Patent ID: 8068442

Claim:
A method for synchronizing spanning tree information between layer two (L2) devices associated with a plurality of L2 networks coupled to an intermediate network that includes a plurality of provider edge routing devices, the method comprising: receiving information associated with a loop detection protocol from a first one of the L2 devices associated with a first one of the L2 networks, wherein the information is received as one or more bridge protocol data units (BPDUs) containing spanning tree information associated with the loop detection protocol; and communicating a routing protocol message that includes the BPDUs through an intermediate network via a provider edge routing device in accordance with a routing protocol, wherein the routing protocol message includes the BPDUs as opaque data of the routing protocol message such that at least one routing device within the intermediate network ignores the opaque data when forwarding the routing protocol message, wherein communicating the routing protocol message comprises communicating the BPDUs such that a second L2 device associated with a second one of the L2 networks receiving the BPDUs can maintain spanning tree information that represents the plurality of L2 networks as a single comprehensive spanning tree in which the plurality of provider edge routing devices are represented as a single node, wherein the intermediate network does not run the loop detection protocol between the provider edge routers of the intermediate network.