Quantifying the effects of recent protocol improvements to TCP: Impact on Web performance

We assess the state of Internet congestion control and error recovery through a controlled study that considers the integration of standards-track TCP error recovery and both TCP and router-based congestion control. The goal is to examine and quantify the benefits of deploying standards-track technologies for contemporary models of Internet traffic as a function of the level of offered network load. We limit our study to the dominant and most stressful class of Internet traffic: bursty HTTP flows. We find that for HTTP flows (1) using SACK only improves performance for larger-than-typical HTTP transfers, (2) unless congestion is a serious concern (i.e., unless average link utilization is approximately 80% or higher), there is little benefit to using RED queue management, (3) above 80% link utilization there is potential benefit to using Adaptive RED with ECN marking, however, complex performance trade-offs exist and the results are dependent on parameter settings.