4A0-116 Sample Questions Answers

The exhibit shows that both R-LFA and TI-LFA have been enabled on router R1. R-LFA (Remote Loop-Free Alternate) is a method that is used to protect the active segment of a tunnel, and it allows the router to find a backup path that coincides with the path that will become active after IGP reconvergence. TI-LFA (Topology Independent LFA) is a method that is used to protect an end-to-end multi-segment tunnel, it allows the router to find a backup path that does not rely on the IGP topology, but on the segment routing topology.

With R-LFA and TI-LFA enabled, router R1 will use a D-LFA (Dual-Loop-Free Alternate) path, which is a combination of both R-LFA and TI-LFA, this path will coincide with the path after IGP re-convergence.

A standard LFA, R-LFA, and D-LFA which do not coincide with the path after IGP re-convergence are not the options.

On a Nokia 7750 SR, R-LFA and TI-LFA cannot be enabled independently; they must be enabled together. The parameter "max-sr-frr-labels" limits the number of labels that R-LFA can add to the data packet encapsulation.

Seamless-BFD is a mechanism that allows the detection of faults in MPLS LSPs more quickly by using BFD (Bidirectional Forwarding Detection) protocol. Seamless-BFD responses are sent back using the MPLS data-plane, not the LSP label stack.