MPLS-based VPN technology uses a combination of connection-oriented and connectionless VPN technologies, including the following features:
The interface between the CE routers and the PE routers is connectionless. No additional configuration is needed on the CE devices.
The PE routers use a modified IP forwarding paradigm; a distinct IP routing and forwarding table (called virtual routing and forwarding table, or VRF) is created for each customer.
The customer's addresses are extended with 64-bit route distinguishers to make nonunique 32-bit IP addresses globally unique within the service providers' backbone. The resulting 96-bit addresses are called VPNv4 addresses.
A single routing protocol is run between the PE routers for all ...