What is a Local Area Network?
In this tutorial, we are going to see What is a Local Area Network?
A local area network (LAN) is a network that interconnects the computers of a company or organization. Thanks to this concept, created in 1970, the employees of a company have at their disposal a system allowing them to :
- To exchange information
- To communicate
- To have access to various services
A local area network generally connects computers (or resources such as printers) using wired transmission media (twisted pair or coaxial cables in most cases) over a hundred-meter perimeter. Beyond that, we consider that the network is part of another category of a network called MAN (metropolitan area network), for which the transmission media are more adapted to long distances…
Hardware components of a local area network:
A local area network is made up of computers connected by a set of hardware and software elements. The hardware elements allowing to interconnect the computers are the following ones :
- The network card (sometimes called coupler): it is a card connected on the motherboard of the computer and allowing to connect it to the physical support, that means to the physical lines which allow transmitting the information
- The transceiver (also called adapter): it allows to ensure the transformation of the signals circulating on the physical support, in logical signals manipulable by the network card
- The socket: it is the element allowing to realize the mechanical junction between the network card and the physical support
- The physical support: it is the support (generally wired, i.e. in the form of cable) allowing to connect the computers between them. The main physical media used in local networks are the following:
- Coaxial cable
- Twisted pair
- Optical fiber
Local area network topologies
The hardware devices implemented are not sufficient to use the local network. Indeed, it is necessary to define a standard method of access between computers, so that they know the way in which the computers exchange information, especially in the case where more than two computers share the physical medium. This access method is called logical topology. Logical topology is realized by an access protocol. The most commonly used access protocols are :
- Ethernet
- Token ring
The way computers are physically interconnected is called physical topology. The basic physical topologies are :