A Protocol for Packet Network Interconnection".<a href="#cite_note-93">[90]</a></li> <li>1974: <a href="/wiki/Network_Voice_Protocol" title="Network Voice Protocol">Network Voice Protocol</a> (NVP) tested over <a href="/wiki/ARPANET" title="ARPANET">ARPANET</a> in August 1974, carrying barely intelligible 16 kpbs <a href="/wiki/CVSD" class="mw-redirect" title="CVSD">CVSD</a> encoded voice.<a href="#cite_note-Gray-89">[86]</a></li> <li>1974: The first successful real-time conversation over ARPANET achieved using 2.4 kpbs LPC, between Culler-Harrison Incorporated in <a href="/wiki/Goleta,_California" title="Goleta, California">Goleta, California</a>, and <a href="/wiki/MIT_Lincoln_Laboratory" title="MIT Lincoln Laboratory">MIT Lincoln Laboratory</a> in <a href="/wiki/Lexington,_Massachusetts" title="Lexington, Massachusetts">Lexington, Massachusetts</a>.<a href="#cite_note-Gray-89">[86]</a></li> <li>1977: Danny Cohen and <a href="/wiki/Jon_Postel" title="Jon Postel">Jon Postel</a> of the USC <a href="/wiki/Information_Sciences_Institute" title="Information Sciences Institute">Information Sciences Institute</a>, and <a href="/wiki/Vint_Cerf" title="Vint Cerf">Vint Cerf</a> of the Defense Advanced Research Projects Agency (DARPA), agree to separate IP from TCP, and create UDP for carrying real-time traffic.</li> <li>1981: <a href="/wiki/IPv4" title="IPv4">IPv4</a> is described in RFC 791.</li> <li>1985: The <a href="/wiki/National_Science_Foundation" title="National Science Foundation">National Science Foundation</a> commissions the creation of <a href="/wiki/NSFNET" class="mw-redirect" title="NSFNET">NSFNET</a>.<a href="#cite_note-94">[91]</a></li> <li>1985: <a href="/wiki/Code-excited_linear_prediction" title="Code-excited linear prediction">Code-excited linear prediction</a> (CELP), a type of LPC algorithm, developed by <a href="/wiki/Manfred_R._Schroeder" title="Manfred R. Schroeder">Manfred R. Schroeder</a> and <a href="/wiki/Bishnu_S._Atal" title="Bishnu S. Atal">Bishnu S. Atal</a>.<a href="#cite_note-Schroeder-91">[88]</a></li> <li>1986: Proposals from various standards organizations[<a href="/wiki/Wikipedia:Citing_sources" title="Wikipedia:Citing sources">specify</a>] for <a href="/wiki/VoATM" title="VoATM">Voice over ATM</a>, in addition to commercial packet voice products from companies such as <a href="/wiki/StrataCom" title="StrataCom">StrataCom</a></li> <li>1991: Speak Freely, a voice-over-IP application, was released to the public domain.<a href="#cite_note-B2C-95">[92]</a><a href="#cite_note-McCraw-96">[93]</a></li> <li>1992: The Frame Relay Forum conducts development of standards for voice over <a href="/wiki/Frame_Relay" title="Frame Relay">Frame Relay</a>.</li> <li>1992: <a href="/wiki/InSoft_Inc." title="InSoft Inc.">InSoft Inc.</a> announces and launches its desktop conferencing product Communique, which includes VoIP and video.<a href="#cite_note-B2C-95">[92]</a><a href="#cite_note-Inc1992-97">[94]</a> The company is credited with developing the first generation of commercial, US-based VoIP, Internet media streaming and real-time Internet telephony/collaborative software and standards that would provide the basis for the Real Time Streaming Protocol (RTSP) standard.[<a href="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed">citation needed</a>]</li> <li>1993 Release of VocalChat, a commercial packet network PC voice communication software from <a href="/wiki/VocalTec" title="VocalTec">VocalTec</a>.[<a href="/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed">citation needed</a>]</li> <li>1994: MTALK, a freeware LAN VoIP application for <a href="/wiki/Linux" title="Linux">Linux</a><a href="#cite_note-98">[95]</a></li> <li>1995: <ul><li><a href="/wiki/VocalTec" title="VocalTec">VocalTec</a> releases Internet Phone commercial Internet phone software.<a href="#cite_note-99">[96]</a><a href="#cite_note-100">[97]</a></li> <li><a href="/wiki/Intel" title="Intel">Intel</a>, <a href="/wiki/Microsoft" title="Microsoft">Microsoft</a> and <a href="/wiki/Radvision" title="Radvision">Radvision</a> initiated standardization activities for VoIP communications system.<a href="#cite_note-101">[98]</a></li></ul></li> <li>1996: <ul><li><a href="/wiki/ITU-T" title="ITU-T">ITU-T</a> begins development of standards for the transmission and signaling of voice communications over Internet Protocol networks with the <a href="/wiki/H.323" title="H.323">H.323</a> standard.<a href="#cite_note-102">[99]</a></li> <li>US telecommunications companies petition the US Congress to ban Internet phone technology.<a href="#cite_note-103">[100]</a></li> <li><a href="/wiki/G.729" title="G.729">G.729</a> speech codec introduced, using CELP (LPC) algorithm.<a href="#cite_note-104">[101]</a></li></ul></li> <li>1997: <a href="/wiki/Level_3_Communications" title="Level 3 Communications">Level 3</a> began development of its first <a href="/wiki/Softswitch" title="Softswitch">softswitch</a>, a term they coined in 1998.<a href="#cite_note-ilocus_softswitch-105">[102]</a></li> <li>1999: <ul><li>The <a href="/wiki/Session_Initiation_Protocol" title="Session Initiation Protocol">Session Initiation Protocol</a> (SIP) specification RFC 2543 is released.<a href="#cite_note-106">[103]</a></li> <li><a href="/wiki/Mark_Spencer_(computer_engineer)" title="Mark Spencer (computer engineer)">Mark Spencer</a> of <a href="/wiki/Digium" title="Digium">Digium</a> develops <a href="/wiki/Asterisk_(PBX)" title="Asterisk (PBX)">Asterisk</a>, the first <a href="/wiki/Open_source_software" class="mw-redirect" title="Open source software">open source</a> <a href="/wiki/Private_branch_exchange" class="mw-redirect" title="Private branch exchange">private branch exchange</a> (PBX) software.<a href="#cite_note-107">[104]</a></li> <li>A <a href="/wiki/Discrete_cosine_transform" title="Discrete cosine transform">discrete cosine transform</a> (DCT) variant called the <a href="/wiki/Modified_discrete_cosine_transform" title="Modified discrete cosine transform">modified discrete cosine transform</a> (MDCT) is adopted for the <a href="/wiki/Siren_(codec)" title="Siren (codec)">Siren</a> codec, used in the <a href="/wiki/G.722.1" title="G.722.1">G.722.1</a> <a href="/wiki/Wideband_audio" title="Wideband audio">wideband audio</a> coding standard.<a href="#cite_note-Hersent-108">[105]</a><a href="#cite_note-Lutzky-109">[106]</a></li> <li>The MDCT is adapted into the LD-MDCT algorithm, used in the <a href="/wiki/AAC-LD" title="AAC-LD">AAC-LD</a> standard.<a href="#cite_note-Schnell-110">[107]</a></li></ul></li> <li>2001: <a href="/wiki/INOC-DBA" title="INOC-DBA">INOC-DBA</a>, the first inter-provider <a href="/wiki/Session_Initiation_Protocol" title="Session Initiation Protocol">SIP</a> network is deployed; this is also the first voice network to reach all seven continents.<a href="#cite_note-111">[108]</a></li> <li>2003: <a href="/wiki/Skype" title="Skype">Skype</a> released in August 2003. This was the creation of Niklas Zennström and Janus Friis, in cooperation with four Estonian developers. It quickly became a popular program that helped democratize VoIP.</li> <li>2004: Commercial VoIP service providers proliferate.</li> <li>2005: <a href="/wiki/PhoneGnome" title="PhoneGnome">PhoneGnome</a> VoIP service is launched by TelEvolution, Inc. of California.<a href="#cite_note-112">[109]</a></li> <li>2006: <a href="/wiki/G.729.1" title="G.729.1">G.729.1</a> wideband codec introduced, using MDCT and CELP (LPC) algorithms.<a href="#cite_note-Nagireddi-113">[110]</a></li> <li>2007: VoIP device manufacturers and sellers boom in Asia, specifically in the Philippines where many families of overseas workers reside.<a href="#cite_note-114">[111]</a></li> <li>2009: <a href="/wiki/SILK" title="SILK">SILK</a> codec introduced, using LPC algorithm,<a href="#cite_note-IETF79-115">[112]</a> and used for voice calling in <a href="/wiki/Skype" title="Skype">Skype</a>.<a href="#cite_note-116">[113]</a></li> <li>2010: <a href="/wiki/Apple_Inc." title="Apple Inc.">Apple</a> introduces <a href="/wiki/FaceTime" title="FaceTime">FaceTime</a>, which uses the LD-MDCT-based AAC-LD codec.<a href="#cite_note-AppleInsider_standards_1-117">[114]</a></li> <li>2011: <ul><li>Rise of <a href="/wiki/WebRTC" title="WebRTC">WebRTC</a> technology which supports VoIP directly in browsers.</li> <li><a href="/wiki/CELT" title="CELT">CELT</a> codec introduced, using MDCT algorithm.<a href="#cite_note-presentation-118">[115]</a></li></ul></li> <li>2012: <a href="/wiki/Opus_(audio_format)" title="Opus (audio format)">Opus</a> codec introduced, using MDCT and LPC algorithms.<a href="#cite_note-Valin-119">[116]</a></li></ul> <div class="mw-heading mw-heading2"><h2 id="See_also">See also</h2>[<a href="/w/index.php?title=Voice_over_IP&action=edit&section=36" title="Edit section: See also">edit</a>]</div> <style data-mw-deduplicate="TemplateStyles:r1184024115">.mw-parser-output .div-col{margin-top:0.3em;column-width:30em}.mw-parser-output .div-col-small{font-size:90%}.mw-parser-output .div-col-rules{column-rule:1px solid #aaa}.mw-parser-output .div-col dl,.mw-parser-output .div-col ol,.mw-parser-output .div-col ul{margin-top:0}.mw-parser-output .div-col li,.mw-parser-output .div-col dd{page-break-inside:avoid;break-inside:avoid-column}</style><div class="div-col" style="column-width: 20em;"> <ul><li><a href="/wiki/Audio_over_IP" title="Audio over IP">Audio over IP</a></li> <li><a href="/wiki/Call-through_telecom" title="Call-through telecom">Call-through telecom</a></li> <li><a href="/wiki/Comparison_of_audio_network_protocols" title="Comparison of audio network protocols">Comparison of audio network protocols</a></li> <li><a href="/wiki/Comparison_of_VoIP_software" title="Comparison of VoIP software">Comparison of VoIP software</a></li> <li><a href="/wiki/Differentiated_services" title="Differentiated services">Differentiated services</a></li> <li><a href="/wiki/High_Bit_Rate_Media_Transport" class="mw-redirect" title="High Bit Rate Media Transport">High Bit Rate Media Transport</a></li> <li><a href="/wiki/Integrated_services" title="Integrated services">Integrated services</a></li> <li><a href="/wiki/Internet_fax" title="Internet fax">Internet fax</a></li> <li><a href="/wiki/IP_Multimedia_Subsystem" title="IP Multimedia Subsystem">IP Multimedia Subsystem</a></li> <li><a href="/wiki/List_of_VoIP_companies" title="List of VoIP companies">List of VoIP companies</a></li> <li><a href="/wiki/Mobile_VoIP" title="Mobile VoIP">Mobile VoIP</a></li> <li><a href="/wiki/RTP_payload_formats" title="RTP payload formats">RTP payload formats</a></li> <li><a href="/wiki/SIP_trunking" title="SIP trunking">SIP trunking</a></li> <li><a href="/wiki/UNIStim" title="UNIStim">UNIStim</a></li> <li><a href="/wiki/Voice_over_LTE" title="Voice over LTE">Voice over LTE</a></li> <li><a href="/wiki/VoiceXML" title="VoiceXML">VoiceXML</a></li> <li><a href="/wiki/VoIP_VPN" title="VoIP VPN">VoIP VPN</a></li> <li><a href="/wiki/VoIP_recording" title="VoIP recording">VoIP recording</a></li></ul> </div> <div class="mw-heading mw-heading2"><h2 id="Notes">Notes</h2>[<a href="/w/index.php?title=Voice_over_IP&action=edit&section=37" title="Edit section: Notes">edit</a>]</div> <style data-mw-deduplicate="TemplateStyles:r1239543626">.mw-parser-output .reflist{margin-bottom:0.5em;list-style-type:decimal}@media screen{.mw-parser-output .reflist{font-size:90%}}.mw-parser-output .reflist .references{font-size:100%;margin-bottom:0;list-style-type:inherit}.mw-parser-output .reflist-columns-2{column-width:30em}.mw-parser-output .reflist-columns-3{column-width:25em}.mw-parser-output .reflist-columns{margin-top:0.3em}.mw-parser-output .reflist-columns ol{margin-top:0}.mw-parser-output .reflist-columns li{page-break-inside:avoid;break-inside:avoid-column}.mw-parser-output .reflist-upper-alpha{list-style-type:upper-alpha}.mw-parser-output .reflist-upper-roman{list-style-type:upper-roman}.mw-parser-output .reflist-lower-alpha{list-style-type:lower-alpha}.mw-parser-output .reflist-lower-greek{list-style-type:lower-greek}.mw-parser-output .reflist-lower-roman{list-style-type:lower-roman}</style><div class="reflist reflist-lower-alpha"> <div class="mw-references-wrap"><ol class="references"> <li id="cite_note-2"><a href="#cite_ref-2">^</a> Variously pronounced as individual letters, V-O-I-P, or as a word, <a href="/wiki/Help:IPA/English" title="Help:IPA/English">/vɔɪp/</a> (<a href="/wiki/Help:Pronunciation_respelling_key" title="Help:Pronunciation respelling key">VOYP</a>)<a href="#cite_note-1">[1]</a> </li> <li id="cite_note-26"><a href="#cite_ref-26">^</a> IP networks may also be more prone to <a href="/wiki/DoS_attacks" class="mw-redirect" title="DoS attacks">DoS attacks</a> that cause congestion.<a href="#cite_note-25">[24]</a> </li> <li id="cite_note-32"><a href="#cite_ref-32">^</a> Technologies such as <a href="/wiki/802.3ah" class="mw-redirect" title="802.3ah">802.3ah</a> can be used for DSL connectivity without using ATM. </li> </ol></div></div> <div class="mw-heading mw-heading2"><h2 id="References">References</h2>[<a href="/w/index.php?title=Voice_over_IP&action=edit&section=38" title="Edit section: References">edit</a>]</div> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1239543626"><div class="reflist"> <div class="mw-references-wrap mw-references-columns"><ol class="references"> <li id="cite_note-1"><a href="#cite_ref-1">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation encyclopaedia cs1"><a rel="nofollow" class="external text" href="http://dictionary.cambridge.org/pronunciation/british/voip">"VoIP"</a>. Cambridge Dictionaries Online.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=bookitem&rft.atitle=VoIP&rft.btitle=Cambridge+Dictionaries+Online&rft_id=http%3A%2F%2Fdictionary.cambridge.org%2Fpronunciation%2Fbritish%2Fvoip&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-Arora_2023_t525-3"><a href="#cite_ref-Arora_2023_t525_3-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFArora1999" class="citation web cs1">Arora, Rakesh (November 23, 1999). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20240119062648/https://www.cse.wustl.edu/~jain/cis788-99/ftp/voip_protocols/">"Voice Over IP : Protocols and Standards"</a>. cse.wustl.edu. Archived from <a rel="nofollow" class="external text" href="https://www.cse.wustl.edu/~jain/cis788-99/ftp/voip_protocols/">the original</a> on January 19, 2024. Retrieved March 19, 2024. <q>Voice over IP (VOIP) uses the Internet Protocol (IP) to transmit voice as packets over an IP network. ...in the Internet, anyone can capture the packets meant for someone else. Some security can be provided by using encryption and tunneling. The common tunneling protocol used is <a href="/wiki/Layer_2_Tunneling_Protocol" title="Layer 2 Tunneling Protocol">Layer 2 Tunneling Protocol</a> and the common encryption mechanism used is <a href="/wiki/Secure_Sockets_Layer" class="mw-redirect" title="Secure Sockets Layer">Secure Sockets Layer</a> (SSL).</q></cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=cse.wustl.edu&rft.atitle=Voice+Over+IP+%3A+Protocols+and+Standards&rft.date=1999-11-23&rft.aulast=Arora&rft.aufirst=Rakesh&rft_id=https%3A%2F%2Fwww.cse.wustl.edu%2F~jain%2Fcis788-99%2Fftp%2Fvoip_protocols%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-4"><a href="#cite_ref-4">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://googletalk.blogspot.com/2006/01/xmpp-federation.html">"XMPP Federation"</a>. Google Talkabout. 2006. Retrieved May 11, 2012.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=XMPP+Federation&rft.pub=Google+Talkabout&rft.date=2006&rft_id=http%3A%2F%2Fgoogletalk.blogspot.com%2F2006%2F01%2Fxmpp-federation.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-EBSCOhost-5"><a href="#cite_ref-EBSCOhost_5-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFBooth2010" class="citation journal cs1">Booth, C (2010). "Chapter 2: IP Phones, Software VoIP, and Integrated and Mobile VoIP". Library Technology Reports. 46 (5): 11–19.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Library+Technology+Reports&rft.atitle=Chapter+2%3A+IP+Phones%2C+Software+VoIP%2C+and+Integrated+and+Mobile+VoIP&rft.volume=46&rft.issue=5&rft.pages=11-19&rft.date=2010&rft.aulast=Booth&rft.aufirst=C&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-6"><a href="#cite_ref-6">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFWright2023" class="citation web cs1">Wright, Arol (October 12, 2023). <a rel="nofollow" class="external text" href="https://www.makeuseof.com/what-is-vo5g-vonr/">"What Is Vo5G (VoNR) and How Does It Compare to VoLTE?"</a>. MUO. Retrieved November 30, 2024.