This is probably a simple one but I haven't found the answer yet
In spanning tree there is a number called the "designated port id" that can be seen by doing a <show spanning tree detail> the number looks like 128.2 if you do a <show spanning-tree active> command the number is called "Prio.Nbr". I'm just trying to find a definition of this value, what is it? what is it used for? and how can it be changed (or would I want to change it)?