I'm trying to better understand where a communication issue is happening between VMware on UCS and ACI. UCS is a pretty simple config with a port channel to upstream ACI. Server ports are not using port channels today.
I've got two interfaces (virtual on VMware, not vnics) split between the FIs. If they don't talk for a long time, then they can't talk to each other.
If I try to ping from A to B, it fails. Using other interfaces, I can ping A to A and B to B just fine. Still A to B fails.
As soon as I ping B to A it starts working, in both directions.
It doesn't matter which direction I start but it always manifests the same way.
I know UCS drops unknown unicast but I'm not clear on what is causing this. Is this some functionality within ACI that is modifying the normal broadcast behavior? Or am I missing something?