Differentiated predictive fair service for TCP flows

The majority of the traffic (bytes) flowing over the Internet today have been attributed to the Transmission Control Protocol (TCP). This strong presence of TCP has spurred further investigations into its congestion control mechanism and its effect on the performance of short and long data transfers. We investigate the interaction among short and long TCP flows, and how TCP service can be improved by employing a low-cost service differentiation scheme. Through control-theoretic arguments and extensive simulations, we show the utility, of isolating TCP flows into two classes based on their life-time/size, time/size one class of short flows and another of long flows. With such class-based isolation, short and long TCP flows have separate service queues at routers. This protects each class of flows from the other as they possess different characteristics, such as burstiness of arrivals/departures and congestion/sending window dynamics. We show the benefits of isolation, in terms of better predictability and fairness, over traditional shared queueing systems with both tail-drop and random-early-drop (RED) packet dropping policies.