3.0 : COMPUTER NETWORK AND COMMUNICATION
COMPUTER NETWORK ?
A computer network is a system of interconnected computers and peripheral devices. For example, it may connect computers, printers, scanners and cameras.
Using hardware and software, these interconnected computing devices can communicate with each other through defined rules of data communications. In a network, computers can exchange and share information and resources. A computer network may operate on wired connections or wireless connections.
When two or more networks are linked or connected and are able to communicate with one another using suitable hardware and software, it is called an internetwork.
COMMUNICATIONS ?
Communications is about the transfer of information from a sender, across a distance, to a receiver.Using electricity, radio waves or light, information and data in the form of codes are transmitted through a physical medium such as wire, cable, or even the atmosphere.
We transmit information or data by using two types of signals, namely analog and digital. Computers communicate with digital signals. The older forms of communications technology, such as telephones and radios, use analog signals.
Therefore, in order to make communications possible from computers, across telephones and radios and back to computers and other digital devices again, there must be a signal translator, which we call – a modem.
The modem, which is short for modulator or demodulator, converts digital signals into analog and back again into digital signals for information to move across the telephone line.
In order for a network to properly operate, two categories of network communications components are needed; ‘Hardware’ and ‘Software’. Computers, hub, switch, router, network interface cards and both wired and wireless communications media fall under the ‘Hardware’ category. Operating systems and applications fall under the ‘Software’ category.
NETWORKING DEVICES ?
- NIC (Network Interface Card)
- Wireless Network Interface Card
- Internal Modem
- External Modem
- Hub
- Switch
- Router
- Wireless AP (Access Point)
TYPES OF NETWORKS
Three types of networks:
LAN - the email system within the school lab in SMK KL MAN - the email system within KL city WAN - the email system between KL and
A client/server network is a network in which the shared files and applications are stored in the server but network users (clients) can still store files on their individual PCs.
A server is a computer that shares information and resources with other computers on a network. A client is a computer which requests services or files from a server computer.
CLIENT ?
The client computers are computers on the network that rely on the server for its resources and services.
Client computers send requests to a server for resources or services to perform their job. For example, a client computer can send a request asking permission to use the printer attached to the server, to print a document.
Usually a client computer has to log onto the network using a user name and password to use the server’s resources and services.
SERVER ?
A server is sometimes called a host computer. A server is a computer that provides services to other computers called clients. A server controls access to the hardware, software and other resources on the network.
It provides a centralised storage area for programs, data and information.
PEER-TO-PEER NETWORK ?
Peer-to-peer or P2P network is a network with all the nodes acting as both servers and clients. A PC can access files located on another PC and can also provide files to other PCs.
All computers in the peer-to-peer network has equal responsibilities and capabilities to use the resources available on the network.
With peer-to-peer network, no server is needed; each computer in the network is called a peer.