Class VIII Chapter 1 Networking Concept
Network: A computer network can be defined as a group of computers and other peripheral devices that are linked together for the purpose of sharing data and resources. With the help of network we can do following things.
We can share files with other computer on the network. We can share resources such as printers, hard disk etc. We can share application software.
Network allows electronic communication (such as e-mail, messaging etc.) For eg if one computer is having printer attached to it, then all computers in trhat network can access the printer and use it for printing. No separate printer is required for each computer.
Each computer in a network is called node. They can be connected by cables, telephone lines, radio waves etc.
Advantages of Networking:
Better use of storage. We can have bigger hard disk in the server instead of separate hard disk on each computer. Cost will be reduced.
We can keep back up of files at one place.
Cost will be reduced, as one printer can be shared by many. Up gradation of software is to be done at single place only. By sharing soft copy we can avoid duplication of data. We can deliver soft copy throughout the world very fast. Networking components:
To established wired networking in a group of computers, we require the additional components are called networking components. These are the major parts which are needed to install software. Some important network components are NIC, Switch, Cables, Hub, Router and Modem (depending on the type of network that we need to install), for example wireless network doesn’t require a cable.
NIC : Network Interface Card. It is a hardware component used to connect a computer on the network.
Networking Cable: network uses twisted pair cable and Rj-45 Connector (like used in telephone wire) is crimped at both ends of the cable.
Hub: we cannot directly connect the computers together, we need an interface. Now hubs are obsolete, we are using switch.
Switch: it is a hardware device that connects multiple devices on a computer network. It is more advanced than Hub.
Basically, the hub/switch is box with a set of RJ-45 ports. Each Computer on a network is connected to the hub/switch via cables.
To establish Wireless Networking We require Following components:
Wireless Network Cards: most laptops computers comes with wireless network card. Radio signals are used for transferring data.
Routers: these are used in wireless networking instead of hubs/switches. Types of Network:
Network can be classified on the basis of their size, complexity and geographical area covered by them. According to geographical area 4 types of network are there.
1) PAN 2) LAN 3) MAN 4) WAN
1) PAN:- Personal Area Network. It is mainly created for an individual person. PAN is used for connecting the computer devices of personal use like desk top, laptop, cell phone etc. It is typically with a range of 10 meters. Eg. In home, small office etc.
2) LAN:- Local Area Network is group of computers connected to each other in small area like school building , offices, two different departments in a building etc. Data transmission speed is high about 1000 Mbps (Mega bits per second). Transmission errors are less as it covers short distance.
3) MAN:-Metropolitan Area Network covers large area than LAN but smaller than WAN, like we can connect two or more LANs with telephone lines. It covers a distance approx 10 km and 100 km. For eg network of cable television, local branches of a bank, in university etc.
4) WAN:-It covers large geographical area such as a network within a city, states, countries all around the world. It often uses leased telecommunication lines (telephone, telegraph, radio, microwave towers, fiber optics, satellite etc.)Data transmission speed is about 150 Mbps due to large distance to be covered.
eg. Internet, Intranet, ATM facility etc.
Network Architecture:
It is the design of a computer network. It is of two types.
1) Client -Server Network:-A computer network in which one centralized, powerful computer (called Server) is a hub to which many less powerful workstations (called clients) are connected.
Clients:-These are the computers which requests services like data access, storage etc. from the Server.
Server:- A server is a computer that provided services to the clients and controls access to the hardware, software and other resources.
2) Peer- to- Peer Network:- In this network no centralized computer is there. All computers are powerful and equally capable are connected together to use the resources available on the network. Each computer can act as client as well server.
Network Security:- It means protecting data and resources from any unauthorized access, hacking and misuse. It includes both hardware and software technologies. Two levels of network security are as follows: 1) Login security:- By giving a login name and password.
2) Right security:- Rights can be given like Read-only access( means only read is allowed, no changes can be made to data) , Read-Write access (means reading as well as changes are allowed) or no access ( neither ca read or write).
Some Important terms
Intranet: It is a private network operated by a company or organization, which uses internet technology. It is restricted to an organization.
Extranet:- It allows limited access to the non- members of an organization.
Internet:- It generally allows everyone to access all network access. Bluetooth:- It is wireless technology using radio waves instead of wires
or cables to interconnect mobile phone, computers, printers etc.
Protocols:- these are set of rules which determine how data should be transferred on network, compressed and presented on the screen. Wireless networking:- A network without wires or cables.
Wi-Fi:- It is wireless networking that allows devices to communicate without cables or wires. It was developed for mobile computer devices like laptops etc. It uses radio waves to provide wireless high speed Internet and network connections.
WAP: Wireless Access Point is a device that connects wireless communication devices to form a wireless network.
