Question

A service provider uses AS 65500 for its MPLS L3VPN backbone. A customer owns two sites that both use the same private AS 65001 for their PE-CE eBGP sessions. Users at Site 1 report they cannot reach any prefixes advertised from Site 2, even though both CE-PE sessions are up and the VPNv4 routes are present on the PEs. What should the provider configure on the PE routers to resolve this?

Accepted Answer

Enable 'as-override' on the PE-CE BGP neighbor configuration under the VRF address family

Answer

Configure 'allowas-in' on the PE-CE BGP neighbor toward the customer CE

Answer

Set the route target import/export values to match on both PE VRFs

Answer

Apply 'neighbor next-hop-self' on the PE toward the CE routers