Multicast routing with heterogeneous quality

In the common multicast problem, it is funda mental that destinations receive exactly the same information. In this paper, we examine the heterogeneous problem where destinations receive subsets of common information. It is worth noting that this scenario can be met in practice in audio and video sessions, as long as the data is encoded with the hierarchical encoding scheme. In this paper, we focus on the case where each destination requires a specific subset of the total information. For this problem, we design polynomial algorithms that meet some efficiency criteria. Theoretical and experimental work demon strates the advantage of the proposed algorithms over previous solutions.