How is VPN routing information controlled/distributed in an MPLS VPN?

VPN routing information in an MPLS VPN is controlled and distributed using VPN target communities, which are BGP extended communities. These communities are attached to VPNv4 routes by the ingress Provider Edge (PE) router and specify which other PE routers are allowed to import those routes. This mechanism ensures that customer routes are exchanged only between PE routers that belong to the same VPN, maintaining isolation between different VPNs. The top level of the customer data packet directs it to the correct CE device is incorrect because MPLS forwarding is based on labels, not directly on customer IP headers. VPN IPsec peers are used for IPsec VPNs, not for MPLS VPNs. RD (Route Distinguisher) is used to make VPNv4 routes unique within the BGP routing table, preventing address overlap, but it doesn't control the distribution of these routes; that's the role of VPN target communities.