[Xorp-hackers] Adding static routes with unresolved next-hop router

[Mark Handley]

>I was suggesting that we can use routes with different metrics to
>configure StaticRoutes such that if the original route fails, and if
>we don't want to use the RIP routes for a particular destination,
>then the second route (that points to /dev/null) will be used by
>StaticRoutes and installed into the RIB. Obviously, this can't be
>used to install fallback static routes if the dynamic routing fails,
>but can be used to keep _some_ high-priority static routes into the
>RIB.

Agreed - both capabilities are useful.

But we need to be careful about feature interaction here.  From BGP's
point of view, is a static route for a BGP nexthop that points
explicitly to the discard interface a resolvable nexthop, or an
unresolvable one?  Currently if there's a route in the RIB for a BGP
nexthop, then BGP will consider it resolvable, even if it points to
the discard interface.

There may be other interactions that also need to be considered, but
this is the obvious one that occurs to me.

 - Mark