Eliminating Bottlenecks in Overlay Multicast Min Sik Kim Yi Li - - PowerPoint PPT Presentation

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Feb 04, 2024 336 likes •521 views

Eliminating Bottlenecks in Overlay Multicast Min Sik Kim Yi Li Simon S. Lam Department of Computer Sciences The University of Texas at Austin Overlay Multicast IP multicast overlay multicast N unicast Bottleneck How to

SLIDE 1

Eliminating Bottlenecks in Overlay Multicast

Min Sik Kim Yi Li Simon S. Lam Department of Computer Sciences The University of Texas at Austin

SLIDE 2

Overlay Multicast

 How to construct an efficient overlay tree?

Bottleneck

IP multicast

verlay multicast

N unicast

SLIDE 3

Eliminating Shared Bottlenecks

 Shared congestion detection  Bottleneck Elimination  Why difficult?

1 2 3 4 5 1 2 3 4 5

SLIDE 4

Outline

 Introduction  Types of Shared Bottlenecks  Bottleneck Elimination  Performance Evaluation  Summary

SLIDE 5

Inter-path Shared Bottleneck

u1 v1 u2 v2 u1 u2 v1 v2

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Intra-path Shared Bottleneck

u1 v1 u2 v2 u1 u2 v2 v1

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Algorithm

 Eliminate both types of shared bottlenecks  No tree oscillation  One-way process  Finite steps

Tree 1 Tree 2 Tree 3 Tree N

… Remove a shared bottleneck

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Example

 # of leaves ↓  Height ↑

1 2 3 4 1 2 3 4

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Leaf Distance Vector

 Depths of all leaf nodes in descending

rder

D = (1,1,1)

D = (2,1)

1 2 3 4 1 2 3 4

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Total Cost

 Sum of costs of all edges in the tree

u1 u2 v2 v1 u1 u2 v2 v1

1 1 1 1 1 1 1 1 1 1 1 1

C = 3+1+ 3 = 7

C = 2 +1+ 2 = 5

u1v1 v1u2 u2v2 u1u2 u2v1 v1v2

>

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Proof Sketch

 Bottleneck elimination algorithms

 Remove-Inter-Path-Shared-Bottleneck  Remove-Intra-Path-Shared-Bottleneck

 Applying either algorithm causes

 D ↑  C ↓

 Only a finite # of changes

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Protocol

 Measure delay for congested edges  Detect shared congestion  Eliminate shared bottlenecks  Forward remaining bottlenecks

u1 v1 u2 v2

SLIDE 13

Performance Evaluation

 Comparison

 Delay heuristic  Bandwidth heuristic  Bottleneck-free

 Metrics

 Links stress  Link load  Relative delay penalty  Receiving rate

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Link Stress

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Link Load

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Receiving Rate

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Relative Delay Penalty

SLIDE 18