Design and investigation of scalable multicast recursive protocols for wired and wireless ad hoc networks

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

E2M: A Scalable Explicit Multicast Protocol for MANETs

In this paper, we propose a new scheme for small group multicast in Mobile Ad hoc Networks (MANETs) named Extended Explicit mechanisms to make it scalable with number of group members for a given multicast session. E M is based on the novel concept of dynamic selection of Xcast Forwarder (XF) between a source and its potential destinations. The XF selection is carried out based on group membership and the processing overhead involved in supporting the Xcast procedure at a given node. If the number of members in a given session is small, E M works just like the basic Xcast scheme with no intermediate XFs. As group membership increases, the overhead involved in supporting an Xcast session also increases. Therefore, to reduce the overhead and provide scalability, in E M nodes may dynamically decide to become a XF. This scheme, which can work with few E M aware nodes in the network, provides the transparency of stateless multicast, reduces header processing overhead and makes Xcast scalable with the number of group members