"Networks: the last pirate utopia of the Information Age", published journalists Mondo 2000, the magazine cyber1 time [Wiz94]. A dominant technology has each of the last three centuries scored. The eighteenth century was the era of the great industrial revolution specific mechanical systems. The nineteenth century was the age of steam. During the twentieth century, the key technology concerned the collection, processing and distribution of information. We saw, among others, the establishment of a global telephone network, the invention of the radio and television, the birth and unprecedented growth of the IT industry and launch communication satellites [Tan89 ]. During the last years of this century, these areas converge and differences between 'collection, processing, transportation and storage of information quickly fade. The fusion of computers and telecommunications has had a profound influence on the structure of systems. The old model of the single computer serving all processing needs of an organization is found quickly supplanted by that of the performance of work by separate but interconnected computers. Such systems are called computer networks.
