Improving the Fairness and the Response Time of TCP-Vegas

Abstract

Unfairness of the Internet has galvanized numerous studies toward fair allocation of bandwidth. Study of TCP-Vegas is one of them. TCP-Vegas, although not perfect, at least enables bandwidth allocation independent of propagation delay, which is radically different behavior from that of current Internet. In the current Internet, a long-delay connection usually receives less throughput than short-delay connections. Until now, two necessary conditions have been identified to make TCP-Vegas achieve fair allocation of bandwidth: correct estimation of propagation delay and finer control of window by adopting single threshold rather than two.

In this paper, we propose three more fixes to achieve fair bandwidth allocation. First, we provide a fix for packet size independence. Second, we provide a fix regarding the reference value in the control. Third, we provide a fix for reducing both the oscillation and the convergence delay. We argue that fixes of ours and those of previous researchers constitute the necessary and sufficient condition for fair allocation of bandwidth.

This work was supported by Korea Science and Engineering Foundation under the contract number 20005-303-02-2. It was also supported by the Brain Korea 21 Project and National Research Laboratory Project of Korea.