[c-nsp] How to connect two VRFs on the same router? (without a loop-cable)

[Gunther Stammwitz]

Hello colleagues,

I've built two vrfs on the same router and have attached interfaces to them and
everything is fine so far.
Now I'd like to router from one vrf to the other one. 
The only way how this can be achieved seems to me to use two interfaces on the
same router and to connect them with a cable. This might look rather stupid when
there's a cable coming out of the router and going into it again.

Isn't there a way how this can be achieved in software????

Thanks,
Gunther