[Xorp-users] Xorp behavior when underlying physical interfaces are administratively down

[Bruce Simpson]

Williams, Mark wrote:
>
> I am planning on deploying Xorp on a standby router, which normally 
> has all of its interfaces cabled into a switch but administratively 
> down on Linux system.
>
> What will Xorp do in such a situation? I plan on using OSPF, and I 
> want to make sure that I don’t get any IP address conflicts or 
> problems with OSPF routes.
>

So this is not a 'hot standby' in the VRRP / CARP / HSRP sense of the 
word, but a 'warm standby' ?

I believe this should work, however, the OSPF process will remain idle 
most of the time until you bring the interfaces up.

I assume you are using some form of out-of-band access (e.g. serial, or 
a management LAN) to administer your standby router.

It would probably be best to do this using the Router Manager CLI, i.e. 
configure the interfaces as 'disabled: true' in the interfaces {} block, 
and use configuration mode to bring them up manually when failing over 
to your 'warm standby' router.

Of course your router will not have any OSPF state as all your 
interfaces will be down -- it will have to come up and learn that from 
other OSPF routers when you manually fail over to it. It might be better 
to leave it running with an artificially high interface cost, or 
consider using the new VRRP feature in XORP 1.6.

thanks,
BMS