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=MUO&rft.atitle=What+Is+Vo5G+%28VoNR%29+and+How+Does+It+Compare+to+VoLTE%3F&rft.date=2023-10-12&rft.aulast=Wright&rft.aufirst=Arol&rft_id=https%3A%2F%2Fwww.makeuseof.com%2Fwhat-is-vo5g-vonr%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-7"><a href="#cite_ref-7">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.3gpp.org/technologies/volte-vonr">"Communication services (VoLTE/VoNR)"</a>. www.3gpp.org. Retrieved November 30, 2024.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=www.3gpp.org&rft.atitle=Communication+services+%28VoLTE%2FVoNR%29&rft_id=https%3A%2F%2Fwww.3gpp.org%2Ftechnologies%2Fvolte-vonr&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-8"><a href="#cite_ref-8">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.techtarget.com/searchnetworking/definition/voice-over-LTE-VoLTE">"What is Voice Over LTE (VoLTE)? Definition from WhatIs.com"</a>. Search Networking. Retrieved November 30, 2024.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=Search+Networking&rft.atitle=What+is+Voice+Over+LTE+%28VoLTE%29%3F+Definition+from+WhatIs.com&rft_id=https%3A%2F%2Fwww.techtarget.com%2Fsearchnetworking%2Fdefinition%2Fvoice-over-LTE-VoLTE&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-9"><a href="#cite_ref-9">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.voicenter.com/blog/5g-VoNR">"What Is 5G VoNR | Unveiling the Future of Wireless Communication"</a>. www.voicenter.com. Retrieved November 30, 2024.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=www.voicenter.com&rft.atitle=What+Is+5G+VoNR+%7C+Unveiling+the+Future+of+Wireless+Communication&rft_id=https%3A%2F%2Fwww.voicenter.com%2Fblog%2F5g-VoNR&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-10"><a href="#cite_ref-10">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMontazerolghaemMoghaddamLeon-Garcia2018" class="citation journal cs1">Montazerolghaem, Ahmadreza; Moghaddam, Mohammad Hossein Yaghmaee; Leon-Garcia, Alberto (March 2018). <a rel="nofollow" class="external text" href="https://ieeexplore.ieee.org/document/8012472">"OpenSIP: Toward Software-Defined SIP Networking"</a>. IEEE Transactions on Network and Service Management. 15 (1): 184–199. <a href="/wiki/ArXiv_(identifier)" class="mw-redirect" title="ArXiv (identifier)">arXiv</a>:<a rel="nofollow" class="external text" href="https://arxiv.org/abs/1709.01320">1709.01320</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1109%2FTNSM.2017.2741258">10.1109/TNSM.2017.2741258</a>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/1932-4537">1932-4537</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:3873601">3873601</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=IEEE+Transactions+on+Network+and+Service+Management&rft.atitle=OpenSIP%3A+Toward+Software-Defined+SIP+Networking&rft.volume=15&rft.issue=1&rft.pages=184-199&rft.date=2018-03&rft_id=info%3Aarxiv%2F1709.01320&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A3873601%23id-name%3DS2CID&rft.issn=1932-4537&rft_id=info%3Adoi%2F10.1109%2FTNSM.2017.2741258&rft.aulast=Montazerolghaem&rft.aufirst=Ahmadreza&rft.au=Moghaddam%2C+Mohammad+Hossein+Yaghmaee&rft.au=Leon-Garcia%2C+Alberto&rft_id=https%3A%2F%2Fieeexplore.ieee.org%2Fdocument%2F8012472&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-11"><a href="#cite_ref-11">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.cisco.com/en/US/tech/tk652/tk701/technologies_white_paper09186a0080092947.shtml">"H.323 and SIP Integration"</a>. Retrieved January 24, 2020.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=H.323+and+SIP+Integration&rft_id=https%3A%2F%2Fwww.cisco.com%2Fen%2FUS%2Ftech%2Ftk652%2Ftk701%2Ftechnologies_white_paper09186a0080092947.shtml&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-12"><a href="#cite_ref-12">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFOmar" class="citation web cs1">Omar, Ahmed. <a rel="nofollow" class="external text" href="https://www.academia.edu/39621401">"Voice OVER IP (VOIP)"</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Voice+OVER+IP+%28VOIP%29&rft.aulast=Omar&rft.aufirst=Ahmed&rft_id=https%3A%2F%2Fwww.academia.edu%2F39621401&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-13"><a href="#cite_ref-13">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.fcc.gov/general/voice-over-internet-protocol-voip">"Voice Over Internet Protocol (VoIP)"</a>. Federal Communications Commission. November 18, 2010. Retrieved July 19, 2022.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=Federal+Communications+Commission&rft.atitle=Voice+Over+Internet+Protocol+%28VoIP%29&rft.date=2010-11-18&rft_id=https%3A%2F%2Fwww.fcc.gov%2Fgeneral%2Fvoice-over-internet-protocol-voip&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-14"><a href="#cite_ref-14">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://mendocinobroadband.org/wp-content/uploads/VoIP-v77.pdf">"VoIP (v77)"</a> (PDF).</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=VoIP+%28v77%29&rft_id=https%3A%2F%2Fmendocinobroadband.org%2Fwp-content%2Fuploads%2FVoIP-v77.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-15"><a href="#cite_ref-15">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20110809025050/http://www.eetimes.com/electronics-news/4052152/WIRELESS-Carriers-look-to-IP-for-back-haul">"WIRELESS: Carriers look to IP for backhaul"</a>. www.eetimes.com. EE Times. Archived from the original on August 9, 2011. Retrieved April 8, 2015.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=www.eetimes.com&rft.atitle=WIRELESS%3A+Carriers+look+to+IP+for+backhaul&rft_id=http%3A%2F%2Fwww.eetimes.com%2Felectronics-news%2F4052152%2FWIRELESS-Carriers-look-to-IP-for-back-haul&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"><code class="cs1-code">{{<a href="/wiki/Template:Cite_web" title="Template:Cite web">cite web</a>}}</code>: CS1 maint: unfit URL (<a href="/wiki/Category:CS1_maint:_unfit_URL" title="Category:CS1 maint: unfit URL">link</a>) </li> <li id="cite_note-16"><a href="#cite_ref-16">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20060217064211/http://www.totaltele.com/View.aspx?ID=77588&t=4">"Mobile's IP challenge"</a>. www.totaltele.com. Total Telecom Online. Archived from the original on February 17, 2006. Retrieved April 8, 2015.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=www.totaltele.com&rft.atitle=Mobile%27s+IP+challenge&rft_id=http%3A%2F%2Fwww.totaltele.com%2FView.aspx%3FID%3D77588%26t%3D4&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"><code class="cs1-code">{{<a href="/wiki/Template:Cite_web" title="Template:Cite web">cite web</a>}}</code>: CS1 maint: unfit URL (<a href="/wiki/Category:CS1_maint:_unfit_URL" title="Category:CS1 maint: unfit URL">link</a>) </li> <li id="cite_note-17"><a href="#cite_ref-17">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.callcentric.com/support/device/android/sip_client">"Android SIP Client"</a>. Retrieved January 30, 2018.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Android+SIP+Client&rft_id=https%3A%2F%2Fwww.callcentric.com%2Fsupport%2Fdevice%2Fandroid%2Fsip_client&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-18"><a href="#cite_ref-18">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.lifewire.com/apps-for-sip-on-android-3426471">"Learn to Make Free or Inexpensive Calls Using SIP on Android"</a>. Retrieved January 30, 2018.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Learn+to+Make+Free+or+Inexpensive+Calls+Using+SIP+on+Android&rft_id=https%3A%2F%2Fwww.lifewire.com%2Fapps-for-sip-on-android-3426471&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-19"><a href="#cite_ref-19">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMichael_Dosch_and_Steve_Church" class="citation web cs1">Michael Dosch and Steve Church. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20111007231611/http://www.axiaaudio.com/tech/voip/default.htm">"VoIP in the Broadcast Studio"</a>. Axia Audio. Archived from <a rel="nofollow" class="external text" href="http://www.axiaaudio.com/tech/voip/default.htm">the original</a> on October 7, 2011. Retrieved June 21, 2011.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=VoIP+in+the+Broadcast+Studio&rft.pub=Axia+Audio&rft.au=Michael+Dosch+and+Steve+Church&rft_id=http%3A%2F%2Fwww.axiaaudio.com%2Ftech%2Fvoip%2Fdefault.htm&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-20"><a href="#cite_ref-20">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFJackson2009" class="citation web cs1">Jackson, William (May 27, 2009). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20110728164137/http://gcn.com/Articles/2009/06/01/SSA-VOIP-implementation.aspx?s=gcndaily_280509&Page=1">"SSA goes big on VOIP"</a>. Government Computer News. Archived from <a rel="nofollow" class="external text" href="http://gcn.com/Articles/2009/06/01/SSA-VOIP-implementation.aspx?s=gcndaily_280509&Page=1">the original</a> on July 28, 2011. Retrieved May 28, 2009.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=SSA+goes+big+on+VOIP&rft.pub=Government+Computer+News&rft.date=2009-05-27&rft.aulast=Jackson&rft.aufirst=William&rft_id=http%3A%2F%2Fgcn.com%2FArticles%2F2009%2F06%2F01%2FSSA-VOIP-implementation.aspx%3Fs%3Dgcndaily_280509%26Page%3D1&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-21"><a href="#cite_ref-21">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.govtech.com/gt/275677">"Social Security to Build "World's Largest VOIP""</a>. Government Technology. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20090602094711/http://www.govtech.com/gt/275677">Archived</a> from the original on June 2, 2009. Retrieved May 29, 2009.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Social+Security+to+Build+%22World%27s+Largest+VOIP%22&rft.pub=Government+Technology&rft_id=http%3A%2F%2Fwww.govtech.com%2Fgt%2F275677&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-Korzeniowski-22">^ <a href="#cite_ref-Korzeniowski_22-0">a</a> <a href="#cite_ref-Korzeniowski_22-1">b</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFKorzeniowski2009" class="citation journal cs1">Korzeniowski, Peter (January 8, 2009). <a rel="nofollow" class="external text" href="https://www.forbes.com/2009/01/08/small-business-voip-ent-tech-cx_bm_0108bmightytech09.html/">"Three Technologies You Need In 2009"</a>. Forbes. Retrieved March 2, 2009.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Forbes&rft.atitle=Three+Technologies+You+Need+In+2009&rft.date=2009-01-08&rft.aulast=Korzeniowski&rft.aufirst=Peter&rft_id=https%3A%2F%2Fwww.forbes.com%2F2009%2F01%2F08%2Fsmall-business-voip-ent-tech-cx_bm_0108bmightytech09.html%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-23"><a href="#cite_ref-23">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFCallahan2008" class="citation journal cs1">Callahan, Renee (December 9, 2008). <a rel="nofollow" class="external text" href="https://www.forbes.com/2008/12/09/skype-vonage-ringcentral_leadership_clayton_in_rc_1209claytonchristensen_inl.html">"Businesses Move To Voice-Over-IP"</a>. Forbes. Retrieved March 3, 2009.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Forbes&rft.atitle=Businesses+Move+To+Voice-Over-IP&rft.date=2008-12-09&rft.aulast=Callahan&rft.aufirst=Renee&rft_id=https%3A%2F%2Fwww.forbes.com%2F2008%2F12%2F09%2Fskype-vonage-ringcentral_leadership_clayton_in_rc_1209claytonchristensen_inl.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-24"><a href="#cite_ref-24">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.skype.com/business/allfeatures/3skypephone/">"Skype For Business"</a>. skype.com. Retrieved March 16, 2009.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Skype+For+Business&rft.pub=skype.com&rft_id=http%3A%2F%2Fwww.skype.com%2Fbusiness%2Fallfeatures%2F3skypephone%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-25"><a href="#cite_ref-25">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.continuitycentral.com/feature074.htm">"VoIP - Vulnerability over Internet Protocol?"</a>. www.continuitycentral.com.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=www.continuitycentral.com&rft.atitle=VoIP+-+Vulnerability+over+Internet+Protocol%3F&rft_id=https%3A%2F%2Fwww.continuitycentral.com%2Ffeature074.htm&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-cisco-27">^ <a href="#cite_ref-cisco_27-0">a</a> <a href="#cite_ref-cisco_27-1">b</a> <a href="#cite_ref-cisco_27-2">c</a> <a href="#cite_ref-cisco_27-3">d</a> <a href="#cite_ref-cisco_27-4">e</a> <a href="#cite_ref-cisco_27-5">f</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.cisco.com/en/US/docs/ios/solutions_docs/qos_solutions/QoSVoIP/QoSVoIP.html">"Quality of Service for Voice over IP"</a>. Retrieved May 3, 2011.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Quality+of+Service+for+Voice+over+IP&rft_id=http%3A%2F%2Fwww.cisco.com%2Fen%2FUS%2Fdocs%2Fios%2Fsolutions_docs%2Fqos_solutions%2FQoSVoIP%2FQoSVoIP.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-28"><a href="#cite_ref-28">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFPrabhakarRastogi,_R.Thotton,_M2005" class="citation journal cs1">Prabhakar, G.; Rastogi, R.; Thotton, M (2005). "OSS Architecture & Requirements for VoIP Networks". Bell Labs Technical Journal. 10 (1): 31–45. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1002%2Fbltj.20077">10.1002/bltj.20077</a>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/1089-7089">1089-7089</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:12336090">12336090</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Bell+Labs+Technical+Journal&rft.atitle=OSS+Architecture+%26+Requirements+for+VoIP+Networks&rft.volume=10&rft.issue=1&rft.pages=31-45&rft.date=2005&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A12336090%23id-name%3DS2CID&rft.issn=1089-7089&rft_id=info%3Adoi%2F10.1002%2Fbltj.20077&rft.aulast=Prabhakar&rft.aufirst=G.&rft.au=Rastogi%2C+R.&rft.au=Thotton%2C+M&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-ciscoPacket-29">^ <a href="#cite_ref-ciscoPacket_29-0">a</a> <a href="#cite_ref-ciscoPacket_29-1">b</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.cisco.com/en/US/docs/ios/solutions_docs/qos_solutions/QoSVoIP/QoSVoIP.html#wp1029054">"Quality of Service for Voice over IP"</a>. Retrieved May 3, 2011.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Quality+of+Service+for+Voice+over+IP&rft_id=http%3A%2F%2Fwww.cisco.com%2Fen%2FUS%2Fdocs%2Fios%2Fsolutions_docs%2Fqos_solutions%2FQoSVoIP%2FQoSVoIP.html%23wp1029054&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-30"><a href="#cite_ref-30">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.researchgate.net/publication/220429109_Optical_Packet_Buffers_for_Backbone_Internet_Routers">"Optical Packet Buffers for Backbone Internet Routers | Request PDF"</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Optical+Packet+Buffers+for+Backbone+Internet+Routers+%7C+Request+PDF&rft_id=https%3A%2F%2Fwww.researchgate.net%2Fpublication%2F220429109_Optical_Packet_Buffers_for_Backbone_Internet_Routers&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-:1-31"><a href="#cite_ref-:1_31-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFCaceres" class="citation cs1">Caceres, Ramon. <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc3611">RTP Control Protocol Extended Reports (RTCP XR)</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.17487%2FRFC3611">10.17487/RFC3611</a>. <a href="/wiki/Request_for_Comments" title="Request for Comments">RFC</a> <a rel="nofollow" class="external text" href="https://datatracker.ietf.org/doc/html/rfc3611">3611</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=RTP+Control+Protocol+Extended+Reports+%28RTCP+XR%29&rft_id=info%3Adoi%2F10.17487%2FRFC3611&rft.aulast=Caceres&rft.aufirst=Ramon&rft_id=https%3A%2F%2Fdatatracker.ietf.org%2Fdoc%2Fhtml%2Frfc3611&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-33"><a href="#cite_ref-33">^</a> CableLabs, PacketCable Residential SIP Telephony Feature Definition, Technical Report, PKT-TR-RST-V03-071106 (2007) </li> <li id="cite_note-34"><a href="#cite_ref-34">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.it-innovations.ae/iit005/proceedings/articles/H_3_IIT05_Amin.pdf">"VoIP performance measurement using QoS parameters"</a> (PDF). A.H.Muhamad Amin. August 14, 2016.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=VoIP+performance+measurement+using+QoS+parameters&rft.pub=A.H.Muhamad+Amin&rft.date=2016-08-14&rft_id=http%3A%2F%2Fwww.it-innovations.ae%2Fiit005%2Fproceedings%2Farticles%2FH_3_IIT05_Amin.