It is known that one of the most significant achievements of mankind in the last century was the creation and rapid development of information technologies - technologies that allow, using computers and various types of computer networks, to store, process and transfer huge amounts of information. It is worth noting that such a rapid information leap of mankind became possible only after the computer communication networks were created.
All kinds of computer networks are a set of computers distributed over a certain territory and interconnected by specialized channels that allow data transfer. To date, computer networks have become widespread, various kinds of computer networks function all over the world and interact with each other. The modern understanding of the signs of networks has led to the emergence of classification by territorial sign. According to this classification, such types of computer networks are distinguished:
Global Area Network (GAN) - global networks that unite computers and networks located in different parts of the world.
Wide Area Network (WAN) - large-scale networks that integrate computer networks at the level of continents and states;
Metropolitan Area Network (MAN) - inter-city networks that connect computers and networks within the regions and other administrative units;
Local Area Network (LAN) - local networks, involving the unification of computers located at relatively short distances - for example, within a single building.
WAN and MAN are regional networks. It is worth noting that today the separation of computer networks into WAN and MAN is very conditional, since now almost every regional network is included in any global network.
Many organizations that are interested in ensuring a high level of protection of information from attacks from outside (for example, military, banks, etc.), create their own networks, called corporate. The corporate network can include tens of thousands of computers that are located at a considerable distance from each other, for example, in different countries.
The most common in the world are numerically local computer networks.
The main distinguishing feature of local networks is the ability to connect computers with a cable, without resorting to channels for data transmission used by global networks (telephone network, fiber optic cable, radio ether, etc.). Since computers are located close to each other, to create a network it is enough to connect them with a cable and set up accordingly. Networking computers into an in-house computing network gives its owners a lot of advantages.
Types of local computer networks are often divided by topology - the way of connecting computers with each other. Topology is an important characteristic of local networks, since it is the connection method that determines the most important indicators, represented by the performance and reliability of operation.
The most advantageous are the networks made according to the topology "star" - to one central source all the other computers of this network are connected.
There are networks made according to the topology "ring" - all computers communicate with each other in sequence and eventually form something resembling a ring.
The third type of topology on which local computer networks are created is the bus topology - all computers in the network are connected to the same cable - the data bus.
Computer networks, the principles of their operation, protocols, and hardware components are constantly being improved and developed.