We would like to end this chapter with a diagram depicting the IP VPN family tree (Figure 5.9). The goal of the discussion in this chapter was to help the reader better understand general VPN technology, taxonomy, and terminology and then to add mobility into the mix by introducing Mobile VPN. Here we provided an overview of the VPN enablers, such as tunneling and security, as well as main VPN topology examples, such as site-to-site extranets and remote access outsourcing. Figure 5.9 summarizes most of the discussion we had and creates a clear VPN hierarchy, which should serve as a good foundation for the material presented in the following chapters, which discuss Mobile VPN in much greater detail.
Figure 5.9: VPN family tree.