A Source Tree Reliable Multicast Protocol for Ad-Hoc Networks

Multicasting is an essential service for ad-hoc wireless networks. Many reliable multicast schemes were studied in order to reduce packet losses in the network. This paper describes our effort to build a source tree reliable multicast protocol for ad-hoc networks. Source tree reliable multicast protocol provides the delivery of an ordered contiguous sequence of data packets from one sender to many receivers in an ad-hoc network. It is designed to support applications based on bulk data transfer, like files, images and software packages. The core to its support of node mobility, and also what makes the protocol unique, is the dynamic selection of a sub set of 1-hop neighbors from the sender as its forward servers. The key idea behind the selecton of this sub set 1-hop neighbors is to forward the retransmitted lost data packets that are needed by some receivers to achieve a higher throughput and to receive the acknowledgment packet from receivers to avoid the acknowledgment-implosion problem inherent in any reliable multicast scheme. Finally, simulation results show that the protocol has a high delivery ratio and low end-to-end delay compared to ReMHoc protocol.