- The paper presents a comprehensive assessment of Starlink using extensive crowdsourced data and controlled experiments to evaluate global and local performance.
- It highlights competitive latency and throughput alongside issues like bufferbloat and regional disparities tied to ground station density.
- Controlled experiments reveal periodic latency fluctuations caused by centralized reconfiguration, suggesting areas for optimization in LEO networks.
The paper "A Multifaceted Look at Starlink Performance" provides an extensive examination of Starlink's global and last-mile performance based on numerous measurements. It draws from over 19.2 million crowdsourced M-Lab speed tests from 34 countries, performance metrics from Starlink-enabled RIPE Atlas probes, and controlled experiments with Starlink dishes in two European countries. This research aims to offer a holistic understanding of Starlink's network capabilities and limitations, framing it against the backdrop of alternative terrestrial networks such as wireless cellular systems.
The paper begins with a global analysis highlighting Starlink's competitive latency and throughput performance relative to terrestrial cellular networks. Despite this, variations in performance were found across different regions, strongly correlated with the density and distribution of ground stations (GS) and points-of-presence (PoP). In well-served regions like the United States and parts of Europe, Starlink achieved sub-50 ms latencies similar to those of terrestrial ISPs. However, in areas with fewer GSs and PoPs, like parts of Africa and South America, Starlink's performance was somewhat inconsistent and often inferior to terrestrial services. The authors also observe significant signs of bufferbloat in Starlink's network as latency inflated considerably under high traffic conditions, an area that may benefit from improvements in active queue management techniques.
Real-time Application Support
The ability of Starlink to handle real-time applications was tested with Zoom video conferencing and Amazon Luna cloud gaming. It was observed that Starlink could adequately support these applications under optimal conditions comparable to 5G cellular networks. However, periodic fluctuations in latency and throughput every 15 seconds were linked to Starlink's internal reconfiguration intervals, which significantly impact application performance.
Examination of Starlink's Last-Mile Access
For a deeper understanding of Starlink's last-mile performance, targeted measurements were taken using Starlink RIPE Atlas probes. These measurements showcased that the typical "bent-pipe" latency—a critical measure of satellite network performance—remains consistent at about 40 ms worldwide within the dense 53-degree satellite shell. In contrast, regions covered predominantly by the 70-degree and 97.6-degree orbits experienced larger latencies due to less satellite density.
Controlled Experiments and Network Reconfigurations
Through meticulous controlled experiments, the researchers were able to monitor the sub-second performance variations during network reconfiguration intervals. The synchronization of reconfiguration intervals globally rather than being tied to individual satellite handoffs suggests that Starlink employs a centralized or global scheduling approach for network resource allocation. This insight not only highlights the operational underpinnings of Starlink's architecture but also suggests potential areas for optimization, as these reconfiguration operations are a noticeable cause of brief latency and throughput degradations.
Implications and Future Direction
The findings from this paper are significant for both the practical deployment and theoretical modeling of LEO satellite networks. They suggest that while Starlink effectively competes with terrestrial networks in many parameters, geographical disparities in ground infrastructure provisioning remain a key influence on performance. Additionally, the periodic reconfiguration-induced fluctuations highlight an important aspect of satellite network management that could benefit from advanced scheduling algorithms to minimize their impact.
As LEO satellite networks continue to scale, the methodologies employed in this analysis can be pivotal in further studies. The dataset published alongside this research opens avenues for future investigations into adaptive networking protocols and enhanced satellite-ground coordination strategies. Such efforts will be crucial to improving the quality of service delivered by satellite ISPs, especially in areas beyond the reach of existing terrestrial infrastructure. The exploration of Starlink's network instantiates a critical evaluation that could shape strategies for emerging LEO systems like OneWeb and Kuiper, guiding them in optimizing systems for consistent global Internet access.