On the isochronous paths selection problem in an interconnected WDM network

In this paper, a new wavelength division multiplexing (WDM) interconnection architecture for supporting both isochronous and asynchronous traffic is proposed. Based on this architecture, the problem of allocating an isochronous bandwidth is investigated. We show that given a set of established isochronous connections and a set of new isochronous requests, the problem of using a minimal amount of an isochronous bandwidth to serve this isochronous traffic, including the established connections and new requests, is NP-hard. On the other hand, given a limited isochronous bandwidth, the goal is to establish a maximal number of isochronous connections. An efficient isochronous paths selection algorithm, based on the concept of paths merging and splitting, is also proposed for this problem. The proposed algorithm is evaluated by simulation. Simulation results show that for a limited isochronous bandwidth, the proposed algorithm can achieve high performance in terms of isochronous slots utilization, call blocking rate, and the number of successfully established isochronous connections.