摘要
This article describes how to utilize the VPN to construct the new Extranet’s topology. Firstly, it tells what is the Extranet. Secondly, some basic principles and technical idioms of the VPN are dealt with. Thirdly, tunnel protocols about VPN are discussed. Finally, three kinds of Extranet’s architectures with VPNs are given. Through integrating the VPNs into the Extranet, we can get much more benefits from shared networks (e.g., Internet, ISDN, PSDN, etc.).
本文介绍了外部网（Ｅｘｔｒａｎｅｔ）和虚拟专用网（ＶＰＮ）的技术特征与工作原理，并在此基础上，提出了用ＶＰＮ构建Ｅｘｔｒａｎｅｔ的３种实现方案，在公网（如Ｉｎｔｅｒｎｅｔ，ＩＳＤＮ，ＰＳＤＮ）上构建Ｅｘｔｒａｎｅｔ，从而获得很大的益处．