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-35"><a href="#cite_ref-35">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.wseas.us/e-library/transactions/computers/2010/88-134.pdf">"Methodology for SIP Infrastructure Performance Testing"</a> (PDF). Miroslav Voznak, Jan Rozhon. August 14, 2016.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Methodology+for+SIP+Infrastructure+Performance+Testing&rft.pub=Miroslav+Voznak%2C+Jan+Rozhon&rft.date=2016-08-14&rft_id=http%3A%2F%2Fwww.wseas.us%2Fe-library%2Ftransactions%2Fcomputers%2F2010%2F88-134.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-36"><a href="#cite_ref-36">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.vmware.com/content/dam/digitalmarketing/vmware/en/pdf/techpaper/voip-performance-vsphere5-white-paper.pdf">"Voice over IP (VoIP) Performance Evaluation on VMware vSphere® 5"</a> (PDF). VMware. August 14, 2016.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Voice+over+IP+%28VoIP%29+Performance+Evaluation+on+VMware+vSphere%C2%AE+5&rft.pub=VMware&rft.date=2016-08-14&rft_id=http%3A%2F%2Fwww.vmware.com%2Fcontent%2Fdam%2Fdigitalmarketing%2Fvmware%2Fen%2Fpdf%2Ftechpaper%2Fvoip-performance-vsphere5-white-paper.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-37"><a href="#cite_ref-37">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://startrinity.com/VoIP/TestingSipPbxSoftswitchServer.aspx">"Performance and Stress Testing of SIP Servers, Clients and IP Networks"</a>. StarTrinity. August 13, 2016.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Performance+and+Stress+Testing+of+SIP+Servers%2C+Clients+and+IP+Networks&rft.pub=StarTrinity&rft.date=2016-08-13&rft_id=http%3A%2F%2Fstartrinity.com%2FVoIP%2FTestingSipPbxSoftswitchServer.aspx&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-38"><a href="#cite_ref-38">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.ixiacom.com/sites/default/files/resources/whitepaper/voip-whitepaper.pdf">"Testing Voice over IP (VolP) Networks"</a> (PDF). IXIA. August 14, 2016.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Testing+Voice+over+IP+%28VolP%29+Networks&rft.pub=IXIA&rft.date=2016-08-14&rft_id=https%3A%2F%2Fwww.ixiacom.com%2Fsites%2Fdefault%2Ffiles%2Fresources%2Fwhitepaper%2Fvoip-whitepaper.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-39"><a href="#cite_ref-39">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20121111022027/http://www.ixc.ua/importance-of-softswitch-voip-technology-properly">"Importance of Softswitch VoIP Technology"</a>. ixc.ua. May 20, 2011. Archived from the original on November 11, 2012. Retrieved October 4, 2012.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Importance+of+Softswitch+VoIP+Technology&rft.pub=ixc.ua&rft.date=2011-05-20&rft_id=http%3A%2F%2Fwww.ixc.ua%2Fimportance-of-softswitch-voip-technology-properly&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"><code class="cs1-code">{{<a href="/wiki/Template:Cite_web" title="Template:Cite web">cite web</a>}}</code>: CS1 maint: bot: original URL status unknown (<a href="/wiki/Category:CS1_maint:_bot:_original_URL_status_unknown" title="Category:CS1 maint: bot: original URL status unknown">link</a>) </li> <li id="cite_note-40"><a href="#cite_ref-40">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.packetizer.com/rfc/rfc3824/">"RFC 3824– Using E.164 numbers with the Session Initiation Protocol (SIP)"</a>. The Internet Society. June 1, 2004. Retrieved January 21, 2009.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=RFC+3824%E2%80%93+Using+E.164+numbers+with+the+Session+Initiation+Protocol+%28SIP%29&rft.pub=The+Internet+Society&rft.date=2004-06-01&rft_id=http%3A%2F%2Fwww.packetizer.com%2Frfc%2Frfc3824%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-41"><a href="#cite_ref-41">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.skype.com/help/guides/createskypename_windows/">"Create a Skype Name"</a>. Skype. Retrieved January 21, 2009.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Create+a+Skype+Name&rft.pub=Skype&rft_id=http%3A%2F%2Fwww.skype.com%2Fhelp%2Fguides%2Fcreateskypename_windows%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-42"><a href="#cite_ref-42">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.packetizer.com/rfc/rfc3969/">"RFC 3969– The Internet Assigned Number Authority (IANA) Uniform Resource Identifier (URI) Parameter Registry for the Session Initiation Protocol (SIP)"</a>. The Internet Society. December 1, 2004. Retrieved January 21, 2009.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=RFC+3969%E2%80%93+The+Internet+Assigned+Number+Authority+%28IANA%29+Uniform+Resource+Identifier+%28URI%29+Parameter+Registry+for+the+Session+Initiation+Protocol+%28SIP%29&rft.pub=The+Internet+Society&rft.date=2004-12-01&rft_id=http%3A%2F%2Fwww.packetizer.com%2Frfc%2Frfc3969%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-43"><a href="#cite_ref-43">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.skype.com/allfeatures/onlinenumber/">"Your personal online number"</a>. Skype. Retrieved January 21, 2009.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Your+personal+online+number&rft.pub=Skype&rft_id=http%3A%2F%2Fwww.skype.com%2Fallfeatures%2Fonlinenumber%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-44"><a href="#cite_ref-44">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://ipcommunications.tmcnet.com/hot-topics/MCP/articles/1311-application-level-network-interoperability-the-evolution-ims.htm">"Application-level Network Interoperability and the Evolution of IMS"</a>. TMCnet.com. May 24, 2006. Retrieved January 21, 2009.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Application-level+Network+Interoperability+and+the+Evolution+of+IMS&rft.pub=TMCnet.com&rft.date=2006-05-24&rft_id=http%3A%2F%2Fipcommunications.tmcnet.com%2Fhot-topics%2FMCP%2Farticles%2F1311-application-level-network-interoperability-the-evolution-ims.htm&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-45"><a href="#cite_ref-45">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFJeff_Riddel2007" class="citation book cs1">Jeff Riddel (2007). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=8CNBbrxytcAC&pg=PA557">Packetcable Implementation</a>. Cisco Press. p. 557. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-1-58705-181-4" title="Special:BookSources/978-1-58705-181-4"><bdi>978-1-58705-181-4</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Packetcable+Implementation&rft.pages=557&rft.pub=Cisco+Press&rft.date=2007&rft.isbn=978-1-58705-181-4&rft.au=Jeff+Riddel&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3D8CNBbrxytcAC%26pg%3DPA557&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-46"><a href="#cite_ref-46">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20091212070455/http://www.fcc.gov/cgb/consumerfacts/numbport.html">"Keeping your telephone number when you change your service provider"</a>. FCC. Archived from <a rel="nofollow" class="external text" href="https://www.fcc.gov/cgb/consumerfacts/numbport.html">the original</a> on December 12, 2009. Retrieved January 20, 2009.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=FCC&rft.atitle=Keeping+your+telephone+number+when+you+change+your+service+provider&rft_id=http%3A%2F%2Fwww.fcc.gov%2Fcgb%2Fconsumerfacts%2Fnumbport.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-47"><a href="#cite_ref-47">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.itweb.co.za/content/5yONP7EKaWJqXWrb">"TelePassport takes the sting out of MNP"</a>. ITWeb. November 13, 2006. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20220719090004/https://www.itweb.co.za/content/5yONP7EKaWJqXWrb">Archived</a> from the original on July 19, 2022. Retrieved July 19, 2022.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=ITWeb&rft.atitle=TelePassport+takes+the+sting+out+of+MNP&rft.date=2006-11-13&rft_id=https%3A%2F%2Fwww.itweb.co.za%2Fcontent%2F5yONP7EKaWJqXWrb&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-fcc-48">^ <a href="#cite_ref-fcc_48-0">a</a> <a href="#cite_ref-fcc_48-1">b</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20100810193236/http://www.fcc.gov/cgb/consumerfacts/voip911.pdf">"FCC Consumer Advisory VoIP and 911 Service"</a> (PDF). FCC. Archived from <a rel="nofollow" class="external text" href="https://www.fcc.gov/cgb/consumerfacts/voip911.pdf">the original</a> (PDF) on August 10, 2010. Retrieved May 2, 2011.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=FCC&rft.atitle=FCC+Consumer+Advisory+VoIP+and+911+Service&rft_id=http%3A%2F%2Fwww.fcc.gov%2Fcgb%2Fconsumerfacts%2Fvoip911.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-49"><a href="#cite_ref-49">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFNoworatzky2019" class="citation web cs1">Noworatzky, Daniel (February 6, 2019). <a rel="nofollow" class="external text" href="https://info.teledynamics.com/blog/keep-your-voip-e911-service-in-compliance-with-this-checklist">"Keep your VoIP E911 service in compliance with this checklist"</a>. TeleDynamics. Retrieved July 19, 2022.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=TeleDynamics&rft.atitle=Keep+your+VoIP+E911+service+in+compliance+with+this+checklist&rft.date=2019-02-06&rft.aulast=Noworatzky&rft.aufirst=Daniel&rft_id=https%3A%2F%2Finfo.teledynamics.com%2Fblog%2Fkeep-your-voip-e911-service-in-compliance-with-this-checklist&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-50"><a href="#cite_ref-50">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20231218003952/https://www.soft-switch.org/foip.html">"Faxing over IP networks"</a>. Soft-Switch.org. Archived from <a rel="nofollow" class="external text" href="http://soft-switch.org/foip.html">the original</a> on December 18, 2023.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=Soft-Switch.org&rft.atitle=Faxing+over+IP+networks&rft_id=http%3A%2F%2Fsoft-switch.org%2Ffoip.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-51"><a href="#cite_ref-51">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20090604204232/http://www.ictregulationtoolkit.org/en/Section.3083.html">"4.4 VOIP – Regulatory Issues – Universal Service"</a>. ICT Regulation Tool Kit. Archived from <a rel="nofollow" class="external text" href="http://www.ictregulationtoolkit.org/en/Section.3083.html">the original</a> on June 4, 2009. Retrieved September 21, 2017.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=ICT+Regulation+Tool+Kit&rft.atitle=4.4+VOIP+%E2%80%93+Regulatory+Issues+%E2%80%93+Universal+Service&rft_id=http%3A%2F%2Fwww.ictregulationtoolkit.org%2Fen%2FSection.3083.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-52"><a href="#cite_ref-52">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFThermos2006" class="citation web cs1">Thermos, Peter (April 5, 2006). <a rel="nofollow" class="external text" href="http://www.circleid.com/posts/examining_two_well_known_attacks_on_voip1/">"Examining Two Well-Known Attacks on VoIP"</a>. CircleID. Retrieved April 5, 2006.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=CircleID&rft.atitle=Examining+Two+Well-Known+Attacks+on+VoIP&rft.date=2006-04-05&rft.aulast=Thermos&rft.aufirst=Peter&rft_id=http%3A%2F%2Fwww.circleid.com%2Fposts%2Fexamining_two_well_known_attacks_on_voip1%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-53"><a href="#cite_ref-53">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20090825002946/http://iase.disa.mil/stigs/stig/VoIP-STIG-V2R2.pdf">"Internet Protocol Telephony & Voice over Internet Protocol Security Technical Implementation Guide Version 2, Release 2"</a> (PDF). DISA. April 21, 2006. Archived from <a rel="nofollow" class="external text" href="http://iase.disa.mil/stigs/stig/VoIP-STIG-V2R2.pdf">the original</a> (PDF) on August 25, 2009.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Internet+Protocol+Telephony+%26+Voice+over+Internet+Protocol+Security+Technical+Implementation+Guide+Version+2%2C+Release+2&rft.pub=DISA&rft.date=2006-04-21&rft_id=http%3A%2F%2Fiase.disa.mil%2Fstigs%2Fstig%2FVoIP-STIG-V2R2.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-54"><a href="#cite_ref-54">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20150924021100/http://www.gdc4s.com/Documents/Products/SecureVoiceData/GD-SVOIP_FAQ-w.pdf">"Secure Voice over IP (SVoIP) vs. Voice over Secure IP (VoSIP) Installations"</a> (PDF). General Dynamics C4 Systems. Archived from <a rel="nofollow" class="external text" href="http://www.gdc4s.com/Documents/Products/SecureVoiceData/GD-SVOIP_FAQ-w.pdf">the original</a> (PDF) on September 24, 2015.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=General+Dynamics+C4+Systems&rft.atitle=Secure+Voice+over+IP+%28SVoIP%29+vs.+Voice+over+Secure+IP+%28VoSIP%29+Installations&rft_id=http%3A%2F%2Fwww.gdc4s.com%2FDocuments%2FProducts%2FSecureVoiceData%2FGD-SVOIP_FAQ-w.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-55"><a href="#cite_ref-55">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFDunteRuland2007" class="citation journal cs1">Dunte, Markus; Ruland, Christoph (June 2007). <a rel="nofollow" class="external text" href="http://paper.ijcsns.org/07_book/200706/20070610.pdf">"Secure Voice-over-IP"</a> (PDF). International Journal of Computer Science and Network Security. 7 (6): 63–68. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20230419021029/http://paper.ijcsns.org/07_book/200706/20070610.pdf">Archived</a> (PDF) from the original on April 19, 2023.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=International+Journal+of+Computer+Science+and+Network+Security&rft.atitle=Secure+Voice-over-IP&rft.volume=7&rft.issue=6&rft.pages=63-68&rft.date=2007-06&rft.aulast=Dunte&rft.aufirst=Markus&rft.au=Ruland%2C+Christoph&rft_id=http%3A%2F%2Fpaper.ijcsns.org%2F07_book%2F200706%2F20070610.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-56"><a href="#cite_ref-56">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFStringfellow2001" class="citation web cs1">Stringfellow, Brian (August 15, 2001). <a rel="nofollow" class="external text" href="http://www.sans.org/reading_room/whitepapers/voip/secure_voice_over_ip_322">"Secure Voice Over IP"</a>. SANS Institute. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20230601084811/https://www.sans.org/white-papers/322/">Archived</a> from the original on June 1, 2023.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=SANS+Institute&rft.atitle=Secure+Voice+Over+IP&rft.date=2001-08-15&rft.aulast=Stringfellow&rft.aufirst=Brian&rft_id=http%3A%2F%2Fwww.sans.org%2Freading_room%2Fwhitepapers%2Fvoip%2Fsecure_voice_over_ip_322&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-57"><a href="#cite_ref-57">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFWhiteTeague,_K.A.Daniel,_E.J.2004" class="citation book cs1">White, C.M.; Teague, K.A.; Daniel, E.J. (November 7–10, 2004). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20060517201314/http://www.clsp.jhu.edu/~cwhite/papers/asilo_04_LossConceal_final.pdf">"Packet loss concealment in a secure voice over IP environment"</a> (PDF). Conference Record of the Thirty-Eighth Asilomar Conference on Signals, Systems and Computers, 2004. Vol. 1. pp. 415–419. <a href="/wiki/CiteSeerX_(identifier)" class="mw-redirect" title="CiteSeerX (identifier)">CiteSeerX</a> <a rel="nofollow" class="external text" href="https://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.219.633">10.1.1.219.633</a>. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1109%2FACSSC.2004.1399165">10.1109/ACSSC.2004.1399165</a>. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-7803-8622-8" title="Special:BookSources/978-0-7803-8622-8"><bdi>978-0-7803-8622-8</bdi></a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:402760">402760</a>. Archived from <a rel="nofollow" class="external text" href="http://www.clsp.jhu.edu/~cwhite/papers/asilo_04_LossConceal_final.pdf">the original</a> (PDF) on May 17, 2006. Retrieved June 12, 2009.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=bookitem&rft.atitle=Packet+loss+concealment+in+a+secure+voice+over+IP+environment&rft.btitle=Conference+Record+of+the+Thirty-Eighth+Asilomar+Conference+on+Signals%2C+Systems+and+Computers%2C+2004&rft.pages=415-419&rft.date=2004-11-07%2F2004-11-10&rft_id=https%3A%2F%2Fciteseerx.ist.psu.edu%2Fviewdoc%2Fsummary%3Fdoi%3D10.1.1.219.633%23id-name%3DCiteSeerX&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A402760%23id-name%3DS2CID&rft_id=info%3Adoi%2F10.1109%2FACSSC.2004.1399165&rft.isbn=978-0-7803-8622-8&rft.aulast=White&rft.aufirst=C.M.&rft.au=Teague%2C+K.A.&rft.au=Daniel%2C+E.J.&rft_id=http%3A%2F%2Fwww.clsp.jhu.edu%2F~cwhite%2Fpapers%2Fasilo_04_LossConceal_final.