IP FRR is not supported on 7210 SAS platforms. LFA is supported on 7210 SAS platforms that support LDP FRR.
The user first enables Loop-Free Alternate (LFA) computation by SPF under the IS-IS routing protocol level or under the OSPF routing protocol instance level:
config>router>isis>loopfree-alternate
config>router>ospf>loopfree-alternate
The preceding commands instruct the IGP SPF to attempt to precompute both a primary next-hop and an LFA next-hop for every learned prefix. When found, the LFA next-hop is populated into the RTM along with the primary next-hop for the prefix.