Remote Loop Free Alternate (RLFA)
IP Fast ReRoute (IP FRR)

The Fast ReRoute "Remote Loop Free Alternate" (Remote LFA) solution is an extension of LFA. RLFA is specified in RFC 7490 [ IETF 7490 ]. RLFA is similar to LFA, except that the backup next-hop is not necessarily directly connected to the PLR by a physical link, but can be remote and joined by a virtual, tunnel-type link. In this case, RLFA uses an IP or MPLS tunnel to send its packets directly to this RLFA node.

Figure 8 illustrates a ring topology for which LFA cannot find a solution. RLFA finds a solution when the metrics of the links in the ring are close enough. Router "S" uses a tunnel (in blue)...