What is a LAN ?

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LAN stands for Local Area Network, it is a network of computers and other components located relatively close together in a limited area. A SOHO LAN might consist of two computers connected with a hub, while the LAN in a large corporate might include hundreds of computers located in many buildings.

LAN

It is interesting to notice that how similar the LAN and our public transportaion system are. As a car driver, our journey starts at the parking lot, we drive on the road, obey the traffic regulations and always watch for the traffic lights. Finally, our car is parked into a parking lot. The LAN works in the same way.

There are four common components for all the LANs:

• Computers: Computers are the endpoints in the network, sending and receiving data. They are the parking lot in our metaphor.


• Interconnections: Interconnections enable data to travel from one point to another in the network. There are two types of interconnections: Network Interface Cards (NICs) translate the data produced by the computer into a format that can be transmitted over the LAN. Network media, such as cables or wireless media, is the "roads", that transmit signals from one device on the LAN to another.


• Network deives: including hubs, ehternet switches and routers. They are the "traffic lights", controling how data is transmitted in the network.


• Protocols: Protocols is the "traffic regulations", indicating the way the data is transmitted over a LAN and include Ehernet protocols, IP, ARP and RARP, and DHCP.

The LAN allows users to communicate and share resources such as printers, files, softwares locally. In case a resource is not available locally, the LAN can provide connectivity to remote resources via a gateway.

Ethernet is the most common LAN.

ICND1 and ICND2 break down