A deadlock-free tree-based multicast routing algorithm is presented for all direct networks, regardless of interconnection topology. The algorithm delivers a message to any number of destinations using only a single startup phase. In contrast to existing tree-based schemes, this algorithm applies to all interconnection topologies, requires only xed-sized input bu ers that are independent of maximum message length, and uses a simple asynchronous it replication mechanism. The theoretical basis of the technique used here is su ciently general to develop other tree-based multicasting algorithms for regular and irregular topologies. Simulation results demonstrate that this tree-based algorithm provides a very promising means of achieving very low latency multicast.