【摘要】 在介绍企业跨区域通信模式、 VPN通信的安全业务要求、 IPSec协议对 IP数据包的封装加密认证处理过程的基础上，比较了 VPN系统为用户提供服务的多种方式，分析了 VPN核心模块 IPSec在安全网关上驻留的多种层次结构，并对 IPSec的实现作了一些优化改进，最后提出一种基于安全网关的 VPN实用体系结构。更多还原

【Abstract】 Based on the introduction of communication models over wild area, the variant VPN services and IPSec operation, this paper makes the compassion of different methods for VPN to provide these services, analyzes the IPSec’s different location on SG, gives some clues to optimize the IPSec function, and ultimately provides one complete architecture to realize the SG－ based VPN.更多还原