Chapter3-Transport - 宁波大学信息科学与工程学院网络实验室

《Chapter3-Transport - 宁波大学信息科学与工程学院网络实验室》由会员上传分享，免费在线阅读，更多相关内容在行业资料-天天文库。

1、TransportLayer3-1Chapter3TransportLayer自顶向下和互联网特色基于实验和探究式教学计算机网络宁波大学信息科学与工程学院TransportLayer3-2Chapter3:TransportLayerOurgoals:understandprinciplesbehindtransportlayerservices:multiplexing/demultiplexingreliabledatatransferflowcontrolcongestioncontrollearnabouttransportlayerprotocolsintheI

2、nternet:UDP:connectionlesstransportTCP:connection-orientedtransportTCPcongestioncontrolTransportLayer3-3Chapter3outline3.1Transport-layerservices3.2Multiplexinganddemultiplexing3.3Connectionlesstransport:UDP3.4Principlesofreliabledatatransfer3.5Connection-orientedtransport:TCPsegmentstruct

3、urereliabledatatransferflowcontrolconnectionmanagement3.6Principlesofcongestioncontrol3.7TCPcongestioncontrolTransportLayer3-4Transportservicesandprotocolsprovidelogicalcommunicationbetweenappprocessesrunningondifferenthoststransportprotocolsruninendsystemssendside:breaksappmessagesintoseg

4、ments,passestonetworklayerrcvside:reassemblessegmentsintomessages,passestoapplayermorethanonetransportprotocolavailabletoappsInternet:TCPandUDPapplicationtransportnetworkdatalinkphysicalapplicationtransportnetworkdatalinkphysicalnetworkdatalinkphysicalnetworkdatalinkphysicalnetworkdatalink

5、physicalnetworkdatalinkphysicalnetworkdatalinkphysicallogicalend-endtransportTransportLayer3-5Transportvs.networklayernetworklayer:logicalcommunicationbetweenhoststransportlayer:logicalcommunicationbetweenprocessesrelieson,enhances,networklayerservicesHouseholdanalogy:12kidssendingletterst

6、o12kidsprocesses=kidsappmessages=lettersinenvelopeshosts=housestransportprotocol=AnnandBillnetwork-layerprotocol=postalserviceTransportLayer3-6Internettransport-layerprotocolsreliable,in-orderdelivery:TCPcongestioncontrolflowcontrolconnectionsetupunreliable,unordereddelivery:UDPno-frillsex

7、tensionof“best-effort”IPservicesnotavailable:delayguaranteesbandwidthguaranteesTransportLayer3-7Chapter3outline3.1Transport-layerservices3.2Multiplexinganddemultiplexing3.3Connectionlesstransport:UDP3.4Principlesofreliabledatatransfer3.5Connection-orientedtran