A Simulation Study of the WFQ Scheduler in a DiffServ Node under LRD Traffic

The most important desidered characteristic for today´s networks is quality of service (QoS). Currently DiffServ-based MPLS networks are able to the development of efficient methods for QoS provisioning. This article analysis, through computer simulation, the performance of WFQ schedulers in a DiffServ node loaded by long range dependence (LRD) traffic. The adopted process for the traffic generation consists in the aggregation of the traffic produced by several TCP connections transmitting files with a size that is modeled by heavy tail distribution. This distribution was obtained, from the Internet, by one-week long measurements. The objective is to observe the bandwidth distribution obtained with the WFQ scheduler, as well as the latency, i.e., the file transfer average delay, in an environment with different priorities. Simulations were carried out with the network simulator NS-2, and several simulation results are presented and analyzed.