  With the development of Internet technology, the Web is becoming more and
more important in our lives so that it has even become an essential element.
The application of the Web has never been limited to computers; it has been
opened to all kinds of intelligent digital devices like mobile ones. In this
paper, we discuss the main and substantial difference between UDP and TCP, and
how to implement Client-Server model. We also discuss the efficiency of
multi-thread server and its relationship with internet.
