OSPF Remote Loop-Free Alternate (LFA) Fast Reroute (FRR)

Hello Narad

In short, an LFA is a next-hop route that delivers a packet to its destination without looping back.

A Loop-Free Alternate (LFA) is a concept that is used in various technologies, including OSPF, other routing protocols, as well as in MPLS. An LFA is a node other than the primary neighbor, or the primary next hop. It is a backup of sorts. Traffic is immediately directed towards the LFA after a network failure. The LFA will receive traffic and will continue to forward it without any knowledge of a failure. LFAs always use a directly connected next hop.

Remote LFA involves the use of a tunnel to a next-hop that is not directly connected, as shown in the lesson. This is the primary difference between the two.

I hope this has been helpful!