Impact of TCP Congestion Control Algorithms on MPTCP Protocol Efficiency
Many networking devices manufactured today are equipped with multiple communication interfaces. However, the legacy versions of the TCP protocol governing the majority of data exchange between applications are not designed with redundancy in mind. Thus, the applications do not take advantage of multi-interface environments. Recently, a new, multipath, version of TCP – MPTCP – has been designed. MPTCP uses previously developed TCP algorithms to control the particular paths of data transfer. Even if there are multiple versions of TCP installed, due to operating system restrictions, only one is selected to control the data streams. Such an approach may lead to non-optimal transfer properties. In this work, the impact of different TCP congestion control algorithms operating in subpaths on the efficiency of MPTCP stream is examined. The asymmetric, heterogeneous public networks have been used to evaluate the modified MPTCP stack properties. Using the measurements performed for various network loads, recommendations about efficient TCP congestion control algorithm selection have been formulated.
Keywords—Multipath TCP, congestion control, throughput analysis