Patent ID: 7657619

Claim:
In a network having multiple spanning tree domains and multiple inter-domain network paths, a method comprising: sending messages, via an inter-domain switch, on respective network paths from switches that are each members of a first spanning tree domain and a second spanning tree domain toward a root switch of the first spanning tree domain, wherein the switches belong to the same virtual local area network (VLAN); preventing the sending of messages from the switches that are each members of the first spanning tree domain and the second spanning tree domain toward a root switch of the second spanning tree domain; receiving the messages at ports of a switch on the first spanning tree domain; and blocking one or more of the ports when multiple received messages originate from different switches, wherein blocking the one or more of the ports comprises: generating a list of network paths to the switch from the received messages, selecting from the list, a network path that meets a predetermined criteria, and blocking one or more ports that do not correspond to the selected network path.