It's most likely a version of the ATM protocol[1]. Point-to-point, small packets, etc.. We used a version of that when I was working on the Iridium project.

Likely the exact same thing here, especially if they hired the same engineers.

[1]: https://en.wikipedia.org/wiki/Asynchronous_Transfer_Mode

You worked on the original Iridium satellite architecture? I am sure a lot of people here may not know how fully groundbreaking it was. Considering it is now 20-year-old tech the satellite-to-satellite Ka-band trunk links are an amazing technical achievement. That and the voice codec they came up with to make humans intelligible at 2400bps.

Damn, those are some sexy credentials.

Indeed, and I'd expect ATM's fixed packet size to make for more manageable flow control over variable (and simultaneous) pipes.

Are you ever an ex-programmer? I would say, once a programmer, always a programmer.

I refer to myself as a recovering software engineer/programmer. Never really out of the addiction, but not in the weeds anymore.