By default STP works straight out of the box. You buy a switch and plug it in and boom STP works. Well, 802.1D (PVST if using Cisco Switches) works by default. While PVST is great, it's slow so we would configure it for PVRSTP or MST. Again, these work straight away and by default will choose which ports are forwarding and which are blocking. But what if we want to manually choose one link over another? To do this, we first need to understand what we want to change and how the port election process works.
Root Port selection