Information and Communication Technology (ICT)

ICT

§ Forms of technology that are used to transmit, process, store, create, display, share or exchange information by electronic means.

§ It includes not only traditional technologies like radio and television, but also modern ones like cellular phones, computer and network, hardware and software, satellite systems and so on, as well as the various services and applications associated with them, such as videoconferencing.

Computer Network

§ A computer network is a system in which multiple computers are connected to each other to share information and resources.

§ Benefits-§ Communication.§ Resource Utilization.

§ Types-§ PAN§ LAN§ MAN§ WAN

PAN

§ PAN stands for Personal Area Network.

§ It refers to the interconnection of information technology devices or gadgets within the environment of an individual user (typically within 10 meters).

§ These interconnected devices might include laptop computers, PDAs (personal digital assistant), cellphones, printers, PCs or other wearable computer devices.

LAN

§ LAN stands for Local Area Network.

§ LAN is a computer network that occupies relatively a very small area.

§ Usually a LAN is limited to a single room or building.

§ Many of the middle to large-sized School today use LANs.

§ A WLAN is a Local Area Network that is connected wirelessly.

MAN

§ MAN stands for Metropolitan Area Network.

§ A metropolitan area network (MAN) is similar to a local area network (LAN) but spans an entire city or campus.

§ MANs are usually formed by connecting multiple LANs. Thus, MANs are larger than LANs but smaller than wide area networks (WAN).

§ MANs are extremely efficient and provide fast communication via high-speed carriers, such as fiber optic cables.

WAN

§ WAN stands for Wide Area Network.

§ A WAN or Wide Area Network is a group of widely dispersed computers that are connected together.

§ These could be across the same town or across a country or even across the world.

§ Apart from distance, the other feature that distinguishes a WAN from LAN and MAN is that the WAN would make use of a range of communication technologies such as telephone, microwave and satellite links.

§ Most WANs are made from several LANs and MANs connected together.

Wired network

§ In computer science terminology, the term "wired" is used to differentiate between wireless connections and those that involve cables.

§ Wired networks use Ethernet cables to transfer data between connected PCs.

§ It is considered difficult and expensive to set up a wired network.

§ However, they are faster and more secure than wireless networks.

Wireless network

§ Wireless networks are computer networks that are not connected by cables of any kind.

§ The use of a wireless network enables enterprises to avoid the costly process of introducing cables into buildings or as a connection between different equipment locations.

§ Users can access network from anywhere within range.

§ Less secure and slow than wired network.

Internet

§ The Internet is the collection of all computers across the world which can access each other in some way.

§ The links between computers might include telephone, fiberoptic cable, radio, microwave or satellite.

§ Today tens of millions of computers are able to access each other.

§ The Internet has no central organisation which controls its use.

WWW

§ The World Wide Web or WWW is a part of the Internet.

§ The WWW consists of all the sites that can be accessed using a web browser such as Mozilla, Internet Explorer, Opera or Google Chrome.

§ Generally, everyone thinks that the internet and Web World Wide Web (WWW) are same, but it is false.

§ The web is a software application or services that run on the internet .

Networking devices

§ Networking devices are components used to connect computers or other electronic devices together so that they can share files or resources.

§ NIC (Network Interface card)§ Repeater§ Modem§ Hub§ Bridge§ Switch§ Router§ Gateway

NIC

§ NICs are hardware devices that connect a computer with the network.

§ They are installed on the mother board.

§ They are responsible for developing a physical connection between the network and the computer.

§ Computer data is translated into electrical signals send to the network via NICs.

§ It has specific MAC address.

Repeater

§ Network repeaters regenerate incoming electrical, wireless or optical signals.

§ Data transmissions can only span a limited distance before the quality of the signal degrades.

§ Repeaters attempt to preserve signal integrity and extend the distance over which data can safely travel.

§ Repeaters remove the unwanted noise in an incoming signal as well.

Modem

§ The word "modem" comes from "modulator- demodulator“.§ Modulation: digital information into analog signals.§ Demodulation: analog signals back into useful digital

information

§ A modem is a device that enables a computer to transmit data over, for example, telephone or cable lines.

§ Computer information is stored digitally, whereas information transmitted over telephone lines is transmitted in the form of analog waves.

§ A modem converts between these two forms.

Hub

§ Hub connects networking devices physically together.

§ Hubs are fundamentally used in networks that use twisted pair cabling to connect devices.

§ They are designed to transmit the packets to the other appended devices without altering any of the transmitted packets received.

§ They act as pathways to direct electrical signals to travel along.

Switch

§ Just as in hub, devices in switches are connected to them through twisted pair cabling.

§ But the difference shows up in the manner both the devices; hub and a switch treat the data they receive.

§ Hub works by sending the data to all the ports on the device whereas a switch transfers it only to that port which is connected to the destination device.

§ A switch does so by having an in-built learning of the MAC address of the devices connected to it.

Bridge

§ A bridge is a computer networking device that builds the connection with the other bridge networks which use the same protocol.

§ It connects the different networks together and develops communication between them.

§ It connects two local-area networks; two physical LANs into larger logical LAN or two segments of the same LAN that use the same protocol.

Router

§ Routers are network layer devices.

§ They process logical addressing information in the Network header of a packet such as IP Addresses.

§ Router is used to create larger complex networks by complex traffic routing.

§ It has the ability to connect dissimilar LANs on the same protocol.

§ A router primarily comprises of a hardware device or a system of the computer which has more than one network interface and routing software.

Router

§ Routers are network layer devices.

§ They process logical addressing information in the Network header of a packet such as IP Addresses.

§ Router is used to create larger complex networks by complex traffic routing.

§ It has the ability to connect dissimilar LANs on the same protocol.

§ A router primarily comprises of a hardware device or a system of the computer which has more than one network interface and routing software.

Gateway

§ Gateway is a device which is used to connect multiple networks and passes packets from one packet to the other network.

§ Acting as the ‘gateway’ between different networking systems or computer programs, a gateway is a device which forms a link between them.

§ It allows the computer programs, either on the same computer or on different computers to share information across the network through protocols.

§ A router is also a gateway, since it interprets data from one network protocol to another.