Basic knowledge about Computer Networking

Data, Information and Data Communication:

Data : Data is raw, unorganized facts that need to be processed.

When data is processed, organized, structured or presented in a given context so as to make it useful, it is called Information.

The process of transferring data from one location to another is called Data Communication. In this process, data is transmitted from one location to another by using transmission media.

Components of Data Communication……

1- Message

The message is the information or data that is to be communicated. It may consist of text, numbers, pictures, sounds, videos or any combination of these.

2- Sender
A device that is used for sending messages (or data) is called sender or transmitter or source.  E.g. computer, telephone, or a video camera etc.


3- Receiver
A device that is used for receiving messages is called receiver or sink.  E.g.  computer, telephone set, printer, or a fax machine etc.

4- Medium
The path through which data is transmitted (or sent) from one location to another is called transmission medium or communication channel. It may be a wire, or fiber optic cable, or telephone line etc.

5- Encoder and Decoder
In communication systems, computers are used for senders and receivers. A computer works with digital signals. The communication channels usually use analog signals. The encoder and decoder are used in communication systems to convert signals from one form to another.

Encoder: The encoder is an electronic device. It receives data from sender in the form of digital signals. It converts digital signals into a form that can be transmitted through transmission medium.

Decoder: The decoder is an electronic device. It receives data from  transmission medium. It converts encoded signals (i.e. analog signals) into digital form.

Computer Network:

When you have two or more computers connected to each other, you have a network.

purpose : to enable the sharing of files and information between multiple systems.

The Internet could be described as a global network of networks.

Computer networks can be connected through cables, such as Ethernet cables or phone lines, or wirelessly, using wireless networking cards that send and receive data through the air.

 Types of computer network:

local-area networks (LANs): The computers are geographically close together (that is, in the same building).

  e.g. A networked office building, school, or home usually contains a single LAN

wide-area networks (WANs): The computers are farther apart and are connected by telephone lines or radio waves.

  e.g. The Internet is the largest WAN, spanning the Earth.

     A WAN is a geographically-dispersed collection of LANs. A network device called a router connects LANs to a WAN.

metropolitan-area networks (MANs): A data network designed for a town or city. This network spans a physical area larger than a LAN but smaller than a WAN.

campus-area networks (CANs): The computers are within a limited geographic area, such as a campus or military base.  This network spans multiple LANs but smaller than a MAN.

home-area networks (HANs): A network contained within a user's home that connects a person's digital devices.

wireless local area network (WLANs): a LAN based on WiFi wireless network technology.

 

SAN - Storage Area Network, System Area Network, Server Area Network, or sometimes Small Area Network

CAN - Campus Area Network, Controller Area Network, or sometimes Cluster Area Network

PAN - Personal Area Network

DAN - Desk Area Network