I have two 5520's in a stack serving as our core switch. Two weeks ago I upgraded the stack to v6.3.0.013. On Sunday the network came to its knees because traffic was not passing through the core switch. I found that the LED status lights were normal on the base unit and the UP/DOWN lights on unit 2 were steady amber. A reboot of both switches got everything back to normal...but for how long I wonder.
Critical, serious, and informational events are being logged locally and remotely. However, I don't know why I don't see the this local-critical event showing in the remote syslog (NVR Hello Module unable to communicate with neighbor(s), unit reset).
These switches have been in place for quite a while with out any stack errors/issues. Is a cascade cable going bad? Is a cascade module going bad? Is it purely ironic that it started happening after upgrading the firmware? I am looking for suggestions before creating a downtime to run the stack loopback test. I assume the loopback test wont show any failures if the LED status lights are now green. Please correct me if I am wrong.
Your help is appreciated!