端到端的VoLTE通话(1)--初始接入和默认承载创建.docx

HSSPCRFDiameter(Gx)MMEGTP-C(S11)RRCDRBS1-AP(S1-MME)GTP-U(S1)SAEGWIMSPDNDefau1tEPSBearer(QCI=9)forInternetInternetPDNDefau1tEPSBearer(QCI=5)forSIPDedicatedEPSBeerer(Qa=1)forRTPIIMSPDN4:Ta格康一起学5g端至IJ端的Vo1TE通话一初始接入和默认承载创建#4G#VO1TE#IMSAPN4G(1TE)网络中终端(UE)开机后将使用默认APN建立PDN连接；支持Vo1TE通话的网络运营商;1$为UE提供两个APNs9WiInternetAPN和IMSAPNo其中:默认APNdnternetAPN)用于互联网数据流量,EPS承载的QCI值为“9”。在与互联网APN建立PDN连接后，UE尝试与IMS的APN即“IMSAPN”建立额外的PDN连接。IMSAPN在UE中预先配置,默认EPS承载的QC1值为5,用于SIP信令。一旦完成与IMSAPN的PDN连接并成功创建默认EPS承载，UE就能够与IMSCore通信进行Vo1TE呼叫月艮务。VO1TE附着和承载初始附着由两个例程组成。一是在RRC、S1AP和GTP-C接口上建立信令路径；二是建立承载路径其中包括数据无线承载(DRB)和GTP-U(即S1和S5承载)，见图1所示。-SignaIingPathBearerPathDiameter(S6a)图1支持VO1TE的4G网络终端(UE)的信令连接过程涉及:认证、NAS安全程和位置更新过程。因此当信令连接完成后，UE开始拥有与网络通信的安全连接并且网络侧掌握终端(UE)位置、用户信息、QoS要求等的上下文；UE到PGW间建立了默认EPS承载，其中包括:DRB、S1和S5承载。一、初始附着(Ii1itia1attachment)包括UE与eNB建立RRC连接，eNB与MME建立S1AP会话用于信令。一旦RRC和SIAP连接建立，NAS消息就在UE和MME之间交换，它由两层组成即:EPS会话管理(ESM)层和EPS移动管理(EMM)层。ESM消息用于控制PDN连接、承载资源分配/修改、默认/专用EPS承载的激活/去激活。EMM消息用于使用例如附着、去附着、跟踪区域更新(TAU)以维持UE的移动性。期间NAS消息通过SI链路在RRC和eNB透明地传输。UEeNBMMEISGW/PGWIPCRF1. RRCConnec1Estab1ishmentcinformation,Dc2. RRCConnedPredefinedC(XMode.Defau1tdements3. AcceptRequonRequest0use.PredebnedcomainMdkator,nthgurationstatusMUE1DtfthrnRequest)UTRAN-nAnswer)KASME)onSetupfigurationidentity.ConfigurationIdentst(PONConnectDefau1tConhgurati1y,PCHInfOrmMVitYRequest)ferece)onIHSSI<EPSAttachTyPP.VoKedomainRWConnectionS«tiRJtCtr>Mctionid,UErYoaccesC4f>ab/typComp1eteinitia1UEMessa<eRtCtfMCt1onM.IaccessG>ab11<ty.TAIIIIENd1o.iCG.J4.AIR(Authenti1TFAuthentkaioncationIfformatque$todfonatk：S,AUTN,MS,Ve<1P1AuthentKatkxv5.AIA(Authent5NId.匕IdcationitE-UTRANVecto(RAN5RNA5SecuritySeup(integfttyproMion&ciperin<2JRRCa_3S1AP»4-NASSecurity»图2.VO1TE终端的初始附着o1-2空闲模式的UE通过发送RRCConnectionrequest请求eNB建立信令连接。eNB根据接收到的无线配置分配网络资源，并通过发送RRC连接设置向UE发起RRe连接。of3UE根据接收到的预定义配置标识所标识的预定义参数来配置无线承载和传输信道，并通过向eNB发送RRC连接设置完成来确认RRC连接。同时，NAS消息(即EMM层的附着请求和ESM层PDN连接请求)通过包含在RRC和SIAP消息(即分别为RRC连接设置完成和Initia1UEMeSSage)中的eNB透明地传递给MMEoSIAP接口IniIia1UEMeSSage的NAS部分消息如下：Non-Access-StratumNAS-P1MJ:07417208495078040040990805e0e0c0401900270209d031.securityheadertype:P1ainnasmessage,notsecurityprotected(O).O111Protoco1discriinaor:EPSobi1ityEanagementmessages(0x07)NASEPSMObi1itvManaaPtnPtTtMPqSaaeTVd:AttaChroauost(0x41)0Typeofsecuritycontextf1ag(TSC):Nativesecuritycontext(forsiasme).111.