ABSTRACT
The ever-increasing demand on content distribution and media streaming over the Internet
has created the need for efficient methods of delivering information. One of the most
promising approaches is based on multicasting. However, multicast solutions have to cope
with several constraints as well as being able to perform in different environments such as
wired, wireless, and ad hoc environments. Additionally, the scale and size of the Internet
introduces another dimension of difficulty. Providing scalable multicast for mobile hosts in
wireless environment and in mobile ad hoc networks (MANETs) is a challenging problem. In
the past few years, several protocols have been proposed to efficient multicast solutions over
the Internet, but these protocols did not give efficient solution for the scalability issue. In this
thesis, scalable multicast protocols for wired, wireless and wireless ad hoc networks are
proposed and evaluated. These protocols share the idea of building up a multicast tree
gradually and recursively as join/leave of the multicast group members using a dynamic
branching node-based tree (DBT) concept. The DBT uses a pair of branching node messages
(BNMs). These messages traverse between a set of dynamically assigned branching node
routers (BNRs) to build the multicast tree. In the proposed protocols only the branching node
routers (BNRs) carry the state information about their next BNRs rather than the multicast
group members, which gives a fixed size of control packet header size as the multicast group
size increases, i.e. a good solution to the problem of scalability. Also the process of
join/leave of multicast group members is carried out locally which gives low join/leave
latency.
The proposed protocols include: Scalable Recursive Multicast protocol (SReM) which is
proposed using the DBT concepts mentioned above, Mobile Scalable Recursive Multicast
protocol (MoSReM) which is an extension for SReM by taking into consideration the
mobility feature in the end hosts and performing an efficient roaming process, and finally, a
Scalable Ad hoc Recursive Multicast protocol (SARM) to achieve the mobility feature for all
nodes and performing an efficient solution for link recovery because of node movement. By
cost analysis and an extensive simulation, the proposed protocols show many positive
features like fixed size control messages, being scalable, low end to end delay, high packet
rate delivery and low normalized routing overhead. The thesis concludes by discussing the
contributions of the proposed protocols on scalable multicast in the Internet society.
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