We run what can essentially be thought of as a WAN service. We have a core switch, with many edge switches off it. Off those edge switches are 3rd party switches we have no control over.
Core ---> Edge ---> 3rd Party Switch
I am trying to correctly configure STP to block loops potentially created by the 3rd parties. i.e.
Core ---> Edge1 ---> 3rd party ---> 3rd party ---> edge2 ---> Core (so the 3rd party could potentially bridge 2 of our edge ports therefore create a loop).
I thought setting the ports between the core and edge switches to "point-to-point" would achieve this, however I have set it up in a lab and the ports continue to say "forwarding". If i set the ports to stp edge mode it sets the port to blocking as i would expect.
Given I'm configuring STP between 2 extreme switches, I thought Point-to-point was the correct method and "edge" mode was for endpoints.
Could someone please advise how to correctly set up STP to achieve what I want - to protect against a 3rd party bridging our network?