说明：  UDP是TCP/IP协议中的传输层协议的一种，本文介绍了在Linux下编写基于UDP协议的Client/Server模型的程序的方法，并给出了一个echo Client/Server例子程序。
(UDP is a TCP/IP protocol in a Transport Protocol, this article describes the preparation of Linux based on the UDP protocol under the Client/Server model procedures, and gives an echo Client/Server examples of procedures.)