What is Session Initiation Protocol (SIP)? - Twilio

Using SIP to connect to Twilio is one way to get access to Twilio's global reach and powerful automation and scripting functions. It's easy to connect your on- ... TwilioDocs SMS Voice Runtime Video Studio Alldocs... SDKs Help Login Signup SMS Voice Runtime Video Studio Alldocs... SDKs Help Login Signup SessionInitiationProtocol(SIP)isasignallingprotocolforinitiating,terminating,andmodifyingusersessionsoveranIPnetwork. Mostcommonly,SIPisusedforVoiceOverIP(VoIP)services,butisalsooftenusedforothercommunicationssessionssuchasvideo callsandinstantmessagingsessions. AnEasytoImplementStandardforDigitalCommunications ComparedtopredecessorssuchasH.323,SIPisamucheasiertoimplementandmuchmoreflexibleprotocol.ItwasfirststandardizedinMarch1999'sRFC2543andhasbeensubsequentlyrevisedinJune2002'sRFC3261(withvariousupdatessincethen). BymappingSIPendpoints(useragents,inSIPterminology)toUniformResourceIdentifiers(URIs),SIPisquitesimilartotheHTTPmodelofrequestsandresponses.UnlikeHTTP,SIPcanuseUDPorothertransporttypes.SIPisatext-basedprotocolandusesUTF-8encoding. *SeeTwilio'sBestPracticesforSIPSecurity* HowTwilioUsesSIP UsingSIPtoconnecttoTwilioisonewaytogetaccesstoTwilio'sglobalreachandpowerfulautomationandscriptingfunctions. It'seasytoconnectyouron-siteorvirtualPrivateBranchExchange(PBX)withTwilio'sservers.Here'souroverviewofconnectingyourexistingSIPcommunicationsinfrastructuretous. TwilioalsooffersTwilioInterconnect,avariedservicewhereweofferadirectconnectionthatcanlargelyorwhollyavoidthepublicinternet.Wehaveprovisionstoconnectwithyourcloudinfrastructuredirectly(suchaswithAmazonWebServices,Google'sComputeCloud,andMicrosoftAzure),physicallyinterconnectatoneofourgloballocations,tunneloveraVPN,orconnecttoyourMPLSNetwork. TwilioInterconnectalsooffersadditionalQoSguaranteesandSLAsaswellasenterprise-gradesecurity. SIPTrunkingwithTwilio TwilioalsooffersourElasticSIPTrunkingservice,wherewecaninstantlyprovisionaSIPnetworkforyouworldwide.ConnecttoaSIPURIthat'slocaltoyourfirmandwewilldotherest-alloveraglobalprivatebackbonethatminimizestraversalonthepublicinternet.SeesomepossibleSIPTrunkingsetups. Weofferunlimitedconcurrentcallcapacity-letusworryaboutthescalingandthecapacitywhileyourunyourbusiness.We'vealsowrittenmoreaboutSIPTrunkingifyou'reitchingtogetstartedorjustwanttolearnmore. HowSIPandTwilioCanWorkwithYourBusiness Whetheryou'retakingthefirststepstowardsmodernizingacallcenter,addingadditionalchannelsofsupportsuchasWebRTC,Chat,andSMS,orlookingtoreducelatencyandleverageourmassivescale,Twiliohasasolutionforyou. ReadaboutourSIPTrunkingofferings,readaboutourSIPintegrationinourdocumentation,ortalktosales.Wecan'twaittohelpyoubuild. Readytostartbuilding?Signupnow. Ratethispage: ⬅Backtoglossary Contributors: Thankyouforyourfeedback! Pleaseselectthereason(s)foryourfeedback.Theadditionalinformationyouprovidehelpsusimproveourdocumentation: IfapplicablefillinthecountrieswhereyouareusingTwilio Missinginformationorcode Contentisconfusingorhardtofollow Inaccurateoroutdatedinformation Brokenlinkortypo Didnotsolvemyproblem Contentiseasytofollow Solvedmyproblem Other Sendyoursuggestions Needhelp?TalktoSupport ProtectedbyreCAPTCHA–Privacy-Terms Sendingyourfeedback... 🎉Thankyouforyourfeedback! Somethingwentwrong.Pleasetryagain. Thanksforyourfeedback! Referusandget$10in3simplesteps! Step1 Getlink Getafreepersonalreferrallinkhere Step2 Give$10 Yourusersignsupandupgradeusinglink Step3 Get$10 1,250freeSMSesOR1,000freevoiceminsOR12,000chatsORmore Learnmoreaboutthereferralprogram