[Bloat] A Transport Protocol's View of Starlink

Kenneth Porter shiva at sewingwitch.com
Wed May 22 14:55:41 EDT 2024


The Register came out with this summary today:

https://www.theregister.com/2024/05/22/starlink_tcp_performance_evaluation/

Excerpt:

> Using PING, he found "minimum latency changes regularly every 15 
> seconds" and surmised "It appears that this change correlates to the 
> Starlink user's terminal being assigned to a different satellite. That 
> implies that the user equipment 'tracks' each satellite for a 
> 15-second interval, which corresponds to a tracking angle of 11 
> degrees of arc."
>
> During those handovers, Huston observed some packet loss – and a 
> significant increase in latency. "The worst case in this data set is a 
> shift from 30ms to 80ms," he wrote. Further: "Within each 15-second 
> satellite tracking interval, the latency variation is relatively high. 
> The average variation of jitter between successive RTT intervals is 
> 6.7ms. The latency spikes at handover impose an additional 30ms to 
> 50ms indicating the presence of deep buffers in the system to 
> accommodate the transient issues associated with satellite handover."
>
> Overall, Huston believes Starlink has "a very high jitter rate, a 
> packet drop rate of around one percent to two percent that is 
> unrelated to network congestion, and a latency profile that jumps 
> regularly every 15 seconds."

[No need to cc me in replies, I'll read them on the mailiing list.]




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