Hi!

Mikrotik offers a config paramter "priority" for every port of a bridge.

Could you help me to understand this? I never saw such a paramter. I do only know bridge-priority which is used to determine which one is the root-bridge and I know path costs to determine which paths are "alternate"-paths.

When is port-priority used and what is is for?

Thank you for your help
Stril

Basically, it's the priority of a root port candidate based on which a non-root bridge elects a root port when there's more than one with equal cost.
That's pretty much RSTP basics - I can highly recommend this easy-to-understand article
-Chris