hsrp

[carl_townshend]

Hi all, Can anyone tell me the difference between using hsrp to track an interface, and putting the interfaces to want to make for redundancy in the same group, surely this would achieve the same thing ?

[Amit Singh]

Hi Carl,

HSRP interface tracking is used to track the WAN connection on the router and in case of the WAN link failure making the active router which was forwarding the traffic as a standby router to the other routers become active and starts forwarding the traffic.Without WAN interface tracking, the router will not have any intelligent to make another router active, if its WAN interface fail and it will continue to forward the traffic which will eventually get drop. This is done by decreasing the priority of the active router lower than the standby router, so the other router becomes active.

Please refer the link below for understanding it:

http://cisco.com/en/US/tech/tk648/tk362/technologies_tech_note09186a0080094e8c.shtml

By putting the interface in same group we actually make one interface as an active and other as standby.There will be a virtual Ip and MAC for each group and in case of an interface failure the other one will take care of forwarding the traffic and provides high-availability in the network.

HTH,Please rate if it does.

-amit singh