By definition, a Computer network o computer network is a set of hardware and software (devices and programs) connected to each other through physical devices for sending and receiving information, in order to share data, manage resources and offer various types of services. For example: a home network, a network between branches, the Internet.
These networks operate like any form of established communication: through the coordinated interaction and reciprocal of emitters and receivers through a physical channel and using a common code. The operation of the network will depend on the arrangement of these elements, for example, its data transmission speed.
The largest man-made network to date is the Internet: a vast network of million computers interconnected in different parts of the planet, sharing information on a global scale and allowing processes and services to be undertaken.
Types of networks
There are numerous classifications of computer networks, serving various aspects of their functioning: its type of connection, its functional relationship, its physical topology, its degree of diffusion, authentication or its data directionality, but perhaps the best known is the classification according to its scope.
Accordingly, we can talk about three types of network, mainly:
- LAN networks (Local Area Network). Its name consists of the acronym in English for Local Area Network, and are those that limit its scope to a well-defined area of small spans, such as a department, an office, an airplane, even the same building. Lacking public means of interconnection, they are managed as a single location network, despite the fact that they can serve many users at the same time.
- MAN networks (Metropolitan Area Network). Its name consists of the acronym in English for Metropolitan Area Network, since it is a high-speed network that provides coverage to a larger geographical area than a LAN (in fact it contains several of them), but still concrete and defined, as a portion of a city.
- WAN networks (Wide Area Network). Its name consists of the acronym in English for Wide Area Network, and this time it is about wide-range and high-speed networks, which make use of satellites, cabling, microwaves and new technologies to cover an extensive geographical portion. The Internet, without a doubt, is a WAN of global proportions.
The computers that make up the networks communicate with each other speaking the same “language”, called network protocol. There are several possible protocols, communication standards, and general network operating considerations, but the two most common are OSI (Open Systems Interconnection: open interconnection of systems) and TCP / IP (transport layer and network layer).
Both protocols differ in that they structure communication in different ways. While the OR IF has seven defined layers of communication and concrete functions, the TCP / IP it has only four but structured on the basis of a double structure. The latter is the most common and most widely used globally.
Examples of LAN networks
- A home network. Like the wireless (WiFi) that anyone can install at home to serve a couple of computers and cell phones. Its scope will hardly exceed the margins of the department.
- A store network. Often the small branches of a business or a store have their own network, to provide Internet connection to their computers and, often, to customers.
- An internal network of an office. In offices, an internal network (intranet) is often implemented that connects the computers of all workers, allowing them joint access to peripherals (such as the same printer) and sharing work folders or material of mutual interest.
- A public network in a square. In many cities, the free public Internet program is implemented through wireless connection points with a range no greater than a few meters in a radius.
- A serial network in a parlor. Internet cafes or phone booths are businesses that gained a lot of boom with the penetration of the Internet prior to the arrival of the Smartphones. They used to contain a series of computers with Internet connection available for the use of the public, but framed in an internal network whose control resided in the computer of the manager of the premises.
Examples of MAN networks
- An inter-ministerial network. Many government agencies require joint work or share important data, which is why they are interconnected through a fiber optic network that allows them to be on the other side of the city and not lose contact.
- A network between branches. Many stores and businesses are interconnected in the same city, allowing a user to search for a product in the nearest branch and, if it is not available, they can request it at another location further away or, in the worst case, direct the customer to the book in some other branch.
- A network of a local ISP. It’s called ISP (Internet Service Provider) to companies that sell people local Internet access. They do it precisely through various MAN networks, each of which manages the resources of a city or a locality to the various clients requesting it, that is, to each particular LAN.
- A network on a university campus. Also called CAN (Campus Area Network), they are actually a MAN adapted to all the various buildings that make up a university city, and which may well be separated from each other by considerable distances.
- A municipal government network. The data of a municipality or mayoralty are often shared in a network that concerns only those who live in it, since citizens of other localities will have their own. Thus, the payment of municipal taxes or bureaucratic procedures can be carried out more effectively.
Examples of WAN networks
- The Internet. The best example of a WAN available is the Internet, capable of communicating various technological devices over enormous distances, even from one side of the world to the other. It is a gigantic network that has often been compared to an ocean, a superhighway, or an entire universe.
- A national banking network. Bank branches in a country are managed through a vast network and in connection with other banks and even with banks abroad. Each of these networks is a WAN that allows a user to withdraw money at an ATM on the other side of the country, or even in a different country.
- Transnational business networks. Large business franchises that have a presence in different countries of the world, keep their workers communicated through an exclusive WAN of the company, so that they can exchange information and stay in permanent contact despite being in different countries.
- Military satellite networks. The various defense and military surveillance networks that concern satellites, ships, airplanes and other vehicles scattered around the world, are necessarily wide-ranging and enormous, so they could only be of the WAN type.
- Pay TV networks. Cable or satellite television and other entertainment and information services based on new technologies necessarily use a WAN network to connect their subscribers in various countries in various regions of the continent.