AMTCP: an adaptive multi-path transmission control protocol

Enabling multiple paths in datacenter networks is a common practice to improve the performance and robustness. Multi-path TCP (MPTCP) explores multiple paths by splitting a single flow into multiple subflows. The number of the subflows in MPTCP is determined before a connection is established, and it usually remains unchanged during the lifetime of that connection. While MPTCP improves both bandwidth efficiency and network reliability, more subflows incur additional overhead, especially for small (so-called mice) subflows. Additionally, it is difficult to choose the appropriate number of the subflows for each TCP connection to achieve good performance without incurring significant overhead. To address this problem, we propose an adaptive multi-path transmission control protocol, namely the AMTCP, which dynamically adjusts the number of the subflows according to application workloads. Specifically, AMTCP divides the time into small intervals and measures the throughput of each subflow over the latest interval, then adjusts the number of the subflows dynamically with the goal of reducing resource and scheduling overheads for mice flows and achieving a higher throughput for elephant flows. Our evaluations show that AMTCP increases the throughput by over 30% compared to conventional TCP. Meanwhile, AMTCP decreases the average number of the subflows by more than 37.5% while achieving a similar throughput compared to MPTCP.