It discusses the multicast routing problem with QoS constraints and describes a network model that is suitable to research such routing problem.The paper mainly presents a dynamic QoS multicast routing protocol(DQMRP).The DQMRP can operate on top of the unicast routing protocol.It only requires the local state information of the link(or the node)

but does not require any global network state to be maintained.The DQMRP can significantly reduce the overhead for constructing a multicast tree with QoS constraints.In DQMRP

a multicast group member can join or leave the multicast session dynamically.The protocol can search multiple feasible tree branches

and select the optimal or near-optimal branch for connecting the new receiver to the multicast tree if it exists.The proof of correctness and complexity analysis of the DQMRP are given

and the performance measures of the protocol are evaluated using simulation.The study shows that DQMRP provides an available approach to multicast routing with QoS constraints.