Chapter 1. Introduction to VPN Technologies

Modern business environments have been consistently changing since the advent of the Internet in the 1990s. Now more than ever, organizational leaders are asking themselves how efficiencies can be gained through making their workforce more mobile and thus increasing the scope of sales and distribution channels while continuing to maximize the economies of scope in their existing data infrastructure investments. Virtual private network (VPN) technologies provide a means by which to realize these business efficiencies in tandem with greatly reduced IT operational expenditures. In this chapter, we will discuss how today's VPN technologies enable enterprise workforces to share data seamlessly and securely over common yet separately maintained network infrastructures, such as through an Internet service provider (ISP) between enterprise networks or with corporate extranet partners. We will introduce several IPsec VPN topologies commonly found in today's enterprise networks, and we will conclude with the overview of two IPsec VPN business models, complete with cost savings realized by the enterprise.