Abstract: This paper proposes a multicast protocol at the application level for efficiently broadcasting live media streams to a large number of users.The main idea of this protocol is to self-organize the end hosts into a locality-aware overlay multicast tree based on their network position coordinates.The result is that the overlay multicast tree has a good match to the underlying physical network such that the link stress and the end-to-end delay can be effectively reduced.In the mean time, real-life network constraints can be handled.

Key words: stream media, multicast tree, locality-aware, network position coordinate