3.6.g Implement, troubleshoot and optimize OSPF convergence and scalability

3.6.g [iv] IP FRR/fast reroute [single hop]

The OSPFv2 Loop-Free Alternate Fast Reroute feature uses a pre-computed alternate next hop to reduce failure reaction time when the primary next hop fails. It lets you configure a per-prefix loop-free alternate (LFA ) path that redirects traffic to a next hop other than the primary neighbor. The forwarding decision is made and service is restored without other routers’ knowledge of the failure.

Adam, Paul (2014-07-12). All-in-One CCIE V5 Written Exam Guide (Kindle Locations 3680-3682).  . Kindle Edition.

http://www.cisco.com/c/en/us/td/docs/ios-xml/ios/iproute_ospf/configuration/xe-3s/iro-lfa-frr-xe.html#GUID-71E8EBB1-BA15-4012-B735-AE714F4BDDBF