11.1 Introduction

The phenomenal growth of the Internet continues apace. IP networks are cheap, highly flexible, endlessly upgradable, and ubiquitous. Everyone uses them; nobody can now afford not to. Businesses have been quick to recognise the value of the Internet as a source of information, and as a new medium for communicating with customers. However, they have been slightly more reluctant to use the Internet as a means of interconnecting their own internal networks, despite the obvious cost savings offered. Accustomed for so long to being isolated from the outside world by firewalls, and to the connection of remote sites using private networks, the idea of trusting private packets to a public transport medium like the Internet has been slow to catch on. Although virtual private network (VPN) technologies, which allow the creation of secure overlays on untrusted networks, have been in existence for some years, it is only recently that implementations and standards have reached a level of maturity appropriate to the commercial world.

The automotive and finance industries have been among the first to realise the potential benefits of VPNs. Motor manufacturers in the USA quickly recognised IP networks as a more efficient way of communicating with partners, suppliers, customers, and attracting new customers. The result was the Automotive Network Exchange (ANX), the world's first commercial secure IP network [1]. The ANX now extends into Europe and Asia/Pacific, and has even begun to offer its services...