Differentiated pacing on multiple paths to improve one-way delay estimations

Several works in the literature show that accurate estimations of the actual One-Way Delays (OWD) could improve the performance of various network protocol, such as Transport Control Protocol (TCP) throughput. With the emergence of multipath transport protocols like Multipath TCP or the Stream Control Transport Protocol (SCTP), the potential impact can be even higher. Indeed, as multipath transport protocols send data concurrently on heterogeneous paths, the knowledge of corresponding OWDs can greatly help mitigating packet arrival disorder. Theoretically, clock synchronization protocols between endpoints could ensure OWD knowledge, but their efficiency at the Internet scale is debatable. In practice, TCP uses the Round Trip Time (RTT) to take into account congestion or to compute retransmission timeouts, and the OWD is assumed to be half the RTT. However, numerous studies show that a majority of Internet connections experience latency asymmetry. In this paper, we propose a technique based on differential pacing over multiple paths to obtain an estimation of the difference in OWDs between the different paths, motivated by its strong utility for multipath transport protocols such as MPTCP and SCTP. Simulations show which are the interesting scenarios of application.