Establishing a trade-off between unicast and multicast retransmission modes for reliable multicast protocols

The conventional approach to reliable multicast in computer networks relies on the retransmission on demand of lost packets. Existing multicast protocols adopt a static packet retransmission scheme (unicast or multicast) to retransmit these packets often leading to performance loss due to wasting bandwidth resources. This is worse if we consider the limited bandwidth resources wireless interfaces currently offer. Therefore, careful continuous monitoring and control is fundamental in these wireless mobile environments. This paper looks at solutions to the retransmission problem while taking into consideration network topology and the number of fixed and mobile users. Precise conditions and rules for packet retransmission are set taking into account the dynamics of the network state. Finally, this algorithm has been incorporated into a reliable multicast protocol with support to mobile users, known as the reliable mobile multicast protocol (RM2), for performance analysis.