Matthias Scheler wrote:
> It is very useful if you have more than one internet connection (and
> therefore several IP addresses signed to your machine) e.g. for
> load balancing or high availability.
> 

No, this is usually achieved by using interfaces into the same VRF (unless
you want the control plane on a route-server, which is not the usual case).
VRFs are used mostly for different VPNs tranziting the same router. Imagine
you have two VPN clients connected to the same router using the same
addresses like this:

C1(site1) - R - C1(site2)
C2(site1) /   \ C2(site2)

Imagine one of the C1 sites has address 10.0.0.1/30 and overlaps with one of
the C2 sites that uses the same prefix. So, in this case you simply put
interfaces to C1 into a VRF and interfaces to C2 in another VRF and problem
is solved.

-- 
Mihai CHELARU