Once mankind were created personal computers needed to create a new approach to the organization of systems, data processing, as well as the creation of new technologies in the field of storage, transfer and use of information.A little later there was a need to move from individual use of computers, operating systems, centralized data processing systems that can handle data distribution.
distributed data processing referred to such information processing, which is performed independent but interconnected computers, is a distributed system.
computer network is a collection of computers that are interconnected by communication channels that allows you to create a single system, fully meet the requirements of the rules of distributed information processing.Thus, the main purpose of computer networks - a joint data processing, which involves all components of the system, regardless of their physical location.
Classification of computer networks involves their separation on the types of computer networks, depending on the location of computers and other components relative to each other.Thus, the classification of computer networks involves their separation on:
global - it's computing networks of subscribers who are located far from each other - from hundreds to tens of thousands of kilometers.These networks make it possible to solve the problem of integration of information resources of all mankind, and arrange immediate access to these resources;
Regional - a computer network connecting subscribers who are located at less than the global networks, but still considerable distances.An example of a regional network can serve as a network of a large city or a separate state.
Local - a computing networks of subscribers who are located at a relatively short distance from each other - often in the same building or a few closely spaced buildings.This network of companies, offices of companies, firms, etc.
In addition, the classification of computer networks suggests that the global, regional and local networks can be combined, which makes it possible to create a hierarchy of multihomed, that is a powerful tool that can handle huge information arrays and provide almost unlimited access to information resources.
Among other things, the classification of computer networks, rather it gives the opportunity to build an understanding of just such a system that will satisfy the needs of an enterprise, office, city or state in the information.In general, computer networks consist of three subsystems nested: a network of workstations, network servers and network data base.
workstations (can be represented by the client machine, workplace, subscriber station, terminal) is called the computer that runs the subscriber computer network.Network Workstation is a collection of workstations, as well as communication tools, which are designed to provide interaction between a workstation and a server.
server is called a computer that performs common tasks and provides network workstations various services.Network Server is a set of servers, network, and communications to ensure connectivity of servers to the core network.
Basic data network is the set of means of information transfer between servers.The base network includes communication links and communication nodes.The communication center is a set of switching tools, as well as transmission of information concentrated in one point.The purpose of the communication is the reception of data that comes through communication channels, as well as their transfer to the channels that lead to subscribers.
