Patent ID: 8811168

Claim:
A method, comprising: operating a first switch located at a first border between first networks that utilize a Spanning Tree Protocol (STP) to detect and break loops and second networks that utilize a protocol other than STP to detect and break loops, the first switch interconnected via the first networks with a second switch located at a second border between the first networks and the second networks; detecting, via the protocol other than STP, addition of a link in the second networks that provides a new path across the second networks between the first switch and the second switch; in response to the detecting addition of the link, blocking data packets from traversing through one or more network boundary ports of the first switch coupled to the first networks, while allowing STP Bridge Protocol Data Units (BPDUs) to traverse through the one or more network boundary ports of the first switch coupled to the first networks, for a period of time sufficient for the first networks to discover the new path using STP; and after the period of time, unblocking the one or more network boundary ports of the first switch coupled to the first networks.