Dynamic multicast routing for distributing hierarchically encoded video data

In this paper, the dynamic multicast routing problem for distributing hierarchically encoded video data is studied. The video signal is encoded hierarchically into a number of layers with the first layer containing the essential information such that the least capable receivers can reconstruct the video signal with lower quality. Each of the higher layers contains information which can further enhance the quality of the video signal. The cost associated with a network link is dependent on the number of layers of video signal it is carrying. The nodes in the network may be allowed to join or leave the multicast connection dynamically for some network applications. The problem is to find a path to attach a node which wishes to join the multicast connection to the existing multicast tree such that a certain performance measure is optimized. Two heuristic algorithms, namely, shortest path minimum additional cost (SP-MAC) and minimum additional cost (MAC) algorithms are proposed for this problem. The performances of the proposed algorithms are compared with those of the shortest path and dynamic greedy algorithms by extensive simulations. Our results show that the proposed algorithms outperform the shortest path and dynamic greedy algorithms