VPN

A Virtual Private Network is a private network configured within a public network. Common carriers for years have built VPNs that appear as private national or international networks to the customer, but physically share backbone trunks with other customers. VPNs have been built over X.25, Switched 56, frame relay, and ATM. There is currently tremendous activity building VPNs over the Internet. VPNs use access control and encryption to maintain privacy in a public environment.