Exploring Performance Balancing in a Meshed Satellite MultiWAN Using MPTCP

Abstract

Improvements to communication protocols has been an active research area with the recent introduction of MultiPath TCP (MPTCP) in the in-tree Linux kernel. This may benefit the area of Satellite Communication as it can be a more reliable and performant alternative in the lossy, high-latency links characterising Satellite Communication. Just like TCP, MPTCP requires a congestion control algorithm to manage its congestion window, which is one of the factors deciding how much data that can be sent on a link at a time. Additionally, MPTCP extends TCPs path manager with a scheduling algorithm which decides on which subflow to send each packet on. This thesis is a performance comparative study on different congestion control- and scheduling algorithms. The research is conducted on a semi-simulated testbed and with portable satellite terminals connecting to GEO satellites providing real-world results, in addition to more easily reproducible tests using an emulated satellite network.

The study revolves around the congestion control algorithms LIA, OLIA, BALIA, and wVegas due to them being readily available with well tested MPTCP implementations. As for packet schedulers, MinRTT, ECF, BLEST, Round Robin, and the currently default scheduling algorithm are tested. The results indicate that some improvements in performance can be made through the choice of congestion controland scheduling algorithm, especially if tailored to specific network use cases. At the end multiple points for future work and improvements are presented.