Routing in ATM networks with multiple classes of QoS

In this paper we study the path-constrained-cost-optimized routing problem, which tries to minimize path cost while satisfying the QoS requirements of a connection. In previous research, each link of the network is associated with a set of QoS metrics, which represents the QoS metrics that can be provided by this link. However, in a real network, ATM switches are able to provide a finite number of QoS classes, instead of just one QoS class. Therefore, in this paper, we studied the path-constrained-cost-optimized routing problem where each link of the network is associated with several sets of QoS metrics. Our solution to this problem consists of two tasks: QoS decomposition and QoS-constrained least cost routing. We propose a greedy algorithm to decompose the end-to-end QoS constraint to local QoS constraints such that the path cost can be minimized. For QoS-constrained least cost routing, we first study three approaches for defining link costs. We then propose two routing algorithms for finding QoS-constrained paths