Improving the performance of multipath TCP over heterogeneous paths using slow path adaptation

Multipath TCP (MPTCP) is an extension of TCP, developed by Internet Engineering Task Force (IETF) to support communication between source and destination through multiple flows under a single connection session. We have conducted several experiments with real hardware on flows with extreme variation in path quality and found that unless receive buffer size is increased to a much higher value, the overall throughput decreases below the level of single-path TCP throughput. We propose a Slow Path Adaptation (SPA) technique to overcome this issue without affecting other performance parameters. The implementation is done on Linux kernel and experimental results are presented.