Since pc can be easily connected to the network and get all kinds of internal information , there exists information security hidden troubles in the system . aas can establish a hierarchical communication safeguard to enforce the strict authentication on those who want to connect into the network . this action insures that only those expected users will be connected into the network and avoid the illegal entry 针对个人计算机可以很方便的接入网络而获取各种内部资源的信息安全隐患, aas接入认证服务器可以构筑一种分层次通信保护结构,对试图接入网络的用户进行严格的认证,保证只有系统期望的用户才能接入网络,避免非法用户的侵入。