NETWORK:
What is network?
Network is a collection of computers and devices interconnected by communications channels that facilitate communications and allows sharing of resources and information among interconnected devices
for example (PC, ROUTER, SWITCHES,MODEM,PRINTER,SCANNER ETC... )
TYPES OF NETWORKS
1) LAN
2) MAN
3) WAN
4) PAN
1)LAN
Local Area Network
it is a private network
it communicates with in kilometers
HUB IS USED IN LAN.(HUB: HYPER USAGE BRIDGE)
SWITCH IS ALSO USED IN LAN.
2)MAN
Metropolitan Area Network
it can been classified both public and private network
communicate with in many states.
Router is used in MAN NETWORK
for example cable tv network.
3)WAN
WIDE AREA NETWORK.
EXAMPLE INTERNET.
IT IS A COMBINATION OF BOTH LAN AND MAN NETWORK.
IT COMMUNICATE WITH THE WORLD
4)PAN
PERSONAL AREA NETWORK.
BLUE TOOTH COMMUNICATION.
DATA COMMUNICATION
We all are acquainted with some sorts of communication in our day to day life. For communication of information and messages we use telephone and postal communication systems. Similarly data and information from one computer system can be transmitted to other systems across geographical areas. Thus data transmission is the movement of information using some standard methods. These methods include electrical signals carried along a conductor, optical signals along an optical fibers and electromagnetic areas.
Suppose a manager has to write several letters to various clients. First he has to use his PC and Word Processing package to prepare his letter. If the PC is connected to all the client's PCs through networking, he can send the letters to all the clients within minutes. Thus irrespective of geographical areas, if PCs are connected through communication channel, the data and information, computer files and any other program can be transmitted to other computer systems within seconds. The modern form of communication like e-mail and Internet is possible only because of computer networking.
Basic Elements of a Communication System
1)SENDER
2)RECEIVER
3)TRANSMISSION MEDIUM
4)PROTOCOL. THESE ARE THE NECESSARY ELEMENTS FOR THE EFFECTIVE COMMUNICATION.
1. A sender (source) which creates the message to be transmitted. A medium that carries the message.
2. A device which receives the data (Or) the device which sends acknowledgment for the received data.
3.Transmission medium Communication of data achieved by the processing of signals.
4. protocol: set of rules to govern the data communication.
THREE MAJOR ELEMENTS TO DESIGN THE MAJOR PROTOCOL, they are
1.syntax
2.semantic
3.timing
1.syntax- format of the data.
2.semantic - individual meaning of the each and every bit in syntax
3.timing it defines, when where how to communicate.
