Many Internet multicast applications such as teleconferencing and remote diagnosis have Quality-of-Service (QoS) requirements. Such requirements can be additive (end-to-end delay), multiplicative (loss rate) or with a bottleneck nature (bandwidth). For these applications, QoS multicast routing protocols are important in enabling new receivers to join a multicast group. However, current routing protocols are either too restrictive in their search for a feasible path between a new receiver and the multicast tree, or burden the network with excessive overhead.
In this paper we propose S-QMRP, a new Stateless Qos Multicast Routing Protocol that supports all three QoS requirement types. S-QMRP is scalable because it has very small communication overhead and requires no state outside the multicast tree; yet, it retains a high success probability. S-QMRP achieves the favorable tradeoff between routing performance and overhead by carefully selecting the network sub-graph in which it conducts the search for a path that can support the QoS requirement, and by auto-tuning the selection according to the current network conditions. S-QMRP does not require any global network state to be maintained and can operate on top of any unicast routing protocol. Our extensive simulation shows that S-QMRP performs better than the previously suggested protocols.