Performance analysis of multicast flow control algorithms over combined wired/wireless networks

A multicast flow control framework for data traffic traversing both a wired and wireless network is proposed. Markov-modulated fluid (MMF) models are used for the receivers to capture the dynamics of the wireless links. Our study shows that the phase differences of the instantaneous throughput capabilities of the receivers are a distinctive feature of multicast connections. The objectives of the multicast flow control algorithms are to cope with the receiver phase differences (RPDs) cost effectively in addition to the general goals such as maximizing throughput and minimizing delay. Three ad hoc algorithms have been studied: listen to slowest request (LSQ), source estimation (SE), and open-loop control. A fluid-flow analysis technique is applied to study the effect of receiver phase differences assuming zero propagation delay. The effect of propagation delay in multicast connections is then discussed. Simulation results are presented to verify the analysis for the zero-delay case and to compare the performance of the algorithms under nonnegligible delays. It turns out that the zero-delay case reveals the characteristics of the multicast algorithms and provides good performance bounds for the cases with nonnegligible propagation delays