Minimizing Delay and Packet Loss in Single-Hop Lightwave WDM Networks Using TDM Schedules

Abstract

We consider packet-switched lightwave WDM networks with stations equipped with tunable transmitters and fixed receivers. Access to each of the available channels is controlled by a weighted TDM scheme, whereby the channels are not necessarily shared equally among the various sources. While previous work focused on the throughput characteristics of such schemes, in this paper we study the problem of designing TDM frames to minimize the mean packet delay, as well as the mean packet loss probability given a finite buffer capacity. The corresponding optimization problems are shown to be hard allocation problems, and heuristics to obtain near-optimal solutions are developed. For (potentially non-uniform) communication patterns common to parallel and distributed computations, our approach represents a significant improvement over I-TDMA*. In addition, the margin of improvement increases with the size of the network.