How to Use the standby preempt

[Ayush Srinet]

Hello All,

Do i required preempt command on both router ( Active and Standby Router. )

Thanks 

Ayush

[Charles Hill]

Hello Ayush,

The Preempt command is only needed on the router that is the preferred active HSRP router.

If the active HSRP router A fails, the standby HSRP router B becomes the active.  However when router A returns to service(without the preempt command), router B will continue to stay active even though router A has the higher priority. 

The preempt command will force Router A to an active state after failure and router B would return to the standby state.

Hope this makes sense.

Please rate hepful posts.

Thanks.

[Seb Rupik]

Preempt should also be configured on the standby, see:

http://www.cisco.com/c/en/us/support/docs/ip/hot-standby-router-protocol-hsrp/9281-3.html#q6

...this allows the standby to become active when its priority value becomes the highest (as the result of a primary router decrement), not just in the situation that the holdtime expires.

cheers,

Seb.

[Charles Hill]

Good point Seb,

I wasn't thinking of the scenario with an interface being tracked.

"The standby preempt command is needed in situations when you want an occurring state change of a tracked interface to cause a standby router to take over from the active router. "