A layered QoS multicast protocol

Multimedia applications require guaranteed quality of service and multicast connection. We present, layered QoS, a new QoS-based multicast routing protocol. We adopt multiple central points (CPs) and assign QoS-levels for each CP to maximize the resource sharing. When a new receiver wishes to join a tree, the receiver considers on-tree nodes as a joining point based on their QoS capabilities, not based on the minimum distance. Maximizing the share of resource and minimizing the total tree cost are acquired by means of sharing upstream branches among the receivers with similar QoS requirements. Layered QoS improves network utilization by decreasing the total tree cost and provides a stricter guarantee of QoS. The protocol is verified by simulation, and it is shown that the protocol exhibits much better performance than the existing ones in terms of the QoS guarantee