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-58"><a href="#cite_ref-58">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20090424030128/http://www.networkworld.com/news/2009/041609-cellcrypt-secure-voip-heading-to.html">"Cellcrypt secure VOIP heading to BlackBerry"</a>. Networkworld.com. Archived from <a rel="nofollow" class="external text" href="http://www.networkworld.com/news/2009/041609-cellcrypt-secure-voip-heading-to.html">the original</a> on April 24, 2009. Retrieved June 12, 2009.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=Networkworld.com&rft.atitle=Cellcrypt+secure+VOIP+heading+to+BlackBerry&rft_id=http%3A%2F%2Fwww.networkworld.com%2Fnews%2F2009%2F041609-cellcrypt-secure-voip-heading-to.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-59"><a href="#cite_ref-59">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.freesoftwaremagazine.com/columns/secure_voip_calling_free_software_right_to_privacy">"Secure VOIP calling, free software, and the right to privacy"</a>. Free Software Magazine.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=Free+Software+Magazine&rft.atitle=Secure+VOIP+calling%2C+free+software%2C+and+the+right+to+privacy&rft_id=http%3A%2F%2Fwww.freesoftwaremagazine.com%2Fcolumns%2Fsecure_voip_calling_free_software_right_to_privacy&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-60"><a href="#cite_ref-60">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.nsa.gov/Press-Room/News-Highlights/Article/Article/2661746/nsa-releases-guidance-on-securing-unified-communications-and-voice-and-video-ov">"NSA Releases Guidance on Securing Unified Communications and Voice and Video over IP Systems"</a>. National Security Agency/Central Security Service. Retrieved September 26, 2022.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=National+Security+Agency%2FCentral+Security+Service&rft.atitle=NSA+Releases+Guidance+on+Securing+Unified+Communications+and+Voice+and+Video+over+IP+Systems&rft_id=https%3A%2F%2Fwww.nsa.gov%2FPress-Room%2FNews-Highlights%2FArticle%2FArticle%2F2661746%2Fnsa-releases-guidance-on-securing-unified-communications-and-voice-and-video-ov&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-61"><a href="#cite_ref-61">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://media.defense.gov/2021/Jun/17/2002744054/-1/-1/1/CTR_DEPLOYING%20SECURE%20VVOIP%20SYSTEMS.PDF">"Deploying Secure Unified Communications/Voice and Video over IP Systems"</a> (PDF). media.defense.gov. Retrieved September 27, 2023.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=media.defense.gov&rft.atitle=Deploying+Secure+Unified+Communications%2FVoice+and+Video+over+IP+Systems&rft_id=https%3A%2F%2Fmedia.defense.gov%2F2021%2FJun%2F17%2F2002744054%2F-1%2F-1%2F1%2FCTR_DEPLOYING%2520SECURE%2520VVOIP%2520SYSTEMS.PDF&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-62"><a href="#cite_ref-62">^</a> <a rel="nofollow" class="external text" href="http://voipsa.org/blog/2006/09/29/hello-mom-im-a-fake/">VOIPSA.org</a>, Blog: "Hello Mom, I'm a Fake!" (Telespoof and Fakecaller). </li> <li id="cite_note-63"><a href="#cite_ref-63">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.fcc.gov/consumers/guides/hearing-aid-compatibility-wireline-and-wireless-telephones">"Hearing Aid Compatibility for Wireline and Wireless Telephones"</a>. Federal Communications Commission. October 30, 2014. Retrieved July 9, 2019.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=Federal+Communications+Commission&rft.atitle=Hearing+Aid+Compatibility+for+Wireline+and+Wireless+Telephones&rft.date=2014-10-30&rft_id=https%3A%2F%2Fwww.fcc.gov%2Fconsumers%2Fguides%2Fhearing-aid-compatibility-wireline-and-wireless-telephones&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-64"><a href="#cite_ref-64">^</a> <a rel="nofollow" class="external text" href="https://www.fcc.gov/voip/">FCC.gov</a>, What are some advantages of VoIP? </li> <li id="cite_note-65"><a href="#cite_ref-65">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20110917005100if_/http://www.hp.com/rnd/pdfs/final_voip_techbrief.pdf">"network infrastructure: getting started with VoIP"</a> (PDF). Archived from <a rel="nofollow" class="external text" href="http://www.hp.com/rnd/pdfs/final_voip_techbrief.pdf">the original</a> (PDF) on September 17, 2011.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=network+infrastructure%3A+getting+started+with+VoIP&rft_id=http%3A%2F%2Fwww.hp.com%2Frnd%2Fpdfs%2Ffinal_voip_techbrief.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-66"><a href="#cite_ref-66">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.ipall.org/matrix/">"Global VOIP Policy Status Matrix"</a>. Global IP Alliance. 2005. Retrieved November 23, 2006.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Global+VOIP+Policy+Status+Matrix&rft.pub=Global+IP+Alliance&rft.date=2005&rft_id=http%3A%2F%2Fwww.ipall.org%2Fmatrix%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-67"><a href="#cite_ref-67">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFProenza" class="citation web cs1">Proenza, Francisco J. <a rel="nofollow" class="external text" href="https://web.archive.org/web/20120602021012/http://www.e-forall.org/pdf/Wireless&VOIP_10July2006.pdf">"The Road to Broadband Development in Developing Countries is through Competition Driven by Wireless and VOIP"</a> (PDF). Archived from <a rel="nofollow" class="external text" href="http://www.e-forall.org/pdf/Wireless&VOIP_10July2006.pdf">the original</a> (PDF) on June 2, 2012. Retrieved April 7, 2008.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=The+Road+to+Broadband+Development+in+Developing+Countries+is+through+Competition+Driven+by+Wireless+and+VOIP&rft.aulast=Proenza&rft.aufirst=Francisco+J.&rft_id=http%3A%2F%2Fwww.e-forall.org%2Fpdf%2FWireless%26VOIP_10July2006.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-68"><a href="#cite_ref-68">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.123seminarsonly.com/Seminar-Reports/037/50930740-Voice-over-IP.doc">"VOICE OVER INTERNET PROTOCOL"</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=VOICE+OVER+INTERNET+PROTOCOL&rft_id=http%3A%2F%2Fwww.123seminarsonly.com%2FSeminar-Reports%2F037%2F50930740-Voice-over-IP.doc&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-69"><a href="#cite_ref-69">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://crtc.gc.ca/eng/archive/2005/dt2005-21.htm">"Telecom Decision CRTC 2005-21"</a>. Canadian Radio-television and Telecommunications Commission. Government of Canada. April 4, 2005. Retrieved April 29, 2017.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=Canadian+Radio-television+and+Telecommunications+Commission&rft.atitle=Telecom+Decision+CRTC+2005-21&rft.date=2005-04-04&rft_id=http%3A%2F%2Fcrtc.gc.ca%2Feng%2Farchive%2F2005%2Fdt2005-21.htm&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-70"><a href="#cite_ref-70">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.123seminarsonly.com/Seminar-Reports/037/50930740-Voice-over-IP.doc">"Voice over IP"</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Voice+over+IP&rft_id=http%3A%2F%2Fwww.123seminarsonly.com%2FSeminar-Reports%2F037%2F50930740-Voice-over-IP.doc&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-71"><a href="#cite_ref-71">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMetz" class="citation web cs1">Metz, Cade. <a rel="nofollow" class="external text" href="https://www.theregister.co.uk/2009/11/20/oman_and_voip/">"Oman cuffs 212 for selling VoIP calls"</a>. The Register. Retrieved September 20, 2016.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=The+Register&rft.atitle=Oman+cuffs+212+for+selling+VoIP+calls&rft.aulast=Metz&rft.aufirst=Cade&rft_id=https%3A%2F%2Fwww.theregister.co.uk%2F2009%2F11%2F20%2Foman_and_voip%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-72"><a href="#cite_ref-72">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation news cs1"><a rel="nofollow" class="external text" href="https://www.bbc.com/news/world-middle-east-41332743">"Saudi Arabia to lift ban on internet calls"</a>. BBC News. September 20, 2017. Retrieved January 10, 2018.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=BBC+News&rft.atitle=Saudi+Arabia+to+lift+ban+on+internet+calls&rft.date=2017-09-20&rft_id=https%3A%2F%2Fwww.bbc.com%2Fnews%2Fworld-middle-east-41332743&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-73"><a href="#cite_ref-73">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation news cs1"><a rel="nofollow" class="external text" href="https://www.reuters.com/article/us-saudi-telecoms-ban/saudi-arabia-to-lift-ban-on-internet-calls-idUSKCN1BV128">"Saudi Arabia to lift ban on internet calls"</a>. Reuters. September 20, 2017. Retrieved January 10, 2018.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Reuters&rft.atitle=Saudi+Arabia+to+lift+ban+on+internet+calls&rft.date=2017-09-20&rft_id=https%3A%2F%2Fwww.reuters.com%2Farticle%2Fus-saudi-telecoms-ban%2Fsaudi-arabia-to-lift-ban-on-internet-calls-idUSKCN1BV128&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-74"><a href="#cite_ref-74">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation news cs1"><a rel="nofollow" class="external text" href="https://www.khaleejtimes.com/technology/dont-worry-skype-is-working-in-uae-">"Don't worry, Skype is working in UAE"</a>. Khaleejtimes. June 26, 2017. Retrieved January 11, 2018.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Khaleejtimes&rft.atitle=Don%27t+worry%2C+Skype+is+working+in+UAE&rft.date=2017-06-26&rft_id=https%3A%2F%2Fwww.khaleejtimes.com%2Ftechnology%2Fdont-worry-skype-is-working-in-uae-&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-75"><a href="#cite_ref-75">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFDebusmann2018" class="citation news cs1">Debusmann, Bernd Jr. (January 9, 2018). <a rel="nofollow" class="external text" href="http://www.arabianbusiness.com/technology/387211-etisalat-launches-new-unlimited-calling-plan-with-voip-apps">"Etisalat launches new unlimited calling plan with VoIP apps"</a>. Arabian Business. Retrieved January 9, 2018.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Arabian+Business&rft.atitle=Etisalat+launches+new+unlimited+calling+plan+with+VoIP+apps&rft.date=2018-01-09&rft.aulast=Debusmann&rft.aufirst=Bernd+Jr.&rft_id=http%3A%2F%2Fwww.arabianbusiness.com%2Ftechnology%2F387211-etisalat-launches-new-unlimited-calling-plan-with-voip-apps&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-76"><a href="#cite_ref-76">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMaceda2018" class="citation news cs1">Maceda, Cleofe (January 8, 2018). <a rel="nofollow" class="external text" href="http://gulfnews.com/business/sectors/technology/no-skype-pay-dh50-monthly-for-video-calls-1.2153623">"No Skype? Pay Dh50 monthly for video calls"</a>. Gulf News. Retrieved January 9, 2018.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Gulf+News&rft.atitle=No+Skype%3F+Pay+Dh50+monthly+for+video+calls&rft.date=2018-01-08&rft.aulast=Maceda&rft.aufirst=Cleofe&rft_id=http%3A%2F%2Fgulfnews.com%2Fbusiness%2Fsectors%2Ftechnology%2Fno-skype-pay-dh50-monthly-for-video-calls-1.2153623&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-77"><a href="#cite_ref-77">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFZacharias2018" class="citation news cs1">Zacharias, Anna \ (January 8, 2018). <a rel="nofollow" class="external text" href="https://www.thenational.ae/uae/etisalat-launches-new-calling-app-plan-days-after-skype-disruptions-1.693837">"Etisalat launches new calling app plan days after Skype disruptions"</a>. The National. Retrieved January 9, 2018.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=The+National&rft.atitle=Etisalat+launches+new+calling+app+plan+days+after+Skype+disruptions&rft.date=2018-01-08&rft.aulast=Zacharias&rft.aufirst=Anna+%5C&rft_id=https%3A%2F%2Fwww.thenational.ae%2Fuae%2Fetisalat-launches-new-calling-app-plan-days-after-skype-disruptions-1.693837&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-78"><a href="#cite_ref-78">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.cnbc.com/2020/03/26/coronavirus-lockdown-uae-residents-call-for-end-to-whatsapp-skype-ban.html">"UAE loosens some VoIP restrictions as residents in lockdown call for end to WhatsApp and Skype ban"</a>. CNBC. March 26, 2020. Retrieved March 26, 2020.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=CNBC&rft.atitle=UAE+loosens+some+VoIP+restrictions+as+residents+in+lockdown+call+for+end+to+WhatsApp+and+Skype+ban&rft.date=2020-03-26&rft_id=https%3A%2F%2Fwww.cnbc.com%2F2020%2F03%2F26%2Fcoronavirus-lockdown-uae-residents-call-for-end-to-whatsapp-skype-ban.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-TRAI-voip-gateway-79">^ <a href="#cite_ref-TRAI-voip-gateway_79-0">a</a> <a href="#cite_ref-TRAI-voip-gateway_79-1">b</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMahanagar_Doorsanchar_Bhawan_and_Jawahar_Lal_Nehru_Marg2008" class="citation web cs1">Mahanagar Doorsanchar Bhawan and Jawahar Lal Nehru Marg (May 2008). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20141006100940/http://www.trai.gov.in/WriteReaddata/ConsultationPaper/Document/cpaper12may08.pdf">"Telecom Regulatory Authority of India (TRAI) Consultation paper on Issues related to Internet Telephony. Consultation Paper No. 11/2008"</a> (PDF). New Delhi India: Telecom Regulatory Authority of India (TRAI). p. 16 (Section 2.2.1.2 PC–to–Phone Internet telephony). Archived from <a rel="nofollow" class="external text" href="http://www.trai.gov.in/WriteReaddata/ConsultationPaper/Document/cpaper12may08.pdf">the original</a> (PDF) on October 6, 2014. Retrieved September 19, 2012. <q>An end-user is allowed to make PC–to-Phone Internet Telephony calls only on PSTN/PLMN abroad.</q></cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Telecom+Regulatory+Authority+of+India+%28TRAI%29+Consultation+paper+on+Issues+related+to+Internet+Telephony.+Consultation+Paper+No.+11%2F2008.&rft.place=New+Delhi+India&rft.pages=16+%28Section+2.2.1.2+PC-to-Phone+Internet+telephony%29&rft.pub=Telecom+Regulatory+Authority+of+India+%28TRAI%29&rft.date=2008-05&rft.au=Mahanagar+Doorsanchar+Bhawan+and+Jawahar+Lal+Nehru+Marg&rft_id=http%3A%2F%2Fwww.trai.gov.in%2FWriteReaddata%2FConsultationPaper%2FDocument%2Fcpaper12may08.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-80"><a href="#cite_ref-80">^</a> Harish Kumar Gangwar <a rel="nofollow" class="external text" href="https://www.scribd.com/doc/101919043/TECHNICAL-NOTE-ON-ILLEGAL-INTERNATIONAL-LONG-DISTANCE-TELEPHONE-EXCHANGE-IN-INDIA">Technical Note on Illegal International Long Distance telephone Exchange in India</a> </li> <li id="cite_note-81"><a href="#cite_ref-81">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation cs2"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20100113013434/http://www.stripes.com/article.asp?section=104&article=41826&archive=true">Stars and Stripes: USFK deal keeps VoIP access for troops</a>, archived from <a rel="nofollow" class="external text" href="http://www.stripes.com/article.asp?section=104&article=41826&archive=true">the original</a> on January 13, 2010</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Stars+and+Stripes%3A+USFK+deal+keeps+VoIP+access+for+troops&rft_id=http%3A%2F%2Fwww.stripes.com%2Farticle.asp%3Fsection%3D104%26article%3D41826%26archive%3Dtrue&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-82"><a href="#cite_ref-82">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFPershing" class="citation web cs1">Pershing, Genny. <a rel="nofollow" class="external text" href="http://www.cybertelecom.org/voip/fcc.htm">"Cybertelecom :: VoIP :: FCC"</a>. www.cybertelecom.org. Retrieved September 21, 2017.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=www.cybertelecom.org&rft.atitle=Cybertelecom+%3A%3A+VoIP+%3A%3A+FCC&rft.aulast=Pershing&rft.aufirst=Genny&rft_id=http%3A%2F%2Fwww.cybertelecom.org%2Fvoip%2Ffcc.htm&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-83"><a href="#cite_ref-83">^</a> <a rel="nofollow" class="external text" href="http://www.access.gpo.gov/nara/cfr/waisidx_07/47cfr9_07.html">GPO.gov</a> <a rel="nofollow" class="external text" href="https://web.archive.org/web/20100608124332/http://www.access.gpo.gov/nara/cfr/waisidx_07/47cfr9_07.html">Archived</a> June 8, 2010, at the <a href="/wiki/Wayback_Machine" title="Wayback Machine">Wayback Machine</a>, 47 C.F.R. pt. 9 (2007) </li> <li id="cite_note-FCC-VoIP-911-84"><a href="#cite_ref-FCC-VoIP-911_84-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.fcc.gov/guides/voip-and-911-service">"VoIP and 911 Service"</a>. FCC. May 26, 2011. Retrieved August 16, 2014.