An efficient scheduling mechanism using multiple thresholds for multimedia traffic in ATM switching nodes

Abstract

We propose QLT/MT (Queue Length Threshold with Multiple Thresholds) as a dynamic priority cell scheduling mechanism to serve efficiently the multimedia traffic in ATM networks. The multimedia traffic can be categorized into three classes based on its real time properties and loss tolerance. QLT/MT is designed to schedule the traffic so that first served can be the most urgent class in terms of the priority of its class and the state of its queue. In the QLT/MT model, the cell scheduling relies on the number of cells in the queue of each class and its state determined by multiple thresholds. In order to evaluate our mechanism, the cell loss rate and average delay of QLT/MT are compared with those of the conventional mechanisms such as SPS, QLT, DQLT and DHOL. The simulation result shows that both the cell loss rate and average delay of QLT/MT measured for each class are lower in most cases than those of the other schemes.