Cisco CCNA (200-301)IP ConnectivityMedium
Two routers, R1 and R2, are running HSRP for VLAN 10. R1 has a priority of 120, and R2 has a priority of 110. Both routers have HSRP preemption enabled. R1 is currently the Active router. What will happen if R1's GigabitEthernet0/1 interface, which serves as the HSRP interface, goes down and then comes back up?
- AR2 will remain the Active router, as R1's priority is no longer relevant after a failure.
- BR2 will remain the Active router until its HSRP timers expire, then R1 will take over.
- CBoth routers will enter a Speak state and attempt to re-elect the Active router, with R2 likely winning due to its established active role.
- DR1 will immediately become the Active router again due to preemption and its higher priority.
Show answer & explanationAnswer & explanation
Correct answer: D. R1 will immediately become the Active router again due to preemption and its higher priority.
With preemption enabled, if a router with a higher priority comes online or recovers from a failure, it will immediately take over the Active role from the current Active router. Since R1 has a higher priority (120) and preemption is enabled, it will reassume the Active role once its interface comes back up.
Why the other options are wrong
- A. This is incorrect. With preemption, a higher-priority router will reclaim the Active role.
- B. HSRP timers are relevant for initial election and state transitions, but preemption dictates immediate takeover by a higher-priority router when it becomes available.
- C. HSRP is designed for fast failover; preemption ensures a quicker return to the preferred Active router, not a lengthy re-election process.
HSRP Preemption
HSRP preemption allows a router with a higher priority to take over the Active role from a lower-priority Active router, even if the lower-priority router is already active.
- Enabled with 'standby <group-number> preempt' command.
- Ensures the highest priority router is always Active.
- Critical for returning to a preferred primary gateway after recovery.
Memory trick: Preemption means the KING always takes the crown back if he's able.