Patent Document ID: 8467316
Application ID: 12980731
Patent Flag: 1

Claim One:
1. A method comprising: executing a loop-prevention protocol on a first one of a plurality of network devices that provide multi-homed layer two (L2) connectivity between an L2 customer network and an intermediate network, wherein each of the plurality of network devices is coupled to the L2 customer network by a different one of a plurality of links, and wherein the loop-prevention protocol determines a bridge identifier for each of the plurality of network devices; in accordance with the bridge identifiers, selecting with the loop-prevention protocol a second one of the plurality of network devices as a current root bridge to forward L2 communications between the L2 customer network and the intermediate network without forwarding the L2 communications with other ones of the plurality of network devices; detecting, with the first one of the plurality of network devices, a topology change that splits the L2 customer network into a plurality of L2 sub-networks; and in response to detecting the topology change, outputting a message from the first one of the plurality of network devices to direct the remaining ones of the plurality of network devices to clear L2 address information learned when forwarding the L2 communications, wherein the first one of the plurality of network devices formulates the message to include the bridge identifier determined by the loop-prevention protocol as the current root bridge prior to detecting the topology change to direct the remaining ones of the plurality of network devices to clear only L2 addresses learned from the bridge identifier determined by the loop-prevention protocol as the current root bridge.