I have a strange issue with several WS-3850-24XS switches.
Recently we have upgraded 14 WS-3850-24XS switches from version 16.3.7 to 16.6.7.
After the upgrade of the switches we noticed on 5 out of 14 devices that several interfaces (between 1 and 10 ports) were in err-disable due to UDLD.
We reloaded the switch a second time….without result. When tried replacing the GBIC, but this did not solve the issue.
When resetting the old uplink port to default and re-applying the config, the issue is not solved.
When moving the existing GBIC to another free port and re-applying the same config the issue is solved.
We have moved all the impacted ports to other free ports on the same switch, so everything is working fine now.
I have upgraded several customers to version 16.6.7 without issues. I’m wondering if it’s maybe hardware related. Since only 5 out of 14 switches are showing this issue at this customer.
the only thing I could find was something about a missing native Vlan in the Vlan database that might cause the errors. Do you have trunks configured with a different native Vlan than the default (1) ?