I have an Aruba 6000 that is connected upstream to a Cisco Nexus 7K. I have been having intermittent performance issues for the past few weeks and started delving into configuration as well as possible path related issues. I noticed on my controller that I'm taking a fairly large amount of inbound/crc/giant errors. After swapping cables, moving connections from different ports, hard coding duplex, etc I finally opened a TAC case. TAC identified that my MTU on my gigabitethernet interfaces on the controller is set to 1500 while it's set to 9216 on the upstream Nexus 7K. I cannot change the MTU for an individual interface on the 7K as it's a global change that affects all interfaces. So now I'm left trying to determine if:
1. The issues with inbound errors are in fact a result of different MTU between switch gigabitethernet interfaces and controller
2. If the inbound errors are having an actual impact
I've tried clearing counters to get an idea of whether or not these inbound errors are the result of some PMTU discovery firing off at a predetermined interval, but it doesn't appear to be the case as they increment nearly instantanously and consistently.
Thoughts?