HSRP State Machine
HSRP is a state machine consisting of these five states:
Initial: HSRP doesn’t run. This state is seen when an interface comes up
Listen: listens for hellos, knows the virtual IP
Speak: sends hellos and participates in the election
Standby: candidate for next active router
Active: currently forwards packets sent to the virtual IP
Listen: listens for hellos, knows the virtual IP
Speak: sends hellos and participates in the election
Standby: candidate for next active router
Active: currently forwards packets sent to the virtual IP
Preempt
An HSRP router won’t attempt to become the active router when introduced to an existing topology, even if it has a higher priority. We want DSW1 to always be the Active router if it is up and the topology is stable so we need to turn on “preempt.” Preempt will cause the router to initiate an election if it has a higher priority. If priorities are equal, the router with the highest IP address will win an election.
#standby preempt
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