55VOIP培训

深圳市格林耐特通信技术有限公司GreenNET12020/1/24VOIP培训2002年3月深圳市格林耐特通信技术有限公司GreenNET22020/1/24OUTLINE★VOIP简介VOIP协议族媒体流传输信令H323SIPMGCP声音处理NGNVOIP应用中的NAT问题深圳市格林耐特通信技术有限公司GreenNET32020/1/24Whatisit•VoIPStandsforVoiceoverIP•V2oIPStandsforVoice&VideooverIP深圳市格林耐特通信技术有限公司GreenNET42020/1/24采样深圳市格林耐特通信技术有限公司GreenNET52020/1/24编码深圳市格林耐特通信技术有限公司GreenNET62020/1/24传送UDP深圳市格林耐特通信技术有限公司GreenNET72020/1/24寻址•电话号码/别名和IP地址的对应TerminalPacketBasedNetworksGatekeeperGatewayCircuitSwitchedNetworks深圳市格林耐特通信技术有限公司GreenNET82020/1/24呼叫建立和控制PSTNGatekeeperTerminalH.225/RASmessagesoverRASchannelGatewayH.245messagesovercallcontrolchannelH.225/Q.931messagesovercallsignalingchannelH.225/RASmessagesoverRASchannelH.225/Q.931(optional)H.225/Q.931(optional)H.245messages(optional)深圳市格林耐特通信技术有限公司GreenNET92020/1/24OUTLINEVOIP简介★VOIP协议族媒体流传输信令H323SIPMGCP声音处理NGNVOIP应用中的NAT问题深圳市格林耐特通信技术有限公司GreenNET102020/1/24VOIP协议族RTCPRTPIPMGCPCallControlandSignalingSignalingandGatewayControlMediaH.225Q.931H.323TCPRASUDPSIPH.245Audio/VideoRTSP深圳市格林耐特通信技术有限公司GreenNET112020/1/24OUTLINEVOIP简介VOIP协议族★媒体流传输信令H323SIPMGCP声音处理深圳市格林耐特通信技术有限公司GreenNET122020/1/24实时媒体流•实时流–在一个给定的时间必须可用或就绪的数据流•和普通数据的区别：实时•分组交换网上传输实时流的问题：–时延–抖动–错序–丢失深圳市格林耐特通信技术有限公司GreenNET132020/1/24时延深圳市格林耐特通信技术有限公司GreenNET142020/1/24固定延迟的构成•传播－－每公里6毫秒•串行化•处理–编码/压缩/解压缩/解码–分组化ProcessingDelayPropagationDelaySerializationDelay—BuffertoSerialLink深圳市格林耐特通信技术有限公司GreenNET152020/1/24变化时延构成•排队延迟•消抖缓冲器•可变分组规模DejitterBufferQueuingDelayQueuingDelayQueuingDelay深圳市格林耐特通信技术有限公司GreenNET162020/1/24丢失深圳市格林耐特通信技术有限公司GreenNET172020/1/24解决的方法深圳市格林耐特通信技术有限公司GreenNET182020/1/24RTP/RTCPRFC1889/1890深圳市格林耐特通信技术有限公司GreenNET192020/1/24RTP/RTCPRFC1889/1890•时间戳：抖动•序列号：错序、丢失•通过JITTERBUFFER实现深圳市格林耐特通信技术有限公司GreenNET202020/1/24OUTLINEVOIP简介VOIP协议族媒体流传输★信令H323SIPMGCP声音处理NGNVOIP应用中的NAT问题深圳市格林耐特通信技术有限公司GreenNET212020/1/24信令•用户的接入•呼叫的建立和控制•H323–ITU-T•SIP/MGCP--IETF•Megaco/H248–IETF/ITU-TIPMGCPCallControlandSignalingSignalingandGatewayControlH.225Q.931H.323TCPRASUDPSIPH.245深圳市格林耐特通信技术有限公司GreenNET222020/1/24H323框架•Callestablishmentandteardown.•AudiovisualormultimediaconferencingTerminalGatewayPacketBasedNetworksMultipointControlUnitGatekeeperCircuitSwitchedNetworks深圳市格林耐特通信技术有限公司GreenNET232020/1/24H323框架深圳市格林耐特通信技术有限公司GreenNET242020/1/24H323终端•H.323terminalsareclientendpointsthatmustsupport:–H.225callcontrolsignaling.–H.245controlchannelsignaling.–RTP/RTCPprotocolsformediapackets.