H248协议介绍(英文)

1IntroductionofH.248-MediaGatewayControl(Megaco)AgendaContext&TerminationConnectModelTransactionsCommandsTransportsExampleWhatisH.248SoftswitchSGMGBICC/SIPBCP-TH.248RTP/RTCPISUP/IPISUP/MTPTDMTrunkControlEdgeWhatisH.248ContextsTransactionsTransportsSupportingreliabletransportmechanismoftransactionsbetweenMGCandMGCommandsbetweenMGCandMGaregroupedintoTransactionsDescribingtheconnectmodelandSupportingthecallcontrolLayereddescriptionofH.248ContextandTerminationContextsTerminationMediaGatewayTerminationTerminationTerminationTerminationTerminationTerminationTerminationTerm.XTerminationsContext.XContextsContextIDTopologyPriorityContextIDisassignedbyMGContextNORMALvalue:1~429467293.ContextCHOOSEValue:429467294ContextALLValue:4294967295(0xFFFFFFFF)Nullcontextvalue:0ContextsContextIDTopologyPriorityTerm.xTerm.yTerm.ZTrafficControlTerminationsTerminationSemi-permanentTerminationEphemeralTerminationRootTerminationTerminationisalogicalentityonaMGthatsourcesand/orsinksmediaand/orcontrolstreamsTerminationsTerminationIDAterminationIDisarbitrarychoosenbyMG.TerminationIDsofphysicalTerminationsareprovisionedinMG.TwotypesofWildcardingisusedwithTerminationIDs:ALL,CHOSE.DescriptorsTerminationsTerminationIDDescriptorsModemMuxMediaTerminationStateStreamLocalRemoteLocalControlEventsEventBufferSignalsAuditPackagesDigitMapServiceChangeObservedEventsStatisticsConnectModel(1)CONTEXTTerminationTerminationRTPStreamSCNBearerChannelTerminationSCNBearerChannelMediaGatewayConnectModel(2)NullCONTEXTTerminationSCNBearerChannelTerminationSCNBearerChannelMediaGatewayConnectModel(3)CONTEXTTerminationSCNBearerChannelTerminationSCNBearerChannelMediaGatewayConnectModel(4)MediaGatewayCONTEXTC1Term.T2RTPStreamTerm.T1SCNBearerChannelTerm.T3SCNBearerChannelCONTEXTC2ConnectModel(5)MediaGatewayCONTEXTC1Term.T2RTPStreamTerm.T3SCNBearerChannelCONTEXTC2Term.T1SCNBearerChannelMessages&TransactionAction1Command1Command1Command2CommandnAction2ActionnTransaction1Transaction2TransactionnMessage1Message2MessagenAHTransactionsTransactionXAction1Command1Action2Command1Command2Command3TransactionTransactionAPITransactionRequestTransactionReplySenderReceiverTransactionResponseAckTransactionPendingTransactionTransactionRequest(TransactionId{ContextID{Command_Command},...ContextID{Command_Command}})TransactionReply(TransactionID{ContextID{Response_Response},...ContextID{Response_Response}})TransactionPending(TransactionID{})TransactionAPIStructureTransactionResponseAck(TransactionID{}TransactionID{})CommandsAddModifySubtractMoveAuditValueAuditCapabilitiesNotifyServiceChangeMGCMGTransportSoftswitchMGH.248TCP/UDPIPThree-wayHandshakePort2944:Text-encodedPort2945:Binary-encodedH.248TransportSoftswitchMG1MG3MG4MG5MG2ServiceChangeRestarttimerofeveryMGisneededtoprotectedagainstrestartavalancheTimershouldbeinitiatearandomvaluebetween0andaMaximumwaitingdelay(MWD)RestartAvalancheAG-AG的呼叫建立流程(2)Reply(1)Notify{E:al/of}(4)Reply(3)Modify{SG:cg/dt;DM;E:al/on,dd/ce}(5)Notify{OE:dd/ce}}摘机(6)Reply(9)Add=User{SG:al/ri},Add=${M:SendReceive,LocalSdp,Remotesdp}(10)Reply(8)Reply(7)Add=User,Add=${M:RecOnly,LocalSDP}(18)Reply(17)Modify=User{SG:};Modify=RTP{M:SendReceive}(12)Reply(11)Modify=User{SG:cg/rt};Modify=RTP{RemoteSdp}(14)Reply拨号(13)Notify{OE:al/of}(15)Modify{E:al/on,al/fl}(16)Reply通话开始MGCMG1MG2摘机MG1挂机(1)Notify(2)Reply(5)Subtract(6)Reply(12)Reply(11)Subtract(3)Modify(4)Reply(8)Reply(7)Modify(10)Reply(9)Notify挂机(13)Modify(14)ReplyMGCMG2AG-AG的呼叫释放流程(2)Reply(1)AddIAMTG1(3)Add(4)Reply(5)Modify通话开始IAMACM(6)ReplyANMACMANMMGCTG2TG-TG的呼叫建立流程Details-ProgrammingMGTerminationforidleBehavior1.AnMGregisterswithanMGCusingtheServiceChangecommand:MG1toMGC:MEGACO/1[124.124.124.222]Transaction=9998{Context=-{ServiceChange=ROOT{Services{Method=Restart,ServiceChangeAddress=55555,Profile=ResGW/1}}}}2.TheMGCsendsareply:MGCtoMG1:MEGACO/1[123.123.123.4]:55555Reply=9998{Context=-{ServiceChange=ROOT{Services{ServiceChangeAddress=55555,Profile=ResGW/1}}}}3.TheMGCprogramsaTerminationintheNULLcontext.MGCtoMG1:MEGACO/1[123.123.123.4]:55555Transaction=9999{Context=-{Modify=A4444{Media{Stream=1{LocalControl{Mode=SendReceive,tdmc/gain=2,;indB,tdmc/ec=on},Local{v=0c=INIP4$m=audio$RTP/AVP0a=fmtp:PCMUVAD=X-NNVAD;specialvoiceactivity;detectionalgorithm}}},Events=2222{al/of}}}}Details-ProgrammingMGTerminationforidleBehavior4.TheMG1acceptstheModifywiththisreply:MG1toMGC:MEGACO/1[124.124.124.222]:55555Reply=9999{Context=-{Modify=A4444}}5.AsimilarexchangehappensbetweenMG2andtheMGC,resultinginanidleTerminationcalledA5555.Details-ProgrammingMGTerminationforidleBehavior6.MG1detectsanoffhookeventfromUser1andreportsittotheMediaGatewayControllerviatheNotifyCommand.MG1toMGC:MEGACO/1[124.124.124.222]:55555Transaction=10000{Context=-{Notify=A4444{ObservedEvents=2222{19990729T22000000:al/of}}}}7.AndtheNotifyisacknowledged.MGCtoMG1:MEGACO/1[123.123.123.4]:55555Reply=10000{Context=-{Notify=A4444}}Details-CollectingdigitsandInit.Termination.Details-CollectingdigitsandInit.Termination.8.MGCModifiestheterminationtoplaydialtone