Download - 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 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
2000 ACM SIGMETRICS
OUTLINE
1. ABSTRACT2. INTRODUCTION3. NARADA DESIGN4. SIMULATION RESULT 5. CONCLUSIONS
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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
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1.INTRODUCTION
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End Systems
Routers
Gatech
CMU
Stanford
Berkeley
- Unicast Transmissiont
1.INTRODUCTION
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- IP Multicast
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•No duplicate packets•Highly efficient bandwidth usage
Berkeley
Gatech Stanford
CMU
Routers with multicast support
1.INTRODUCTION
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- End System Multicast 1
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Stanford
CMU
Stan1
Stan2
Berk2
Overlay Tree
Gatech
Berk1
Berkeley
Gatech Stan1
Stan2
Berk1
Berk2
CMU
1.INTRODUCTION
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- End System Multicast 2
3.NARADA DESIGN
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3.NARADA DESIGN (con.)
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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
“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 2
3.NARADA DESIGN(con.)1. Group Management
– Member Join– Member Leave and Failure
2. Repairing Mesh Partitions3. Improving mesh quality
– Addition of links– Dropping of links
4. Data Delivery
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4.SIMULATION RESULT - INDICES
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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
4.SIMULATION RESULT - RDP
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4.SIMULATION RESULT - STABLIZE
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5.CONCLUSIONS
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• 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