ECN-based shared bottleneck detection for multi-path TCP

Abstract

Multi-Path TCP (MPTCP) shows its unique advantages over single-path TCP thanks to its aggregate throughput from multiple paths, balancing efficiency and fairness over multipath transmission. However, MPTCP senders should tackle the friendliness issue carefully when sharing the same bottleneck with single-path TCP. Unfortunately, existing shared bottleneck detection schemes either utilize end-to-end delay without consideration of multiple-bottleneck scenarios, or identify subflows on switches with large operation overhead. In this paper, we propose a lightweight yet accurate approach, ECN-based MPTCP (EMPTCP), to detect shared bottleneck of multiple subflows. EMPTCP uses the widely deployed ECN scheme to capture the real congestion state of shared bottlenecks, while at the same time is compatible with various MPTCP congestion control algorithms. Through model analysis, simulation test and real experiment, we show that EMPTCP achieves higher than 85% accuracy in shared bottleneck detection, thus improving the network efficiency and fairness.