On Traffic Long-Range Dependence at the Output of Schedulers with Multiple Service Classes

Abstract

Long-range dependence (LRD) is a widely verified property of Internet traffic, which severely impacts network performance yielding longer queuing delays. Moreover, LRD is almost ubiquitous and very hard to remove or control. In this work, we investigated by thorough simulation the effect of schedulers on traffic LRD. We analyzed the output traffic of schedulers merging LRD flows according to various service policies, viz. plain FIFO, static-priority, earliest-deadline-first and general processor sharing. First, we noticed that traffic LRD is not affected much by crossing the scheduler, for any type of service policy. Second, we showed that LRD also propagates across different service classes with any policy except balanced GPS, which ensures complete separation between classes. This phenomenon may explain in part why LRD is so widespread in Internet traffic.