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Explore an architecture where end systems handle multicast functionality, overcoming scalability concerns of IP Multicast. Simulation results show efficiency. A feasible overlay approach for small groups.
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2000 ACM SIGMETRICS A Case for End System Multicast 學號:96325523 報告人:通訊所 吳瑞益 指導教授:楊峻權 日期:2009.04.30
OUTLINE • ABSTRACT • INTRODUCTION • NARADA DESIGN • SIMULATION RESULT • CONCLUSIONS
ABSTRACT • IP is the natural protocol layer for implementing multicast related functionality • IP Multicast is still plagued with concerns pertaining to scalability network management deployment • The explore an alternative architecture for small and sparse groups where end systems implement all multicast related functionality including membership management and packet replication
Stanford Gatech CMU Berkeley End Systems Routers 1.INTRODUCTION - Unicast Transmissiont
Routers with multicast support 1.INTRODUCTION - IP Multicast Gatech Stanford CMU Berkeley • No duplicate packets • Highly efficient bandwidth usage 5
1.INTRODUCTION - End System Multicast 1 CMU Stan1 Gatech Stanford Stan2 Berk1 Berkeley Berk2 Overlay Tree Stan1 Gatech Stan2 CMU Berk1 Berk2 6
1.INTRODUCTION - End System Multicast 2
3.NARADA DESIGN (con.) • “Mesh”: Richer overlay that may have cycles and • includes all group members • Members have low degrees • Shortest path delay between any pair of members along mesh is small Step 1 • Source rooted shortest delay spanning trees of mesh • Constructed using well known routing algorithms • Members have low degrees • Small delay from source to receivers Step 2
3.NARADA DESIGN(con.) • Group Management • Member Join • Member Leave and Failure • Repairing Mesh Partitions • Improving mesh quality • Addition of links • Dropping of links • Data Delivery
4.SIMULATION RESULT - INDICES • RDP = Relative Delay PenaltyThe ratio of the delay between two members along the overlay to the unicast delay between them • Ex :(show in figure(f) at Page-6) • <A,D> = 29/27 • <A,C> and <A,B> = 1
5.CONCLUSIONS • Proposed in 1989, IP Multicast is not yet widely deployed • Per-group state, control state complexity and scaling concerns • Difficult to support higher layer functionality • Difficult to deploy, and get ISP’s to turn on IP Multicast • For small-sized groups, an end-system overlay approach • is feasible • has a low performance penalty compared to IP Multicast • has the potential to simplify support for higher layer functionality • allows for application-specific customizations