SCALABLE MULTICAST ROUTING USING STEINER TREES AND GATEKEEPERS

Abstract

With the ever-increasing Multicasting applications, design of a scalable multicast routing protocol gained importance. Till date, four major multicast routing protocols, for single autonomous system, have been deployed in the Internet. These are Distance Vector Multicast Routing Protocol (DVMRP), Multicast Extensions for Open Shortest Path First (MOSPF), Core Based Trees (CBT), and Protocol Independent Multicast (PIM). The first two are based on shortest path trees and the rest, on shared trees. In particular, with the increasing sparse mode applications in Internet, shortest path based routing protocols pose major performance bottlenecks with respect to scalability ' of the protocol. Both DVIVIRP and MOSPF, utilize extra resources at the routers and burden the network by generating more number of packets. CBT and PIM make use of shared trees, but these protocols have not specified their implementation details. This dissertation work compares the performance of Steiner trees (a type of shared tree) and shortest path trees, for sparse conferences in terms of average delay etc. A new routing protocol, called Conference Steiner Multicast (CSM) routing protocol, has been demonstrated on a prototype network. CSM protocol makes use of Gatekeepers for its operation. Two types of Gatekeepers, Gatekeeper Application (GA) and Gatekeeper Router (GR) have been demonstrated. Software is written in C++ and runs in LINUX environment. Low level graphics in Linux are used for demonstration purpose.