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ID:34614737
大小:2.76 MB
页数:22页
时间:2019-03-08
《cse 573s protocols for computer networks (spring 2005 – final project) to investigate the》由会员上传分享,免费在线阅读,更多相关内容在教育资源-天天文库。
1、CSE573SProtocolsforComputerNetworks(Spring2005–FinalProject)ToInvestigatethedegreeofcongestioncontrolsynchronizationofwindow-basedconnectionsbottleneckedatthesamelinkKumar,Vikram(vp3@cec.wustl.edu)So-InChakchai(cs5@cec.wustl.edu)thMay10,2005(1)Abstract:O
2、urprojectbasicallyinvestigatesthedegreeofcongestioncontrolsynchronizationofwindow-basedconnectionsbottleneckedatthesamelinkandforthisweconductedexperiment’sinns2andinceclabswhichislocatedinWashingtonUniversityinSt.louis.Thequestionswhichweexpectedtoanswe
3、rwhere“Whatisthefractionofconnectionsthatdonotnoticecongestionbeforeitisresolvedbytheotherconnections?”&toidentifytheconditionsforthebuffertoalwaysremainfull.Someoftheconsideredparameterswherenumberofconnections,buffersize,delayoftheirpathsandthebottlene
4、cklinkcapacity.1.Introduction1.1QueuingDropModelFigure1.1:DropTailQueue[1]FirstmodelisDropTailQueue.Inthismodel,FIFOqueuingmechanismisimplementedinordertodroppacketswhenthequeueoverflows.ThistechniqueissimpleuseandlesscomplexitywhichwidelyusesintheIntern
5、et;however,itwouldintroducesglobalsynchronizationwhenpacketsaredroppedfromseveralconnections.Figure1.2:RandomDropQueue[1]SecondmodelisRandomDropQueue.Whenapacketarrivesandthequeueisfull,randomlychooseapacketfromthequeuetodrop.Figure1.3:RandomEarlyDropQue
6、ue[1](2)ThirdmodelisRandomEarlyDropQueue.Ifthequeuelengthexceedsadroplevel,thentherouterdropseacharrivingpacketwithafixeddropprobability.Thebigadvantageforthistechniqueisthatitcanreducetheglobalsynchronization.1.2TCPSynchronizationTCPsendsasmanypacketsas
7、possibleuntilitdetectsalossinpacketatwhichpointitreducesthesendingrate.Likemanycongestioncontrolprotocols,TCPusespacketlossasanindicationofcongestion.(Figure1.4)Ideally,iflossesaresynchronized,TCPflowssharingbottleneckreceivelossindicationsataroundthesam
8、etimedecreaseratesataroundthesametimeperiodsduetowhichthelinkbandwidthissignificantlyunderutilized.(Figure1.5)Asaresult,ifratesynchronizationcanbeprevented,thenbandwidthwillbeusedmoreefficiently.(Figure1.6)Figure1.4:TCPbeh
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