Years ago when HSRP was all the rage, and before VRRP and GLBP, enterprises used hundreds
of HSRP groups. With the hello timer set to 3 seconds and a hold time of 10 seconds,
these timers worked just fine and we had great redundancy with our core routers.
However, in the last few years, and certainly in the future, 10 seconds is now a lifetime!
Some of my customers have been complaining with the failover time and loss of connectivity
to their virtual server farm.
So lately I’ve been changing the timers to well below the defaults. Cisco had changed the
timers so you could use sub-second times for failover. Because these are multicast packets,
the overhead that is seen on a current high-speed network is almost nothing.
The hello timer is typically set to 200 msec and the hold time is 700 msec. The command
is as follows:
(config-if)#Standby 1 timers msec 200 msec 700
This almost ensures that not even a single packet is lost when there is an outage.