Supporting best-effort traffic with fair service curve

Abstract

While PFQ algorithms can provide per-flow end-to-end delay guarantees for real-time traffic or protection among competing best-effort traffic, they have two important limitations. The first one is that, since only one parameter (a weight) is used to allocate resource for each flow, there is a coupling between delay and bandwidth allocation. When used for real-time traffic, this can result in network under-utilization. The second and less well known limitation is that, when used for best-effort traffic, PFQ algorithms favor throughputoriented applications such as FTP over delay-sensitive bursty applications such as WWW, and telnet. This is due to the memory-less instantaneous fairness property of PFQ algorithms. In a previous study [1], we proposed the Fair Service Curve (FSC) algorithm which enables more flexible delay and bandwidth allocation for real-time traffic through the use of non-linear service curves. In this paper, we show that, when used for best-effort traffic, FSC can improve performance of delay-sensitive bursty applications without negatively affecting the performance of throughput-oriented applications.

Enhancing router QoS through job scheduling with weighted shortest processing time-adjusted

“…To examine QoS performance, we implement the three router models using OPNET Modeler software [13]. We then conduct simulation experiments under various tra c conditions.…”

“…Many scheduling rules and associated performance problems have also been studied in the context of real-time and queuing systems with the goals of optimizing various performance measures such as delay and throughput [9,12,13]. However, existing job scheduling rules target the optimal performance on average, in sum or with an upper bound, for a population of jobs.…”