  Starlink constellations are currently the largest LEO WAN and have seen
considerable interest from the research community. In this paper, we use
high-frequency and high-fidelity measurements to uncover evidence of
hierarchical traffic controllers in Starlink -- a global controller which
allocates satellites to terminals and an on-satellite controller that schedules
transmission of user flows. We then devise a novel approach for identifying how
satellites are allocated to user terminals. Using data gathered with this
approach, we measure the characteristics of the global controller and identify
the factors that influence the allocation of satellites to terminals. Finally,
we use this data to build a model which approximates Starlink's global
scheduler. Our model is able to predict the characteristics of the satellite
allocated to a terminal at a specific location and time with reasonably high
accuracy and at a rate significantly higher than baseline.
