In multirate multicasting, different users (receivers) within the same multicastgroup could receive service at different rates, depending on user requirementsand network congestion level. Compared to unirate multicasting, this provides moreflexibility to the user, and allows more efficient usage of network resources.

In this paper, we address the rate control problem for multirate multicast sessions,with the objective of maximizing the total receiver utility.This aggregate utility maximization problem not only takes into account the heterogeneityin user requirements, but also provides a unified framework for diverse fairness objectives.

We propose an algorithm for this problem and show, through analysis andsimulation, that it converges to the optimal rates.

In spite of the non-separability of the problem,the solution that we develop is completely decentralized, scalableand does not require the network to know the receiver utilities.Moreover, the algorithm requires very simple computations both forthe user and the network, and also has very low overhead of network congestionfeedback.