[c-nsp] HSRP question

[Kevin Graham]

> Unless you use "standby use-bia", changing the HSRP group number will
> change your virtual IP's mac address, so I would expect some service
> interruption (possibly << 1 sec) as the server needs to update its ARP
> table.

To minimize interruption for devices that really don't like to give up
arp entries, I'll usually leave the old group number configured w/ a
bogus address, then add the real addr to the new group. This will keep
the router responsive to the old group mac addr and give you time to
go through and verify that arp caches are updated.

If you configure the new group w/ a 'preempt 0', your service impact
is limited only by how fast you can cut and paste.