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=VoIP+and+911+Service&rft.pub=FCC&rft.date=2011-05-26&rft_id=http%3A%2F%2Fwww.fcc.gov%2Fguides%2Fvoip-and-911-service&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-85"><a href="#cite_ref-85">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.fcc.gov/voip/">"Voice Over Internet Protocol (VoIP)"</a>. November 18, 2010. Retrieved September 21, 2017.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Voice+Over+Internet+Protocol+%28VoIP%29&rft.date=2010-11-18&rft_id=http%3A%2F%2Fwww.fcc.gov%2Fvoip%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-Greenberg-86"><a href="#cite_ref-Greenberg_86-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFGreenberg2008" class="citation web cs1">Greenberg, Andy (May 15, 2008). <a rel="nofollow" class="external text" href="https://www.forbes.com/2008/05/15/wiretapping-voip-lichtblau-tech-security08-cx_ag_0515wiretap.html/">"The State Of Cybersecurity Wiretapping's Fuzzy Future"</a>. Forbes. Retrieved March 2, 2009.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=Forbes&rft.atitle=The+State+Of+Cybersecurity+Wiretapping%27s+Fuzzy+Future&rft.date=2008-05-15&rft.aulast=Greenberg&rft.aufirst=Andy&rft_id=https%3A%2F%2Fwww.forbes.com%2F2008%2F05%2F15%2Fwiretapping-voip-lichtblau-tech-security08-cx_ag_0515wiretap.html%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-87"><a href="#cite_ref-87">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.internethalloffame.org/inductees/danny-cohen">"Danny Cohen"</a>. INTERNET HALL of FAME. Retrieved December 6, 2014.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Danny+Cohen&rft.pub=INTERNET+HALL+of+FAME&rft_id=http%3A%2F%2Fwww.internethalloffame.org%2Finductees%2Fdanny-cohen&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-88"><a href="#cite_ref-88">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation book cs1"><a rel="nofollow" class="external text" href="https://books.google.com/books?id=3yaUBAAAQBAJ&q=Network+Voice+Protocol+%28NVP%29+developed+by+Danny+Cohen&pg=PA34">Advanced Content Delivery, Streaming, and Cloud Services (Pg 34)</a>. Willey. September 19, 2014. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/9781118909706" title="Special:BookSources/9781118909706"><bdi>9781118909706</bdi></a>. Retrieved December 6, 2014.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Advanced+Content+Delivery%2C+Streaming%2C+and+Cloud+Services+%28Pg+34%29&rft.pub=Willey&rft.date=2014-09-19&rft.isbn=9781118909706&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3D3yaUBAAAQBAJ%26q%3DNetwork%2BVoice%2BProtocol%2B%2528NVP%2529%2Bdeveloped%2Bby%2BDanny%2BCohen%26pg%3DPA34&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-Gray-89">^ <a href="#cite_ref-Gray_89-0">a</a> <a href="#cite_ref-Gray_89-1">b</a> <a href="#cite_ref-Gray_89-2">c</a> <a href="#cite_ref-Gray_89-3">d</a> <a href="#cite_ref-Gray_89-4">e</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFGray2010" class="citation journal cs1">Gray, Robert M. (2010). <a rel="nofollow" class="external text" href="https://ee.stanford.edu/~gray/lpcip.pdf">"A History of Realtime Digital Speech on Packet Networks: Part II of Linear Predictive Coding and the Internet Protocol"</a> (PDF). Found. Trends Signal Process. 3 (4): 203–303. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1561%2F2000000036">10.1561/2000000036</a>. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/1932-8346">1932-8346</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Found.+Trends+Signal+Process.&rft.atitle=A+History+of+Realtime+Digital+Speech+on+Packet+Networks%3A+Part+II+of+Linear+Predictive+Coding+and+the+Internet+Protocol&rft.volume=3&rft.issue=4&rft.pages=203-303&rft.date=2010&rft_id=info%3Adoi%2F10.1561%2F2000000036&rft.issn=1932-8346&rft.aulast=Gray&rft.aufirst=Robert+M.&rft_id=https%3A%2F%2Fee.stanford.edu%2F~gray%2Flpcip.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-90"><a href="#cite_ref-90">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFGupta2016" class="citation journal cs1">Gupta, Shipra (May 2016). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20191018231621/https://pdfs.semanticscholar.org/2aa9/c2971342e8b0b1a0714938f39c406f258477.pdf">"Application of MFCC in Text Independent Speaker Recognition"</a> (PDF). International Journal of Advanced Research in Computer Science and Software Engineering. 6 (5): 805–810 (806). <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/2277-128X">2277-128X</a>. <a href="/wiki/S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:212485331">212485331</a>. Archived from <a rel="nofollow" class="external text" href="https://pdfs.semanticscholar.org/2aa9/c2971342e8b0b1a0714938f39c406f258477.pdf">the original</a> (PDF) on October 18, 2019. Retrieved October 18, 2019.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=International+Journal+of+Advanced+Research+in+Computer+Science+and+Software+Engineering&rft.atitle=Application+of+MFCC+in+Text+Independent+Speaker+Recognition&rft.volume=6&rft.issue=5&rft.pages=805-810+%28806%29&rft.date=2016-05&rft.issn=2277-128X&rft_id=https%3A%2F%2Fapi.semanticscholar.org%2FCorpusID%3A212485331%23id-name%3DS2CID&rft.aulast=Gupta&rft.aufirst=Shipra&rft_id=https%3A%2F%2Fpdfs.semanticscholar.org%2F2aa9%2Fc2971342e8b0b1a0714938f39c406f258477.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-Schroeder-91">^ <a href="#cite_ref-Schroeder_91-0">a</a> <a href="#cite_ref-Schroeder_91-1">b</a> M. R. Schroeder and B. S. Atal, "Code-excited linear prediction (CELP): high-quality speech at very low bit rates," in Proceedings of the IEEE <a href="/wiki/International_Conference_on_Acoustics,_Speech,_and_Signal_Processing" title="International Conference on Acoustics, Speech, and Signal Processing">International Conference on Acoustics, Speech, and Signal Processing</a> (ICASSP), vol. 10, pp. 937–940, 1985. </li> <li id="cite_note-92"><a href="#cite_ref-92">^</a> <a rel="nofollow" class="external text" href="https://patents.google.com/patent/US5825771">Audio Transceiver</a> </li> <li id="cite_note-93"><a href="#cite_ref-93">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFCerfKahn,_R.1974" class="citation journal cs1">Cerf, V.; Kahn, R. (May 1974). <a rel="nofollow" class="external text" href="http://www.cs.rice.edu/~eugeneng/teaching/f07/comp529/papers/ck74.pdf">"A Protocol for Packet Network Intercommunication"</a> (PDF). IEEE Transactions on Communications. 22 (5): 637–648. <a href="/wiki/Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1109%2FTCOM.1974.1092259">10.1109/TCOM.1974.1092259</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=IEEE+Transactions+on+Communications&rft.atitle=A+Protocol+for+Packet+Network+Intercommunication&rft.volume=22&rft.issue=5&rft.pages=637-648&rft.date=1974-05&rft_id=info%3Adoi%2F10.1109%2FTCOM.1974.1092259&rft.aulast=Cerf&rft.aufirst=V.&rft.au=Kahn%2C+R.&rft_id=http%3A%2F%2Fwww.cs.rice.edu%2F~eugeneng%2Fteaching%2Ff07%2Fcomp529%2Fpapers%2Fck74.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-94"><a href="#cite_ref-94">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20060507225813/http://www.nsf.gov/about/history/nsf0050/internet/launch.htm">"The Launch of NSFNET"</a>. The National Science Foundation. Archived from <a rel="nofollow" class="external text" href="https://www.nsf.gov/about/history/nsf0050/internet/launch.htm">the original</a> on May 7, 2006. Retrieved January 21, 2009.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=The+Launch+of+NSFNET&rft.pub=The+National+Science+Foundation&rft_id=https%3A%2F%2Fwww.nsf.gov%2Fabout%2Fhistory%2Fnsf0050%2Finternet%2Flaunch.htm&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-B2C-95">^ <a href="#cite_ref-B2C_95-0">a</a> <a href="#cite_ref-B2C_95-1">b</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFDua2021" class="citation web cs1">Dua, Amit (July 29, 2021). <a rel="nofollow" class="external text" href="https://www.business2community.com/communications/voip-basics-everything-beginners-should-know-02422214">"VoIP Basics: Everything Beginners Should Know!"</a>. business2community.com. Business 2 Community. Retrieved September 14, 2021.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=business2community.com&rft.atitle=VoIP+Basics%3A+Everything+Beginners+Should+Know%21&rft.date=2021-07-29&rft.aulast=Dua&rft.aufirst=Amit&rft_id=https%3A%2F%2Fwww.business2community.com%2Fcommunications%2Fvoip-basics-everything-beginners-should-know-02422214&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-McCraw-96"><a href="#cite_ref-McCraw_96-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFMcCraw2022" class="citation web cs1">McCraw, Corey (October 12, 2022). <a rel="nofollow" class="external text" href="https://fitsmallbusiness.com/history-of-voip/">"The History of VoIP Over the Last 55 Years (1966 to 2021)"</a>. fitsmallbusiness.com. Fits Small Business.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=unknown&rft.jtitle=fitsmallbusiness.com&rft.atitle=The+History+of+VoIP+Over+the+Last+55+Years+%281966+to+2021%29&rft.date=2022-10-12&rft.aulast=McCraw&rft.aufirst=Corey&rft_id=https%3A%2F%2Ffitsmallbusiness.com%2Fhistory-of-voip%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-Inc1992-97"><a href="#cite_ref-Inc1992_97-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFIDG_Network_World_IncEckerson1992" class="citation journal cs1">IDG Network World Inc; Eckerson, Wayne (September 21, 1992). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=DhQEAAAAMBAJ&pg=PA39">"Network World - Startup targets desktop Videoconferencing arena"</a>. Network World. IDG Network World Inc: 39–. <a href="/wiki/ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/0887-7661">0887-7661</a>. Retrieved February 10, 2012.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Network+World&rft.atitle=Network+World+-+Startup+targets+desktop+Videoconferencing+arena&rft.pages=39-&rft.date=1992-09-21&rft.issn=0887-7661&rft.au=IDG+Network+World+Inc&rft.au=Eckerson%2C+Wayne&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DDhQEAAAAMBAJ%26pg%3DPA39&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-98"><a href="#cite_ref-98">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://sunsite.unc.edu/pub/Linux/apps/sound/talk/mtalk.README">"MTALK-Readme"</a> (TXT). Sunsite.edu. Retrieved April 29, 2012.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=MTALK-Readme&rft.pub=Sunsite.edu&rft_id=http%3A%2F%2Fsunsite.unc.edu%2Fpub%2FLinux%2Fapps%2Fsound%2Ftalk%2Fmtalk.README&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-99"><a href="#cite_ref-99">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFKeating" class="citation web cs1">Keating, Tom. <a rel="nofollow" class="external text" href="http://blog.tmcnet.com/blog/tom-keating/docs/cti-buyers-guide-1996.pdf">"Internet Phone Release 4"</a> (PDF). Computer Telephony Interaction Magazine. Retrieved November 7, 2007.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Internet+Phone+Release+4&rft.pub=Computer+Telephony+Interaction+Magazine&rft.aulast=Keating&rft.aufirst=Tom&rft_id=http%3A%2F%2Fblog.tmcnet.com%2Fblog%2Ftom-keating%2Fdocs%2Fcti-buyers-guide-1996.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-100"><a href="#cite_ref-100">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.ilocus.com/2007/07/the_10_that_established_voip_p_2.html">"The 10 that Established VOIP (Part 1: VocalTec)"</a>. iLocus. Retrieved January 21, 2009.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=The+10+that+Established+VOIP+%28Part+1%3A+VocalTec%29&rft.pub=iLocus&rft_id=http%3A%2F%2Fwww.ilocus.com%2F2007%2F07%2Fthe_10_that_established_voip_p_2.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-101"><a href="#cite_ref-101">^</a> The free Library <a rel="nofollow" class="external text" href="http://www.thefreelibrary.com/RADVision+and+Intel+Target+Compatibility+Between+RADVision%27s+...-a019467970">RADVision and Intel Target Compatibility Between RADVision's H.323/320 Videoconferencing Gateway And Intel's Business Video Conferencing And TeamStation Products.</a> <a rel="nofollow" class="external text" href="https://web.archive.org/web/20131030095918/http://www.thefreelibrary.com/RADVision+and+Intel+Target+Compatibility+Between+RADVision%27s+...-a019467970">Archived</a> October 30, 2013, at the <a href="/wiki/Wayback_Machine" title="Wayback Machine">Wayback Machine</a> June 2, 1997 <a rel="nofollow" class="external text" href="http://www.radvision.com/Developer-Solutions/">VoiP Developer Solutions</a> <a rel="nofollow" class="external text" href="https://web.archive.org/web/20110616001931/http://www.radvision.com/Developer-Solutions">Archived</a> June 16, 2011, at the <a href="/wiki/Wayback_Machine" title="Wayback Machine">Wayback Machine</a> </li> <li id="cite_note-102"><a href="#cite_ref-102">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.itu.int/rec/T-REC-H.323-199611-S/en">"H.323 Visual telephone systems and equipment for local area networks which provide a non-guaranteed quality of service"</a>. ITU-T. Retrieved January 21, 2009.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=H.323+Visual+telephone+systems+and+equipment+for+local+area+networks+which+provide+a+non-guaranteed+quality+of+service&rft.pub=ITU-T&rft_id=http%3A%2F%2Fwww.itu.int%2Frec%2FT-REC-H.323-199611-S%2Fen&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-103"><a href="#cite_ref-103">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.faqs.org/rfcs/rfc2235.html">"RFC 2235"</a>. R. Zakon. Retrieved January 21, 2009.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=RFC+2235&rft.pub=R.+Zakon&rft_id=http%3A%2F%2Fwww.faqs.org%2Frfcs%2Frfc2235.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-104"><a href="#cite_ref-104">^</a> International Telecommunication Union, Standardization Sector (ITU-T), Study Group 15 (1993-1996), Recommendation G.729, March 1996. </li> <li id="cite_note-ilocus_softswitch-105"><a href="#cite_ref-ilocus_softswitch_105-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.ilocus.com/2007/07/the_10_that_established_voip_p_1.html">"The 10 that Established VOIP (Part 2: Level 3)"</a>. iLocus. July 13, 2007. Retrieved November 7, 2007.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=The+10+that+Established+VOIP+%28Part+2%3A+Level+3%29&rft.pub=iLocus&rft.date=2007-07-13&rft_id=http%3A%2F%2Fwww.ilocus.com%2F2007%2F07%2Fthe_10_that_established_voip_p_1.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-106"><a href="#cite_ref-106">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.ietf.org/rfc/rfc2543.txt">"RFC 2543, SIP: Session Initiation Protocol"</a>. Handley, Schulzrinne, Schooler, Rosenberg. Retrieved January 21, 2009.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=RFC+2543%2C+SIP%3A+Session+Initiation+Protocol&rft.pub=Handley%2C+Schulzrinne%2C+Schooler%2C+Rosenberg&rft_id=http%3A%2F%2Fwww.ietf.org%2Frfc%2Frfc2543.txt&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-107"><a href="#cite_ref-107">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20090123154417/http://www.asterisk.org/about">"What is Asterisk"</a>. Asterisk.org. Archived from <a rel="nofollow" class="external text" href="http://www.asterisk.org/about">the original</a> on January 23, 2009. Retrieved January 21, 2009.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=What+is+Asterisk&rft.pub=Asterisk.org&rft_id=http%3A%2F%2Fwww.asterisk.org%2Fabout&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-Hersent-108"><a href="#cite_ref-Hersent_108-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFHersentPetitGurle2005" class="citation book cs1">Hersent, Olivier; Petit, Jean-Pierre; Gurle, David (2005). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=SMvNToRs-DgC&pg=PA55">Beyond VoIP Protocols: Understanding Voice Technology and Networking Techniques for IP Telephony</a>. <a href="/wiki/John_Wiley_%26_Sons" class="mw-redirect" title="John Wiley & Sons">John Wiley & Sons</a>. p. 55. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/9780470023631" title="Special:BookSources/9780470023631"><bdi>9780470023631</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Beyond+VoIP+Protocols%3A+Understanding+Voice+Technology+and+Networking+Techniques+for+IP+Telephony&rft.pages=55&rft.pub=John+Wiley+%26+Sons&rft.date=2005&rft.isbn=9780470023631&rft.aulast=Hersent&rft.aufirst=Olivier&rft.au=Petit%2C+Jean-Pierre&rft.au=Gurle%2C+David&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3DSMvNToRs-DgC%26pg%3DPA55&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-Lutzky-109"><a href="#cite_ref-Lutzky_109-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFLutzkySchullerGayerKrämer2004" class="citation conference cs1">Lutzky, Manfred; Schuller, Gerald; Gayer, Marc; Krämer, Ulrich; Wabnik, Stefan (May 2004). <a rel="nofollow" class="external text" href="https://www.iis.fraunhofer.de/content/dam/iis/de/doc/ame/conference/AES-116-Convention_guideline-to-audio-codec-delay_AES116.pdf">A guideline to audio codec delay</a> (PDF). 