DIGITAL LIBRARY : CLASS - VIII ( Chapter

CHAPTER-1

Networking Basics

Computer network

A computer network is a group of computers that use a set of common communication protocols over digital interconnections for the purpose of sharing resources located on or provided by the network nodes. The interconnections between nodes are formed from a broad spectrum of telecommunication network technologies, based on physically wired, optical, and wireless radio-frequency methods that may be arranged in a variety of network topologies.

A computer network is an inter-connection of two or more computer is such a way they can communicate with each other and share data and hardware resource.

Need and Importance of a Network

Here are some of the advantages offered by the networking of computers.

1. Data Transfer: A networked allows easier, faster and reliable transfer of data file (like Document, image, video and audio etc) from one computer to the other computer. Some special communication software ( Like google Talk and Share All etc) help in faster and reliable exchange of messages between network users at zero cost.

2. Hardware & Software Sharing: The hardware devices (like Hard disk, CD drive, Scanner, Printer and USB Device etc) attached to one computer in a network can be shared by all other computers in that network. A network also allows sharing of software.

3. Money Saver: A network allows sharing of hardware and software, it saves an amount that would otherwise be spent on buying separate hardware and software for each computer.

4. Remote Computer: The Network allows access to information stored on remote computers. This enable us to do number of things like booking airline, Railway, Bus, Movie and event ticket booking, hotel booking, payment of utility bills etc sitting on the computer in our home.

5. Security: Password protection on important file and program so only authorized users accessed the file and program.

Type of Network

Based on the geographical area they cover, network can be classified into three main types-

· Local Area Network (LANs)

· Metropolitan Area Networks (MANs)

· Wide Area Network (WANs)

Ø Local Area Network:

A Local Area Network (LAN) is a computer network that interconnects computers within a limited area such as a residence, school, laboratory, university campus or office building.

Ø Metropolitan Area Networks (MANs):

A Metropolitan Area Network (MAN) is a computer network that interconnects users with computer resources in a geographic region of the size of a metropolitan area. The term MAN is applied to the interconnection of local area networks (LANs) in a city into a single larger network which may then also offer efficient connection to a wide area network. The term is also used to describe the interconnection of several local area networks in a metropolitan area through the use of point-to-point connections between them .

Ø Wide Area Network (WANs):

A Wide Area Network (WAN) is a telecommunications network that extends over a large geographical area for the primary purpose of computer networking. Wide area networks are often established with leased telecommunication circuits.

Some Common Network Devices

· Local Area network Card (LAN Card)

· Hub and Switch

· Router

· Modem

Local Area network Card (LAN Card)

A Local Area Network Card allows a computer to connect to a network through a wired or wireless medium. Each computer in a network must have a card inside it. In fact, any device that is to be connected to a network like printer, scanner and so on must have a LAN card inside it.

Hub and Switch

Hub and Switch are ‘boxes’ to which computers, printer and other network device connected. Their function is to direct information around the network, facilitating communication between all the connected devices. A switch is often termed as smart hub. Hubs are outdated and are seldom used for new installations.

Router

A router is a networking device that forwards data packets between computer networks. Routers perform the traffic directing functions on the Internet. Data sent through the internet, such as a web page or email, is in the form of data packets.

Modem

A modem stand for "modulator-demodulator" – is a hardware device that converts data into a format suitable for a transmission medium so that it can be transmitted from one computer to another. A modem modulates one or more carrier wave signals to encode digital information for transmission and demodulates signals to decode the transmitted information.

Wireless Technologies

Very Soon you will be working in a wireless environment, where you will see the appliances lying but not a single wire. In fact, these are invisibly inter-linked using wireless technology and can interect with each other to share data and other control signals.

Let us learn about the popular wireless technologies, which are becoming popular day by day.

Device	Expalination	Images
Infrared Communication	In infrared communication for transmission and reception of signals, devices must lie close to each other (usually called a line-of-sight distance) to be able to work.
Bluetooth	Bluetooth technology uses short-range radio links to connect and replace the necessity of cables.
WiFi	Wifi, stands for Wireless Fidelity, is the term for a high-speed wirless access technology. It uses long range radio waves, hence the distance covered is more.
WiMAX	WiMAX operates on the same general principal as WiFi but will cover a radius of approximately 50 kms with wireless access.
GPRS	The General packet Radiio Service (GPRS) is a new non-voice service that allows Mobile Phone to connect to the Internet for sending and receiving data.
GPS	The Global Positioning System(GPS) is based on satellites which allows a user with a receiver to detemine the precise coordinatetes for his location on the earth’s surface.
3G	3G network enable network opoerators to offer users a wider range of more advanced service like wide-area wireless voice telephony, video calls and brodband wireless data, all in a mobile environment.
Cloud Computing	Cloud Computing is Internet computing, where “Cloud” is the term used for the Internet. It is an Internet-based computing, whereby shared resources, software, and information areprovided to computers and other devices on demand.
Hot-Spot	HOT-SPOTs are generally available at convenient public location such as airports, hotels or resturants. Using either a laptop or a handheld PDA that is WiFi enabled, you can access the Internet at a very High speed.