Watching Stars in Pixels: The Interplay Of Traffic Shaping and YouTube Streaming QoE over GEO Satellite Networks

Geosynchronous satellite (GEO) networks are an important Internet access option for users beyond terrestrial connectivity. However, unlike terrestrial networks, GEO networks exhibit high latency and deploy TCP proxies and traffic shapers. The deployment of proxies effectively mitigates the impact of high network latency in GEO networks, while traffic shapers help realize customer-controlled data-saver options that optimize data usage. However, it is unclear how the interplay between GEO networks’ high latency, TCP proxies, and traffic-shaping policies affects the quality of experience for commonly used video applications. To address this gap, we analyze the quality of over 2 k YouTube video sessions streamed across a production GEO network with a 900 Kbps shaping rate. Given the average bit rates of the videos, we expected streaming to be seamless at resolutions of 360p, and nearly seamless at resolutions approaching 480p. However, our analysis reveals that this is not the case: \(30\%\) of both TCP and QUIC sessions experience rebuffering, while the median average resolution is only 404p for TCP and 360p for QUIC. Our analysis identifies two key factors that contribute to sub-optimal performance: (i) unlike TCP, QUIC only utilizes \(70\%\) of the network capacity; and (ii) YouTube’s chunk request pipelining neglects network latency, resulting in idle periods that disproportionately harm the throughput of smaller chunks. As a result of our study, Viasat discontinued support for the low-bandwidth data-saving option in U.S. business and residential markets to avoid potential degradation of video quality—highlighting the practical significance of our findings.