Priority-based distribution trees for application-level multicast

In this paper, we propose a novel multicast routing algorithm that is based on application-level priorities and network characteristics: The application may specify an individual priority for each packet-receiver pair. The multicast distribution tree is then constructed such that the higher the priority, the more direct the path from the sender to the packet's destination and the lower the resulting end-to-end delay. This algorithm can be used to realize application-level multicast for delay-sensitive applications such as networked computer games. However, optimizing the multicast tree with respect to the end-to-end delay comes at the cost of an increase in link stress - the more direct a path, the less likely it is that it can be integrated efficiently into an overlay distribution tree. Our algorithm takes this tradeoff into account and constructs efficient priority-based multicast trees. We demonstrate the performance and characteristics of the algorithm through simulation.