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吳柏均

吳柏均. About This Paper. Show the properly tuned instant queue length based ECN at switches Use Dequeue masking on ECN and DCTCP. ECN. Explicit Congestion Notification Incoming packets will be marked CE instead of dropped. DCTCP. Instant queue length instead of average queue length

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吳柏均

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  1. 吳柏均

  2. AboutThisPaper • ShowtheproperlytunedinstantqueuelengthbasedECNatswitches • UseDequeuemaskingonECNandDCTCP

  3. ECN • ExplicitCongestionNotification • IncomingpacketswillbemarkedCEinsteadofdropped.

  4. DCTCP • Instantqueuelengthinsteadofaveragequeuelength • CutsthecongestionwindowinproportiontotheratioofCEmarking.

  5. ECN*

  6. ECN*:instantqueuelengthbasedECN • UseinstantqueuelengthandsinglethresholdinECN • WellsupportbycommodityECN-capableswitches. • Twothresholds:setthesamevalue. • Averagequeuelength:set1. • ECNatend-serversfollowstheECNstandard

  7. LowerboundofECN* • Goal: TCPthroughputperformancewon’tbeaffectedafterthecongestionwindowsreductionbyECN • Thequeuelengthshouldneverbe0

  8. UpperBoundofECN* • Goal:effectively controlled to avoid buffer overflow. • In other words, when the ECN* threshold is lower than the upper bound, there is no TCP packet loss.

  9. RTTinDCnetwork • ThethresholdforECN* relatetoBDP(TxC),sowehaveinterestonRTT • 90%ofconnectionRTTlowerthan400us • BDP=TxC=1G*400us=50KB(~33MTU)

  10. PerformanceofDCTCPandECN*

  11. DequeueMarking

  12. ProblemStatement • 1.Allcompetingflowarelongflows • 2.Afewshortflowtrytodeliverdatafast,whiletherearesomebackgroundlongflows • 3.DuringTCPincast,largenumberofshortflowarecompetingforaportinaveryshorttime.

  13. DequeueMarking • CEinformationmustwaituntilthemarkedpacketmovetotheheadofqueue. • ItisnotEfficientenough!!

  14. IncastPerformance

  15. Interactionoflongflowsandshowflows

  16. Longflowswithlargelatency

  17. Conclustion • ECN* canachievesasimilarperformancecomparetoDCTCP • DequeuemarkingiseffectiveforincreasingthemaximumincastsendersclosetotheperformancelimitofECN,achievingagainform16%to140%

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