Provably good approximation to minimum cost delay-constrained multicast trees

Multicast is an important operation in communication systems. In many real-time system applications, we are interested in finding a low-cost multicast tree satisfying a set of delay-constraints. Finding a minimum cost multicast tree is NP-hard, even in the case where the cost and delay of an edge are identical. In this paper, we present an efficient approximation algorithm for computing a low-cost multicast tree satisfying delay-constraints. Unlike most algorithms proposed in the literature, our algorithm has a provably good performance bound when the cost and delay of an edge are identical. This is achieved using a trade-off between a Steiner minimum tree and a shortest path tree. We also discuss extensions to communication systems where the cost and delay of an edge are different