A Synchronizing Scheduler for Reduced Protocol Delay in Multipath Transmission

Efficient transfer of time-sensitive data plays an essential role in entertainment, personal and business communication, and in industry, especially in the systems of monitoring and robotic automation. In those application areas high network throughput together with short latency, and resiliency from network problems are expected. One of the most promising methods of answering those challenges is to simultaneously engage multiple paths of communication. Currently, only two protocols provide such a possibility in public networks - the multipath version of TCP (MPTCP) and the multipath version of QUIC (MPQUIC). Both protocols split data units over available paths via a component named scheduler. The default scheduler favors throughput over protocol delay, which is unsuitable in industrial applications. In the paper, a balanced solution - a synchronizing scheduler - that reduces the protocol delay is proposed. Its properties are analyzed formally and tested experimentally in the framework of both MPTCP and MPQUIC in the open Internet.