TS-TCP: Two-stage Congestion Control Algorithm for High Concurrency TCPs in Data center Networks

Nowadays, TCP has been used as the de facto transport layer protocol on the Internet. However, TCP incast happens inevitably in data centers, where exist massive concurrent flows, leading to packets loss, unacceptable long transmission time, and throughput collapse. Furthermore, DCTCP is widely used to solve these problems. Unfortunately, DCTCP cannot work well under a high concurrency environment. To this end, in this paper, we introduce a two-stage congestion control algorithm (TS-TCP) for high concurrency flows. The first step is to reduce the congestion window of long-lived flows aggressively to release bandwidth for short-lived flows. The second step is to decline the sending rate by adjusting the sending interval. Through the above steps, the proposed algorithm can mitigate the TCP incast effectively. The results, by using extensive ns3 simulation, show that TS-TCP can significantly outperform the DCTCP and TCP NewReno in terms of throughput and flow completion time. Moreover, TS-TCP can support hundreds of concurrent flows while maintaining about 85% link utilization.