Minimum-delay self-clocked fair queueing algorithm for packet-switched networks

摘要

The minimum-delay self-clocked fair queueing (MD-SCFQ) algorithm that we present in this paper is the first algorithm that achieves the same delay bounds as the packet by packet version of generalized processor sharing (P-GPS), has fairness properties similar to P-GPS, and uses a system-potential function of 0(1) complexity. To prove that MD-SCFQ achieves the same delay bounds of P-GPS, we have shown that the fluid version of MD-SCFQ belongs to the class of rate proportional server (RPS) schedulers; thus, its packet-by-packet version inherits all the well-known single-node and multiple-node delay properties of P-RPS schedulers. We have also computed the fairness index of MD-SCFQ, and show that is very close to that of P-GPS. Because of the properties of its system potential, MD-SCFQ, when combined with a shaper which declares packets eligible for scheduling according to their virtual starting times, is a work-conserving worst-case fair scheduler.