Author: Christian.Queinnec@lip6.fr

## Outline of the Chapter

This chapter presents the basic elements of the Internet, sockets, for the purpose of building distributed applications (particularly client-server applications) while detailing the problems in designing communications protocols.
The first section briefly explains the Internet, its addressing system and its main services.
The second section illustrates communications through sockets between different Objective CAML processes, both local and remote.
The third section describes the client-server model, while presenting server programs and universal clients.
The fourth section shows the importance of communications protocols for building network services.
This chapter is best read after the chapters on systems programming (Chapter 18) and on concurrent programming (Chapter 19).