Hi all, wanted to report back here with this info. Just got a definitive answer from a Level-3 tech support person at DRI. The answer was “We don’t support Jumbo Frames”.
Not sure if that means they don’t “support” as in they don’t want you to turn them on if you’re having troubles, or that the hardware doesn’t actually support an MTU of 9000.
Just wanted to share the info here as I know quite a few people have asked about it and it’s unclear from the documentation and KB.