116th AES Convention. <a href="/wiki/Fraunhofer_IIS" class="mw-redirect" title="Fraunhofer IIS">Fraunhofer IIS</a>. <a href="/wiki/Audio_Engineering_Society" title="Audio Engineering Society">Audio Engineering Society</a>. Retrieved October 24, 2019.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=conference&rft.jtitle=Fraunhofer+IIS&rft.atitle=A+guideline+to+audio+codec+delay&rft.date=2004-05&rft.aulast=Lutzky&rft.aufirst=Manfred&rft.au=Schuller%2C+Gerald&rft.au=Gayer%2C+Marc&rft.au=Kr%C3%A4mer%2C+Ulrich&rft.au=Wabnik%2C+Stefan&rft_id=https%3A%2F%2Fwww.iis.fraunhofer.de%2Fcontent%2Fdam%2Fiis%2Fde%2Fdoc%2Fame%2Fconference%2FAES-116-Convention_guideline-to-audio-codec-delay_AES116.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-Schnell-110"><a href="#cite_ref-Schnell_110-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFSchnellSchmidtJanderAlbert2008" class="citation conference cs1">Schnell, Markus; Schmidt, Markus; Jander, Manuel; Albert, Tobias; Geiger, Ralf; Ruoppila, Vesa; Ekstrand, Per; Bernhard, Grill (October 2008). <a rel="nofollow" class="external text" href="https://www.iis.fraunhofer.de/content/dam/iis/de/doc/ame/conference/AES-125-Convention_AAC-ELD-NewStandardForHighQualityCommunication_AES7503.pdf">MPEG-4 Enhanced Low Delay AAC - A New Standard for High Quality Communication</a> (PDF). 125th AES Convention. <a href="/wiki/Fraunhofer_IIS" class="mw-redirect" title="Fraunhofer IIS">Fraunhofer IIS</a>. <a href="/wiki/Audio_Engineering_Society" title="Audio Engineering Society">Audio Engineering Society</a>. Retrieved October 20, 2019.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=conference&rft.jtitle=Fraunhofer+IIS&rft.atitle=MPEG-4+Enhanced+Low+Delay+AAC+-+A+New+Standard+for+High+Quality+Communication&rft.date=2008-10&rft.aulast=Schnell&rft.aufirst=Markus&rft.au=Schmidt%2C+Markus&rft.au=Jander%2C+Manuel&rft.au=Albert%2C+Tobias&rft.au=Geiger%2C+Ralf&rft.au=Ruoppila%2C+Vesa&rft.au=Ekstrand%2C+Per&rft.au=Bernhard%2C+Grill&rft_id=https%3A%2F%2Fwww.iis.fraunhofer.de%2Fcontent%2Fdam%2Fiis%2Fde%2Fdoc%2Fame%2Fconference%2FAES-125-Convention_AAC-ELD-NewStandardForHighQualityCommunication_AES7503.pdf&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-111"><a href="#cite_ref-111">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFStapleton-Gray2009" class="citation book cs1">Stapleton-Gray, Ross (2009). Inter-Network Operations Center Dial-by-ASN (INOC-DBA), a Resource for the Network Operator Community. Los Alamitos: IEEE Computer Society Press. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/978-0-7695-3568-5" title="Special:BookSources/978-0-7695-3568-5"><bdi>978-0-7695-3568-5</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=Inter-Network+Operations+Center+Dial-by-ASN+%28INOC-DBA%29%2C+a+Resource+for+the+Network+Operator+Community&rft.place=Los+Alamitos&rft.pub=IEEE+Computer+Society+Press&rft.date=2009&rft.isbn=978-0-7695-3568-5&rft.aulast=Stapleton-Gray&rft.aufirst=Ross&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-112"><a href="#cite_ref-112">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFPogue2007" class="citation news cs1">Pogue, David (August 2, 2007). <a rel="nofollow" class="external text" href="https://www.nytimes.com/2007/08/02/technology/circuits/02pogue.html">"State of the Art: Get Your Free Net Phone Calls Here"</a>. The New York Times. Retrieved January 20, 2009.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=The+New+York+Times&rft.atitle=State+of+the+Art%3A+Get+Your+Free+Net+Phone+Calls+Here&rft.date=2007-08-02&rft.aulast=Pogue&rft.aufirst=David&rft_id=https%3A%2F%2Fwww.nytimes.com%2F2007%2F08%2F02%2Ftechnology%2Fcircuits%2F02pogue.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-Nagireddi-113"><a href="#cite_ref-Nagireddi_113-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFNagireddi2008" class="citation book cs1">Nagireddi, Sivannarayana (2008). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=5AneeZFE71MC&pg=PA69">VoIP Voice and Fax Signal Processing</a>. <a href="/wiki/John_Wiley_%26_Sons" class="mw-redirect" title="John Wiley & Sons">John Wiley & Sons</a>. p. 69. <a href="/wiki/ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <a href="/wiki/Special:BookSources/9780470377864" title="Special:BookSources/9780470377864"><bdi>9780470377864</bdi></a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=book&rft.btitle=VoIP+Voice+and+Fax+Signal+Processing&rft.pages=69&rft.pub=John+Wiley+%26+Sons&rft.date=2008&rft.isbn=9780470377864&rft.aulast=Nagireddi&rft.aufirst=Sivannarayana&rft_id=https%3A%2F%2Fbooks.google.com%2Fbooks%3Fid%3D5AneeZFE71MC%26pg%3DPA69&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-114"><a href="#cite_ref-114">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFRemo2007" class="citation news cs1">Remo, Michelle V. (August 27, 2007). <a rel="nofollow" class="external text" href="https://news.google.com/newspapers?nid=2479&dat=20070827&id=j1M1AAAAIBAJ&pg=1974,4860651">"Prospects bright for voice calls over internet"</a>. Philippine Daily Inquirer. Retrieved January 1, 2015.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.jtitle=Philippine+Daily+Inquirer&rft.atitle=Prospects+bright+for+voice+calls+over+internet&rft.date=2007-08-27&rft.aulast=Remo&rft.aufirst=Michelle+V.&rft_id=https%3A%2F%2Fnews.google.com%2Fnewspapers%3Fnid%3D2479%26dat%3D20070827%26id%3Dj1M1AAAAIBAJ%26pg%3D1974%2C4860651&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-IETF79-115"><a href="#cite_ref-IETF79_115-0">^</a> <a rel="nofollow" class="external text" href="http://nagasaki.bogus.com/ietf79/ietf79-ch8-tue-noon.mp3">Audio-Mitschnitt</a> <a rel="nofollow" class="external text" href="https://web.archive.org/web/20130210051956/http://nagasaki.bogus.com/ietf79/ietf79-ch8-tue-noon.mp3">Archived</a> February 10, 2013, at the <a href="/wiki/Wayback_Machine" title="Wayback Machine">Wayback Machine</a> vom Treffen der IETF-Codec-Arbeitsgruppe auf der Konferenz IETF79 in Peking, China mit einer Darstellung der grundlegenden Funktionsprinzipien durch Koen Vos (MP3, ~70 MiB) </li> <li id="cite_note-116"><a href="#cite_ref-116">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="http://www.wirevolution.com/2009/01/13/skypes-new-super-wideband-codec/">"Skype's new super wideband codec"</a>. Wirevolution.com. January 13, 2009. Retrieved March 31, 2009.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Skype%27s+new+super+wideband+codec&rft.pub=Wirevolution.com&rft.date=2009-01-13&rft_id=http%3A%2F%2Fwww.wirevolution.com%2F2009%2F01%2F13%2Fskypes-new-super-wideband-codec%2F&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-AppleInsider_standards_1-117"><a href="#cite_ref-AppleInsider_standards_1_117-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFDaniel_Eran_Dilger2010" class="citation web cs1">Daniel Eran Dilger (June 8, 2010). <a rel="nofollow" class="external text" href="http://www.appleinsider.com/articles/10/06/08/inside_iphone_4_facetime_video_calling.html">"Inside iPhone 4: FaceTime video calling"</a>. <a href="/wiki/Apple_community#AppleInsider" title="Apple community">AppleInsider</a>. Retrieved June 9, 2010.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=unknown&rft.btitle=Inside+iPhone+4%3A+FaceTime+video+calling&rft.pub=AppleInsider&rft.date=2010-06-08&rft.au=Daniel+Eran+Dilger&rft_id=http%3A%2F%2Fwww.appleinsider.com%2Farticles%2F10%2F06%2F08%2Finside_iphone_4_facetime_video_calling.html&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> <li id="cite_note-presentation-118"><a href="#cite_ref-presentation_118-0">^</a> <a rel="nofollow" class="external text" href="http://people.xiph.org/~greg/video/linux_conf_au_CELT_2.ogv">Presentation of the CELT codec</a> <a rel="nofollow" class="external text" href="https://web.archive.org/web/20110807182250/http://people.xiph.org/~greg/video/linux_conf_au_CELT_2.ogv">Archived</a> August 7, 2011, at the <a href="/wiki/Wayback_Machine" title="Wayback Machine">Wayback Machine</a> by Timothy B. Terriberry (65 minutes of video, see also <a rel="nofollow" class="external text" href="http://www.celt-codec.org/presentations/misc/lca-celt.pdf">presentation slides</a> <a rel="nofollow" class="external text" href="https://web.archive.org/web/20110810032741/http://www.celt-codec.org/presentations/misc/lca-celt.pdf">Archived</a> August 10, 2011, at the <a href="/wiki/Wayback_Machine" title="Wayback Machine">Wayback Machine</a> in PDF) </li> <li id="cite_note-Valin-119"><a href="#cite_ref-Valin_119-0">^</a> <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1238218222"><cite id="CITEREFValinMaxwellTerriberryVos2013" class="citation conference cs1">Valin, Jean-Marc; Maxwell, Gregory; Terriberry, Timothy B.; Vos, Koen (October 2013). High-Quality, Low-Delay Music Coding in the Opus Codec. 135th AES Convention. <a href="/wiki/Audio_Engineering_Society" title="Audio Engineering Society">Audio Engineering Society</a>. <a href="/wiki/ArXiv_(identifier)" class="mw-redirect" title="ArXiv (identifier)">arXiv</a>:<a rel="nofollow" class="external text" href="https://arxiv.org/abs/1602.04845">1602.04845</a>.</cite><span title="ctx_ver=Z39.88-2004&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.genre=conference&rft.btitle=High-Quality%2C+Low-Delay+Music+Coding+in+the+Opus+Codec&rft.pub=Audio+Engineering+Society&rft.date=2013-10&rft_id=info%3Aarxiv%2F1602.04845&rft.aulast=Valin&rft.aufirst=Jean-Marc&rft.au=Maxwell%2C+Gregory&rft.au=Terriberry%2C+Timothy+B.&rft.au=Vos%2C+Koen&rfr_id=info%3Asid%2Fen.wikipedia.org%3AVoice+over+IP" class="Z3988"> </li> </ol></div></div> <div class="mw-heading mw-heading2"><h2 id="External_links">External links</h2>[<a href="/w/index.php?title=Voice_over_IP&action=edit&section=39" title="Edit section: External links">edit</a>]</div> <ul><li><a href="/wiki/File:Wiktionary-logo-en-v2.svg" class="mw-file-description"><img alt="" src="//upload.wikimedia.org/wikipedia/commons/thumb/9/99/Wiktionary-logo-en-v2.svg/16px-Wiktionary-logo-en-v2.svg.png" decoding="async" width="16" height="16" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/9/99/Wiktionary-logo-en-v2.svg/24px-Wiktionary-logo-en-v2.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/9/99/Wiktionary-logo-en-v2.svg/32px-Wiktionary-logo-en-v2.svg.png 2x" data-file-width="512" data-file-height="512" /></a> The dictionary definition of <a href="https://en.wiktionary.org/wiki/VoIP" class="extiw" title="wiktionary:VoIP">VoIP</a> at Wiktionary</li> <li><a href="/wiki/File:Wikivoyage-Logo-v3-icon.svg" class="mw-file-description"><img alt="" src="//upload.wikimedia.org/wikipedia/commons/thumb/d/dd/Wikivoyage-Logo-v3-icon.svg/16px-Wikivoyage-Logo-v3-icon.svg.png" decoding="async" width="16" height="16" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/d/dd/Wikivoyage-Logo-v3-icon.svg/24px-Wikivoyage-Logo-v3-icon.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/d/dd/Wikivoyage-Logo-v3-icon.svg/32px-Wikivoyage-Logo-v3-icon.svg.png 2x" data-file-width="193" data-file-height="193" /></a> <a href="https://en.wikivoyage.org/wiki/Internet_telephony#Q81945" class="extiw" title="voy:Internet telephony">Internet telephony</a> travel guide from Wikivoyage</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="Computer-mediated_communication" style="padding:3px"><table class="nowraplinks hlist mw-collapsible autocollapse navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="2"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><style data-mw-deduplicate="TemplateStyles:r1239400231">.mw-parser-output .navbar{display:inline;font-size:88%;font-weight:normal}.mw-parser-output .navbar-collapse{float:left;text-align:left}.mw-parser-output .navbar-boxtext{word-spacing:0}.mw-parser-output .navbar ul{display:inline-block;white-space:nowrap;line-height:inherit}.mw-parser-output .navbar-brackets::before{margin-right:-0.125em;content:"[ "}.mw-parser-output .navbar-brackets::after{margin-left:-0.125em;content:" ]"}.mw-parser-output .navbar li{word-spacing:-0.125em}.mw-parser-output .navbar a>span,.mw-parser-output .navbar a>abbr{text-decoration:inherit}.mw-parser-output .navbar-mini abbr{font-variant:small-caps;border-bottom:none;text-decoration:none;cursor:inherit}.mw-parser-output .navbar-ct-full{font-size:114%;margin:0 7em}.mw-parser-output .navbar-ct-mini{font-size:114%;margin:0 4em}html.skin-theme-clientpref-night .mw-parser-output .navbar li a abbr{color:var(--color-base)!important}@media(prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .navbar li a abbr{color:var(--color-base)!important}}@media print{.mw-parser-output .navbar{display:none!important}}</style><div class="navbar plainlinks hlist navbar-mini"><ul><li class="nv-view"><a href="/wiki/Template:Computer-mediated_communication" title="Template:Computer-mediated communication"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Computer-mediated_communication" title="Template talk:Computer-mediated communication"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Computer-mediated_communication" title="Special:EditPage/Template:Computer-mediated communication"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="Computer-mediated_communication" style="font-size:114%;margin:0 4em"><a href="/wiki/Computer-mediated_communication" title="Computer-mediated communication">Computer-mediated communication</a></div></th></tr><tr><td class="navbox-abovebelow" colspan="2"><div> <ul><li><a href="/wiki/Online_chat" title="Online chat">Online chat</a></li> <li><a href="/wiki/Online_discussion" class="mw-redirect" title="Online discussion">Online discussion</a></li> <li><a href="/wiki/Communication_software" title="Communication software">Communication software</a></li> <li><a href="/wiki/Collaborative_software" title="Collaborative software">Collaborative software</a></li> <li><a href="/wiki/Social_network_service" class="mw-redirect" title="Social network service">Social network service</a></li> <li><a href="/wiki/Virtual_learning_environment" class="mw-redirect" title="Virtual learning environment">Virtual learning environment</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Asynchronous_conferencing" class="mw-redirect" title="Asynchronous conferencing">Asynchronous conferencing</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Email" title="Email">Email</a></li> <li><a href="/wiki/Electronic_mailing_list" class="mw-redirect" title="Electronic mailing list">Electronic mailing list</a></li> <li><a href="/wiki/FidoNet" title="FidoNet">FidoNet</a></li> <li><a href="/wiki/Usenet" title="Usenet">Usenet</a></li> <li><a href="/wiki/Internet_forum" title="Internet forum">Internet forum</a> <ul><li><a href="/wiki/Textboard" title="Textboard">Textboard</a></li> <li><a href="/wiki/Imageboard" title="Imageboard">Imageboard</a></li></ul></li> <li><a href="/wiki/Bulletin_board_system" title="Bulletin board system">Bulletin board system</a></li> <li><a href="/wiki/Guestbook" title="Guestbook">Online guestbook</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Synchronous_conferencing" class="mw-redirect" title="Synchronous conferencing">Synchronous conferencing</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Data_conferencing" title="Data conferencing">Data conferencing</a></li> <li><a href="/wiki/Instant_messaging" title="Instant messaging">Instant messaging</a></li> <li><a href="/wiki/Internet_Relay_Chat" class="mw-redirect" title="Internet Relay Chat">Internet Relay Chat</a></li> <li><a href="/wiki/LAN_messenger" title="LAN messenger">LAN messenger</a></li> <li><a href="/wiki/Talker" title="Talker">Talker</a></li> <li><a href="/wiki/Videoconferencing" class="mw-redirect" title="Videoconferencing">Videoconferencing</a></li> <li><a class="mw-selflink selflink">Voice over IP</a> <ul><li><a href="/wiki/Voice_chat_in_online_gaming" title="Voice chat in online gaming">Voice chat in online gaming</a></li></ul></li> <li><a href="/wiki/Web_chat" class="mw-redirect" title="Web chat">Web chat</a></li> <li><a href="/wiki/Web_conferencing" title="Web conferencing">Web conferencing</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Publishing</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Blog" title="Blog">Blog</a></li> <li><a href="/wiki/Microblogging" title="Microblogging">Microblogging</a></li> <li><a href="/wiki/Wiki" title="Wiki">Wiki</a></li></ul> </div></td></tr></tbody></table></div> <div class="navbox-styles"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236075235"></div><div