Loop-Free Alternate (LFA) and remote LFA

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 for a particular route. 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 LFAs are LFAs that are not directly connected to the router in question. To achieve this, a tunnel is created from the router in question to the remote LFA node to "simulate" the next-hop nature of a neighbor.

For more information, see:

Protocols with LFA support