data communication and it enabled services - 3

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Data Communication andData Communication and

IT Enabled ServicesIT Enabled Services

A N K Prasanna Anjaneyulu



ContentsContents

IntroductionSoftware Functions

Software Categories

Data Processing

Data Transmission

Computer Network

IT Enabled Services



IntroductionIntroduction

Set of Instructions – RoutineComplete set of instructions –

Program

Instructions that direct theoperation of the hardware –Software



Software FunctionsSoftware Functions

Manage the Computer Resourcesof organization

Provide tools for human beings to

take advantage of theseresources

Act as an intermediary between

organizations and storedinformation



Software CategoriesSoftware Categories

System Software◦ Operating System

◦ Language Translations

◦ Utility Programs◦ Communication Software

Application Software



Data ProcessingData Processing

Data & InformationData Sequence

◦ Bit - Byte – Character – Field –

Record – Block – File – DatabaseData processing

◦ Read, sort, collate, compare, store

etc. Transaction Processing



Data Processing ModesData Processing Modes

Batch processingOn-Line Processing System

◦ Verification of Data immediately but

processing may be laterOn-Line Real-time Processing

System

◦ Verification of Data and processing isimmediate

Distributed Processing



Other Processing ModesOther Processing Modes

Time SharingMulti Programming

Multi processing



Data TransmissionData Transmission

Data Communication consists of Data processing and datatransmission

◦ Transmitter◦ Converter at Transmitting end

◦ Transmission Channel/ Carrier

◦

Converter at the receiving End◦ Receiver



Transmission Signals Transmission Signals

Analog Signal◦ Amplitude (Strength of Signal)

◦ Phase (Direction of ‘flow’ of the

signal in a cycle time)◦ Frequency (no. of times the wave

form is repeated during a specificinterval)

Digital Signal



Communication ChannelsCommunication Channels

Physical Connection Lines◦ Twisted pair of copper wires

◦ Coaxial Cables

◦ Optical FibreMicro Wave Lines

◦ Line of Sight

◦ Radio / Wireless transmission waves◦ Satellite



Characteristics of Characteristics of

Communication LinesCommunication Lines Transmission speedBandwidth

Transmission Modes

◦ Synchronous

◦ Asynchronou

Transmission Direction

◦ Simplex

◦ Half-Duplex

◦ Duplex



Communication Processor◦ Frond End Processors

◦ Concentrator

◦ Controller◦ Multiplexer

◦ Telecommunication Software



Computer NetworkComputer Network

A Computer Network consists of two or more autonomouscomputers that are

linked/connected together inorder to

◦ Share Resources

◦

Share Applications◦ Allows Electronic Communication

◦ Increase Productivity



Data CommunicationData Communication

Communication means sharing of Information. It may be Local or RemoteCommunication

Data Communication is the exchange of data between two devices via some form

of transmission mediumData Communication made up of five

components◦ Message◦ Sender◦ Receiver◦ Medium◦ ProtocolSyntaxSemantics

Timing



Classification of NetworksClassification of Networks

Categories of Networks◦ Local Area Network (LAN)◦ Metro Area Network (MAN)◦ Wide Area Network (WAN)

◦ internetNetworks can be classified based on

transmission technology◦ Broadcast Network / Multi Point

Packet Radio NetworkSatellite NetworkLAN

◦ Point-to-Point



Network TopologyNetwork Topology

Topology refers to the shape of anetwork or network’s layout

Types of Topologies

◦ Bus Topology

◦ Star Topology

◦ Ring Topology

◦ Tree Topology◦ Mesh Topology

◦ Cellular Topology



Topologies – Bus Topology Topologies – Bus Topology

In Bus Topology all devices areconnected to a central cable, called bus.

Each workstation connects to nextworkstation in a point-to-point fashion

Advantages◦ Installation is easy◦ Less cabling required◦ Connections are simple

Disadvantages◦ Used only in small networks◦ Single fault in cable stops all transmission◦ Fault Identification is difficult



Topologies - Star Topology Topologies - Star Topology

Star Topology uses a central hub throughwhich, all computers are connected.

Nodes communicate across the network bypassing data through the hub.

Advantages◦ Faults in the networks can be easily traced◦ Single computer failure does not affect network◦ Installation and configuration is easy

Disadvantages◦

Failure in the central hub brings entire networkto a halt◦ More cabling is required in comparison to tree

or bus topology because each node isconnected to the central hub



Topologies – Ring Topologies – Ring

Topology TopologyIn Ring Topology all devices are

connected to one another in theshape of a closed loopAdvantages

◦ Easy to install and modify the network◦ Fault isolation is simplified

Disadvantages◦ Adding or removing computers disrupts

the entire network◦ A break in the ring can stop the

transmission in the entire network◦ Expensive when compared to other

topologies◦ Finding fault is difficult



Topologies – Tree Topologies – Tree

Topology Topology Tree topology is a LAN topology in which

only one route exists between any twonodes in the network.

Tree topology is hybrid topology, similar tothe star topology but the nodes are

connected to secondary hubAdvantages

◦ Installation and configuration is easy◦ Faults in the network can be detected and

traced◦ Addition of secondary hub allows more devices

to be attached to the central hubDisadvantages

◦ Failure in the central hub brings the entirenetwork to a halt



Topologies – Mesh Topologies – Mesh

Topology TopologyDevices are connected with many

redundant interconnections betweennetwork nodes.Advantages

◦ Use of dedicated links eliminates trafficproblems

◦ Failure in one of the computers doesnot affect the entire network

◦ Privacy between computers ismaintained as messages travel alongdedicated path

Disadvantages◦ The amount of cabling required is high



Applications of NetworksApplications of Networks

Marketing and SalesFinancial ServicesManufacturingElectronic MessagingDirectory ServicesInformation ServicesElectronic Interchange

TeleconferencingCellular PhonesCable Television



IT Enabled ServicesIT Enabled Services

Business Process Outsourcing &Mgmt.

Call Centres

Medical TranscriptionLegal Databases (Judicial

System)

Digital Content DevelopmentGeographic/Global Information

System (GIS)

data communication and it enabled services - 3

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