With the objective of share services, information and resources Are crated computer networks, which comprise a set of devices of different classes (computers, routers, modems), connected using signals, cables, radio waves or any other type of digital data transport.
It is recognized that the foundation of the concept of "networks" has been born of biology. Indeed, the design of modern computer interactions bears enormous similarities to the behavior of neurons in the central nervous system. Each of these cells acts in itself as a "computer", capable of multiple interconnection with tens of thousands of other "computers" directly or indirectly. Paradoxically, at present the application of networks Computer science allows a better understanding of neurosciences, almost as if paying back the original contribution of neurology to computer science.
In this context, ISO has defined the OSI model (Open System Interconnection), which made it possible to simplify communication between programs on different machines. This model, free and open design, specifies 7 layers of abstraction ranging from physics to application level. Although the original OSI model dates back to 1977, when the current Internet was almost a science fiction dream, its validity stands out with little modification over the decades.
exist private and public networks. A Intranet is a private network that uses the technology created for the Internet: TCP / IP protocols, being the most important of the system. These networks are usually limited to the scope of a single entity, and offer the typical services that are also found on the Internet: SMTP, POP3, HTTP, FTP and others such as IRC chat. This type of network is very commonly used in large companies, or entities such as a University, in order to optimize communication between the different areas and departments of the organization. In radio and television stations, it is also used to share information and send links to pages from which to obtain data. It cannot be forgotten that Intranets are a form of data communication of great relevance in financial institutions, for which the security protocols acquire an importance of great proportions.
Secondly, There are Free networks and Non-Free networks. Free networks are generally formed by enthusiasts of the software free that connect different nodes to each other using wireless technology (Wifi): share files stored on disk and transmit data at high speeds. For example, a free network can operate at 54 MB / s, while currently non-free networks, such as Internet, provide home users with 3MB / s as a typical standard in Europe, with even less bandwidth in South America. Free networks are managed cooperatively and, in general, access is free. The free software movement, at least on the part of Free Software Foundation, it is proposed to create a network of free networks worldwide, parallel to the Internet. The project is ambitious, but it is based on principles such as the execution of the contents with free purpose, the copying and unrestricted distribution and the free study and modification of the source codes.
On the other hand, in general Internet providers provide the customer with a modem, a user name and a password. In other cases the connection from PC to Internet outlet is configured automatically via DHCP (dynamic host configuration protocol), with which the user must not enter any data in the system to connect to "the network of networks": this is frequent in cable modem connections, such as the Flash service in Argentina. These kinds of simple connections use "ethernet modems"that do not require any configuration by the user both in Windows systems, GNU / Linux or Mac OS X.
In many cases, connections are even made between two or more computers within the same home, through the installation and configuration of "local" networks facilitated by the use of devices called routers, which can be connected to computers on the network by cable or by connecting Wifi (if the router includes an antenna for this purpose). The number of computers that we can connect to the router's network will basically depend on the number of inputs supported by it (different routers with two, four, six and up to eight inputs for computers). In addition, it should be taken into account that the speed at which we are used to browsing the web will surely be decreased, and this especially, when two (or more) computers are being used at the same time, which are connected to the same router.
It is emphasized that the management of the networks it has suffered various impacts that have led to progressive optimization over time. While the first Intranets and the old Internet connections depended exclusively on the operation of the telephone modems, the use of asymmetric telephone connections and the cable modem significantly modified the connection speed and the applicability of the technology. The next step has been defined by smartphones, capable of interacting with the "network of networks" without cables and covering considerable distances. Undoubtedly, the next level, of which the real birth is contemplated in our days, consists of the accelerated diffusion of the satellite connection to networks and the appearance and dissemination of the so-called "smart TVs", that is, of television equipment with the ability to act as input and output peripherals through the Internet. Therefore, networks are part of everyday life, in an increasingly widespread mode and with notable results on the people's quality of life.
