LAN | Local Area Network

LAN | Local Area Network

What is a LAN or Local Area Network?

The local area network (or LAN, which stands for local area network), or even local network is a computer network used to interconnect processing equipment for the purpose of data exchange. A more accurate term would be: is a set of hardware and software that allows individual computers to establish communication among them, exchanging and sharing information and resources. Such networks are called by local cover only a limited area (10 km at most, beyond what are now called MANs).

Networks in larger areas require more sophisticated technologies, since, physically, the greater the distance from one node to another network, the higher the rate of errors that occur due to signal degradation. LANs are used for connecting workstations, servers, peripherals and other devices with processing capacity in a home, office, school and nearby buildings.

Components of a LAN — Servers

Servers are computers with high processing power and storage which is to provide services, applications or files to a network. As service providers, they can provide e-mail, hosting Web pages, firewall, proxy, print, database, serving as domain controllers and many other utilities. Such as file servers, they can serve as a deposit so that users save their files in a secure and centralized. And finally, as application servers, deploy applications that require high processing power to machines with smaller capacity.

Components of a LAN — Stations

Workstations, also called clients, are generally desktop computers, laptops or PDAs, which are used for access to services provided by the server, or to perform local tasks. These are machines that have less processing power. Sometimes used diskless workstations (diskless), which use completely the files and programs made available by the server – now these stations are sometimes called thin clients, or literally “thin clients”.

Network Operating System

The network operating system is a computer program for machine control that supports the network, and there are two system classes: client and server system.

The client system has features simple, focused on use of services, while the server system has a greater amount of resources such as services to be available to customers.

The Unix-based systems are potential clients and servers, with the choice made during installation of the packages, whereas Windows systems, there are client versions (Windows 2000 Professional, Windows XP) and server versions (Windows 2000 Server, Windows 2003 Server and Windows 2008 Server).

Means of transport of data

Currently, the means of transportation data are used more ethernet or wireless, operating at speeds ranging from 10 to 10,000 Mbps. The transmission media used most often are the cables (twisted pair, coaxial, fiber optic) and air (wireless networks).

Network Devices

Network devices are the physical means necessary for communication between the components of network participants. Examples include hubs, routers, repeaters, switches, bridges, network cards and wireless access points.

Communication protocols

Protocol is the “language” that the various devices on a network use to communicate. To be able to communicate, all devices must speak the same language, i.e., the same protocol. The currently most used protocols are TCP / IP, IPX / SPX and NetBEUI.

In the days before personal computers, the companies had only one central computer, the mainframes, with users accessing via terminals using a simple low-speed cable. Networks such as Systems Network Architecture (SNA) from IBM were focused on connecting terminals or other mainframes via dedicated connections. Some of these terminals could be in remote locations – which would give rise to a WAN.

The first LANs were created in the late 1970s and used to create high-speed links between several large central computers at a particular location. Of many competing systems created at this time, Ethernet and ARCNET were the most popular.

The growth of CP / M and then the DOS-based personal computers meant that a single site could have dozens or even hundreds of computers. The initial attraction of networking these was generally to share disk space and laser printers, which were extremely expensive at the time. A greater enthusiasm with the concept of LAN appeared around 1983, which was declared by the computer industry as “the year of the LAN.”

In fact, the concept was marred by the proliferation of physical layer and protocol implementations which were incompatible and confusion over how best to share resources. Typically, each manufacturer had its own type of network card, cables, protocols and network operating system.

A solution appeared with the advent of Novell NetWare which provided support to more than 40 types of network cards and cables, and an operating system more sophisticated than any of the contestants. NetWare dominated the LAN of personal computers until the introduction of Microsoft Windows NT Advanced Server 1993 and Windows for Workgroups.

Study: From Wikipedia, the free encyclopedia. The text is available under the Creative Commons.