Hello Andrea
The statement:
refers to the priorities that are given to the tie breakers. Remember the following in the lesson?
R1#show running-config all | incl break
fast-reroute per-prefix tie-break primary-path index 10
fast-reroute per-prefix tie-break interface-disjoint index 20
fast-reroute per-prefix tie-break lowest-metric index 30
fast-reroute per-prefix tie-break linecard-disjoint index 40
fast-reroute per-prefix tie-break broadcast-interface-disjoint index 50
Here Rene is showing the priorities that are given to the tie breakers, which are shown at the end of each line. Originally, node protection is not included by default. But with the fast-reroute command, Rene assigns a priority to the tiebreaker of 5. This priority is the lowest value of all currently active tie breakers.
These changes do not actually change the OSPF cost of the repair paths. What it does do is it changes the way the paths are evaluated. That results in OSPF preferring router 4 with a cost of 9 over router 3 with a cost of 7 as the next repair path, simply because R3 has the same next hop as R1 originally did.
I hope this has been helpful!
Laz