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Chapter 1
Introduction
1.1 The OSI model
In 1979, the International Organization for Standardization (ISO) had developed a model with
the aim to structure and standardise the world of data communication and networks. The
ISO is the committee that has developed the Open Systems Interconnection (OSI) reference
model. The ISO’s objective was to develop a reference model whereby mutual communication
between two systems, e.g. two computers, could take place.
In accordance with the ISO
OSI model (also called the 7-layer model), system A can communicate with system B (2 systems
from 2 different suppliers). Between these systems, different networks can be present;
public as well as private networks.
A public network is a network that is accessible by everyone, provided that the conditions
that apply to this network are complied with. A private network is mostly company-specific.
Figure 1.1: The OSI model