A Price to Pay for Increased Throughput in MPTCP Transmission of Video Streams
Michał Morawski, Przemysław Ignaciuk · 2020
Nowadays, providing an efficient service of video streaming goes much beyond the domain of entertainment. It plays an important role in the industry, especially in the systems of monitoring and robotic automation. The modern multimedia applications require both high network throughput and short latency, rarely available within a single data channel. Until recently, nonhomogeneous channels could not have been concurrently employed to boost the throughput owing to the protocol legacy restrictions. In order to answer the current challenges, new protocols, in particular, Multipath TCP (MPTCP), have been elaborated. In the standard MPTCP implementation, however, only one type of congestion control (CC) algorithm is used to manage the stream dynamics. Instead of providing benefits, such an approach may actually downgrade the user experience through the intensified perturbations caused by Head-of-Line blocking in the multipath connection (inability to reconstruct the stream in a timely manner due to missing pieces on certain paths). In this work, the impact of current TCP CC algorithms, operating at the path and MPTCP level, on the video stream characteristics is investigated. The considered scenarios, involving a live-video connection passing through heterogeneous, public networks, set the basis for recommendations about the CC algorithm selection for the modern multimedia networking services.