I have a Cisco 3650 switch in production with port 24 in trunk mode (dot1q) to port 1 of a nortel switch.
These 2 switches have been working fine for about 3 weeks since I set them up, but today the trunk link went down.
"sh ip interface brief" showed port 24 as down and (as this was at a remote site) a user said the ports on both switches (port 1 on the nortel and 24 on the cisco) were off.
I got the user to swap the cable which didn't change anything then told him to reboot the nortel, however he rebooted both which fixed the issue!
Now I'm not sure why it fixed it or whether it was the nortel or cisco switch (I guess the nortel).
Are there any commands etc that can help me on this, or put inplace in case it happens again?