Patent ID: 7864712

Claim:
A method for preventing loops in a network comprising network devices operating different protocols for providing loop-free topology, the method comprising: receiving link state information at a network device operating a first protocol and in communication with a network device operating a second protocol, wherein said first protocol is a link state routing protocol and said second protocol is a spanning tree protocol; creating at the network device operating said first protocol at least one tunnel to one or more other network devices operating said first protocol and in communication with one of the network devices operating said second protocol, the tunnel and the network devices operating said first protocol defining an overlay network, wherein the overlay network comprises only the network devices operating said first protocol and in communication with the network devices operating said second protocol; receiving at the network device operating said first protocol, a spanning tree protocol message from one of the network devices operating said second protocol following a topology change; running a loop prevention protocol at the network device operating said first protocol on the overlay network; and performing a synchronization between said loop prevention protocol and said first protocol.