A VPN T1 or Virtual Private Network is a great alternative to costly private line or frame relay applications.  The VPN uses the public Internet to simulate a frame relay network.  Using the public Internet is a much more cost affective way of communication between Intranet, Extranet, and Remote access users.  

Intranet:  Include users within an internal private enterprise.  Enterprise users utilize VPN applications to exchange day to day operating information between locations.  For example, a department store sends detailed sales information to the home office.

Extranet:  A closed network which allows certain external users limited access to some applications.  Extranet applications are popular among companies that work closely with outside suppliers and partners.  As an example, a company that supplies thread to a clothing manufacture can go in to the closed network in a limited capacity to maintain supply levels.

Remote Access:  This application is designed for mobile and remote users to access networks through the VPN T1.  Remote users typically include employees that have home offices, traveling on business, or in the field.  The Remote access application allows employees real time access to mission critical business information.

Businesses are also concerned with the security of the information they are transporting.  Depending on the T1 provider a company is using, the methods they use for security may differ. Most ISP’s offer some type of tunneling that is facilitated by a router.   The router offers a certain level of security by encryption and authentication of the information streaming through the Internet.  The tunnels connect different sites through the Internet, mimicking the private line setup.  These VPN T1 tunnels can be setup in a number of different ways, offering a wide degree of flexibility and security depending on the needs of an enterprise.