Global computer networks

A computer network is nothing more than the combination of several computers among themselves, allowing them to exchange data. Global networks are called when they cover users from all over the world. Note that the first computer networks of civil purpose appeared in the United States. But very few people know that the very principle of this technology was first used in the USSR, and thanks to this, once the first missile defense system was created a long time ago.

Today there is a fairly wide classification of networks. According to territorial prevalence, global, local and regional computer networks are distinguished. Global computer networks Are networks located on the territory of the state or several states, for example, the worldwide Internet network. Local networks cover the territory within a few tens of square meters, and regional networks are those located on the territory of the region or city.

However, the two main terms in the classification of networks are: WAN and LAN.

WideAreaNetwork (WAN) - global computer networks covering large regions, which include local networks and other telecommunications devices and networks.

LocalAreaNetwork (LAN) - local networks that have a closed infrastructure prior to their access to service providers. The very term "LAN" is able to describe both a small office network and a network of a large plant that covers several hundred hectares.

The oldest global network is the Internet. It provides different ways to connect remote computers and the general use of information resources and distributed services.

Initially, global computer networks dealt with the task of accessing various remote terminals and computers to powerful computers called host-s. These connections were made using unswitched or switched channels of telephone networks or using satellite dedicated data networks, for example, working on X.25 protocol.

To connect to such networks, modems were used that operated specialized telecommunications programs, such as COMIT, PROCOM, BITCOM, MITEZ, etc. Managed MS-DOS, they exchanged information with the computer to which the connection was established.

The very construction of a global network It is not difficult to describe. A global network consists of cells, which are local networks. In turn, local networks consist of smaller networks and individual computers. Here such multi-level hierarchy also provides construction of a network. In addition, each device on the network must have its own IP address or unique identifier.

Today, single computers that are part of the global computer networks are becoming less common. Basically, these are home PCs. For the most part, network subscribers are those computers that are included in local computer networks, hence, most often experts are working out options for how best to ensure the interaction of several local computer networks. It is necessary at the same time to provide for the remote computer the presence of communication with any computer entering the remote local network, or vice versa. The latter option is very relevant when increasing the number of home and personal computers.

Now, as switching equipment, switching centers are used for X.25 networks by specialized devices manufactured by Telenet, Ericsson, Siemens, Alcatel, etc., but for TCP / IP networks, Decnis and Cisco routers are used. However, technologies do not stand still, and it is likely that in the future we will see an even more effective organization of a global network, which today has a huge impact on the lives of almost everyone.