STP is spanning tree protocol and OVS is openvswitch.
Documentation for OVS is somewhat sparse. There are complicated topics covered, and some basics skipped.
It’s a totally obscure topic for people outside ovs, you are free to ignore.
When a port is added in openvswitch, it gets a special ID for the sake of openflow operations (those, which are happen in ovs-ofctl). It’s called ofport . You can…
ovs-ofctl
ofport