A virtual private network (VPN) is a communications network tunneled through another network, and dedicated for a specific network. One common application is secure communications through the public Internet.

Some advantages:  

 

• Shared facilities may be cheaper
• Can rapidly link enterprise offices, as well as small-and-home-office and mobile workers.
• Allow customization of security and quality of service as needed for specific applications.
• Can scale to meet sudden demands, especially when provider-provisioned on shared infrastructure.
• Can reduce operational expenditure (OPEX) by outsourcing support and facilities.