A Simulation Study of a Reliable Dynamic Multicast Environment

Abdelaziz Araar, Hakim Khali, and Riyadh Mahdi

Ajman University of Science and Technology Network, UAE

Abstract: In the dynamic multicast environment, static multicast retransmission modes may lead to congestion and loss of packets due to propagation errors of the wireless network. This paper logically divides the dynamic multicast network into fixed and mobile parts, and focuses on the dynamic wireless environment, where mobile member may enter in non-covered areas. The group is divided into many subgroups of mobile members. Each subgroup has one Designated Receiver (DR), which is responsible of multicast. Simulation studies have been conducted to determine the benefits of integrating an improved Forward Error Control (FEC) codes to a reliable multicast protocol P_Mul in the dynamic environment. Members can leave and join the subgroup based on some distributions. DR can support two modes of FEC, proactive and reactive. The simulation tool using OPNET shows that reactive FEC is better with high rate of leave and low rate of join. However, for proactive FEC, it is the opposite. Also, simulation results show that the number of designated receivers is parabolic with respect to the number of retransmissions. This paper investigates the benefits of an improved FEC mechanism for the reliable dynamic wireless networks.

Keywords: OPNET, proactive/reactive FEC, dynamic multicast retransmission, designated receiver.

Received February 11, 2004; accepted July 3, 2004