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1、QualityofServiceforMultimediaoverNextGenerationDataNetworksMohammedAtiquzzamanDepartmentofElectrical&ComputerEngineeringUniversityofDaytonDayton,OH45469.Tel:(937)2293183,Fax:(520)9628422www.engr.udayton.edu/faculty/matiquzz/atiq@ieee.orgMohammedAtiquzzama
2、n,UniversityofDayton,1Email:atiq@ieee.orgOutlineofTalk!PresentstateoftheInternet.!CharacteristicsofMultimedia!QoSrequirementsformultimedia!AsynchronousTransferModenetworks!IntegratedServices!DifferentiatedServices!QoSmappingfromIntegratedServicestoDiffere
3、ntiatedServicesMohammedAtiquzzaman,UniversityofDayton,2Email:atiq@ieee.orgExistingSwitchingTechnologies!Circuitswitching"Pathsetupbeforedatatransmission."Goodforhighvolumedatatransfer."StrongQoSguarantees."Example:Telephonenetwork.!Packetswitching"Packetc
4、ontainsinformationaboutthedestination"Goodforburstytraffic."QoSguaranteeishardtoachieve."Example:Internet.MohammedAtiquzzaman,UniversityofDayton,3Email:atiq@ieee.orgCurrentInternet!TCP/IPgluestogetherallthecomputersintheInternet.!TCP/IPwasdesignedfor"Terr
5、estrialnetworks"Non-realtimedataservices!Internetrouterstreatallpacketsequally.!TCP/IPdoesnot"offerQoStorealtimeapplications,or"performwellinlongdelaybandwidthnetworks.MohammedAtiquzzaman,UniversityofDayton,4Email:atiq@ieee.orgQoSParameters!Bandwidth!Dela
6、y(Latency)!Jitter!LossMohammedAtiquzzaman,UniversityofDayton,5Email:atiq@ieee.orgMultimedia!Realtimeconstraints.!Interactiveapplicationshavelowdelayandjitterrequirements.!Largebandwidthrequirement.!Certainapplicationscantoleratesomeloss.MohammedAtiquzzama
7、n,UniversityofDayton,6Email:atiq@ieee.orgMPEG!Codingstandardtocompressaudioandvideo.!Exploitsthetemporalandspatialredundancyinvideo.!Typesofframes:"Intracoded(I)"Bidirectional(B)"Predictive(P)!I,B,Pframes"BWusagetypically5:3:1(I:P:B)!Compressionmakesthetr
8、afficstreambursty."Difficulttomanagetrafficinthenetwork.MohammedAtiquzzaman,UniversityofDayton,7Email:atiq@ieee.orgMPEG(cont.)!MPEG"Constantbitrate:#variableimagequality#bufferattheoutputoftheencoder"Variablebitrate
