HSRP Tracking an Ip

Question

In this lap, I can edit configuration on R1 and R2 only. I configured HSRP protocol in both 2 routers in e0/0. where R1 has priority 150 and another router (R2) has priority 100. and made a track 1 with ip SLA and applied it on R1 and R2 to check connectivity between both routers and loopback 7.7.7.7 now when the link between R1 & internet is down the default gateway should be routed to the backup router (R2) in this case.but this not occurred because of R1 priority still more than other so tacking is not working but when I changed the priority to be equal to R2 tracking was worked. Now My goal that making R1 is default with high priority but when link between it and internet down convert to R2 my configuration

R1:
ip sla monitor 57
 type echo protocol ipIcmpEcho 7.7.7.7
 timeout 4500
 frequency 5
ip sla monitor schedule 57 life forever start-time now

track 1 rtr 57 reachability
 standby track 1
 standby 57 track 1 decrement 20


 standby track 1
 standby 57 ip 172.21.57.1
 standby 57 preempt
 standby 57 track 1 decrement 20

the configuration on another router but with default priority

Answer 1

For R2 to become the active HSRP router, the priority has to be higher than R1. You've set the priority on R1 to 150, and the decrement value in the track statement to 20.

So when the IPSLA "fails" R1's priority changes to 130 (150-20). but that is still higher than R2, so it remains the active router.

You can change R1's priority to 110, so when the IP SLA fails, the priority value will be 90 -- less than R2, which will make R2 the active router.