计算机的网络安全

On Computer Network Security

计算机网络是一个分层的体系结构，对每一层都有其有代表的物理设备，每一层都有其相应的服务与协议，而网络安全就渗入到每一层中，采取相应的网络设备和安全策略，从传输技术上分类的两种网络：局域网和广域网采取了不同的安全方法。

Computer network is a hierarchy with different layers. Every layer has its representative physicaI devices as well as corresponding services and protocols. We must take different safety mea- sures in LAN and WAN by Permeating each layer to ensure network security.