Comparative study of TCP compatible binomial congestion control schemes

Current TCP implementations employ additive increase multiplicative decrease (AIMD) as the congestion control mechanism. Previously, a new set of schemes called binomial congestion control schemes (BCCS) were proposed and a section of these schemes is TCP compliant. In this paper we evaluate the performance of these TCP compliant binomial schemes and show through simulations that AIMD performs better than the other BCCS policies in a wide range networking environments. Specifically, we study the performance of these schemes with respect to throughput, fairness, losses, timeouts and self-similarity. We show that the superior performance of AIMD can be attributed to its more conservative attitude in the presence of losses when it reduces its transmission rate much faster than the other schemes. This results in smaller congestion periods thereby reducing the losses and timeouts which in turn increases the throughput and decreases the degree of self-similarity of the traffic. We also evaluated the performance of TCP Compatible BCCS when they compete with TCP flows. It was found that with sufficiently large number of flows, BCCS competes fairly with TCP. However, with a smaller number of flows in the network TCP flows get a smaller share of the bottleneck and disproportionately higher losses and timeouts.