role="navigation" class="navbox" aria-labelledby="Telephony" style="padding:3px"><table class="nowraplinks mw-collapsible uncollapsed 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"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1239400231"><div class="navbar plainlinks hlist navbar-mini"><ul><li class="nv-view"><a href="/wiki/Template:Telephony" title="Template:Telephony"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Telephony" title="Template talk:Telephony"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Telephony" title="Special:EditPage/Template:Telephony"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="Telephony" style="font-size:114%;margin:0 4em"><a href="/wiki/Telephony" title="Telephony">Telephony</a></div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%">Types</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/Landline" title="Landline">Landline</a></li> <li><a href="/wiki/Cable_telephony" title="Cable telephony">Cable telephony</a></li> <li><a href="/wiki/Mobile_phone" title="Mobile phone">Mobile phone</a></li> <li><a href="/wiki/Satellite_phone" title="Satellite phone">Satellite phone</a></li> <li><a href="/wiki/Photophone" title="Photophone">Photophone</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Accessories</th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Answering_machine" title="Answering machine">Answering machine</a></li> <li><a href="/wiki/Caller_ID" title="Caller ID">Caller ID</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Connectivity</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/Cable_protection_system" title="Cable protection system">Cable protection system</a></li> <li><a href="/wiki/Communications_satellite" title="Communications satellite">Communications satellites</a></li> <li><a href="/wiki/Fiber-optic_communication" title="Fiber-optic communication">Fibre-optical</a></li> <li><a href="/wiki/Free-space_optical_communication" title="Free-space optical communication">Free-space optical</a></li> <li><a href="/wiki/Integrated_Services_Digital_Network" class="mw-redirect" title="Integrated Services Digital Network">ISDN</a></li> <li><a href="/wiki/Mobile_phone_signal" title="Mobile phone signal">Mobile phone signal</a></li> <li><a href="/wiki/Plain_old_telephone_service" title="Plain old telephone service">POTS</a></li> <li><a href="/wiki/Public_switched_telephone_network" title="Public switched telephone network">PSTN</a></li> <li><a href="/wiki/Submarine_communications_cable" title="Submarine communications cable">Submarine cables</a></li> <li><a class="mw-selflink selflink">VoIP</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Calls</th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Missed_call" title="Missed call">Missed call</a></li> <li><a href="/wiki/Misdialed_call" title="Misdialed call">Misdialed call</a></li> <li><a href="/wiki/Nuisance_call" title="Nuisance call">Nuisance call</a></li> <li><a href="/wiki/Phone_tag" title="Phone tag">Phone tag</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Applications</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Fax" title="Fax">Fax transmission</a></li> <li><a href="/wiki/Telephone_call" title="Telephone call">Telephone calls</a></li> <li><a href="/wiki/Telephone_newspaper" title="Telephone newspaper">Telephone newspapers</a></li> <li><a href="/wiki/Th%C3%A9%C3%A2trophone" title="Théâtrophone">Théâtrophone</a></li> <li><a href="/wiki/Videotelephony" title="Videotelephony">Video calls</a></li></ul> </div></td></tr><tr><td class="navbox-abovebelow" colspan="2"><div><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" /> <a href="/wiki/Portal:Telecommunication" title="Portal:Telecommunication">Telecommunication portal</a> <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" /> <a href="/wiki/Portal:Telephones" title="Portal:Telephones">Telephones portal</a></div></td></tr></tbody></table></div> <div class="navbox-styles"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236075235"></div><div role="navigation" class="navbox" aria-labelledby="Telecommunications" style="padding:3px"><table class="nowraplinks hlist mw-collapsible mw-collapsed 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"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1239400231"><div class="navbar plainlinks hlist navbar-mini"><ul><li class="nv-view"><a href="/wiki/Template:Telecommunications" title="Template:Telecommunications"><abbr title="View this template">v</abbr></a></li><li class="nv-talk"><a href="/wiki/Template_talk:Telecommunications" title="Template talk:Telecommunications"><abbr title="Discuss this template">t</abbr></a></li><li class="nv-edit"><a href="/wiki/Special:EditPage/Template:Telecommunications" title="Special:EditPage/Template:Telecommunications"><abbr title="Edit this template">e</abbr></a></li></ul></div><div id="Telecommunications" style="font-size:114%;margin:0 4em"><a href="/wiki/Telecommunications" title="Telecommunications">Telecommunications</a></div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/History_of_telecommunication" title="History of telecommunication">History</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Beacon#For_defensive_communications" title="Beacon">Beacon</a></li> <li><a href="/wiki/History_of_broadcasting" title="History of broadcasting">Broadcasting</a></li> <li><a href="/wiki/Cable_protection_system" title="Cable protection system">Cable protection system</a></li> <li><a href="/wiki/Cable_television" title="Cable television">Cable TV</a></li> <li><a href="/wiki/Communications_satellite#History" title="Communications satellite">Communications satellite</a></li> <li><a href="/wiki/Computer_network#History" title="Computer network">Computer network</a></li> <li><a href="/wiki/Data_compression" title="Data compression">Data compression</a> <ul><li><a href="/wiki/Audio_coding_format" title="Audio coding format">audio</a></li> <li><a href="/wiki/Discrete_cosine_transform" title="Discrete cosine transform">DCT</a></li> <li><a href="/wiki/Image_compression" title="Image compression">image</a></li> <li><a href="/wiki/Video_coding_format" title="Video coding format">video</a></li></ul></li> <li><a href="/wiki/Digital_media" title="Digital media">Digital media</a> <ul><li><a href="/wiki/Internet_video" title="Internet video">Internet video</a></li> <li><a href="/wiki/Online_video_platform" title="Online video platform">online video platform</a></li> <li><a href="/wiki/Social_media" title="Social media">social media</a></li> <li><a href="/wiki/Streaming_media" title="Streaming media">streaming</a></li></ul></li> <li><a href="/wiki/Drums_in_communication" title="Drums in communication">Drums</a></li> <li><a href="/wiki/Edholm%27s_law" title="Edholm's law">Edholm's law</a></li> <li><a href="/wiki/Electrical_telegraph#History" title="Electrical telegraph">Electrical telegraph</a></li> <li><a href="/wiki/Fax#History" title="Fax">Fax</a></li> <li><a href="/wiki/Heliograph#History" title="Heliograph">Heliographs</a></li> <li><a href="/wiki/Hydraulic_telegraph#Greek_hydraulic_semaphore_system" title="Hydraulic telegraph">Hydraulic telegraph</a></li> <li><a href="/wiki/Information_Age" title="Information Age">Information Age</a></li> <li><a href="/wiki/Information_revolution" class="mw-redirect" title="Information revolution">Information revolution</a></li> <li><a href="/wiki/History_of_the_Internet" title="History of the Internet">Internet</a></li> <li><a href="/wiki/Mass_media#History" title="Mass media">Mass media</a></li> <li><a href="/wiki/History_of_mobile_phones" title="History of mobile phones">Mobile phone</a> <ul><li><a href="/wiki/Smartphone" title="Smartphone">Smartphone</a></li></ul></li> <li><a href="/wiki/Optical_communication" title="Optical communication">Optical telecommunication</a></li> <li><a href="/wiki/Optical_telegraph" title="Optical telegraph">Optical telegraphy</a></li> <li><a href="/wiki/Pager" title="Pager">Pager</a></li> <li><a href="/wiki/Photophone" title="Photophone">Photophone</a></li> <li><a href="/wiki/History_of_prepaid_mobile_phones" title="History of prepaid mobile phones">Prepaid mobile phone</a></li> <li><a href="/wiki/History_of_radio" title="History of radio">Radio</a></li> <li><a href="/wiki/Radiotelephone" title="Radiotelephone">Radiotelephone</a></li> <li><a href="/wiki/Communications_satellite" title="Communications satellite">Satellite communications</a></li> <li><a href="/wiki/Semaphore" title="Semaphore">Semaphore</a> <ul><li><a href="/wiki/Phryctoria" title="Phryctoria">Phryctoria</a></li></ul></li> <li><a href="/wiki/Semiconductor" title="Semiconductor">Semiconductor</a> <ul><li><a href="/wiki/Semiconductor_device" title="Semiconductor device">device</a></li> <li><a href="/wiki/MOSFET" title="MOSFET">MOSFET</a></li> <li><a href="/wiki/History_of_the_transistor" title="History of the transistor">transistor</a></li></ul></li> <li><a href="/wiki/Smoke_signal" title="Smoke signal">Smoke signals</a></li> <li><a href="/wiki/History_of_telecommunication" title="History of telecommunication">Telecommunications history</a></li> <li><a href="/wiki/Telautograph" title="Telautograph">Telautograph</a></li> <li><a href="/wiki/Telegraphy" title="Telegraphy">Telegraphy</a></li> <li><a href="/wiki/Teleprinter" title="Teleprinter">Teleprinter</a> (teletype)</li> <li><a href="/wiki/History_of_the_telephone" title="History of the telephone">Telephone</a></li> <li><a href="/wiki/The_Telephone_Cases" title="The Telephone Cases">The Telephone Cases</a></li> <li><a href="/wiki/History_of_television" title="History of television">Television</a> <ul><li><a href="/wiki/Digital_television" title="Digital television">digital</a></li> <li><a href="/wiki/Streaming_television" title="Streaming television">streaming</a></li></ul></li> <li><a href="/wiki/Submarine_communications_cable#Early_history:_telegraph_and_coaxial_cables" title="Submarine communications cable">Undersea telegraph line</a></li> <li><a href="/wiki/History_of_videotelephony" title="History of videotelephony">Videotelephony</a></li> <li><a href="/wiki/Whistled_language" title="Whistled language">Whistled language</a></li> <li><a href="/wiki/Wireless_revolution" class="mw-redirect" title="Wireless revolution">Wireless revolution</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Pioneers</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Nasir_Ahmed_(engineer)" title="Nasir Ahmed (engineer)">Nasir Ahmed</a></li> <li><a href="/wiki/Edwin_Howard_Armstrong" title="Edwin Howard Armstrong">Edwin Howard Armstrong</a></li> <li><a href="/wiki/Mohamed_M._Atalla" title="Mohamed M. Atalla">Mohamed M. Atalla</a></li> <li><a href="/wiki/John_Logie_Baird" title="John Logie Baird">John Logie Baird</a></li> <li><a href="/wiki/Paul_Baran" title="Paul Baran">Paul Baran</a></li> <li><a href="/wiki/John_Bardeen" title="John Bardeen">John Bardeen</a></li> <li><a href="/wiki/Alexander_Graham_Bell" title="Alexander Graham Bell">Alexander Graham Bell</a></li> <li><a href="/wiki/Emile_Berliner" title="Emile Berliner">Emile Berliner</a></li> <li><a href="/wiki/Tim_Berners-Lee" title="Tim Berners-Lee">Tim Berners-Lee</a></li> <li><a href="/wiki/Francis_Blake_(inventor)" title="Francis Blake (inventor)">Francis Blake</a></li> <li><a href="/wiki/Jagadish_Chandra_Bose" title="Jagadish Chandra Bose">Jagadish Chandra Bose</a></li> <li><a href="/wiki/Charles_Bourseul" title="Charles Bourseul">Charles Bourseul</a></li> <li><a href="/wiki/Walter_Houser_Brattain" title="Walter Houser Brattain">Walter Houser Brattain</a></li> <li><a href="/wiki/Vint_Cerf" title="Vint Cerf">Vint Cerf</a></li> <li><a href="/wiki/Claude_Chappe" title="Claude Chappe">Claude Chappe</a></li> <li><a href="/wiki/Yogen_Dalal" class="mw-redirect" title="Yogen Dalal">Yogen Dalal</a></li> <li><a href="/wiki/Daniel_Davis_Jr." title="Daniel Davis Jr.">Daniel Davis Jr.</a></li> <li><a href="/wiki/Donald_Davies" title="Donald Davies">Donald Davies</a></li> <li><a href="/wiki/Amos_Dolbear" title="Amos Dolbear">Amos Dolbear</a></li> <li><a href="/wiki/Thomas_Edison" title="Thomas Edison">Thomas Edison</a></li> <li><a href="/wiki/Lee_de_Forest" title="Lee de Forest">Lee de Forest</a></li> <li><a href="/wiki/Philo_Farnsworth" title="Philo Farnsworth">Philo Farnsworth</a></li> <li><a href="/wiki/Reginald_Fessenden" title="Reginald Fessenden">Reginald Fessenden</a></li> <li><a href="/wiki/Elisha_Gray" title="Elisha Gray">Elisha Gray</a></li> <li><a href="/wiki/Oliver_Heaviside" title="Oliver Heaviside">Oliver Heaviside</a></li> <li><a href="/wiki/Robert_Hooke" title="Robert Hooke">Robert Hooke</a></li> <li><a href="/wiki/Erna_Schneider_Hoover" title="Erna Schneider Hoover">Erna Schneider Hoover</a></li> <li><a href="/wiki/Harold_Hopkins_(physicist)" title="Harold Hopkins (physicist)">Harold Hopkins</a></li> <li><a href="/wiki/Gardiner_Greene_Hubbard" title="Gardiner Greene Hubbard">Gardiner Greene Hubbard</a></li> <li><a href="/wiki/List_of_Internet_pioneers" title="List of Internet pioneers">Internet pioneers</a></li> <li><a href="/wiki/Bob_Kahn" class="mw-redirect" title="Bob Kahn">Bob Kahn</a></li> <li><a href="/wiki/Dawon_Kahng" title="Dawon Kahng">Dawon Kahng</a></li> <li><a href="/wiki/Charles_K._Kao" title="Charles K. Kao">Charles K. Kao</a></li> <li><a href="/wiki/Narinder_Singh_Kapany" title="Narinder Singh Kapany">Narinder Singh Kapany</a></li> <li><a href="/wiki/Hedy_Lamarr" title="Hedy Lamarr">Hedy Lamarr</a></li> <li><a href="/wiki/Roberto_Landell_de_Moura" title="Roberto Landell de Moura">Roberto Landell de Moura</a></li> <li><a href="/wiki/Innocenzo_Manzetti" title="Innocenzo Manzetti">Innocenzo Manzetti</a></li> <li><a href="/wiki/Guglielmo_Marconi" title="Guglielmo Marconi">Guglielmo Marconi</a></li> <li><a href="/wiki/Robert_Metcalfe" title="Robert Metcalfe">Robert Metcalfe</a></li> <li><a href="/wiki/Antonio_Meucci" title="Antonio Meucci">Antonio Meucci</a></li> <li><a href="/wiki/Samuel_Morse" title="Samuel Morse">Samuel Morse</a></li> <li><a href="/wiki/Jun-ichi_Nishizawa" title="Jun-ichi Nishizawa">Jun-ichi Nishizawa</a></li> <li><a href="/wiki/Charles_Grafton_Page" title="Charles Grafton Page">Charles Grafton Page</a></li> <li><a href="/wiki/Radia_Perlman" title="Radia Perlman">Radia Perlman</a></li> <li><a href="/wiki/Alexander_Stepanovich_Popov" class="mw-redirect" title="Alexander Stepanovich Popov">Alexander Stepanovich Popov</a></li> <li><a href="/wiki/Tivadar_Pusk%C3%A1s" title="Tivadar Puskás">Tivadar Puskás</a></li> <li><a href="/wiki/Johann_Philipp_Reis" title="Johann Philipp Reis">Johann Philipp Reis</a></li> <li><a href="/wiki/Claude_Shannon" title="Claude Shannon">Claude Shannon</a></li> <li><a href="/wiki/Almon_Brown_Strowger" title="Almon Brown Strowger">Almon Brown Strowger</a></li> <li><a href="/wiki/Henry_Sutton_(inventor)" title="Henry Sutton (inventor)">Henry Sutton</a></li> <li><a href="/wiki/Charles_Sumner_Tainter" title="Charles Sumner Tainter">Charles Sumner Tainter</a></li> <li><a href="/wiki/Nikola_Tesla" title="Nikola Tesla">Nikola Tesla</a></li> <li><a href="/wiki/Camille_Tissot" title="Camille Tissot">Camille Tissot</a></li> <li><a href="/wiki/Alfred_Vail" title="Alfred Vail">Alfred Vail</a></li> <li><a href="/wiki/Thomas_A._Watson" title="Thomas A. Watson">Thomas A. Watson</a></li> <li><a href="/wiki/Charles_Wheatstone" title="Charles Wheatstone">Charles Wheatstone</a></li> <li><a href="/wiki/Vladimir_K._Zworykin" title="Vladimir K. Zworykin">Vladimir K. Zworykin</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Transmission_medium" title="Transmission medium">Transmission media</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Coaxial_cable" title="Coaxial cable">Coaxial cable</a></li> <li><a href="/wiki/Fiber-optic_communication" title="Fiber-optic communication">Fiber-optic communication</a> <ul><li><a href="/wiki/Optical_fiber" title="Optical fiber">optical fiber</a></li></ul></li> <li><a href="/wiki/Free-space_optical_communication" title="Free-space optical communication">Free-space optical communication</a></li> <li><a href="/wiki/Molecular_communication" title="Molecular communication">Molecular communication</a></li> <li><a href="/wiki/Radio_wave" title="Radio wave">Radio waves</a> <ul><li><a href="/wiki/Wireless" title="Wireless">wireless</a></li></ul></li> <li><a href="/wiki/Transmission_line" title="Transmission line">Transmission line</a> <ul><li><a href="/wiki/Telecommunication_circuit" title="Telecommunication circuit">telecommunication circuit</a></li></ul></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Network_topology" title="Network topology">Network topology</a> and