Transcript A Case for End System Multicast

A Case for End System Multicast
2000 ACM SIGMETRICS
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
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2.
3.
4.
5.
ABSTRACT
INTRODUCTION
NARADA DESIGN
SIMULATION RESULT
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
- Unicast Transmissiont
Stanford
Gatech
CMU
Berkeley
End Systems
Routers
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1.INTRODUCTION
Gatech
- IP Multicast
Stanford
CMU
Berkeley
Routers with multicast support
•No duplicate packets
•Highly efficient bandwidth usage
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1.INTRODUCTION
CMU
Gatech
- End System Multicast 1
Stanford
Stan1
Stan2
Berk1
Berkeley
Overlay Tree
Gatech
Berk2
Stan
1
Stan2
CMU
Berk1
Berk2
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1.INTRODUCTION
- End System Multicast 2
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3.NARADA DESIGN
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3.NARADA DESIGN (con.)
“Mesh”: Richer overlay that may have cycles and
includes all group members
Step 1
• Members have low degrees
• Shortest path delay between any pair of members along mesh is
small
•Source rooted shortest delay spanning trees of mesh
Step 2 •Constructed using well known routing algorithms
– Members have low degrees
– Small delay from source to receivers
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3.NARADA DESIGN(con.)
1. Group Management
– Member Join
– Member Leave and Failure
2. Repairing Mesh Partitions
3. Improving mesh quality
– Addition of links
– Dropping of links
4. Data Delivery
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4.SIMULATION RESULT - INDICES

RDP = Relative Delay Penalty
The 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
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4.SIMULATION RESULT - RDP
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4.SIMULATION RESULT - STABLIZE
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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
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