[c-nsp] Does "backup interface" gratuitous ARP?

[Sam Stickland]

Hi,

On Wed, Aug 13, 2014 at 6:14 PM, Gert Doering <gert at greenie.muc.de> wrote:

> Hi,
>
> On Wed, Aug 13, 2014 at 04:44:49PM +0100, Sam Stickland wrote:
> > I'm exploring redundancy possibilities for a router hand off without a
> > dynamic routing protocol. It's ugly and I'm not going to explain all the
> > details here, but I basically have this configuration on a router:
> >
> > interface Gi1/1
> >   backup interface Gi1/2
> >   ip address 192.168.1.1 255.255.255.252
> >
> > interface Gi1/2
> >   ip address 192.168.1.1 255.255.255.252
>
> I can't answer your question, but have one of my own - can you do IPv6
> with this nowadays?  "backup interface" suppresses the "I have seen this
> IP config elsewhere!" check, but they forgot to do this for IPv6 as well
> (and I have lost the need to do backup interface, as we moved to
> 6500s and just do port-channels or "put both interface into the same
> vlan, use SVI").


I just tried it with ipv6 address on my 12.4T dyanmips setup and it didn't
like the overlapping addresses.

Someone suggested to me, off-list, that I could use BVI. I seem to have
some memory of BVI being quite CPU intensive but it's been a *long* time
since I looked at it. Does anyone know if there's any truth to that?