Network coding based multipath TCP

Multipath TCP (MPTCP) suffers from the degradation of goodput in the presence of diverse network conditions on the available subflows. The goodput can even be worse than that of one regular TCP, undermining the advantage gained by using multipath transfer. In this work, we propose a new multipath TCP protocol, namely NC-MPTCP, which introduces network coding (NC) to some but not all subflows traveling from source to destination. At the core of our scheme is the mixed use of regular and NC subflows. Thus, the regular subflows deliver original data while the NC subflows deliver linear combinations of the original data. The idea is to take advantage of the redundant NC data to compensate for the lost or delayed data in order to avoid receive buffer becoming full. We design a packet scheduling algorithm and a redundancy estimation algorithm to allocate data among different subflows in order to optimize the overall goodput. We also give a guideline on how to choose the NC subflows among the available subflows. We evaluate the performance of NC-MPTCP through a NS-3 network simulator. The experiments show that NC-MPTCP achieves higher goodput compared to MPTCP in the presence of different subflow qualities. And in the worst case, the performance of NC-MPTCP is close to that of one regular TCP.