摘要：
ICMP is a control protocol that is considered to be an integral part of IP, although it is architecturally layered upon IP, i.e., it uses IP to carry its data end- to-end just as a transport protocol like TCP or UDP does. ICMP provides error re... 阅读全文
摘要：
网络层主要是IP协议。但是其他一些辅助进行包转发、路由和包安全的协议也算入了网络层。例如ICMP,EIGRP等ICMP is the Internet Control Message Protocol.ICMP is a complementary protocol to IP (Internet Protocol). Like IP, ICMP resides on theNetwork Layerof theOSI Model.ICMP is designed for sending control and test messages across IP networks.Unlike t 阅读全文
摘要：
http://technet.microsoft.com/en-us/library/bb726946.aspx 阅读全文