A virtual private network (VPN) is a private data network that makes use of the public telecommuni-cation infrastructure, maintaining privacy through that use of a tunneling protocol and security procedures.
Existing WAN technologies, such as International Private Leased Circuit (IPLC) or general broadband services, are not stable, flexible and cost-effective enough to fully satisfy the corporates use of internet. However, IP-VPN technology has emerged as the solution to overcome the problems.
The main purpose of a VPN is to give the company the same capabilities as private leased lines at much lower cost by using the shared public infrastructure. Companies today are looking at using a private virtual network for both extranets and wide-area intranets.