Question

I have computers and Motu Ultralites in each side of the Cat6 cable. If I put only one switch in one of the sides (switch to connect the AVB interface + a computer), and connect the interface without switch in the other side, it works well. So Cables and switches are ok.
But having a switch in each side connected by the same cable (and a computer and an audio interface in each switch) doesn't work. The led doesn't even flash.

Answer 1

It is a  bit hard to get the picture but as far as I know you should be able to connect two switches with a cable and connect both computers and AVB devices on both ends. You might have to make sure your devices have correct IP-addresses too so if there is no DHCP, you need to set them manually.

If you do not get link, you might have a faulty cable or something other going on.