摘要：In Part I we introduced a working definition of the term “Virtual Private Network” (VPN), and discussed the motivations behind the adoption of such networks. We outlined a framework for describing the various forms of VPNs, and then examined numerous networklayer VPN structures, in particular, that of controlled route leakage and tunneling techniques. We begin Part II with examining other networklayer VPN techniques, and then look at issues that are concerned with non-IP VPNs and Quality-of-Service (QoS) considerations.
