You have seen in this chapter what a VPN is and what the building blocks of MPLS VPN are. It explained the operation of MPLS VPN, both in the control plane and in the forwarding plane. It also examined BGP and detailed the enhancements needed for MPLS VPN. This chapter covered intranet, extranet, and hub-and-spoke scenarios. It also reviewed each PE-CE routing protocol and provided its specific operation across the MPLS VPN backbone.