After humanity created personal computers, it required the creation of a new approach to the organization of systems that process data, as well as the creation of new technologies in the field of storage, transmission and use of information. A little later, the need arose to move from the use of separate computers operating in systems that process data centrally to systems that can process data distributed.
Distributed data processing refers to such processing of information that is performed by independent, but interconnected computers, which are a distributed system.
A computer network is a set of computers that are interconnected by communication channels, which allows you to create a single system that fully meets the requirements of the rules of distributed information processing. Thus, the main purpose of computer networks is the joint processing of data, in which all components of the system participate, regardless of their physical location.
The classification of computer networks involves their division into types of computer networks, depending on the territorial location of computers and other components relative to each other. Thus, the classification of computer networks involves their division into:
Global - a computer network that unites subscribers that are located at a great distance from each other - from hundreds to tens of thousands of kilometers. Such networks make it possible to solve the problem of combining the information resources of all mankind, as well as organize instant access to these resources;
Regional - these are computer networks connecting subscribers that are located at shorter distances than global networks . An example of a regional network is the network of a large city or an individual state.
Local - a computer network that unites subscribers who are located at relatively small distances from each other - most often in the same building or several nearby buildings. These are networks of enterprises, company offices, firms, etc.
In addition, the classification of computer networks suggests that global, regional and local networks can be combined, which makes it possible to create multi-network hierarchies, which are powerful tools that allow you to process huge information arrays and provide almost unlimited access to information resources.
Among other things, the classification of computer networks, or rather its understanding, makes it possible to build just such a system that will fully satisfy the information needs of an enterprise, office, city or state. In the general case, computer networks consist of three subsystems nested into each other: a network of workstations, a network of servers, and a basic data transmission network.
A workstation (can be represented by a client machine, workstation, subscriber station, terminal) is a computer at which a subscriber of a computer network works. A network of workstations is a set of workstations, as well as communications, which are designed to ensure the interaction of workstations between themselves and the server.
A server is a computer that performs common network tasks and provides workstations with various services. A server network is a set of network servers, as well as communication tools, designed to provide connection of servers to the core network.
A basic data network is a set of means of transferring information between servers. The core network includes communication channels and communication nodes. A communication center is a combination of means of switching, as well as the transmission of information, concentrated in one point. The purpose of the communication node is to receive data that comes through communication channels, as well as transfer it to the channels that lead to subscribers.