Recent directions in virtual private network solutions

VPN services have been around for decades but it did not get wide-spread usage until recently. A combination of new VPN technologies, network technologies and business communication requirements are the driving force behind the VPN services. This survey gives an overview of the recent approaches of VPN solutions and compare their scalability and flexibility aspects. The survey also categorises VPN solutions and relates them to potential customer segments with a view to provide a better understanding of the trade-offs that a network provider faces.