This chapter takes the reader into the modern world of computer networks: it first illustrates the main standardization bodies for telecommunications and data networking, then it exposes the general principles that underlie communications in a packet-switched network and describes the features of the main protocols ruling the proper functioning of the Internet.

An adequate, thorough treatment is devoted to the Internet protocol (IP), as its functionalities are the basis on which the entire Internet communication model relies: the original classful and the current classless addressing schemes are presented, followed by the subnetting and supernetting procedures IP allows. Direct and indirect datagram delivery is also introduced. Every topic is complemented by some explanatory examples, whose aim is immediately to translate into useful, working cases, the theoretical concepts.

The chapter is closed by two sections that present the salient attributes of the transmission control protocol (TCP) and of the user datagram protocol (UDP).

Who's who in the telecommunication world

It is appropriate to place in this opening section a brief, yet meaningful overview of the most representative bodies within the telecommunication and networking arena, and of their role. As the topics covered in the next chapters will quantitatively testify, the networking field heavily relies upon standards: they are needed to guarantee for systems and services not only quality, safety, reliability and efficiency, but also interoperability, a magic word when the ultimate objective is to “connect.”