A Novel Scheduler for the Proportional Delay Differentiation Model by Considering Packet Transmission Time

Abstract

The proportional delay differentiation model provides a consistent packet delay differentiation between various classes of service. The waiting time priority (WTP) scheduler is a priority scheduler in which the priority of a packet increases in proportion to its waiting time, and it is known as the best scheduler to achieve the proportional delay differentiation model. This paper proposes an advanced WTP (AWTP) scheduler, modified from WTP, that accounts for the packet transmission time. Simulation results reveal that when the link utilization is moderate (60%~80%), this scheduler not only obtains more accurate delay proportion than the WTP scheduler, no matter in short or long timescales, but also reduces the average queuing delay (waiting time). The effects of mean packet size and variance of packet size, on both schedulers' performance are also examined. AWTP always outperforms WTP.