The Request URI is the contact information of the next hop in the call route. In the above example, the username of the next hop is bob, who is hosted by biloxi ...
MenuSIPINVITEheaderfieldsUnderstandingcommonheaderfieldsinaSIPINVITETheSIPINVITEisthefoundationforeverySIPphonecall.Itissimpleandflexible,butoftenpoorlyunderstoodbyusers.ThepurposeofthisarticleistoprovideaquickandeasyreferencetothecriticalheadersinaSIPINVITE.TheSIPINVITErequestisthemessagesentbythecallingparty,invitingtherecipientforasession.TheSIPheadersincludedinthisSIPINVITErequestprovideinformationaboutthemessage.ConsiderthefollowingSIPmessage,withthecommonSIPheadershighlighted:INVITEsip:[email protected]/2.0Via:SIP/2.0/TCPclient.atlanta.example.com:5060;branch=z9hG4bK74bf9Max-Forwards:70From:Alice;tag=9fxced76slTo:BobCall-ID:[email protected]:2INVITEContact:Diversion:Carol;privacy=off;reason=no-answer;counter=1;screen=noRemote-Party-ID:AliceP-Asserted-Identity:AliceP-Charge-Info:P-Source-Device:216.3.128.12Content-Type:application/sdpContent-Length:151X-BroadWorks-DNC:network-address=sip:[email protected];user=phoneUser-Agent:X-Literelease1104ostamp56125v=0o=alice28908445262890844526INIP4client.atlanta.example.coms=-c=INIP4192.0.2.101t=00m=audio49172RTP/AVP0a=rtpmap:0PCMU/8000Thefollowingsectionsexplaintheseheaderfields.RequestURIINVITEsip:[email protected]/2.0TheRequestURIisthecontactinformationofthenexthopinthecallroute.Intheaboveexample,theusernameofthenexthopisbob,whoishostedbybiloxi.example.com.ViaVia:SIP/2.0/TCPclient.atlanta.example.com:5060;branch=z9hG4bK74bf9Max-Forwards:70TheViaheaderfieldindicatesthepathtakenbytherequestsofarandhelpsinroutingtheresponsesbackalongthesamepath.IftheSIPINVITEpassedthroughmultipleSIPproxies,therewillbemultipleVIAheaders.Inthegivenexample,theresponseswillbesentbacktoclient.atlanta.example.comattheport5060.FromFrom:Alice;tag=9fxced76slTheFromheaderfieldindicatescontactinformationoftheinitiatoroftheSIPINVITErequest,Aliceinthiscase.ToTo:BobTheToheaderfieldcontainstheinformationaboutthecalledpartyortherecipientoftherequest,Bobinthisexample.Call-IDCall-ID:3848276298220188511@atlanta.example.comTheCall-IDheaderfieldisauniqueIDidentifyingtheSIPcall.Allmessagescontainingthiscall-idwillbeassignedtothesameSIPcall.ContactContact:TheContactheaderfieldprovidesaSIPorSIPSURIthatshouldbeusedtocontactthesenderoftheINVITE,Alice.DiversionDiversion:Carol;privacy=off;reason=no-answer;counter=1;screen=noThediversionheadercontainstheredirectioninformationofthecall.ItincludesthecontactinformationofthedevicethatforwardstheINVITE,andalsothereasonfordiversion.RemotePartyIDRemote-Party-ID:AliceThisSIPheaderisconsideredobsolete,butisstillusedtoconveythecallingtelephonenumberandsourceIPaddress.P-Asserted-IdentityP-Asserted-Identity:AliceTheP-Asserted-IdentityheaderfieldisanimportantSIPheaderusedamongtrustedSIPentities(typicallyintermediaries)tocarrytheidentityoftheusersendingaSIPmessageasitwasverifiedbyauthentication.Thisheaderiscommonlyusedincallcenterswhoneedtopresentthecallingnumberofitscustomer,ratherthanitactualtelephonenumber.P-Charge-InfoP-Charge-Info:TheP-Charge-Infoheaderisusedtoconveybillinginformationaboutthepartytobecharged.RecentblogpostsSTIR/SHAKENstatisticsfromMay2022BestpracticesforterminatingprovidersusingSTIR/SHAKENMorerulesproposedforSTIR/SHAKENandrobocallmitigationP-Source-Device>P-Source-Device:216.3.128.12Content-Type:application/sdpContent-Length:151ThisisaspecialheaderandincludestheIPaddressofthesourcedevicethroughaBacktoBackUserAgentX-HeaderX-BroadWorks-DNC:network-address=sip:[email protected];user=phoneASIPheaderthatbeginswithXcanbeusedtoconveyanyinformation.Forexample,anX-HeaderinaSIPINVITEisoftenusedtoconveyasubscriberaccountnumberforbilling.User-AgentUser-Agent:X-Literelease1104ostamp56125TheUser-AgentheaderfieldcontainsinformationabouttheUACoriginatingtherequest.ItdescribesthesourcedevicethatgeneratedtheSIPINVITE.ConnectionInformationc=INIP4192.0.2.101ThisisthesourceIPaddressandconnectiontypefortheaudiostream.ThiswasoneofthesimplerSIPINVITErequests,anditcouldbemorecomplexdependingonthecallflow.TheSIPINVITEisanimportantrequestmethod,andtheinformationitcontainscouldbeusednotjustforsessioninitiation,butalsoforsuchcrucialapplicationsasfrauddetection.ASIPAnalytics-drivenFraudDetectionallowsforreal-timecallblockingorcalldiversion.Jun1,2022STIR/SHAKENstatisticsfromMay2022May31,2022BestpracticesforterminatingprovidersusingSTIR/SHAKENMay25,2022MorerulesproposedforSTIR/SHAKENandrobocallmitigationMay23,2022NewSHAKENandrobocallrulesforgatewayprovidersMay16,2022PendingrobocallrulesraiseconcernMay11,2022HighlightsfromtheFCCrobocallsandSHAKENdraftorderMay4,2022STIR/SHAKENstatisticsfromApril2022Apr27,2022FCCtovoteonnewrobocallrulesforgatewayprovidersApr14,2022Webinarrecording—PreparefortheFCCSHAKENdeadlineApr4,2022STIR/SHAKENstatisticsfromMarch2022Mar30,2022DelegatecertificaterolesandbenefitsMar28,2022NoSHAKENclaimssurgeinMarchMar9,2022SHAKENimplementationclaimsamongnon-U.S.serviceprovidersMar7,2022TheevolutionofSHAKENimplementationclaimsFeb21,2022ImpactofFCCchallengestorobocallmitigationfilingsFeb14,2022FCCquestionssomeSHAKENimplementationclaimsDec13,2021FCCorderacceleratesSHAKENdeadlineforsomesmallprovidersNov1,2021CanadianSHAKENtokenaccesspolicyrevisedOct25,2021EnforcementactionagainstrobocallersintheSHAKENeraOct20,2021STI-GAannouncessupportforenhancedSHAKENfunctionalityAugust16,2021CanadianregulatorchangesserviceproviderSHAKENqualificationsJuly15,2021SHAKENforTDMstandardsapprovedSTIR/SHAKENinformationhubWhitepapers,videos,andmoreGoThissiteusescookiestoanalyzeandoptimizewebsitecontentusage.Seeourprivacypolicyformoredetails.Accept