-naskeysetidentifier:nokeyisavai1ab1e(7).0.spareb1t(s):OxOOO1O=EPSattachtvoe:COnbinedeps/imsiattach(2)母EPSmobi1eidentity_UEnetworkCaPabi1IESMmessageCQnta1ength:39ESMmessagecontainercontents：0209d031d12720808021100100108106CXXX)00830600.OOOO.-EPSbeareridentity:NoEP5beareridentityassigned(0).OO1OProtoco1d1scriminator:EPSsessionmanagementmessages(0x02)Proceduretransactionidentity:9nasEPSsessionmanagementmessages:PDNConnectJvirvreoues(OXd(HOO11.=PDNtype:IPv4v6.OOO1Requesttype:initia1request(1)£EsMInformationtransferf1ag±1Protoco1configurationoptionsBDRXParameterMSNetworkcapabi1ity(£TMSIstatus+Mobi1estationc1assmark2÷Mobi1estationc1assmark3SSupportedcodec1ist-supportedcodecsvoicedomainpreferenceandUE,susagesettingE1ementID:OxSd1ength:1OOOO0.-Spareb<t(s):00.«UE'susagesetting:voicecentric.r.iyc-11avoicedomain口refer-forE-IJTRAN：IMSPSVOineDreferr1eHu呢Sa)Mt<r以忘arvI?MSneworkfeaturesupport图3.初始UE消息内容如希望UE同时使用1TE和non1TE则附着类型将设置为“组合EPS/IMSI附着“，其中：EPS连接类型:EPS连接/组合Epszimsi连接eps紧急连接；语音域偏好:语音通话-首选网络。语音域偏好设置为“IMSPS语音优先，CS语音次要”。欢迎参阅：4G中联合附着(COmbinedAttaCh)是个啥？二、终端协议配置UE通过协议配置选项(PCO)来请求某些信息，如UEIP/DNSIP地址等，下图(4)显示在Initia1UEMessage中PCO配置示例。ESMmessagecontainer1ength:39ESMmessagecontainercontents:0209d031d127208080211001000010810600000000830600.OOOO.EPSbeareridentity:NoEPSbeareridentityassigned(O)OO1O=Protoco1discriminator:EPSsessionmanagementmessages(0x02)Proceduretransactionidentity:9NASEPSsessionmanagementmessages:PDNconnectivityrequest(OxdO)OO11.=PDNtype:IPv4v6.OOO1-Requesttype:initia1request(1)±ESMInformat1ontrans/enf1aqProtoco1configurationoptionsE1ementID：0x271ength:321inkdirection:MStonetwork(0)1=Extension:TrueconfigurationProtoco1:pppforusewithippdptypeorippdntype(0)SProtoco1orContainerid：internetProtoco1contro1Protoco1(0x8021)国Protoco1orcontainerid：DNSserverIPv4AddressRequest(OxOOOd)S)Protoco1orContainerid：DNSserverIPv6AddressRequest(0x0003)±Protoco1orcontainerid：IPaddressa11ocationvianas-；，：端口老蜃十也序后5+Protoco1orcontainerid：IPv41inkMTURequest(0x0010)J图4.终端的PCo信息1下图(5)显示了Eitia1UEMessage的其他参数，其中包含UE位置信息(即跟踪区域标识符、E-UTRAN小区全球标识)和RRC建立原因。S1AP-PDU:1ni11at1ngMessage(O)initiatingMessageprocedurecode:id-iniIia1UEMessage(12)critica1ity:ignore(1)va1ueBInitia1uEMessageEprotoco1IEs