A certain service provider offers RFC 2547-based L3VPN service. The service provider is using OSPF to carry infrastructure routes and MP-BGP to carry customer routes. It has also deployed a full…

FRR node protection creates a pre-computed bypass tunnel that routes around a failed P (core) transit node, restoring traffic flow sub-50ms without waiting for IGP or BGP to reconverge.

PE node failure is not addressed by FRR because the ingress and egress PEs are the endpoints of the TE LSP, not transit nodes - FRR only protects intermediate (transit) nodes and links along the LSP path.

The PE-P link is a segment within the TE LSP forwarding path, so FRR link protection applies and a pre-established backup tunnel is activated immediately upon failure detection on that link.

P-P links are the most common failure points in the MPLS core and are directly covered by FRR link protection, which switches traffic to a bypass tunnel within 50 milliseconds of detecting the link failure.

PE-CE links are outside the scope of the MPLS TE tunnel and FRR mechanism entirely; failures on CE-facing links are handled by the routing protocol (such as OSPF or BGP) running between the PE and CE device.