VPNs can offer the same privacy as a physically separate dedicated network at reduced recurring cost.
There is much hype in the Internet industry currently concerning VPNs, their functionality, and how they fit in the enterprise network architecture. Simply defined, a VPN is an enterprise network deployed on a shared infrastructure employing the same security, management, and throughput policies applied in a private network. VPNs are an alternative Wide Area Network (WAN) infrastructure that replace or augment existing private networks that utilize leased-line or enterprise-owned Frame Relay/ATM networks. VPNs do not inherently change WAN requirements, such as support for multiple protocols, high reliability, and extensive scalability, but instead attempt to meet these requirements more cost-effectively using the public IP infrastructure. A VPN can utilize the most pervasive transport technologies available today: the public Internet, service provider IP backbones, DSL terminations, as well as service provider Frame Relay and ATM networks. The functionality of a VPN, however, is defined primarily by the equipment deployed at the edge of the enterprise network and feature integration across the WAN, not by the WAN transport protocol itself. Simply put, VPNs can offer the same privacy as a physically separate dedicated network at reduced recurring cost by utilizing less expensive traditional Internet connectivity and deploying encryption hardware or software at each office or branch location.