MPCP 多点控制协议

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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-pointMACControlfunctionalblockcomprisesthefollowingfunctions:a)DiscoveryProcessing.Thisblockmanagesthediscoveryprocess,throughwhichanONUisdiscoveredandregisteredwiththenetworkwhilecompensatingfo

2、rRTT.b)ReportProcessing.Thisblockmanagesthegenerationandcollectionofreportmessages,throughwhichbandwidthrequirementsaresentupstreamfromtheONUtotheOLT.c)GateProcessing.Thisblockmanagesthegenerationandcollectionofgatemessages,throughwhichmultiplexingofmultipletransmittersisachieved. 多点MAC控制功能模块

3、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ONU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，ONU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,thelayeredsystemmayinstantiatemultipleMACentities,usingasinglephysical

4、layer.EachinstantiatedMACcommunicateswithaninstanceoftheopcodespecificfunctionalblocksthroughtheMulti-pointMACControl.Inadditionsomeglobalvariablesaresharedacrossthemultipleinstances.CommonstatecontrolisusedtosynchronizethemultipleMACsusingMPCPprocedures.Operationofthecommonstatecontrolisgene

5、rallyconsideredoutsidethescopeofthisdocument.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MAC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MPCP使用公共状态控制来同步多个MAC。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-PointControlProtocol Multi-pointMACControlenablesaMACClienttoparticipateinapoint-

6、to-multi-pointopticalnetworkbyallowingittotransmitandreceiveframesasifitwasconnectedtoadedicatedlink.Indoingso,itemploysthefollowingprinciplesandconcepts: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，而对MAC客户端来说就好象连接到一个独享的链路上。为了达到此目的，多点MAC控制协议遵循以下原则： a)AMACclienttransmitsandreceivesframesthroughtheMult

7、i-pointMACControlsublayer.b)TheMulti-pointMACControldecideswhentoallowaframetobetransmittedusingtheclientinterfaceControlMultiplexer.c)Givenatransmissionopportunity,theMACControlmaygeneratecontrolframesthatwouldbetransmittedinadvanceoftheMACC