Acceleration of Multipath TCP by Letting ACKs Take the Shortest Path

Multipath TCP (MPTCP) can improve overall throughput of an end-to-end connection by leveraging different network paths. However, the heterogeneity of these paths can significantly hamper MPTCP's performance. In this paper, we propose to send acknowledgments (ACKs) along the lowest-latency path. This can help improve the performance of MPTCP when subflow throughput is constrained by packet loss by reacting to loss events faster. An active probing module is also developed to dynamically select the lowest-latency path against the potential change of path condition. Experiments demonstrate that overall throughput improvement generally ranges from 10% to 50%.