信息通信专业Data-drivenOverlayNetwork

Data-drivenOverlayNetwork,目录,ApplicationlayermulticastDatadrivenDesignPeer-to-peerReceiver-drivenOverlaysComparison一些想法,ApplicationLevelMulticast,ApplicationLevelMulticastVS.IPMulticast,效率：IP组播比应用层组播效率高，部署：应用层组播比IP组播容易部署。IP组播需要改变路由器和end-system的上的IP层协议。部署困难应用层组播只需要对end-system添加应用层的软件就可以实现。部署容易由于应用层组播只是在end-system添加应用层的软件，所以应用层组播又叫end-systemmulticast,应用层组播的研究现状,应用层的研究由两部分构成：OverlayconstructDatadelivery今天讲的是OverlayconstructApproachesMesh-firstapproach首先构建mesh结构，在mesh基础上构建最佳树Tree-firstapproach直接构建treeOtherapproachesEg:混合模型,NICE;CAN,Scribe,DatadrivenDesign（Receiver-driven）,Availabilityofdataguidestheflowdirections,notaspecificoverlaystructureSuitableforoverlaywithhighdynamicnodes:multipleparentsExamples:Coolstreaming,PRO,PALS,Peer-to-peerReceiver-drivenOverlays,ThemaindesignphilosophyIndependentlyandselfishlychoosethebestwaytoconnecttotheOverlayTwokeyComponentspeerdiscover(PD)peerselection(PS),PeerDiscover,InitialparentsselectionnewpeerconnecttotheoriginalserverTargetselectiondetermineatargetpeerforgossipContentselectionselectsgmrecordsthataremostusefulfortargetpeer.(Bidirectionalgossip)Imagemaintenanceintegratenewrecordsanddiscardexcessrecords,InteractionsbetweenPDandPS,Peer-to-peerReceiver-drivenOverlays,PsmechanismisessentiallyaprogressivesearchwithinthelocalimageforasubsetofparentpeersWhenshouldanewparentbeselectinitialphasereplacingapoorly-performingpeerImprovementinperformanceConservativeapproachademand-drivenfashion!,ComparisonofALMandData-driven,Fairness(Definedbybandwidthratio)Data-drivenapproachisbetter!ReliancetofailuresData-drivenapproachisbetter!LocalityData-drivenapproachcannotconcernlocality!,一些想法,PRO中许多参数如根据带宽和延时对节点进行排序，每个节点拥有的父节点数等，都没有明确，需要进一步的细化工作。Cross-ISP的traffic尽量少符合locality特性与分层编码的结合,分层编码,分层编码的主要思想：把源视频流编码成几个不同的层，一个基础层，多个增强层。比如共有5个层，1，2，3，4，5。由于受到接收端带宽的限制，只能接收3层，则接收端要求发送端只发送1，2，3。这样就能适应不同