Local Area Network

We are said to have a network when two or more computers are connected with one another  for the purpose of communicating data electronically. Besides phisically connecting computer and communication devices, a network system serves the important function of establishing a cohesive architecture that alloes a variety of equipment types to transfer information in a near-seamless fashion. Examples of two basic network types are local-area networks (LANs) and wide-area network (WANs). LANs connect computers and peripheral devices in a limited phisical area, such as a business (bisisiniss) office, laboratory, or college campus, by means of permanent links that transmit data rapidly.

A typical LAN consists of two or more personal computers, printers, and high-capacity disk storage devices called file servers, which enable each computer on the network to access a common set of files. LAN operating system software, which interprets input and instructs networked devices, allows users to communicate with each other, share the printers and storage equipment, and simultaneously access centrally located processors, data, or programs. LAN users may also access other LANs or tap into wide-area networks. LANs with similar architectures are linked by "bridges", which act as transfer points. LANs with different architectures are linked by "gateways", which convert data as it passes betwenn systems. The devices on a LAN are known as nodes, and the nodes are connected by cabling through which messages are transmitted. Types of cables include twisted-pair wiring, coaxial cable, or fibre-optic cable. Nodes on a LAN can be wired together in any of three basic topologies, known as bus, ring, and star. As implied by their names. A bus network is more or less linear, a ring network forms a loop, and a star network radiates from a central hub.

All LANs have at least three basic components:

• Workstation - PCs or terminals;
• File server or disk server - a special PC or larger computer where shared software resources and files are stored;
• Connection harware that includes cabling and interface cards.

Glossary

• Purpose: aim;
• Besides: togeteher with;
• Cohesive: exhibiting or producing cohesion or coherence;
• Near-seamless: almost without interruption;
• Fashion: manner of doing or making something;
• To tap into: to connect;
• To wire: to connect various devices through wires;
• Loop: a closed path or circuit over which a signal can circulate;
• Hub: an electronic socket in a plugboard into whick one may plug many wires;
• At least: at the minimum;
• File server: a computer in a network that is used for storing and managing access to shared files;
• Cabling: the physical connection among nodes;
• Interface card: a printed circuit board that allows a computer to communicate within the network.

Reti su area locale

Si dice di avere una rete quando due o più computer sono connessi gli uni con gli altri allo scopo di comunicare dati elettronicamente. Insieme ai computer connessi fisicamente e ai dispositivi di comunicazione, un sistema di rete fornisce l'importante funzione di stabilire un'architettura coerente che permetta a vari tipi di apparecchiature di trasferire informazioni in maniera tale che non vi siano interruzioni. Esempi dei due tipi di rete di base sono le reti su area locale (LAN) e le reti su area geografica (WAN). Una LAN connette computer e dispositivi periferici in una area fisicamente limitata, come un ufficio, un laboratorio, un college, per mezzo di collegamenti permanenti che trasmettono i dati rapidamente.

Una tipica LAN consiste in due o più personal computer, stampanti e dispositivi ad alta capacità di immagazzinamento chiamati file server, che abilitano ogni computer su una rete ad accedere a insiemi di file comuni. Il software di sistema operativo delle LAN, che interpreta gli input e istruisce i dispositivi di rete, permette agli utenti di comunicare con ogni altro, condividere le stampanti e le apparecchiature di immagazzinamento, e contemporaneamente accede ai processori, dati o programmi localizzati. Gli utenti di una LAN possono anche accedere ad altre LAN o connettersi a reti su area geografica. Le LAN con architetture simili sono collegate da "bridge", che fungono da punti di trasferimento. Le LAN con differenti architetture sono collegate da "gateway", che convertono i dati quando passano attraverso i sistemi. I dispositivi su una LAN sono conosciuti come nodi, e i nodi sono connessi da cavi attraverso i quali i messaggi sono trasmessi. Tipi di cavi includono cavi incrociati-doppi, cavi coassiali, o cavi a fibre ottiche. I nodi su una LAN possono essere connessi insieme in ciascuna delle tre topologie di base, conosciute come bus, anello e stella. Come suggeriscono i loro nomi, una rete a bus e più o meno lineare, una rete ad anello forma, appunto, un anello, e una rete a stella diffonde da un hub centrale.

Tutte le LAN hanno come minimo tre componenti di base:

• Stazioni di lavoro o terminali;
• Files server o disk server - uno speciale PC o un più grande computer dove le risorse software e i file sono immagazzinati;
• Hardware di connessione che include cavi e schede di interfaccia.

Summary

We have a network when two or more computers are linked together for the purpose of communicating data electronically. There are two basic network types:

• LAN (Local Area Network);
• WAN (Wide Area Network).

A typical LAN consists of two or more personal computers, printers, and high capacity disk storage devices called file servers, which allow the computers of the network to access a common set of files or share software resources. LANs with similar architecture are linked by "bridges" while LANs with different architecture are linked by "gateways". The devices on a LAN are known as nodes and those are connected by cables that can be twisted pair wiring, coaxial cables, or fibre-optic cables.

There are three basic topologies in a network:

• Bus (it is more o less linear);
• Ring (it foms a loop);
• Star (it radiates from a central hub).

All LANs have to possess three basic components:

• Workstation - PCs or terminals;
• File server or disk server where shared software resources and files are stored;
• Connection hardware that includes cabling and interface cards.