[c-nsp] Backup Interface & IPv6 - why is Cisco sleeping?

[Phil Mayers]

On 15/12/10 13:13, Ian Henderson wrote:
> On 15/12/2010, at 1:54 AM, Garry wrote:
>
>> I'm really starting to wonder whether we're the only ones on this
>> earth still using a dual switch config for our routers for
>> redundancy purposes ...
>
> So you're using backup interface for two Ethernet interfaces, both
> facing the same switched network? Cool - haven't seen backup
> interfaces since they were used to dial ISDN terminal adaptors. Is
> anyone else out there doing this? Out of curiosity, what kind of
> failover time do you get for IPv4?

We use this to build "out of band" management facility on 6500s with 
dual-sup, so that the SUP is always reachable whichever is active.

interface GigabitEthernet5/2
  description oob
  vrf forwarding OOB
  backup interface GigabitEthernet6/2
  ip address 10.x.x.x
  media-type rj45

interface GigabitEthernet6/2
  description oob
  vrf forwarding OOB
  ip address 10.x.x.x
  media-type rj45

The MAC is the same on both interfaces according so "sh int". As far as 
I can tell, the failover time is "instant" i.e. sub-second.