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8/8/2019 Communication Sustem in Infor Mation Management+Ok

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Data CommunicationData Communication


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Data CommunicationData Communication

Data communication is the exchange of

data between two devices via some form

of transmission medium .


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The effectiveness of a data

communication system depends on thethree Fundamental characteristics:

a) Delivery b) Accuracy c) Timeliness


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Delivery:-the System must deliver data to

the correct destination.


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Accuracy :-the system must deliver data

accurately.


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Timeliness:-The System must deliver

data in a timely manner.


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ComponentsComponents

A data communication system is made up

of five components

A) message b) sender c) receiver d)medium e) protocol


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Message: The message is the information

to be communicated. It can consist of text,number, pictures, sound or video.


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Sender:-The sender is the device thatsends the data message. It can be a

computer ,workstation, telephone handset,

video camera and so on.


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Receiver : The receiver is the device that

received the message. it can be acomputer, workstation ,telephone handset,

television and so on.


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Medium: The transmission medium is the

physical path by which a message travelfrom sender to receiver . It consist of

twisted pair wire, coaxial cable and radio

waves (satellite microwave).


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A protocol defines what is

communicated, how it is

communicated and when it iscommunicated.


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A protocol is a set of rules that govern

data communication .

it represents an agreement between the

communicating devices.


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NetworksNetworks

A networks is a set of devices connected

by media links.

A node can be a computer, printer or anyother device capable of sending/receiving

data generated by other nodes on the

network. The links connecting the devices

are often called communication channels.


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Network mediaNetwork media

With computer networks ,media refers to

the means used to link a networks node

together.


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Type of mediaType of media

1) wire-based media

2) wireless media


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wirewire--based mediabased media

In case of wire based media , data can be

communicate through wire.

For example pair wire( normal electricalwire), coaxial cable( this type of cable

used for cable television) etc.


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wireless mediawireless media

It use radio signals that travels through the

air for transmitting data.

For example satellites communication.


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Transmission ModeTransmission Mode

the term transmission mode is used to

define the direction of signal flow between

two linked devices.

Type transmission mode: 1) Simplex 2)

half duplex 3) full duplex.


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SimplexSimplex

In simplex mode ,the communication is

unidirectional , as on a one way direction.

Only one of the two station on a link can

transmit and other can only received.


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Half DuplexHalf Duplex

In half duplex mode ,each station can both

transmit and receive ,but not at the same

time. When one device is sending ,the

other can only receive.


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Full duplexFull duplex

In full duplex mode ,both station can

transmit and receive simultaneously.


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Types ofNetworkTypes ofNetwork

LAN (local Area Network)

WAN (Wide Area Network)

MAN (Metropolitan Area Network)


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LAN (local Area Network)LAN (local Area Network)

It is a data communication system

consisting of several devices such as

computer and printers.

this type of network contains computers

that are physically connected using

cables.


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Any network that exists within a single

building, or even a group of adjacentbuildings, is considered a LAN.


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WAN (Wide Area Network)WAN (Wide Area Network)

It is two or more LAN connected together,generally across a wide geographical

area.

For example WWW.


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MANMAN

It is a large scale network that connects

multiple LAN together.

For example ortel.


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TopologyTopology

The term topology refers to the way a

network is laid out, either physically or

logically.

Two or more devices connect to a link.


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Type of TopologyType of Topology1)1) MMesh Topology 2)Star Topology 3)Tree Topology 4)Busesh Topology 2)Star Topology 3)Tree Topology 4)Bus

Topology 5)Ring Topology 6) Hybrid TopologyTopology 5)Ring Topology 6) Hybrid Topology


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MMesh Topologyesh Topology

In a mesh topology ,every devices has a

dedicated point to point link to every other

devices.

The term dedicated means that the link

carries traffic only between the two

devices it connects.


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Mesh TopologyMesh Topology


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Advantage: 1) to eliminating the traffic

problems that can occur when links must

be shared by multiple devices. 2) It hasprivacy or security.


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Disadvantage: 1) The amount of cabling

and the number of i/o ports required. 2)More Expensive.


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Star topologyStar topology

In a star topology ,each device has a

dedicated point to point link only to a

central controller, usually called a hub.

The devices are not directly linked to each

other.


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Star topologyStar topology


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Advantage: 1) It is less expensive 2) if

one link fails other link are not fails. Disadvantage: 1) If central hub is fail the

other network will be fail.


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Ring topologyRing topology

In a ring topology ,each device has a

dedicated point to point line configuration

only with the two devices on either side of

it.


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Ring topologyRing topology


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Advantage: A signal is passed along the

ring in one direction ,from device todevice, until it reaches its destination.

Disadvantage: No hub required.


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Bus TopologyBus Topology

In bus topology ,each & every computer

are connected with a common cable.

It follow the multipoint line configuration.


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Bus topologyBus topology


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Advantage: 1) It is ease of installation.

2) if one computer will be fail othercomputer are not fail.

Disadvantage: 1) if main cable are fail

,the entire network will be fail.


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Tree TopologyTree Topology

A tree topology is a variation of a star.

Computer in a tree are linked to a central

hub that controls the traffic to the network.

Not every device plugs directly into thecentral hub.


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The majority of devices connect to a

secondary hub that is connected to thecentral hub.

The central hub in the tree is an active

hub.


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Tree TopologyTree Topology


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Advantage & disadvantage of a tree

topology are generally the same as startopology.

Good example of tree topology can be

seen in cable TV technology.


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Hybrid TopologyHybrid Topology

The combination of bus topology ,star

topology, ring topology, mesh topology,

tree topology are know as hybrid

topology.


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Hybrid TopologyHybrid Topology


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VideoconferencingVideoconferencing

It enables real-time communication over a

distance by allowing people at two or more

sites to communicate with each other by

seeing a video picture of the people at the

other sites.

Each site has one or more cameras,

microphones, loudspeakers and monitor.


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InternetInternet

Internet is an inter-connection between

several computers of different types

belonging to various networks all over the

globe.

It is a network of network.


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IntranetIntranet

An intranet resides completely within the

companys internal network and is

accessible only to people that are

members of the same company .


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ClientClient server Modelserver Model

Client-A client is a program running on the

local machine requesting service from a

server.

Server- A server is a program running on

the remote machine providing service to

the clients.


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DNS(Domain Name systemDNS(Domain Name system))

To identify an entity ,TCP/IP protocols use the IP

Address, which prefer to use names instead of

Addresses.


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FTPFTP

FTP is the standard mechanism provided by

TCP/IP for copying a file from one host to

another.

Transferring files from one computer to anotheris one of the most common tasks expected from

a networking or internetworking environment.


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HTTPHTTP

The HTTP is a protocol used mainly to access

data on the WWW. The protocol transfers data

in the form of plain text , hypertext, audio and

video. It is rapid jumps from one document to another.


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URL(uniform Resource LocatorURL(uniform Resource Locator))

A client that wants to access a document

needs an address. To facilitate the access

of documents distributed throughout the

world ,HTTP uses the concept of locators.

URL is a standard for specifying any kind

of information on the Internet.

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