Active packet dropping for improving performance fairness among modern TCPs

Abstract

Over current long fat networks, enough throughput cannot be obtained using TCP Reno, which is the classical standard TCP congestion avoidance algorithm. For this reason, many high performance TCPs have been proposed, such as Compound TCP and CUBIC TCP. Then, these proposals have caused a new issue, which is fairness among these modern TCPs. For this issue, several fairness evaluations and some proposals for improving fairness were published. However, most of these evaluations are executed using a network simulator, so fairness with actual network elements and actual TCP implementations has not been discussed enough yet. In this paper, we focus on performance fairness of modern TCPs and discuss methods for improving performance fairness with actual TCP implementations and network elements. First, we present fairness evaluation among modern TCPs and demonstrate that fairness among modern TCPs is very poor. Second, we propose methods for improving performance fairness, which drop packets of bandwidth-consuming connections in a network bridge. Third, we evaluate our proposed methods and show that our methods can improve performance fairness.