「串流代理伺服器平台」之設計與實做.ppt

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1、「串流代理伺服器平台」之設計與實做DesignandImplementationofaStreamingProxyServerPlatformforInternetVideoStreaming國科會自由軟體專案計畫(NSC94-2218-E-020-002)國立屏東科技大學資訊管理系童曉儒2006/11/10OutlineBackgroundDesigngoalsSegment-basedCachingSchemesArchitectureofStreamingProxyServer(SPS)Experimental

2、ResultsConclusionBackgroundInternetvideostreaming:Challenges:SignificantWANdelayjitterandunstablethroughput.Currentimplementation:Noproxy,largeclientbuffering/longinitialdelay.Proxy-assistedvideostreamingSegment-basedcachingReducinginitialdelayReducingWANtraffi

3、cbylocallysharingvideos.Background(Contd.)Proxy-assistedvideostreamingDesignGoalsStreamingProxyServer(SPS)Webcompatible:usertransparent(webserver,mediaplayer,Http1.1).Configurable:providegenericmoduleswhichcanbeconfiguredintodifferentsegment-basedcachingschemes

4、.LAN-stream/WAN-segmenthybridtransmissioncontrol:providestablestreamquality.Two-yearproject:Firstyear:unicast-basedapproach(94).Secondyear:unicast/multicasthybridapproach(95).Segment-basedCachingTwoschemeswereimplemented.PrefixCaching：VideoprefixiscachedinSPS.U

5、ponrequest,SPSfirstsendsvideoprefixtoclients.SPSthenretrievesvideosuffixfromtheserver.Reducinginitialwaitingtime.Suffix-Windowcaching(proposedbyus)：SPSfurtherdynamicallycachesawindowofvideosuffixforeachvideostream.Otherclientsrequestingthesamevideowillfirstchec

6、kthesuffix-windowsegmentsavailableinSPSbeforeaskingthevideosuffixfromtheserver.Videosharing->reduceWANtraffic.SystemArchitectureofSPSThreemodules:Storagemanagementsubsystem(SMS),Cachingpolicysubsystem(CPS),flowcontrolsubsystem(FCS).SystemArchitectureofSPSSystem

7、Architecture-SMSPerformancemonitoringinterface.Systemconfigurationinterface.HTTPConnectionmanagement.Cacheresourcemanagement.SystemArchitecture-CPSDefiningconfigurationparameters.Definingcachingpolicy.CachingpoliciesmanagementSystemArchitecture-FCSStreamflowcon

8、troller:StreamingbetweenclientandSPS.Fine-graineddatagram.Segment-basedflowcontroller:SegmentfileretrievalbetweenSPSandserverCoarse-grainedsegment.ATCP+(proposedbyus)Adaptiv