–Audiocodecs.Videocodecssupportisoptional深圳市格林耐特通信技术有限公司GreenNET252020/1/24H323GATEWAY•Agatewayprovidestranslation:–Forexample,agatewaycanprovidetranslationbetweenentitiesinapacketswitchednetwork(example,IPnetwork)andcircuitswitchednetwork(example,PSTNnetwork).–Gatewayscanalsoprovidetransmissionformatstranslation,communicationprocedurestranslation,H.323andnon-H.323endpointstranslationsorcodectranslation深圳市格林耐特通信技术有限公司GreenNET262020/1/24H323GateKeeper•Gatekeepersprovidethesefunctions:–Addresstranslation.–Bandwidthcontrol.–Zonemanagement.–Admissioncontrol.–Callcontrolsignaling(optional).–Callauthorization(optional).–Bandwidthmanagement(optional).–Callmanagement(optional).•GatekeepersareoptionalbutifpresentinaH.323system,allH.323endpointsmustregisterwiththegatekeeperandreceivepermissionbeforemakingacall.深圳市格林耐特通信技术有限公司GreenNET272020/1/24H.323MultipointControlUnit•MCUprovidesupportforconferencesofthreeormoreendpoints.•AnMCUconsistof:–MultipointController(MC)–providescontrolfunctions.–MultipointProcessor(MP)–receivesandprocessesaudio,videoand/ordatastreams.深圳市格林耐特通信技术有限公司GreenNET282020/1/24H323协议栈深圳市格林耐特通信技术有限公司GreenNET292020/1/24H323协议栈•CallControlandSignaling•H.245-Capabilitiesadvertisement,mediachannelestablishment,andconferencecontrol.•H.225•Q.931-callsignalingandcallsetup.•RAS-registrationandotheradmissioncontrolwithagatekeeper.CallControlandSignalingData/FaxMediaIPUDPRTPAudioCodecG.711G.723G.729VideoCodecH.261H.263RTCPH.225Q.931H.225RASH.245T.120T.38TCPTCPUDPTCPData/FaxT.120–Dataconferencing.T.38–Fax.MediaH.261andH.263–Videocodecs.G.711,G.723,G.729–Audiocodecs.RTP/RTCP–Media.H.323深圳市格林耐特通信技术有限公司GreenNET302020/1/24H323实体和信令•H.245–Aprotocolforcapabilitiesadvertisement,mediachannelestablishmentandconferencecontrol.•H.225-CallControl.•-Q.931–Aprotocolforcallcontrolandcallsetup.•-RAS–Registration,admissionandstatusprotocolusedforcommunicatingbetweenanH.323endpointandagatekeeper.PSTNGatekeeperTerminalH.225/RASmessagesoverRASchannelGatewayH.245messagesovercallcontrolchannelH.225/Q.931messagesovercallsignalingchannelH.225/RASmessagesoverRASchannelH.225/Q.931(optional)H.225/Q.931(optional)H.245messages(optional)H.245messages(optional)深圳市格林耐特通信技术有限公司GreenNET312020/1/24ProcessforEstablishingCommunication•EstablishingcommunicationusingH.323mayoccursinfivesteps:1.Callsetup.2.Initialcommunicationandcapabilitiesexchange.3.Audio/videocommunicationestablishment.4.Callservices.5.Calltermination.深圳市格林耐特通信技术有限公司GreenNET322020/1/24简化的H.323CallSetup–Bothendpointshavepreviouslyregisteredwiththegatekeeper.–TerminalAinitiatethecalltothegatekeeper.(RASmessagesareexchanged).–The