RESILIENCY IN MINIMUM COST TREE-BASED VPLS ARCHITECTURE

摘要

A system for providing resilient multimedia broadcasting services over a VPLS network is described. A network Management System (NMS) calculates disjoint minimum cost trees using the Steiner algorithm executed with extra steps to result in the disjoint trees. Destination PE routers in the VPLS network are connected to the disjoint trees so that they can be serviced by either tree in the case of a fault. Each of the disjoint trees is provisioned with enough bandwidth to carry all of the services provided by the VPLS network. Under normal operation, however, the services are distributed evenly over the trees. In the event of a fault, the services on the faulty tree are switched to the other tree using split horizon bridging. Each Steiner tree can also be realized using poin-to- multipoint LSPs which is fully protected by a precomputed point-to-mulltipoint LSP.