Forwarding state reduction for sparse mode multicast communication

Abstract

Reducing forwarding state overhead of multicast routing protocols
is an important issue towards a scalable global multicast solution. We
propose a new approach, dynamic tunnel multicast, which utilizes
dynamically established tunnels on unbranched links of a multicast
distribution tree to eliminate unnecessary multicast forwarding states.
Analysis and simulation results show promising reduction in the state
overhead of sparse mode multicast routing protocols

Full text

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Forwarding State Reduction for Sparse Mode Multicast
Communication
by
Jining Tian
B. E., Tsinghua University, China
A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF
THE REQUIREMENTS FOR THE DEGREE OF
Master of Science
in
THE FACULTY OF GRADUATE STUDIES
(Department of Computer Science)
we accept this thesis as conforming
_toJhe required standard
The University of British Columbia
August 1997
© Jining Tian, 1997

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In presenting this thesis in partial fulfillment of the requirements for an advanced degree
at the University of British Columbia, I agree that the Library shall make it freely
available for reference and study. I further agree that permission for extensive copying
of this thesis for scholarly purposes may be granted by the head of my department or by
his or her representatives. It is understood that copying or publication of this thesis for
financial gain shall not be allowed without my written permission.
The University of British Columbia
2366 Main Mall
Vancouver, Canada
V6T 1Z4
Date:
/

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Abstract
Reducing forwarding state overhead of multicast routing protocols is an im-
portant issue towards a scalable global multicast solution. In this paper, we propose
a new approach, Dynamic Tunnel Multicast, which utilizes dynamically established
tunnels on unbranched links of a multicast distribution tree to eliminate unneces-
sary multicast forwarding states. Analysis and simulation results show promising
reduction in the state overhead of sparse mode multicast routing protocols.
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Contents
Abstract ii
Contents iii
List of Tables vi
List of Figures vii
Acknowledgements viii
1 Introduction 1
1.1 IP multicast Model 1
1.2 Existing Multicast Routing Protocols 3
1.3 Motivation and Problem Definition 4
1.4 Observation and Proposal 5
1.5 Thesis Contributions 6
1.6 Thesis Outline 7
2 Related Work 8
2.1 Classification of Multicast Routing Protocols 8
2.2 Examples of Multicast Routing Protocols 9
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2.2.1 DVMRP 10
2.2.2 CBT 11
2.2.3 PIM-SM 11
3 Tunnel Operations 13
3.1 Assumptions 13
3.2 Concepts 15
3.3 Optimization Goals 18
3.4 Uni-multicast State Detection 19
3.5 Tunnel Tree Establishment 20
3.6 Tunnel Encapsulation 23
3.7 Tunnel State Maintenance 24
3:8 Tunnel Tear Down .25
3.9 Tunnel Splice 25
3.10 Tunnel Split 27
3.11 Early Tunnel Termination 29
3.12 Dynamic Tunnels in PIM-SM 29
3.13 Fault Tolerance 30
3.13.1 Failure in the Middle of a Tunnel 30
3.13.2 Failure of the Tunnel End Point 31
3.13.3 Branching Point Changes 31
4 Protocol Specification 36
4.1 Message Types 36
4.1.1 Common Header 36
4.1.2 Tunnel Request Object 38
iv