摘要：The term “VPN,” or Virtual Private Network , has become almost as recklessly used in the networking industry as has “QoS” (Quality of Service) to describe a broad set of problems and “solutions,” when the objectives themselves have not been properly articulated. This confusion has resulted in a situation where the popular trade press, industry pundits, and vendors and consumers of networking technologies alike generally use the term VPN as an offhand reference for a set of different technologies. This article provides a common-sense definition of a VPN, and an overview of different approaches to building one.
