Cisco 2960X dropping data, but reports look fine?

[mkarab000]

2960X has been in service for about three years.  Recently (within the last 6 months) we started noticing connectivity issues between copper devices.  The switch is primarily used for video traffic, so the issue is becoming very apparent.  

We checked POST, the counters, port status, verified the environment was fine, and swapped out patch cables to test.  It appears everything is indicating the switch is fine, but placing the devices on another switch resolves the issue.

Are there any troubleshooting commands that can be run to determine where the problem exists?

There were multiple power fluctuations that happened previously, so I'm thinking something got funky one of those times, but without concrete evidence, bossman won't let me order a new one.

WS-C2960X-24PS-L.  SW:15.2(4)E6

Any and all help is greatly appreciated!

[Reza Sharifi]

Do the logs show anything when this happens?

HTH

[mkarab000]

The logs are clean. We don't see any port flaps, no PoE drops, or line/protocol discrepancies. If we have a constant ping going through the switch, it'll drop a time or three at random intervals. We did noticed the communication was more stable when we rebooted the switch, but eventually deteriorated the longer it remained online.

[brselzer]

Hello, 

You are pinging between two devices in the same vlan on the same switch?

show proc cpu sort

show proc cpu hist

show controllers cpu-interface

show controllers ethernet-controller [interface]

show spanning-tree detail <----check for TCNs

show mac add | inc [mac of source/dest] <-----Is your mac being learned on another port for some reason

These are the commands I would start with. 

Hope that helps!