[c-nsp] OSPF router gets separated from a broadcast domain

[Peter Rathlev]

On Fri, 2008-02-01 at 18:04 +0100, Gabor Ivanszky wrote:
> Peter Rathlev wrote:
> > If you only use these networks as OSPF transport networks, it's not a
> > big problem if they're black holed. Since they're not destinations,
> > neither clients nor servers ever see them in anything but a trace.
>  
> But not only the transport network itself get blackholed, but all the 
> networks which are reachable through it.

If it's just a transport network, OSPF should take care of this. When
the Dead Interval expires, it will think of the neighbor as down and
invalidate all routes learned from it. Only the still connected network
is left and announced, but since there are no other OSPF routers on that
segment (seen from each of the two) no paths are learned through this
segment.

If you don't want to wait for a long Dead Interval to expire, you can
use BFD or OSPF Fast Hellos.

Regards,
Peter