[c-nsp] routing between VRF and global

[Kenny Sallee]

> > The tunnel source and destination are between different loopbacks
> > within the global table, but one end of the tunnel is within the
> > global and one end within the VRF table. You might be able to NAT
> > across the GRE tunnel.
>

This is a pretty cool config, but I'm having a hard time seeing why you'd
want to do this?  Why not just route-target import/export between VRF's you
want to share routes with?  And use import-maps to filter as necessary?

I did the same type of thing - but instead of a global route table I have
the 'global' table in a VRF so I can RT import/export what I need to it to
and from it.  In the global VRF is a BGP session with our core network.
 Keeps the config simple.  Granted - what I'm doing where I work might be
smaller scale then some - but I believe this config would scale pretty far
(and is not a hack).