文档介绍：传输层协议设计提纲传输层协议概述UDP协议简介TCP协议简介与可靠性设计TCP窗口流控TCP拥塞控制机制分析Tahoe,Reno源算法RED主动队列管理算法TCP/IP协议栈Applications(.,HTTP)TCPUDPICMPARPIPLinkLayer(.,ATM)PhysicalLayer(.,)传输层协议实现端到端的数据传输ProtocolimplementedentirelyattheendsFate-pleteness/correctnessoffunctionimplementations传输层协议UDPprovidesjustintegrityanddemuxTCPadds…Connection-orientedReliableOrderedPoint-to-pointByte-streamFullduplexFlowandcongestioncontrolledUDP:UserDatagramProtocol[RFC768]MinimalTransportService:“Besteffort”service,UDPsegmentsmaybe:LostDeliveredoutofordertoappConnectionless:NohandshakingbetweenUDPsender,receiverEachUDPsegmenthandledindependentlyofothersNoconnectionestablishment(whichcanadddelay)Simple:noconnectionstateatsender,receiverSmallheaderNocongestioncontrol:UDPcanblastawayasfastasdesired:dubious!Multiplexing/worksegment-unitofdataexchangedbetweentransportlayerentitiesakaTPDU:transportprotocoldataunitreceiverHtHnDemultiplexing:workP1MMMP3P4segmentheaderapplication-layerdataMultiplexing/demultiplexingmultiplexing/demultiplexing:basedonsender,receiverportnumbers,IPaddressessource,destport#sineachsegmentwell-knownportnumbersforspecificapplications,,envelopingdatawithheader(laterusedfordemultiplexing)sourceport#destport#32bitsapplicationdata(message)otherheaderfieldsTCP/UDPsegmentformatMultiplexing:UDP,(why?):DNSSNMPReliabletransferoverUDP:addreliabilityatapplicationlayerApplication-specificerrorrecover!Sourceport#Destport#32bitsApplicationdata(message)UDPsegmentformatLengthChecksumLength,inbytesofUDPsegment,municationabstraction:ReliableOrderedPoint-to-pointByte-streamFullduplexFlowandcongestioncontrolledProtocolimplementedentirelyattheendsFatesharing