What does the default packet scheduler do?

[mpiraux]

https://github.com/multipath-tcp/mptcp.dev/blob/main/index.md#packet-scheduler explains the concepts of a packet scheduler but doesn't explain what the available packet scheduler actually does. From my understanding it does a basic round-robin scheduling across available subflows (i.e. non-backup), but this seems not reflected in the documentation.

[matttbe]

Hi Maxime,

doesn't explain what the available packet scheduler actually does

Yes, good point, that's missing indeed. This should be added.

From my understanding it does a basic round-robin scheduling across available subflows (i.e. non-backup), but this seems not reflected in the documentation.

It's not that simple: it implements a simplified version of the BLEST algorithm, trying to avoid HoL blocking. It sends as much as possible over the active path, before using the others. (There is room for improvement on that side.)