[c-nsp] HSRP vs VRRP

[Tim Durack]

> So you've just split your network in half, and built two independent
> HSRP setups.

Nothing wrong with that. Try searching HSRP on www.cisco.com to see
what they recommend...

> Yes, of course this avoids the problem of "when a HSRP setup splits,
> half of the hosts have funny connectivity", but now you're at "when
> a switch dies, all of the hosts have *no* connectivity" - and I'm not
> convinced this is a better failure scenario.

No, half the hosts have no connectivity, same as your original
diagram. Nothing solves that without some kind of multi-homing.

> Standard HSRP setup will achieve that as well - *unless* you lose
> connectivity between the switches.

My ascii art shows a standard HSRP setup.
That *unless* is an ugly failure mode when it happens. My suggestion
avoids that, at the expense of an extra interface on each router.

> > Switch failure is a different matter. The hosts would need to be
> > multi-homed to survive that.
>
> *And* need to run a dynamic routing protocol to figure out which
> network is still usable and which default gateway to use (they still
> might have a local link, depending on the way the switch fails)

Agreed. I don't see how the original diagram overcomes this problem.

Tim:>