preface. preface

The UNIX (GNU/Linux) operating system is used as an example of a standard communications architecture. From the mythical UUCP (Unix-to-Unix CoPy or service for copying between UNIX operating systems) to the current networks, UNIX has always proven its versatility in aspects related to communication and information exchange. With the introduction of computer networks (Local Area Networks, Wide Area Networks or the latest Metropolitan Area Networks) offering multipoint connections at different speeds (from 56 kbits/sec to 1 Gbit/sec), new services that are based on faster protocols, portable between different computers and better adapted, such as TCP/IP (transport control program / Internet protocol), have arisen. [Com01, Mal96, Cis00, Gar98, KD00]