A network administrator configures HSRP group 10 on two switches, R1 and R2, to provide gateway redundancy for VLAN 20. R1 is configured with a priority of 115, preemption enabled, and tracks interface GigabitEthernet0/1 with a priority decrement of 20. R2 is configured with a priority of 105, but preemption is disabled on R2. Initially, all interfaces are operational, and R1 is the Active router. If interface GigabitEthernet0/1 on R1 fails, which router will fulfill the Active role for HSRP group 10, and why?
- R1 remains the Active router because R2 does not have preemption enabled, even though R1's operational priority drops to 95.Answer
- BR2 automatically becomes the Active router because its priority of 105 is higher than R1's reduced priority of 95.
- CR1 relinquishes the Active role and enters the Init state because tracked interface failures force HSRP group shutdown.
- DR2 becomes the Active router only after R1's physical interface IP address is reassigned to match the HSRP virtual IP address.
Answer
R1 remains the Active router because preemption is not enabled on R2, preventing it from taking over despite having a higher operational priority.
In HSRP, when an active router's tracked interface fails, its priority is decremented (115 - 20 = 95). Even though the standby router has a higher priority (105 > 95), it cannot claim the Active role unless preemption ('standby preempt') is explicitly configured on the standby router itself. Therefore, the current Active router remains Active.
Step-by-Step Solution
Key Concept
HSRP Preemption Mechanics and Interface Tracking