With regards to Moshe Werner's post on the Motu 1248 working on Linux, it seems that AVB (AES67) works on Linux as well. This is a dream come frue for me.
Sorry to disappoint but I did not really try the AVB port other than for controlling the device, which is done via standard ethernet.
My audio goes in and out via USB.
Fernando posted that he is combining both (or that's what I understood) but the PC is connected to USB.