Which MPLS VPN component extends an IP address so the VPN membership can be identified?

The Route Distinguisher (RD) is a 64-bit value prepended to an IPv4 prefix, creating a unique 96-bit VPNv4 address. This ensures that identical IP prefixes from different VPNs are treated as distinct routes within the MPLS backbone, preventing conflicts and allowing multiple customers to use the same IP address space. The Route Target (RT) is used for controlling the import and export of VPN routes between VRFs, defining VPN membership and topology, but doesn't extend the IP address itself. LDP (Label Distribution Protocol) is used for distributing labels for MPLS forwarding, not for identifying VPN membership. VPNv4 address family is the type of address used (RD + IPv4 prefix), but the RD is the specific component that extends the IP address for uniqueness.