switching</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Bandwidth_(computing)" title="Bandwidth (computing)">Bandwidth</a></li> <li><a href="/wiki/Telecommunications_link" title="Telecommunications link">Links</a></li> <li><a href="/wiki/Node_(networking)" title="Node (networking)">Nodes</a> <ul><li><a href="/wiki/Terminal_(telecommunication)" title="Terminal (telecommunication)">terminal</a></li></ul></li> <li><a href="/wiki/Network_switch" title="Network switch">Network switching</a> <ul><li><a href="/wiki/Circuit_switching" title="Circuit switching">circuit</a></li> <li><a href="/wiki/Packet_switching" title="Packet switching">packet</a></li></ul></li> <li><a href="/wiki/Telephone_exchange" title="Telephone exchange">Telephone exchange</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Multiplexing" title="Multiplexing">Multiplexing</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Space-division_multiple_access" title="Space-division multiple access">Space-division</a></li> <li><a href="/wiki/Frequency-division_multiplexing" title="Frequency-division multiplexing">Frequency-division</a></li> <li><a href="/wiki/Time-division_multiplexing" title="Time-division multiplexing">Time-division</a></li> <li><a href="/wiki/Polarization-division_multiplexing" title="Polarization-division multiplexing">Polarization-division</a></li> <li><a href="/wiki/Orbital_angular_momentum_multiplexing" title="Orbital angular momentum multiplexing">Orbital angular-momentum</a></li> <li><a href="/wiki/Code-division_multiple_access" title="Code-division multiple access">Code-division</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Concepts</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Communication_protocol" title="Communication protocol">Communication protocol</a></li> <li><a href="/wiki/Computer_network" title="Computer network">Computer network</a></li> <li><a href="/wiki/Data_communication" title="Data communication">Data transmission</a></li> <li><a href="/wiki/Store_and_forward" title="Store and forward">Store and forward</a></li> <li><a href="/wiki/Telecommunications_equipment" title="Telecommunications equipment">Telecommunications equipment</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Telecommunications_network" title="Telecommunications network">Types of network</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Cellular_network" title="Cellular network">Cellular network</a></li> <li><a href="/wiki/Ethernet" title="Ethernet">Ethernet</a></li> <li><a href="/wiki/Integrated_Services_Digital_Network" class="mw-redirect" title="Integrated Services Digital Network">ISDN</a></li> <li><a href="/wiki/Local_area_network" title="Local area network">LAN</a></li> <li><a href="/wiki/Mobile_telephony" title="Mobile telephony">Mobile</a></li> <li><a href="/wiki/Next-generation_network" title="Next-generation network">NGN</a></li> <li><a href="/wiki/Public_switched_telephone_network" title="Public switched telephone network">Public Switched Telephone</a></li> <li><a href="/wiki/Radio_network" title="Radio network">Radio</a></li> <li><a href="/wiki/Television_broadcasting" class="mw-redirect" title="Television broadcasting">Television</a></li> <li><a href="/wiki/Telex" title="Telex">Telex</a></li> <li><a href="/wiki/UUCP" title="UUCP">UUCP</a></li> <li><a href="/wiki/Wide_area_network" title="Wide area network">WAN</a></li> <li><a href="/wiki/Wireless_network" title="Wireless network">Wireless network</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Telecommunications_network" title="Telecommunications network">Notable networks</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/ARPANET" title="ARPANET">ARPANET</a></li> <li><a href="/wiki/BITNET" title="BITNET">BITNET</a></li> <li><a href="/wiki/CYCLADES" title="CYCLADES">CYCLADES</a></li> <li><a href="/wiki/FidoNet" title="FidoNet">FidoNet</a></li> <li><a href="/wiki/Internet" title="Internet">Internet</a></li> <li><a href="/wiki/Internet2" title="Internet2">Internet2</a></li> <li><a href="/wiki/JANET" title="JANET">JANET</a></li> <li><a href="/wiki/NPL_network" title="NPL network">NPL network</a></li> <li><a href="/wiki/Toasternet" title="Toasternet">Toasternet</a></li> <li><a href="/wiki/Usenet" title="Usenet">Usenet</a></li></ul> </div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Locations</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"> <ul><li><a href="/wiki/Category:Telecommunications_in_Africa" title="Category:Telecommunications in Africa">Africa</a></li> <li>Americas <ul><li><a href="/wiki/Category:Telecommunications_in_North_America" title="Category:Telecommunications in North America">North</a></li> <li><a href="/wiki/Category:Telecommunications_in_South_America" title="Category:Telecommunications in South America">South</a></li></ul></li> <li><a href="/wiki/Category:Communications_in_Antarctica" title="Category:Communications in Antarctica">Antarctica</a></li> <li><a href="/wiki/Category:Telecommunications_in_Asia" title="Category:Telecommunications in Asia">Asia</a></li> <li><a href="/wiki/Category:Telecommunications_in_Europe" title="Category:Telecommunications in Europe">Europe</a></li> <li><a href="/wiki/Category:Telecommunications_in_Oceania" title="Category:Telecommunications in Oceania">Oceania</a></li> <li>(<a href="/wiki/List_of_telecommunications_regulatory_bodies" title="List of telecommunications regulatory bodies">Global telecommunications regulation bodies</a>)</li></ul> </div></td></tr><tr><td class="navbox-abovebelow" colspan="2"><div> <ul><li><img alt="" src="//upload.wikimedia.org/wikipedia/commons/thumb/4/4e/Telecom-icon.svg/16px-Telecom-icon.svg.png" decoding="async" width="16" height="16" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/4/4e/Telecom-icon.svg/24px-Telecom-icon.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/4/4e/Telecom-icon.svg/32px-Telecom-icon.svg.png 2x" data-file-width="500" data-file-height="500" /> <a href="/wiki/Portal:Telecommunication" title="Portal:Telecommunication">Telecommunication portal</a></li> <li><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/16px-Symbol_category_class.svg.png" decoding="async" width="16" height="16" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/23px-Symbol_category_class.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/9/96/Symbol_category_class.svg/31px-Symbol_category_class.svg.png 2x" data-file-width="180" data-file-height="185" /> <a href="/wiki/Category:Telecommunications" title="Category:Telecommunications">Category</a></li> <li><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/d/db/Symbol_list_class.svg/16px-Symbol_list_class.svg.png" decoding="async" width="16" height="16" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/d/db/Symbol_list_class.svg/23px-Symbol_list_class.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/d/db/Symbol_list_class.svg/31px-Symbol_list_class.svg.png 2x" data-file-width="180" data-file-height="185" /> <a href="/wiki/Outline_of_telecommunication" title="Outline of telecommunication">Outline</a></li> <li><img alt="" src="//upload.wikimedia.org/wikipedia/en/thumb/4/4a/Commons-logo.svg/12px-Commons-logo.svg.png" decoding="async" width="12" height="16" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/4/4a/Commons-logo.svg/18px-Commons-logo.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/4/4a/Commons-logo.svg/24px-Commons-logo.svg.png 2x" data-file-width="1024" data-file-height="1376" /> <a href="https://commons.wikimedia.org/wiki/Category:Telecommunications" class="extiw" title="commons:Category:Telecommunications">Commons</a></li></ul> </div></td></tr></tbody></table></div> <div class="navbox-styles"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1129693374"><link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1236075235"></div><div role="navigation" class="navbox authority-control" aria-label="Navbox" style="padding:3px"><table class="nowraplinks hlist navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="row" class="navbox-group" style="width:1%"><a href="/wiki/Help:Authority_control" title="Help:Authority control">Authority control databases</a>: National <a href="https://www.wikidata.org/wiki/Q81945#identifiers" title="Edit this at Wikidata"><img alt="Edit this at Wikidata" src="//upload.wikimedia.org/wikipedia/en/thumb/8/8a/OOjs_UI_icon_edit-ltr-progressive.svg/10px-OOjs_UI_icon_edit-ltr-progressive.svg.png" decoding="async" width="10" height="10" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/en/thumb/8/8a/OOjs_UI_icon_edit-ltr-progressive.svg/15px-OOjs_UI_icon_edit-ltr-progressive.svg.png 1.5x, //upload.wikimedia.org/wikipedia/en/thumb/8/8a/OOjs_UI_icon_edit-ltr-progressive.svg/20px-OOjs_UI_icon_edit-ltr-progressive.svg.png 2x" data-file-width="20" data-file-height="20" /></a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"><ul><li><a rel="nofollow" class="external text" href="https://d-nb.info/gnd/4770362-3">Germany</a></li><li><a rel="nofollow" class="external text" href="https://id.loc.gov/authorities/sh98004350">United States</a></li><li><a rel="nofollow" class="external text" href="https://id.ndl.go.jp/auth/ndlna/00959468">Japan</a></li><li><a rel="nofollow" class="external text" href="http://catalogo.bne.es/uhtbin/authoritybrowse.cgi?action=display&authority_id=XX545253">Spain</a></li><li><a rel="nofollow" class="external text" href="https://kopkatalogs.lv/F?func=direct&local_base=lnc10&doc_number=000101676&P_CON_LNG=ENG">Latvia</a></li><li><a rel="nofollow" class="external text" href="https://www.nli.org.il/en/authorities/987007534854905171">Israel</a></li></ul></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=Voice_over_IP&oldid=1263667331">https://en.wikipedia.org/w/index.php?title=Voice_over_IP&oldid=1263667331</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:Voice_over_IP" title="Category:Voice over IP">Voice over IP</a></li><li><a href="/wiki/Category:Broadband" title="Category:Broadband">Broadband</a></li><li><a href="/wiki/Category:Videotelephony" title="Category:Videotelephony">Videotelephony</a></li><li><a href="/wiki/Category:Audio_network_protocols" title="Category:Audio network protocols">Audio network protocols</a></li><li><a href="/wiki/Category:Office_equipment" title="Category:Office equipment">Office equipment</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:CS1_maint:_unfit_URL" title="Category:CS1 maint: unfit URL">CS1 maint: unfit URL</a></li><li><a href="/wiki/Category:CS1_maint:_bot:_original_URL_status_unknown" title="Category:CS1 maint: bot: original URL status unknown">CS1 maint: bot: original URL status unknown</a></li><li><a href="/wiki/Category:Webarchive_template_wayback_links" title="Category:Webarchive template wayback links">Webarchive template wayback links</a></li><li><a href="/wiki/Category:Articles_with_short_description" title="Category:Articles with short description">Articles with short description</a></li><li><a href="/wiki/Category:Short_description_is_different_from_Wikidata" title="Category:Short description is different from Wikidata">Short description is different from Wikidata</a></li><li><a href="/wiki/Category:Use_mdy_dates_from_August_2021" title="Category:Use mdy dates from August 2021">Use mdy dates from August 2021</a></li><li><a href="/wiki/Category:Use_American_English_from_October_2023" title="Category:Use American English from October 2023">Use American English from October 2023</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_needing_additional_references_from_November_2019" title="Category:Articles needing additional references from November 2019">Articles needing additional references from November 2019</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:Wikipedia_articles_in_need_of_updating_from_April_2022" title="Category:Wikipedia articles in need of updating from April 2022">Wikipedia articles in need of updating from April 2022</a></li><li><a href="/wiki/Category:All_Wikipedia_articles_in_need_of_updating" title="Category:All Wikipedia articles in need of updating">All Wikipedia articles in need of updating</a></li><li><a href="/wiki/Category:All_articles_with_unsourced_statements" title="Category:All articles with unsourced statements">All articles with unsourced statements</a></li><li><a href="/wiki/Category:Articles_with_unsourced_statements_from_April_2022" title="Category:Articles with unsourced statements from April 2022">Articles with unsourced statements from April 2022</a></li><li><a href="/wiki/Category:Articles_with_unsourced_statements_from_September_2013" title="Category:Articles with unsourced statements from September 2013">Articles with unsourced statements from September 2013</a></li><li><a href="/wiki/Category:Articles_with_unsourced_statements_from_June_2022" title="Category:Articles with unsourced statements from June 2022">Articles with unsourced statements from June 2022</a></li><li><a href="/wiki/Category:Wikipedia_articles_needing_clarification_from_December_2019" title="Category:Wikipedia articles needing clarification from December 2019">Wikipedia articles needing clarification from December 2019</a></li><li><a href="/wiki/Category:Articles_with_unsourced_statements_from_March_2024" title="Category:Articles with unsourced statements from March 2024">Articles with unsourced statements from March 2024</a></li><li><a href="/wiki/Category:Articles_needing_more_detailed_references" title="Category:Articles needing more detailed references">Articles needing more detailed references</a></li><li><a href="/wiki/Category:Articles_with_unsourced_statements_from_July_2023" title="Category:Articles with unsourced statements from July 2023">Articles with unsourced statements from July 2023</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 18 December 2024, at 00:10 (UTC).</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=Voice_over_IP&mobileaction=toggle_view_mobile" class="noprint stopMobileRedirectToggle">Mobile view</a></li> </ul> <ul id="footer-icons" class="noprint"> <li id="footer-copyrightico"><a href="https://wikimediafoundation.org/" class="cdx-button cdx-button--fake-button cdx-button--size-large cdx-button--fake-button--enabled"><img src="/static/images/footer/wikimedia-button.svg" width="84" height="29" alt="Wikimedia Foundation" loading="lazy"></a></li> <li id="footer-poweredbyico"><a href="https://www.mediawiki.org/" class="cdx-button cdx-button--fake-button cdx-button--size-large cdx-button--fake-button--enabled"><img src="/w/resources/assets/poweredby_mediawiki.svg" alt="Powered by MediaWiki" width="88" height="31" loading="lazy"></a></li> </ul> </footer> </div> </div> </div> <div class="vector-settings" id="p-dock-bottom"> <ul></ul> </div><script>(RLQ=window.RLQ||[]).push(function(){mw.config.set({"wgHostname":"mw-web.codfw.main-55db797859-tnfgk","wgBackendResponseTime":197,"wgPageParseReport":{"limitreport":{"cputime":"1.218","walltime":"1.420","ppvisitednodes":{"value":8463,"limit":1000000},"postexpandincludesize":{"value":260659,"limit":2097152},"templateargumentsize":{"value":8753,"limit":2097152},"expansiondepth":{"value":17,"limit":100},"expensivefunctioncount":{"value":13,"limit":500},"unstrip-depth":{"value":1,"limit":20},"unstrip-size":{"value":407012,"limit":5000000},"entityaccesscount":{"value":1,"limit":400},"timingprofile":["100.00% 1205.876 1 -total"," 49.79% 600.391 2 Template:Reflist"," 22.97% 276.983 75 Template:Cite_web"," 8.47% 102.193 3 Template:Navbox"," 7.75% 93.493 1 Template:Short_description"," 6.49% 78.295 8 Template:Fix"," 6.48% 78.191 1 Template:Computer-mediated_communication"," 5.51% 66.442 2 Template:Pagetype"," 4.50% 54.241 1 Template:Cite_encyclopedia"," 4.04% 48.686 4 Template:Citation_needed"]},"scribunto":{"limitreport-timeusage":{"value":"0.698","limit":"10.000"},"limitreport-memusage":{"value":8075715,"limit":52428800},"limitreport-logs":"table#1 {\n [\"size\"] = \"small\",\n}\ntable#1 {\n [\"size\"] = \"small\",\n}\ntable#1 {\n [\"size\"] = \"tiny\",\n}\n"},"cachereport":{"origin":"mw-api-ext.codfw.main-5d6bddb8cb-wm25n","timestamp":"20241218001010","ttl":2592000,"transientcontent":false}}});});</script> <script type="application/ld+json">{"@context":"https:\/\/schema.org","@type":"Article","name":"Voice over IP","url":"https:\/\/en.wikipedia.org\/wiki\/Voice_over_IP","sameAs":"http:\/\/www.wikidata.org\/entity\/Q81945","mainEntity":"http:\/\/www.wikidata.org\/entity\/Q81945","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":"2002-08-23T01:58:12Z","dateModified":"2024-12-18T00:10:09Z","headline":"commonly refers to methods of delivering voice communications and multimedia over IP networks"}</script> </body> </html>