Trunk Port Shutdown From One Side

 

The setting: two Catalyst switches. On each one of them I created two VLANs. A trunk between both switches is set up.
Scenario:
I shutdown the trunk port on side A:
No more VLANs are detected on the local trunk port:
However, side B’s trunk port is still untouched. And it shows a list of allowed VLANs on the trunk, as if nothing special has happened:
Conclusion
Even if the trunking seems to be OK on one switch, we should check the trunk on both sides of the switches.

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