Very Poor Ethernet Performance

[Jean-Marie]

Does the switch port that your 220 Pro connects to have an LED to tell you whether the Ethernet link is up (independently of whether there's traffic on the port)?  If so, can you see whether the link staying up steadily or cycling between up and down?

One other thing: do you have wi-fi enabled in your 220 configuration?  If so, it might be worth disabling that.  I understand that the wi-fi and Ethernet interfaces are in effect mutually exclusive so if the wi-fi was periodically linking to an access point it might knock out the Ethernet (speculating wildly) - best get that out of the equation in any case.

Many thanks for your reply.  From what I can see the link is up, i.e. it is solid green, but it blinks intermittently (but in amongst all of the other checks I'm doing, I don't spend all my time looking at ethernet ports).  When I have Devialet AIR installed it tells me the status of the connection, and even if it shows a connection I still can't play music.  I also noticed that whenever I tried a fresh configuration (which has been quite a lot these past few days) I could see 'Roon Ready' in Roon which filled me with anticipation.  On switching the input to Roon Ready, Roon lost it, and I was back to Roon - ETH, or whatever it is.  I've got gremlins somewhere, I'm sure.  I'm mindful it could be me and the famous 'user error', but I'm inclined to think not, since I've gone away and come back fresh to the problem more than a few times.  Also I've had wi-fi enabled and disabled in my various permutations.
I'm a big David Bowie fan, so I've been listening quite a lot to the 'Welcome to the Blackout' live album on Tidal.  Despite my frustrations, and when I got USB going, I was able to enjoy that, so it hasn't been all bad.

Did you try to uninstall Air and leave it uninstalled as well as disabling Roon Air in Roon?

As far as I remember, when my Devialet became Roon ready, I could not make it work with both the Roon Air and Roon RAAT zones enabled at the same time. 

Jean-Marie