MPLS FAST RE-ROUTE USING LDP (LDP-FRR)

摘要

MPLS (Multiprotocol Label Switching) fast re-routing using LDP (Label Distribution Protocol) is described. A first network element in an MPLS network receives a first label advertised from a second network element in the MPLS network. The first network element computes a shortest path tree (SPT) to reach a destination network element under a potential failure condition. The second network element is a nexthop of the first network element in the computed SPT and is not upstream from the potential failure condition in the computed SPT. The first network element determines that a third network element in the MPLS network is a Point of Local Repair (PLR) when the potential failure condition is realized. The first network element distributes a second label to the third network element for a backup LDP Label Switched Path (LSP) that will serve as a backup path when the potential failure condition is realized. The first network element installs a swap action from the second label to the first label. In one embodiment, the backup LDP LSP is an existing shortest path LSP from the third network element to the first network element.