Computer Networks

Need for computer communication Networks:

1. An employee of an organization who has PC at home would use it for most of his work and connect it through communication lines to a powerful computer called a server fro executing larger programs and access special library programs and data resident in the server for executing large programs and access special library programs and data resident in the server situated in the organizations.

Internet and The World Wide web:

1. Electronic mail is an application in which any user on a network can send/receive letters using his computer terminal to/from any person in the world who has an electronic mail address Internet provides a worldwide electronic mail facility.

File transfer:

1. Mail is intended for short messages. A file transfer program is available on the internet which allows transferring a large file containing programs or data from a computer in any part of the world another. The rule used on the internet for file transfer is called file transfer protocol or FTP for short.

Remote Login:

1. By remote login or telnet access, we mean a user sitting on his terminal logging on to a machine located anywhere in the world. Remote login allows a user workstation or PC to behave as though it is directly connected to the machine the user is logged in.

World Wide Web:

1. Information is normally dispersed over many computers connected to the internet. If a user wants to obtain information from any of these computers they must be logically linked. The information stored in computers is not only text but also graphics(images), sound, and video. This is called multimedia information. All web pages are addressed starting with HTTP.

Local Area Networks

1. When computers located within a small geographical area such as an office or university campus(within a radius of 10km)are connected together e call it LAN.

Metropolitan Area Networks

1. It is the area that is connected within the city or area of around 100 km radius at speed between 56kbps and 155 Mbps depending on the technology used such as the internet or leased lines.

Wide Area Network

It is connected with all over the world in which also known as long haul networks, operate over the entire world with speeds in the range of 9.6kbps to 156 Mbps.