[c-nsp] PE-CE running BGP : How to deny a VRF to advertise routeslearned from another VRF.

[Oliver Boehmer (oboehmer)]

Murilo Antonio Pugliese <> wrote on Monday, April 03, 2006 3:42 PM:

> Folks.
> 
> I'm facing a problem which I'll try to describe in a really short and
> simple manner. 
> 
> Both Sites A & B have Internet access.
> Site A CE advertises a default route to its VRF (VRF A) through BGP
> when its Internet connection is operational 
> Site B CE also advertises a default route to its VRF (VRF B) through
> BGP  when its Internet connection is operational 
> 
> Both sites A & B may provide Internet access to Site C. When both VRF
> A & VRF B are learning a default route 
> from its respective CE, they retransmit these default routes to VRF
> C. In this scenario VRF C must choose access through 
> VRF A, and this choice is guaranteed through local-preference
> associated to both routes learned (from VRF A & from VRF B). 
> 
> Now the problem description:
> When the Site A Internet access goes down, Site A CE stops to
> advertise a default route to its VRF (VRF A) as expected, 
> VRF A learns the default route that VRF B learns from Site B CE and
> advertises (that's fine), and VRF A advertises the 
> default route (from VRF B) to Site A CE (that's fine); "BUT" VRF A
> also advertises the default route learned from VRF B 
> to VRF C, and that's the problem.

This should not happen. When a PE imports a route via MP-BGP, it does
not re-advertise this route via MP-BGP to other PEs. How does "show ip
bgp vpnv4 vrf VRFA 0.0.0.0" look like?  

	oli