Networking Fundamental

Network Definition:

A network is a set of devices often referred to as nodes connected by media links. A node can be a computer, printer or any other device capable of sending or receiving data generated by other nodes on the network. The basic aim of networking is to be able to exchange data such as text, audio and video from one point to another in the world.

Basic communication model

The fundamental purpose of a communication system is the exchange of data between two points of parties. Depending upon the basic communication model, the figure given below shows one particular example, which establishes communication between a workstation and a server over a public telephone network.

The above figure can be described as under.

i) Source:- This device generates the data to be transmitted. Two examples can be telephone and personal computers.

ii) Transmitter:- A transmitter transforms and encodes the information in such a manner so as to produce electromagnetic waves or signals. These electromagnetic signals can be transmitted across some sort of transmission systems.

iii) Transmission System:- A transmission system can be a single transmission line or a complex network connecting source and destination.

iv) Receiver:- The receiver accepts the signal from the transmission system and converts it into a form which can be handled by the destination device.

v) Destination:- A destination takes the incoming data from the receiver.

Introduction to computer networks

A computer Network is a collection of two or more computer and peripheral device(the network components) connected by communication links that allow the network components to work together which may be located at different location or within same office. The network performs the following operations.

Sharing files and data
Sharing resources
Sharing programs
Communication
Backup

Types of computer network: According to distance covered by a network, or from geographical point of view, network is classified into three classes.

Local Area Network(LAN): The computer network system that are confined within local area such as a single room, inside a building or buildings, complex, campus area etc. known as LAN. It a Local Area Network(LAN) is used to connect a variety of computers over a limited geographical

Advantages / Features of LAN:

i) Data transmission rate is fast compared to MAN and WAN, which is about 100 Mbps or even more.

ii) Installation of computer in a network is very simple.

iii) It provides high security of data.

iv) Dissimilar types of systems can easily be interconnected with the computers.

Metropolitan Area Network (MAN): It is used to connect computers that cover an entire city. It generally doesn’t exceed more than 100 Km. This types of network consist of both bound and unbound media. It comprises of dissimilar system and computers with dissimilar operating system. It is relatively slow compared to LAN but faster than WAN.

Advantages / Features of MAN:

i) It covers larger geographical area compared to LAN.

ii) Dissimilar system can be integrated.

iii) Supports both bound and unbound media.

iv) It is very good in hosting FTP sites especially for internet.

Wide Area Network (WAN): When computers are connected globally using both bound and unbound media, then we call it a WAN. The rate of transmission of data is relatively slow below 1 Mbps. WAN are characterized by the fact that they are owned by different organizations. There is no central controlling system for WAN. WAN generally uses private satellites to connect large number of computers over a large geographical area. WAN is simply a LAN of LAN’s where different types of networks are connected.

Advantages / Features of WAN:

i) It supports dissimilar transmission media.

ii) It supports all types of hardware that vary from network to network.

iii) E-business (E-commerce) has been possible just because of WAN.

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