Measuring Starlink Protocol Performance

Starlink poses some unique issues for TCP protocols. The signal has extremely high jitter, the channel capacity is constantly varying and packet loss is constant. Sustained download speeds of around 30Mbps are see using iperf tools wioth the CUBIC flow control protocol. When we switch over to BBR the throughput rises to some 200Mbps - 2150Mbps. Why is there such a dramatic change? What is goimng on inside the Starlink system that has such an impact on protocol performance? Speaker Geoff Huston - APNIC