GEN05-6: Assessing the Impact of Multiple Active Queue Management Routers

Recent studies have shown that a non-negligible number of packets face multiple congested links on Internet paths. We investigate the impact of using multiple active queue management (AQM) routers on paths that consist of multiple congested links. We present the results of an ns-2 evaluation study of various AQM techniques that, in contrast to previous studies of AQM, uses a complex network topology including up to three congested links, reverse path traffic, and realistic round-trip times. We consider the effects of multiple AQM routers coupled with explicit congestion notification (ECN) on the throughput of long-lived flows and response times of web traffic. We find that, especially for web traffic, performance is improved as the number of AQM routers is increased, but that significant improvements occur with even a single AQM router.