Configuring per-prefix LFA and node to link protection fallback for OSPF

You can configure the following features for OSPF: 

• Per-prefix loop-free alternates (LFAs) 
• Fallback to link protecting LFA from node protecting LFA 

In certain topologies and usage scenarios, it might be possible that multiple destinations are originating the same prefix and there is no viable LFA to the best prefix originator, while the non-best prefix originator has one. In certain topologies, it might be desirable to have local repair protection to node failures in the primary next hop, which might not be available. In that case, to ensure that some level of local repair capabilities exist, a fallback mechanism is required. Since the link protection is less stringent than node protection, it might be possible that link protection exists and provides the same to those destinations (and hence the prefixes originated by the destinations).