VPLS FAILURE PROTECTION IN RING NETWORKS

摘要

A method for communication over a bi-directional ring network (22) includes provisioning a virtual private local area network service (VPLS) over the bi-directional ring network. The VPLS includes connection termination points (54) provisioned respectively on a plurality of the nodes (24) so as to connect each of the plurality of the nodes to a second network (30) external to the ring network. As long as the nodes and spans are fully operational, one or more of the connection termination points are maintained in a deactivated state, so that no more than one of the connection termination points to the second network is active. The nodes exchange messages indicative of a failure associated with the bi-directional ring network, causing at least one of the deactivated connection termination points to be activated so as to maintain connectivity among the users of the VPLS without creating a loop in the VPLS via the second network.