[afnog] Cisco MPLS VPNV4 issue

[Mark Tinka]

On Monday, May 21, 2012 08:34:37 PM Meftah Tayeb wrote:

> so, i do the pe-pe routing directly using bgp, through
> the P?

Yes, the MP-iBGP session will run directly (or via a route 
reflector) between the PE routers. The P router doesn't need 
to know about BGP in an MPLS network, only the IGP and MPLS.

Once l3vpn (VPNv4) routes are exchanged between the PE 
routers, forwarding of the l3vpn traffic between them via 
the P router will be handled by MPLS.

> and the vrf would flow using bgp?

The VRF is just a routing instance attached to an interface 
that defines where the incoming VPN traffic should go, on 
the PE routers.

Yes, VRF information is advertised using BGP (in this case, 
the RD and RT associated with the VPN).

> so the P will only take the PE2851 to the RB493G?

That's right. All the P router needs is an IGP and MPLS 
capabilities. It is service-unaware, and simply forwards 
MPLS traffic regardless of the payload.

Mark.