【精品】MPCP多点控制协议.doc

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1、IEEE802.3ah协议学习(3)——MPCP多点控制协议64.3Multi-PointControlProtocol(MPCP)AsdepictedinFigure64-3,theMulti-pointMACContro1functiona1blockcomprisesthefollowingfunctions:a)DiscoveryProcessing.Thisblockmanagesthediscoveryprocess,throughwhichanONTJisdiscoveredandregistercdwiththenetworkwhilecomp

2、cnsatingforRTT・b)ReportProcessing.Thisblockmcinagesthegenerationandcollectionofreportmessages,throughwhichbandwidthrequirementsarcsentupstrcamfromtheONUtotheOLT.c)GateProcessing・Thisblockmanagesthegenerationandcollectionofgatemessages,throughwhichmultiplexingofmultipletransmittersis

3、achieved・多点MAC控制功能模块包括以下功能：a)发现处理(DiscoveryProcessing)：该模块管理发现流程，通过该进程发现0NU并使其注册到网络中，同时对其RTT进行补偿。b)报告处理(ReportProcessing):该模块管理报告消息的产生和搜集，ONL通过该模块在上行方向向OLT发送带宽请求。c)选通处理(GateProcessing):该模块管理GATE消息的产生和搜集，通过该模块实现多个发送端的复用。AsdepictedinFigure64-3,thelayeredsystemmayinstantiatemultipleMAC

4、entities,usingasinglephysicallayer・EachinstantiatedMACcommunicateswithaninstanceoftheopcodespecificfunctionalblocksthroughtheMuiti-pointMACContro1.Inadditionsomeglobalvariablesaresharedacrossthemultipleinstances・CommonstatecontrolisusedtosynchronizethemultipleMAGsusingHPCPprocedures

5、・Operationofthecommonstatecontrolisgenerallyconsideredoutsidethescopeofthisdocument.如图64-3所示，分层的系统可以实例化多个MAC实体，而只使用一个物理层。每个实例化的MC通过MPCP和与操作码(opcode)相关的功能模块的实例进行通信。此外，多个实例共享一些全局变量。通过IPCP使川公共状态控制来同步多个1AC。有关公共状态控制的操作不在本标准规范的范围内。64.3.1PrinciplesofMulti-PointControlProtocolMulti-pointM

6、ACControlenablesaMACClienttoparticipateinapoint-to-multi-pointopticalnetworkbyallowingittotransmitandreceiveframesasifitwasconnectedtoadedicatedlink.Tndoingso,itemploysthefollowiprinciplesandconcepts:多点MAC控制通过控制MAC客户端的接收和发送使其工作在点对多点光网络中，而対MAC客户端来说就好彖连接到-个独亭的链路上。为了达到此II的，多点MAC控制协议遵循以

7、下原则^a)AMACclienttransmitsandreceivesframesthroughtheMuiti-pointMACControlsublayer・b)TheMuiti-pointMACControldecideswhentoallowaframetobetransmittedusingtheclientinterfaceContm]Multiplexer.c)Givenatransmissionopportunity,theMACControlmaygeneratecontrolframesthatwouldbetransmittedinad

8、vanceoftheMACClient