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, but a VPN need not have explicit security features, such as authentication or content encryption. VPNs, for example, can be used to separate the traffic of different user communities over an underlying network with strong security features.

Benefits

•   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.