Unveiling TCP BBR Dominance in Starlink Internet: Experimental Insights and Analysis
For network researchers and satellite internet providers, this work provides experimental insights and analytical models for congestion control in LEO satellite networks, though the findings are incremental over existing BBR variants.
This study evaluates Google's BBR-v3 congestion control algorithm over SpaceX's Starlink network using a six-city global testbed, benchmarking against eight other CCAs. Results show BBR-v3 achieves balanced fairness, loss, and delay trade-offs, establishing it as a compelling CCA for LEO satellite networks.
This experimental study delivers a global assessment of Google's Bottleneck Bandwidth and Round-trip propagation time-version 3 (BBR-v3) Congestion Control Algorithm (CCA) over SpaceX's Starlink network. Leveraging a strategically deployed six-city testbed across five continents, we systematically benchmark BBR-v3 against eight CCAs: Cubic, Hybla, Vegas, LeoCC, Copa, PCC, BBR-v1, and BBR-v2 under both dedicated and concurrent conditions. Our results demonstrate that BBR-v3's advantage is not aggressive bandwidth capture, but a more balanced fairness, loss, and delay trade-off over the Starlink Internet. We develop pragmatic mathematical models that capture Starlink's complex network dynamics and characterize BBR-v3 behavior to better explain the experimental observations. Our extensive evaluation of queue buildup and fairness further demonstrates BBR-v3's capability to maximize throughput in high-latency, variable satellite environments, while maintaining a balance between aggressiveness and fairness. The findings establish BBR-v3 as a compelling CCA for Low Earth Orbit (LEO) satellite networks and provide a principled analytical foundation for next generation satellite Internet transport design.