Scalable distributed multicast routing with multiple classes of QoS guarantee

This paper proposes dynamic distributed unicast and multicast routing algorithms for multiple classes of QoS guaranteed networks. Each link in such a network is assumed to be able to provide multiple classes of QoS guarantee by reserving various amounts of resource. A distributed unicast routing algorithm, DCSP (Distributed Constrained Shortest Path), for finding a QoS constrained least cost path between each O-D (Originating-Destination} pair, is proposed first. Two class reduction schemes, the linear and logarithmic policies, are develpoed to prevent exponential growth of the number of end-to-end QoS classes. Based on DCSP, two distributed multicast routing algorithms, DCSPT (Distributed Constrained Shortest Path Tree) and DTM (Distributed Takahashi and Mutsuyama), are proposed to find QoS constrained minimum cost trees. Numerical results indicate that DCSP strongly outperforms previously proposed centralized algorithms and it works better with the linear class reduction method. For the multicast routing algorithms, the DCSPT with linear class reduction method yields the best performance of all multicast routing algorithms.