P2P流媒体系统的激励机制

453Vol.45No.3()JournalofShandongUniversity(NaturalScience)20103Mar.2010:2009211209:(60773101,60872024);(Y2007G42):(19782),,,P2P.Email:[e-mail]3:(19672),,,,.Email:[e-mail]:167129352(2010)0320029205P2P1,2,3,23(1.,250100;2.,250100;3.,250100):P2PInternet,,,,,:P2P;;;:TP393:AIncentivemechanismsinP2PstreamingsystemsQINFeng2lin1,2,JIANGLin3,GELian2sheng23(1.SchoolofInformationScienceandEngineering,ShandongUniversity,Jinan250100,Shandong,China;2.NetworkandInformationCenter,ShandongUniversity,Jinan250100,Shandong,China;3.ShandongShandaOumaSoftwareCo.,Ltd,Jinan250100,Shandong,China)Abstract:Recentlypeer2to2peer(P2P)streamingmediatechnologyhasbeenofthemostpopularsolutionforlarge2scalestreamingapplicationsovertheInternet,butitsqualityofservice(QoS)canbeseriouslydegradedbythefree-ridingproblem.Inthispaper,acontentdifferentiationservice(CDS)basedincentivemechanismwasproposed,whereinthepeersreputationwascomputedwithtwofactors:itscontributionlevelandthepopularityoftheprogram,thenadifferentiatedprogramlistwasreturnedtothepeerinaccordancewithitsreputationvalue.Hence,thefree-rid2ingproblemcouldberestrainedbytheimplementationofcontentdifferentiationservice.Thesimulationresultsdemon2stratethattheproposedincentivemechanismcanefficientlyimprovetheplaybackqualityinP2Pstreamingsystems.Keywords:P2Pstreaming;free2riding;incentivemechanism;contentdifferentiationservice0/IP,P2PInternet[1]P2P,CoolStreamingPPLivePPStreamP2P,Internet[2]P2P,,,(free2riding)P2P2000Gnutella66%,,200585%,200797%,30()45[3]AgarwalCoolStreaming[4],P2P,P2PP2P,,,,P2P,P2P,P2P,,P2P[5],BitTorrent(tit2for2tat)[6],[7],P2P,P2PMol[8],(multipledescriptioncoding,MDC);[9]Li,(layeredcoding,LC);,Habib,,P2P[10],(contentdifferentiationservice,CDS),,,,,,,,P2P1P2P,P2P3:111BitTorrent[6],Pareto,Mol[8]MDC,,MDC(stripe),,,Li,LC,,,[9],MDC,LCAgar2wal,,GossipP2PO(logN),[4]112Habib()[10],,,,,,,,PALMS[11],Tang[12]113Tan,P2P,(points),,[13],,,,Shrivastava,[14](),(M2Quote),,,,3,:P2P312CDSP2P,,,,CDS,1,,,,,,,,,1CDSFig.1IncentivemechanismbasedonCDS211,,,;,,ijwi,j,,wi,j,N,K,kpk=(1/N)Ni=1wi,k/Kj=1wi,j,(1),,Kj=1wi,j=1,pk=(1/N)Ni=1wi,k(2),N=3,K=3,r1,r2r3k012014016,(2)pk=014,pk,,212,CDS,,,,iM,jikuj,i,pk,ij(localreputation)LRi,j(3):LRi,j=(2/)arctan(1/pk)uj,i/Mm=1um,i,(3)LRi,j[0,1),,(globalreputation,GR)i,Mi,LR1,i,LR2,i,,LRM,i,iGRiGRi=(1/M)Mm=1LRm,i(4)213CDS4,2,4,4,PLLU,PLU,PLPPLMP2Fig.2Popularityoftheprograms,,,,,,N,N/4,GRii,(programlist)PLi32()45PLi=PLMP+PLP+PLU+PLLU,GRiGRmax;rand(PLMP)+PLP+PLU+PLLU,GRminGRiGRmax;rand(PLP)+PLU+PLLU,GRiGRmin(5)(5)GRmax,GRmin[0,1),,,,,;rand,nN/4(5),GRmax,GRmin,,,214CDS213,CDS,,,1k,O(2),,N,k,CDS,M(MN),(2),pk=(1/M)Mi=1wi,k,pkpk,|pk-pk|,|(1/M)Mi=1wi,k-pk|,|(1/M)Mi=1wi,k-Mpk|M/(6)Z=|(1/M)Mi=1wi,k-Mpk|,M,Z=M/,,Pr(|Z|),,,,Pr(|Z|)=0195,=2,pk0195pk,M/2,M42/2(7)(7)MO(2),,O(2),1,,O(2),P2P,,,CDS3P2PP2PStrmsim[15],ADSL,/768/384kbps,11Table1Simulationparameters/kbps400/s300/ms250BM/ms50015/bytes1450/kbps2000(free2rider),(50%)0,;CDS,,,,,,(8):Q=Ti=1Zi/T,(8)iZi=1,Zi=0,T320010003,:P2P33,,30%,,3,,,,4,,,(0),0196,90%,0120,3(50%)Fig.3Averageplaybackqualityvs.numberofpeers(per2centageoffree2ridersis50%)4(600)Fig.4Averageplaybackqualityvs.percentageoffree2riders(numberofpeersis600)4P2P,CDS,,,,:[1]ZHANGXinyang,LIUJiangchuan,LIBo,etal.DO2NET/CoolStreaming:adata2drivenoverlaynetworkforefficientlivemediastreaming[C]//ProceedingsofIEEEINFOCOM.Miami,FL,USA:IEEE,2005:210222111.[2]GAOWen,HUOLongshe,FUQiang.Recentadvancesinpeer2to2peermediastreamingsystems[J].ChinaCommunications,2006(5):52257.[3]LEEKEVIN,HUGHESDANY,WALKERDINEJAMES.Onthepenetrationofbusinessnetworksbyp2pfilesharing[C]//Proceedingsofthe2ndInternationalConferenceonInternetMonitoringandProtection(ICI2MP07).Washington,DC,USA:IEEEComputerSoci2ety,2007:23.[4]AGARWALSACIN,SINGHJATINDERPALSINGH,DUBESHRUTI.Analysisandimplementationofgossip2basedP2Pstreamingwithdistributedincentivemecha2nismsforpeercooperation[J].JournalonAdvancesinMultimedia,2007,2007(1):1212.[5]ZHANGKan,ANTONOPOULOSNICK,MAHMOODZAIGHAM.Areviewofincentivemechanismsinpeer2to2peersystems[C]//Proceedingsof1stInternationalConferenceonAdvancesinP2PSystems.Sliema,Malta:IEEE,2009:45250.[6]COHENBram.IncentivesbuildrobustnessinBitTorrent[C]//ProceedingoftheWorkshoponEconomicsofPeer2to2PeerSystems(P2PEcon03).Berkeley,CA:[s.n.],2003:1022111.[7]MORTAZAVIB,KESIDISG.Cumulativereputationsystemsforpeer2to2peercontentdistribution[C]//Pro2ceedingsof40thAnnualConferenceonInformationSci2encesandSystems.[S.l.]:IEEE,2006:154621552.[8]MolJD,EPEMADJ,SIPSHJ.Theorchardalgo2rithm:P2Pmulticastingwithoutfreeriding[C]//Pro2ceedingsofthe6thIEEEInternationalConferenceonPeer2to2peerComputing.Washington,DC,USA:IEEEComputerSociety,2006:2752282.[9]LIZhenye,SHENYanming,PANWARSHIVENDRAS,etal,UsinglayeredvideotoprovideincentivesinP2Plivestreaming[C]//Proceedingsofthe2007workshoponpeer2to2peerstreamingandIP2TV(P2P2TV07).NewYork,USA:ACM,2007.(40)40()45ty,2007:294622955.[7]LIFulu,HSIEHMohan.Anempiricalstudyofclusteringbehaviorofspammersandgroup2basedanti2spamstrategies[C]//:Proceedingsofthe3rdConfere