A ug 2 00 9 RANDOMIZED SCHEDULING ALGORITHM FOR QUEUEING NETWORKS

There has recently been considerable interest in design of low-complexity, myopic, distributed and stable scheduling policies for constrained queueing network models that arise in the context of emerging communication networks. Here, we consider two representative models. One, a model for the collection of wireless nodes communicating through a shared medium, that represents randomly varying number of packets in the queues at the nodes of networks. Two, a buffered circuit switched network model for an optical core of future Internet, to capture the randomness in calls or flows present in the network. The maximum weight scheduling policy proposed by Tassiulas and Ephremide [32] leads to a myopic and stable policy for the packet-level wireless network model. But computationally it is very expensive (NP-hard) and centralized. It is not applicable to the buffered circuit switched network due to the requirement of non-premption of the calls in the service. As the main contribution of this paper, we present a stable scheduling algorithm for both of these models. The algorithm is myopic, distributed and performs few logical operations at each node per unit time. 1. Introduction. The primary task of a communication network architect is to provision as well as utilize network resources efficiently to satisfy the demands imposed on it. The main algorithmic problem is that of allocating or scheduling resources among various entities or data units, e.g. packets, flows, that are contending to access them. In recent years, the question of designing a simple, myopic, distributed and high-performance (aka stable) scheduling algorithm has received considerable interest in the context of emerging communication network models. Two such models that we consider this paper are that of a wireless network and a buffered circuit switched network.