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1、DIFFERENTIATEDSERVICESNETWORKS:PRICINGANDSOFTWAREAGENTS1PeterMarbachDepartmentofComputerScience10King’sCollegeRoadUniversityofTorontoToronto,ON,M5S1A4Canadae-mail:marbach@cs.toronto.eduAbstract:Weconsiderpacket-basednetworksthatusetheDifferentiatedServices(DiffServ),wh
2、erewemodelDiffServasapriorityservice.Usersarefreetochoosetheprioritythattheyattachtotheirpacketsandarechargedaccordingly,wherehighprioritypacketsaremoreexpensivethanlowprioritypackets.Forthisservice,onewouldexpectthatuserswillallocateprioritiestotheirtraffictosatisfythe
3、irservicerequirementsatthelowestpossiblecost.Weproposesuchanallocationstrategywhichwestudyandillustratethroughnumericalexperiments.Keywords:Internet,Quality-of-Service,DifferentiatedServices,Pricing,SoftwareAgents.1IntroductionDifferentiatedServices(DiffServ)hasbeenprop
4、osedbytheInternetEngineeringTaskForce(IETF)asamechanismtoprovideQuality-of-Service(QoS)inpacket-basednet-works(suchastheInternet)[1].ThebasicideabehindDiffServisthefollowing.NetworksdeployingDiffServoffera(small)numberofdifferentserviceclasses.Usersaccessingthenetworkass
5、ign(mark)theirtraffictooneoftheseclasses,andthenetworkforwardspack-etsateachnodeaccordingtoclass-specificrules(calledper-hopbehaviors)[2].ThismechanismcanbeusedtoprovidedifferentiatedQoS.Forexample,DiffServcouldbeusedtoimplementapremiumandabest-effortservice,wherepremiumtr
6、afficalwaysgetspreferentialtreatmentoverbest-efforttraffic[3].Asaresult,premiumtrafficwillobtainabetterQoSwhencongestioninthenetworkincreases,i.e.premiumtrafficexperienceslessdelayandislesslikelytobedropped.Arangeofotherserviceclassesarealsopossibleandhavebeenproposed[4,5,6].
7、AnimportantfeatureofDiffServisthatbyaggregatingamultitudeofflowsintoasmallnumberofserviceclasses,DiffServeliminatestheneedtorecognizeandstoreinformationabouteachindividualflowincorerouters;thismakesDiffServscalable.IntheDiffServframework,itisnaturaltoassumethatusersarechar
8、gedbasedontheserviceclassesthattheyuse,i.e.ahigh-quality(premium)serviceismoreexpensivethanalow-quality(best-effort)service.Also,one
