Question

A service provider runs an MPLS L2/L3 VPN backbone. Two different customers, Customer-A and Customer-B, both use the address space 10.1.0.0/16 internally. Both customers connect to the same pair of PE routers. When the provider engineer configures the VRFs, both customers' overlapping routes must be carried across the MP-BGP VPNv4 backbone without one customer's routes being treated as duplicates or overwriting the other's. Which configuration element guarantees that these overlapping IPv4 prefixes remain unique when advertised as VPNv4 NLRI between PE routers?

Accepted Answer

Assign a unique Route Distinguisher (RD) to each customer VRF so the 8-byte value is prepended to the IPv4 prefix, forming a globally unique 96-bit VPNv4 route.

Answer

Assign a unique Route Target (RT) import/export policy to each VRF so MP-BGP can differentiate the overlapping prefixes.

Answer

Enable per-VRF label allocation so each customer receives a distinct MPLS VPN label for its 10.1.0.0/16 prefix.

Answer

Configure a unique loopback-derived BGP router ID per VRF so the PE can advertise each customer's prefix separately.