Trying this out based on the topology above. My issue is that I am trying to favor an ECMP path over a lower cost link by using a tie breaker of primary-path as the only tie breaker. Destination is 6.6.6.6 on R6. Weird thing to note (#1) - If I set it to required (mandatory), the output of the show ip ospf RIB does not list the ECMP G3 and G4 as loadshare. Once I remove the required option it lists them appropriately in the show ip ospf rib 6.6.6.6 output.
Weird thing to note (#2) - Even after the output of the show ip ospf RIB command lists an ECMP path over the lower cost as an LFA, it still uses the lower cost path after shutting down the primary path G1 on CSR router.
This is the CSR router FRR configuration:
All seems to look well with it choosing to use a ECMP link as a repair path due to my specifying it as my only tie breaker:
But when I shut my primary path link G1 down, it still changes and chooses the lower cost path via R2-3 on interface G2 (as seen below) which it said it would ignore in the output above.
In reference to weird thing to note item #1: This is what the OSPF RIB looks like when I use the below command
