A Case for End System A Case for End System MulticastMulticast
Yang-hua Chu, Sanjay G. Rao, Srinivasan Yang-hua Chu, Sanjay G. Rao, Srinivasan Seshan and Hui ZhangSeshan and Hui Zhang
Presentation by Warren CheungPresentation by Warren Cheung
Some Slides from Some Slides from http://eeca2.sogang.ac.kr/publication/seminahttp://eeca2.sogang.ac.kr/publication/semina
r/2000/%EC%9D%B4%EB%AF%BC%EDr/2000/%EC%9D%B4%EB%AF%BC%ED%98%B8/5%98%B8/5
MulticastMulticast
Unicast:Unicast:– Point to Point delivery Point to Point delivery – One Host to One ClientOne Host to One Client
Multicast:Multicast:– Deliver to multiple destinationsDeliver to multiple destinations– One Host to Many ClientsOne Host to Many Clients
IP vs. End System MulticastIP vs. End System Multicast
IP multicastIP multicast– Implemented at Internetworking layerImplemented at Internetworking layer
Routers and switchesRouters and switches
End System multicastEnd System multicast– Implemented in the hosts and clientsImplemented in the hosts and clients
ExamplesExamples
Examples – IP MulticastExamples – IP Multicast
Examples – naive UnicastExamples – naive Unicast
Examples – End System MulticastExamples – End System Multicast
ConsiderationsConsiderations
Transmission Redundancy of DataTransmission Redundancy of Data– Unicast: many copies per linkUnicast: many copies per link– IP Multicast: one copy per linkIP Multicast: one copy per link– End System Multicast:End System Multicast:
slightly more inefficient than IP Multicastslightly more inefficient than IP Multicast
DelayDelay– Unicast same as IP MulticastUnicast same as IP Multicast– End System Multicast incurs penaltyEnd System Multicast incurs penalty
IP multicastIP multicast
ProsPros– Possibly large performance benefitsPossibly large performance benefits
ConsCons– Needs to maintain “group state”Needs to maintain “group state”– Infrastructure level changes are slow to Infrastructure level changes are slow to
deploydeploy
End System MulticastEnd System Multicast
ProsPros– Can be implemented nowCan be implemented now
Hosts (Peer-to-Peer) Hosts (Peer-to-Peer) ProxyProxy
ConsCons– Performance degradationPerformance degradation
Narada ProtocolNarada Protocol
Self-OrganisingSelf-Organising– Constructs OverlayConstructs Overlay– Adapt to Network/Group DynamicsAdapt to Network/Group Dynamics
EfficientEfficient– Latency vs. BandwidthLatency vs. Bandwidth– Self-improvingSelf-improving
Group ManagementGroup Management
Everyone keeps the member listEveryone keeps the member list– Target Medium-Sized GroupsTarget Medium-Sized Groups– Everyone periodically exchanges group Everyone periodically exchanges group
information with neighbours (refresh)information with neighbours (refresh) JoinJoin– BootstrappingBootstrapping
LeaveLeave– Partition repairPartition repair
Mesh PerformanceMesh Performance
Mesh may be suboptimal due to:Mesh may be suboptimal due to:– Network conditionsNetwork conditions– Group dynamicsGroup dynamics
Adding random neighboursAdding random neighbours
Dropping low “cost” links Dropping low “cost” links
Open IssuesOpen Issues
Group size on Average overlay hopsGroup size on Average overlay hops
Short-term Effects of events on Short-term Effects of events on PerformancePerformance
Overlay construction/maintenance Overlay construction/maintenance costs when group sizes get very costs when group sizes get very largelarge
Related Work on OverlaysRelated Work on Overlays
Mesh-basedMesh-based Tree-based overlaysTree-based overlays
Delaunay TriangulationsDelaunay Triangulations– Map addresses to coordinate spaceMap addresses to coordinate space– Find closest neighboursFind closest neighbours
Hierarchies of ClustersHierarchies of Clusters
Related WorksRelated Works
End System Multicast, Narada, Video End System Multicast, Narada, Video StreamingStreaming– http://www-2.cs.cmu.edu/~esm/http://www-2.cs.cmu.edu/~esm/
Comparison of some Application Comparison of some Application Layer Multicast solutionsLayer Multicast solutions– http://citeseer.nj.nec.com/http://citeseer.nj.nec.com/
banerjee01comparative.htmlbanerjee01comparative.html
Not-So-Closely Related WorksNot-So-Closely Related Works
BitTorrent (File Swarming)BitTorrent (File Swarming)– http://bitconjurer.org/BitTorrent/http://bitconjurer.org/BitTorrent/
Herbivore (Anonymity/Security)Herbivore (Anonymity/Security)– http://citeseer.nj.nec.com/http://citeseer.nj.nec.com/
goel02herbivore.htmlgoel02herbivore.html
DiscussionDiscussion
IP MulticastIP Multicast– Basically a failure – deployment issuesBasically a failure – deployment issues– Any fundamental/low level changes to Any fundamental/low level changes to
Internet infrastructure unlikely to Internet infrastructure unlikely to succeedsucceed
End System MulticastEnd System Multicast– Overhead/performance impact no longer Overhead/performance impact no longer
looks as disadvantageous as it originally looks as disadvantageous as it originally appearedappeared
Discussion(2)Discussion(2)
ApplicationsApplications– Limitations to video-conferencing more Limitations to video-conferencing more
due to limitation on the number of people due to limitation on the number of people you can communicate with simultaneouslyyou can communicate with simultaneously
– For large number of clients, more likely to For large number of clients, more likely to be a broadcastbe a broadcast
NaradaNarada– Implemented and usedImplemented and used– Broadcasts the annual SIG networking Broadcasts the annual SIG networking
conferenceconference
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