Differentiated Control of TCP Flows Based on their Sizes

摘要

A careful study of the TCP (transmission control protocol) protocol shows that the congestion control mechanism is unfair in an environment where flows with different sizes compete for scarce resources. Short connections tend to lose to long connections in their competition for bandwidth. This is because short connections do not gain detailed knowledge of the network state, and therefore they are condemned to be less competitive due to the conservative nature of TCP congestion control algorithm. In this paper, we propose to give preferential treatment to the first packets of each flow with help from an active queue management (AQM) inside the bottleneck queue, so that short connections experience less packet drop rate than long connections. Based on analyses and simulations, we show that the sojourn time of short flows is reduced without penalizing the performance of long connections. Indeed, our method of classification treats the first packets of long flows like those of short flows. Therefore, the first packets of each flow (which are more sensible to loss) experience fewer losses