A Virtual Private Network (VPN) is a set of sites that share common routing information and whose connectivity is controlled by a collection of policies. The sites that make up a VPN are connected over a service provider's existing Internet backbone. In a Layer 2 VPN, routing operations are controlled and performed on the customer's routers, typically on the customer edge (CE) routers, whereas in a Layer 3 VPN, they are handled on the service provider's routers. |