Performance enhancement of MPTCP having a bufferbloat path using retransmission of HoL blocking packets

MPTCP is a very promising protocol for improving throughput and reliability for a multi-interface device. However, the throughput of MPTCP is unexpectedly degraded when the characteristics of subflows, such as bandwidth or delay, are different because of HoL blocking at the MPTCP receiver buffer. Therefore, in order to solve this problem, in this paper, we monitor the receiver's reordering buffer to detect the HoL blocking phenomenon and to retransmit the problematic HoL (Head of Line) packet using the fast path. During bufferbloat, the data transmission of the long-RTT path is suppressed and the path re-activation timing is monitored by transmitting the probe packet pairs. Simulation results show that the proposed algorithm not only improves performance degradation due to long-RTT path in bufferbloat situation but also reduces data transmission time.