How It Works network communication.

How It Works network communication.
The messaging network is not simply a process of transmission of bits representing alphanumeric characters.
The communications network may involve personal computers that run on DOS, Macintosh line models, computers minicomputers and large, all having their own forms of management code and data transmission.
Adding the fact that each application of each of these platforms has its own pattern of communication, you
see that the sending and receiving of data simpler becomes a mammoth task.
To make sure that the data from one node of a computer reach another node or server that you want - and come intact and uncorrupted - it is necessary that the system be understood by all network components.
A system of this type follows the OSI (Open Systems Interconnection, or Open Systems Interconnection) that is followed by most Networked PCs. The seven layers of the OSI model is not exactly a specific set of hardware and software, but one scheme that can be implemented in various forms since such an implementation follow the OSI standard.
This standard is based on layers: each network component exists in a certain layer of the system, and each component can communicate only with the layer directly below or directly above it. Each layer provides services to the upper layer and may request the services of the lower layer.

Source: Evolution of Computers