Scheduling Non-stationary Bursts of Real-time and Non-real-time Traffic in ATM Networks

The problem of scheduling real time and non real time traffic in an ATM switch multiplexor when bursts of either type of traffic occur is studied. The scheduling algorithms studied are: Queue Length Threshold (QLT) and Minimum Laxity Threshold (MLT). Analytic results based on Markov Chains are used. In addition the results are compared with an optimal (but impractical) scheduling determined via dynamic programming. Dynamic programming is used in this paper to show that MLT gives a near optimal performance trade off between real time and non real time traffic for constant arrival rates. The trade off QLT allows is not close to optimal. For non real time bursts MLT still gives a close to optimal trade off. For real time bursts the trade off MLT allows between real time and non real time traffic is not as close to optimal, but even where the MLT trade off is not near optimal, the QLT trade off is much worse than the MLT trade off.