ITU-T H.248.4 (11 2000) (英) Gateway control protoc

INTERNATIONALTELECOMMUNICATIONUNIONITU-TH.248.4TELECOMMUNICATIONSTANDARDIZATIONSECTOROFITU(11/2000)SERIESH:AUDIOVISUALANDMULTIMEDIASYSTEMSInfrastructureofaudiovisualservices–CommunicationproceduresGatewaycontrolprotocol:TransportoverStreamControlTransmissionProtocol(SCTP)ITU-TRecommendationH.248.4ITU-TH-SERIESRECOMMENDATIONSAUDIOVISUALANDMULTIMEDIASYSTEMSCHARACTERISTICSOFVISUALTELEPHONESYSTEMSH.100–H.199INFRASTRUCTUREOFAUDIOVISUALSERVICESGeneralH.200–H.219TransmissionmultiplexingandsynchronizationH.220–H.229SystemsaspectsH.230–H.239CommunicationproceduresH.240–H.259CodingofmovingvideoH.260–H.279RelatedsystemsaspectsH.280–H.299SYSTEMSANDTERMINALEQUIPMENTFORAUDIOVISUALSERVICESH.300–H.399SUPPLEMENTARYSERVICESFORMULTIMEDIAH.450–H.499MOBILITYANDCOLLABORATIONPROCEDURESOverviewofMobilityandCollaboration,definitions,protocolsandproceduresH.500–H.509MobilityforH-SeriesmultimediasystemsandservicesH.510–H.519MobilemultimediacollaborationapplicationsandservicesH.520–H.529SecurityformobilemultimediasystemsandservicesH.530–H.539SecurityformobilemultimediacollaborationapplicationsandservicesH.540–H.549MobilityinterworkingproceduresH.550–H.559Mobilemultimediacollaborationinter-workingproceduresH.560–H.569Forfurtherdetails,pleaserefertothelistofITU-TRecommendations.ITU-TRec.H.248.4(11/2000)iITU-TRecommendationH.248.4Gatewaycontrolprotocol:TransportoverStreamControlTransmissionProtocol(SCTP)SummaryThisRecommendationdefinesthetransportofH.248.1GatewayControlProtocolmessagesovertheStreamControlTransmissionProtocol(SCTP).SCTPisanalternativetoUDPorTCP.TransportofH.248.1overUDPorTCPisdefinedinAnnexD/H.248.1.NOTE–ThisRecommendationhasbeenrenumbered.ItwasformerlyknownasITU-TRec.H.248,AnnexH.SourceITU-TRecommendationH.248.4waspreparedbyITU-TStudyGroup16(2001-2004)andapprovedundertheWTSAResolution1procedureon17November2000.iiITU-TRec.H.248.4(11/2000)FOREWORDTheInternationalTelecommunicationUnion(ITU)istheUnitedNationsspecializedagencyinthefieldoftelecommunications.TheITUTelecommunicationStandardizationSector(ITU-T)isapermanentorganofITU.ITU-Tisresponsibleforstudyingtechnical,operatingandtariffquestionsandissuingRecommendationsonthemwithaviewtostandardizingtelecommunicationsonaworldwidebasis.TheWorldTelecommunicationStandardizationAssembly(WTSA),whichmeetseveryfouryears,establishesthetopicsforstudybytheITU-Tstudygroupswhich,inturn,produceRecommendationsonthesetopics.TheapprovalofITU-TRecommendationsiscoveredbytheprocedurelaiddowninWTSAResolution1.InsomeareasofinformationtechnologywhichfallwithinITU-T'spurview,thenecessarystandardsarepreparedonacollaborativebasiswithISOandIEC.NOTEInthisRecommendation,theexpressionAdministrationisusedforconcisenesstoindicatebothatelecommunicationadministrationandarecognizedoperatingagency.INTELLECTUALPROPERTYRIGHTSITUdrawsattentiontothepossibilitythatthepracticeorimplementationofthisRecommendationmayinvolvetheuseofaclaimedIntellectualPropertyRight.ITUtakesnopositionconcerningtheevidence,validityorapplicabilityofclaimedIntellectualPropertyRights,whetherassertedbyITUmembersorothersoutsideoftheRecommendationdevelopmentprocess.AsofthedateofapprovalofthisRecommendation,ITUhadreceivednoticeofintellectualproperty,protectedbypatents,whichmayberequiredtoimplementthisRecommendation.However,implementorsarecautionedthatthismaynotrepresentthelatestinformationandarethereforestronglyurgedtoconsulttheTSBpatentdatabase.ITU2002Allrightsreserved.Nopartofthispublicationmaybereproduced,byanymeanswhatsoever,withoutthepriorwrittenpermissionofITU.ITU-TRec.H.248.4(11/2000)iiiCONTENTSPage1Overview......................................................................................................................12NormativeReference....................................................................................................13ProvidingtheAt-Most-Oncefunctionality...................................................................14Transactionidentifiersandthree-wayhandshake........................................................14.1Transactionidentifiers....................................................................................14.2Three-wayhandshake.....................................................................................15Computingretransmissiontimers.................................................................................26Provisionalresponses...................................................................................................27Orderingofcommands.................................................................................................28Streamindependence....................................................................................................2ITU-TRec.H.248.4(11/2000)1ITU-TRecommendationH.248.4Gatewaycontrolprotocol:TransportoverStreamControlTransmissionProtocol(SCTP)1OverviewThisRecommendationdefinesapackagethatextendstheapplicabilityofITU-TH.248.1,Gatewaycontrolprotocol.Inparticular,thisRecommendationdefinesthetransportofH.248.1GatewayControlProtocolmessagesove