sis3组播转发机制要点分析

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1、DOCSIS3.0组播转发机制要点分析眩晕的猫2013081>Docsis3.0MDF设计核心思想：Removingthe1GMPcontrolplanefromtheCMofferswiderangeofbenefitsasfollows:•Ensureswcl1definedondconsistentmulticastforwardingbehaviorintheCL•SimplifiestheCMsinceprotocolspecificknowledgefortechnologiessuchasASMandSS

2、MforTPv4andIPv6,includingtheprotocolsTGMPv3andMLDv2,isnolongerrequired••EasiertoincorporatemulticastprotocolchangessincetheyonlyaffecttheCMTSandnottheCMs・•OthermulticastprotocolslikeP1McanbesupportedinthefuturebyutilizingthesameCMTStoCMsignalingwithoutaffectingth

3、eCMs.•TtiseasiertosolvoissuesrelatedtoMAClevelaliasing,accessandadmissioncontrolfromtheCMTS.2.MDF高层功能2.1CMTS用DSID标识组播报文a.CM通告CMTS加入组播组时会携带接口信息，CMTS在通告CHDSTD组播转发绑定关系时会携带C[端口信息下来。b.非知名IPv6组播节目:不同的SSM(S,G)或ASM(*,G)在]个MACDomain要分配不同的DSTD.PacketswithaknownDSIDarerece

4、ivedbytheCMandforwardedtothesetofinterfacesassociatedwiththeDSID.AroutingCMTSMUSTlabeltrafficfordifferent"IPmulticastSSMChannels，?or"TPmulticastASMGroups'"withdifferentDSIDs,withtheexceptionofwell-knownIPv6multicasttraffic(refertoAnnexA・l・2)・Thus,withMulticastDSI

5、D-basedForwarding,eachreplicationofan(S,G)IPmulticastsessiontoaparticularDCSisassignedauniqueDSIDlabelwithinaMACDomain.AbridgingCMTSSHOULD支持区分SSM(S,G)的能力，如果不具备至少要能为不同的GroupAddress分配不同的DSID.C・为了使用2.0/3.0CM混合场景，通过1个组播流会分配多个DSIDo参见Figure—3的场景。1)在此场景下bondingCM也只能从1条D

6、C上接受组播节目。2)1个组播流在同一个channel内分发多次。1个DSID是给nonbondingCM用的，另1个DSID是给bondingCM用的。这个应用下有一个问题，即2.0CM也会受到bondingDSID的同一个组播流的部分流量，但2.0的CM是不看DSID的，怎么办？answer:TsolationPacketPDUMACHeaderTheCMTSMISTisolatebondedmulticasttrafficfromnon-bondedreplicationonthesamedownstreamcha

7、nnclbytransmittingthesebondedmulticastpacketswiththeIsolationPacketPDUMACHeader(theFC_TypefieldoftheDOCSISframesettobinary10).BecausetheCMTSdoesnotknowoftheCM'scapabilitiesuntiltheCMregisters,theCMTSMUSTNOTisolatepre-registrationIPv6multicasttraffic(Section9.2.2.

8、2)withtheIsolationPacketPDUMACHeader(FC_Type10).DSTDlabelingenablesdiffcrentiationofmultiplereplicationsofanTPMulticastScssion(bondedornon-bonded)ondownstreamc