VPN as a T-1 Circuit Alternative
Today's business environments demand employees to be connected to corporate intranet resources from remote offices or while traveling. High bandwidth internet connections have made long-distance dial-up connections obsolete and have given birth to a newer technology called the Virtual Private Network (VPN) which can be characterized by a client server approach and is a form of a Wide Area Network (WAN). "VPN clients authenticate users, encrypt data, and otherwise manage sessions with VPN servers utilizing a technique called tunneling" (Mitchell, n.d.a).
What is a VPN?
A VPN is a "communications network tunneled through another network and dedicated for a specific network" (Wikipedia, 2007). A traditional VPN uses the internet (public communication) to communicate directly with a single network (private communication).
Science fiction buffs may also relate a VPN to a wormhole due to its tunneling characteristics between the client and the server.
The term VPN was originally introduced by telecom companies. "The main feature of a telephone VPN is that it can provide users from an organization which uses a public provider's telephone service instead of its own private PBX with something very close to PBX (Private Branch Exchange) functionality" (Olifer, 2007).
Why use a VPN?
VPN solutions become attractive when the need to provide secured long distance access to a private network arises. The traditional method of accomplishing this was to install a high-speed digital link such as a T-1 (or fractional T-1) between the locations or use a remote access server (RAS), or modem pools, incurring long-distance telephone fees.
A dedicated point-to-point communication line such as a T-1 can offer a 1.544-Mbps transmission rate (or multiples of) and can be very costly between $550 and $1,200 a month. (T1 Shopper, 2007). This may be an acceptable approach but does not scale well when trying to connect more than two networks together. For example, a "four branch offices require six lines to directly connect them to each other, six branch offices need 15 lines, and so on"
Today's consumer DSL and cable modems offer speeds many times faster at a small fraction of the monthly costs. Using a VPN to access a company's private network is a cost effective way to leverage existing high-speed internet connections. Each client's public internet connection is used to "tunnel" to the corporate server in a secured manner.
Three practical VPN uses
Affordable high-speed internet has given rise to telecommuting options for employees either full-time or a part-time basis. This provides a company's employees with increased mobility and allows them to travel while maintaining the ability to communicate and access corporate resources.
VPNs can also provide a gateway between networks, by employing a VPN server to server connection. This type of connection is used to join two different networks together. The...