a private data communications network built on public switching and transport facilities rather than dedicated leased facilities such as T1s.

virtual private dial-up network. Also known as virtual private dial network. A VPDN is a network that extends remote access to a private network using a shared infrastructure. VPDNs use Layer 2 tunnel technologies (L2F, L2TP, and PPTP) to extend the Layer 2 and higher parts of the network connection from a remote user across an ISP network to a private network. VPDNs are a cost effective method of establishing a long distance, point-to-point connection between remote dial users and a private network

virtual private dial-up network. Enables IP traffic to travel securely between a remote client, such as a Windows 2000 laptop, over a public TCP/IP network by encrypting all traffic from one network to another. A VPDN uses L2TP "tunneling" to encrypt all information at the IP level.