A routing procedure for multicast communication which evaluates utility functions to find the optimum combination of routes

摘要

The invention deals with the routing of a data stream from a source node to a plurality of end-nodes via relaying nodes. The aim of the invention is to find the optimum combination of routes. This is achieved by evaluating a utility function for each possible route between the source node and each end node, using the evaluated utility functions to obtain an overall utility value for each of the route combinations which link the source node to each of the end-nodes, and then comparing the overall utility values. The utility function is route-dependant and defines a quantitative measure of the end-user benefit that would be experienced at a respective end-node, e.g. by actually displaying a video stream to the user. Factors which affect utility may include transport bitrate, packet loss rate, delays, receiver video window size etc (see pages 25-27). The invention finds particular application in peer-to-peer (p2p) systems. The optimisation procedure may be carried out using a plurality of distributed optimisation nodes - see GB0906410.6.