What Is computer Network ?


Definition: A computer network is a set of nodes connected to each other via communication links for the purpose of sharing there resource or data. The main goal of computer network is the sharing of resources among various devices.

The definition having two key words 1) Nodes 2) Communication links

Nodes: Nodes can be a computer, printer or any other device capable for sending / receiving data generated by other nodes in the network. Example of nodes: Computers, Server, Printer, Security Camera, etc.

Communication links: a link is a communication channel that connects two or more devices for the purpose of data transmission. The link carries the information. A communication link can be wired link or wireless link.

fig 1.1 Types of links

Example of Wire link: Co-axial cable, Optical Fiber Cable.

Example of Wireless link : Air

First computer network is ARPANET (Advance Research Projects Agency Network).

fig 1.2 A sample of Computer Network

In the above figure, how many nodes or devices involved in a network?

In the above figure of computer network, printer is a node, desktop PC is a node, IP phone is a node, scanner, smart phone, laptop PC, router, Wi-Fi router, switches all are called nodes.

In reality all nodes in a network is divided into two types first is End Devices and second is Intermediate Nodes. Where laptop PC, PC, desktop PC, IP phone, smart phone are called end devices because these devices will be either the starting point of communication or the end point of the communication. And router, wi-fi router, switch, server are called intermediate devices. By using Intermediate devices we can easily send or receive data with in a network.

Features of Computer Network

There are number of features of computer network are listed below:

  1. Resource Sharing
  2. Communication Speed
  3. Backup
  4. Scalability
  5. Reliability
  6. Software and hardware sharing
  7. Security

All these features I’ll explain in my next post