Network Basic

Networks

There are different types of networks .
*LAN   -  Local Area Network
*MAN  - Metropolitan Area Network
*WAN  - Wide Area Network.

·         LAN

         A computer network with many computers located in the same building, room or campus is called Local Area Network . They are widely used to connect personal computers and work stations in company offices and factories to share resources and exchange files of information.

There are many different types of LANs token ring networks. Ethernets or Ethernet LANs and ARC nets being the most common for PCs. Ethernet LAN is a standard developed by Digital Equipment corporation. At present Ethernet is one of the most popular Local Area Networks used as it is well proven, standardized and supported by all vendors of computers. Cheaper version of Ethernet are now emerging. One of them is the use of unshielded twisted pair of wires cabbreviated as UTP instead of coaxial cable. The speed of these LANs is also 10Mbps.

Another system using Ethernet protocol is called thin wire Ethernet. This uses a standard coaxial cable like those used in cable T.V.  

LAN are distinguished as follows

* size.

*Transmission technology.
*Topology.

The characteristics of LAN are.

*Restricted in size.

*Simplifies network management.

*Often use a transmission technology.

*Consist of a single cable to which all the networks are attached.

*Run at speeds of 10 to 10 Mbps

*Information travels in LAN with a low delay.

*Few errors.

*Various topologies are possible for broad cast LAN.