A network is a system which includes two or more entities e.g. Computers, Servers, Clients, Switches, Hubs, Routers and Peripherals etc., which allows sharing of resources (like Printers, CD’s and FAX) and information. A network also allows electronic communication between its connected devices. These devices can be connected by means of guided media (which includes all wired connections) or by some unguided media (which includes all wireless connections).

A Computer Network is a network which consists of more than one Computers or computing devices connected to each other (by means of some media) to share their resources or information. These devices may communicate through some guided or unguided media. The very first computer network was made in 1960. Below are some major milestones in the history of Computer Networks:

1950s Early networks of computers included the U.S. military radar system Semi-Automatic Ground Environment

1965 Western Electric introduced the first widely used telephone switch that implemented true computer control

Why we need to create Networks?

1 To share information in the form of data

2 To share resources like hardware and software

3 To centralize administration and support

4 To provide user, access to the files from any workstation

Devices used for creating Inter-networks

Hub
Switch
Router
Repeater
Bridge
Access point

Types of Networks

Networks of computers are further classified into two major types, depending upon their functions and sizes.

LAN (Local Area Network): A group of computers and network devices connected together which are physically close to each other, usually within the same building. The links are high speed and relatively inexpensive
WAN (Wide Area Network): A Network that connects several LAN’s. The technology is high speed and relatively expensive. The Internet is an example of a worldwide public WAN