In an MPLS VPN network, BGP attributes for a VPN site are transparently transported across the service provider backbone to another site in the same VPN. Because there is a single routing protocol used across the VPN between service provider core and customer sites, the concept of redistribution does not apply.
BGP PE-CE peering in an MPLS VPN environment can be performed in two different ways:
1-) BGP PE-CE VPN sites implementing unique AS numbers (in our example, CUSTOMER A between Site 1 and Site 2)
2-) BGP PE-CE VPN sites implementing same AS numbers (in our example, CUSTOMER B between Site 1 and Site 2)
There will be no issue when implementing BGP PE-CE routing for customers which use unique AS in both VPN sites. However, using same AS number in both VPN sites causes an issue because of the BGP loop prevention mechanism. if both sites have same AS number, routing updates from one site would be dropped at the other site; therefore, connectivity cannot be established between the sites without additional configuration on PE routers. ("neighbor XX.XX.XX.XX as-override" under bgp address-family configuration)
here is the configuration of MPLS VPN with BGP PE-CE Routing.
PART 1
PART 2
Very nice. Do you have the project file to share for this configuration?
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