my question is in order to clarify the standard STP functionality.
three switches connected in a
ring and so forming a loop;
only one of the six ports linking the switches has STP enabled (other ports have STP disabled).
Question: is the switch able to detect the loop and so blocking the STP enabled port ?
If no ...in this scenario how many of the ports must be STP enabled ?
Thanks in advance.
I agree, it all comes down to what you mean by disabling STP. If the switches that have STP disabled are flooding BPDUs like user traffic (dumb switches that act like hubs do that, PVST+ switches with "no spanning-tree vlan X" configured attempt to do that also), then the unique bridge running STP should be able to see its own BPDUs coming back at itself around the ring and prevent the loop. Note that you could still have temporary loops when a failed link is recovered, and that convergence will be slow (based on timers).