Which in turn stimulates the cell to invaginate and take in the bacteria. 内陷吞噬细菌。
TCP/IP protocol which is used in the network .Some invaginate is essential and ICMP is the important among them ,so we introduce them relatively; TCP/IP协议，系统主要用到的网络协议，对一些必须的套接字做了介绍，其中ICMP是重要的地方，因此对其介绍的比较详细；
