Communication and Networking in computer system. Definition of Networking?

The term communication means sending or receiving information. When we communicate , we share information or data. A communication system can be defined as the collection of hardware and software that facilitates intersystem exchange of information between different devices.

It is the exchange of data between two devices using some form of transmission  media. It includes the transfer of data or information and the method of preservation of data during the transfer process. Data is transferred from one place to another in the form of signals. 

1.Digital Signal:- In this signal, data is transmitted in electronic form, i.e. binary digits(0 or 1).

2.Analog Signal:- In this signal, data is transmitted in the form of radio waves like in telephone line.

3.Hybrid Signal:- These signals have properties of both analog signal and digital signal.

In simplex channel, the flow of data is always in one direction , with no capability to support response in other direction. This communication is unidirectional. Only one of the communicating devices transmits information and the other can only receive it.

e.g. Radio, Television, Keyboard etc.

In Half-duplex channel the data can flow in both directions, but not at a same time. When one device transmits information, the other can only receives at that point of time.

e.g. Walkie-talkie etc.

In Full-duplex channel the flow of data is in both directions at a same time, i.e. both stations can transmit and receive information simultaneously.

e.g. Wireless handset📞 (mobile phone) etc.

Communication media of a network refer to the transmission media or the connecting media used in the network. It can be broadly defined as anything that can carry information from a source to destination. It refers to the physical media through which communication signals can be transmitted from one point to another point.

The data signal 📶 in guided media is bound by the cabling system that guides the data signal along a specific path. It consists of a cable composed of metals like copper , tin or silver etc.

Basically they are divided into three categories:-  

In this cable, wires are twisted together which are surrounded by an insulating material and an outer layer called jacket. One of the wires is used to carry signals to the receiver and the other is used only as a ground reference.

e.g. Local area networks use twisted pair cable.

It carries the signal of higher frequency data communication through the network. It has a single inner conductor that transmits electric signals and the outer conductor acts as a ground and is wrapped in a sheet of teflon or PVC. Co-axial cable is commonly used in transporting multi-channel television signals in cities.

e.g. Cable TV network etc.

Fibre optics cable is made up of glass or plastic and transmits signals in the form of light from a source at one end to another.

Optical fibres allow transmission over longer distance at higher bandwidth which is not affected by electromagnetic field. The speed of optical fibre is hundred of times faster than the Co-axial cables.

It is the transfer of information over a distance without the use of enhanced electrical conductors or wires. When the computers in a network are interconnected and data is transmitted through waves, then they are said to be connected through unguided media or wireless technology.

When two terminals communicate by using radio frequencies then such type of communication is called radio wave transmission. This transmission is also known as Radio Frequency(RF) transmission. These are omnidirectional. Radio waves are particularly those waves that propagate in the sky mode, can travel long distances..

Microwaves are electromagnetic waves having frequencies range from 0.3 to 300Ghz. Microwaves are unidirectional waves. Microwaves have a higher frequency than that of radio waves. Microwave is one of the fastest media for data transmission over communication channel. It is used in cellular network and television broadcasting.

Infrared waves are the high frequency waves that is used for short range communication. These waves do not pass through the solid objects. They are mainly used in TV remote, wireless speakers etc.

The communication across longer distances can be provided by combining radio frequency transmission with 🛰 satellites'. It works over a long distance and fast communication. It is used for communication to ships, vehicles, planes and handled terminals etc.

The Computer network links together via a combination of infrared signals, radio wave transmissions, telephone lines, television cables, and satellite links to connect with each other. Computer network protocols also includes the flow control, which keeps the data from a sender to a receiver with messages that says it has no time to process or capacity to store it, it gives an error control, which involves the transmission error detection and automatic resending of messages to correct these errors.