Dynamic Priority Scheduling for Proportional Delay Differentiated Services

Recent results on the proportional di erentiation model show that waiting time priority scheduling can be applied to implement proportional delay di erentiatied services reasonably well under limited conditions. While earlier research focused on heavy load conditions only, more recent results provide insights into waiting time priority scheduling under moderate load conditions also, but the applicability of the algorithm has been limited to a two-service-class solution for numerical reasons. In this paper, in contrast, a dynamic adjustment of a waiting time priority scheduler is suggested to meet the di erentiation requirements for any nite number of traÆc classes. Our newly introduced approach is based on genetic algorithms. The dynamically optimized scheduling parameters can be determined with high accuracy. We apply an interpolation function to yield a continuum of parameters rather than discrete values and propose a simple look-up table for a dynamic adjustment of the scheduling parameters. We also focus on feasibility and implementation issues related to the suggested algorithm. Suitability of other time-dependent priority functions for proportional delay di erentiation is also investigated. 2 Essa , Bolch and de Meer