DATA COMM CHAPTER 4.pptx

7/27/2019 DATA COMM CHAPTER 4.pptx

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Prepared by :

Puan Nora Binti Abas

Edited by:

Noor Azura Osman

JKE, POLIMAS (2013)

CHAPTER 4DATA COMMUNICATION


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OBJECTIVE

At the end of the unit you will be able to:

Understand the principle of datacommunication.

Know the history of data communication.

Understand data communication circuitarrangement.

Know network topology.

Understand network classification.


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PRINCIPLE OF DATA COMMUNICATION

Not to be confused withtelecommunication

Any process that permitsthe passage from a senderto one or more receivers ofinformation of any nature,delivered in any easy to

use form by anyelectromagnetic system.

Data communication-

Defined as a subset oftelecommunication involving the

transmission of data to and fromcomputers and components ofcomputer systems.

More specifically data communication istransmitted via mediums such as wires,coaxial cables, fiber optics, or radiated

electromagnetic waves such asbroadcast radio, infrared light,

microwaves, and satellites.

Information that has been

processed, organized, andstored is call data.

Data communications simply meanthe transferring of digital information(usually in binary form) between twoor more points (terminals). At both the

source and destination, data are indigital form; however, during

transmission, they can be in digital oranalog form.


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APPLICATION OF DATA COMMUNICATION

Electronic Mail (e-mail or Email).

Videotext. Teleconferencing.

AutomatedBanking

Machines.

Electronic BulletinBoards (BBS -Bulletin Board

Services).


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SYNCHRONOUS DIGITAL HIERARCHY

SDH

This synchronoussystem has been

speciallydesigned in

order to providea simple and

flexible networkinfrastructure

The SDH is an internationalstandard that is highly popular

and used for its high speed datatransfer of the

telecommunication and digital

signals.


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PLESIOCHRONOUS DIGITAL HIERARCHY

Digital hierarchy is a

popular technology that iswidely used in the networksof telecommunication in order

to transport the hugeamounts of data over thedigital equipment fortransportation

Ex:

microwave radio or fiber

optic systems.PDH

These groups of signals

can be transmitted as an

electrical signal over a

coaxial cable, as radio

signals, or optically via

fiber-optic systems


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Uplink

Downlink

Transponder

Earth Station Microwave


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Fibre Optic


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Coaxial cable

Consists of an inner

conductor wire

surrounded by insulation,

called the dielectric

The dielectric issurrounded by a

conductive shield, which

is surrounded by a non-

conductive jacket. Coaxial

cable has better datatransmission rate than

twisted pair


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No. Features SDH PDH

1. Interleaving Byte Interleaving Bit Interleaving

2. Management capability of powerful management Limited management available

3. Standard digital format world standard in digital format No world standard on digital format(three incompatible regional standards -European, North American and Japanese)

4. Optical interfaces optical Interfaces No world standard for optical interfaces.Networking is impossible at the opticallevel.

5. Multiplexing Structure Flexible synchronous multiplexing

structure .

Rigid asynchronous multiplexing structure.

6. Cost cost effective and easy traffic crossconnection capacity and add and dropfacility

Cost-effective support for access networks

COMPARISON BETWEEN SDH AND PDH


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The History Of Data Communication

.

HISTORY OF DATA COMMUNICATION


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Samuel Morse's 1837

exhibition of a telegraph system.

General Telecom, LLC

points to a telegraph patent .

Great Western Railway

telegraph service.

EARLY HISTORY


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Alexander Graham Bell, 1876introduced the telephone.

Guglielmo Marconi, 1895

developments in communication technology .

1947

Bell Labs introduced the transistor, a device that found integration insubsequent electronic products.

1958

launching of a communications-oriented satellite, and the first facsimiletransmission over standard telephone lines occurred four years later.

HISTORY OF TELECOMMUNICATION


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1962; First fax transmission in themodulation of data into sound fortransmission across telephonelines.

20th century; Modem technologycontinued to carry slower datatraffic.

1969; Development of InternetProtocol (IP) marked a significantmilestone in data communication.

By 1991, more than 1 million servershad used online using Internet

Protocol technology.

COMPUTER CONNECTION


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1921,

the first commercial radio voices broadcast, acommunication channel that transmitted data inthe form of modulated radio waves and policedispatchers had adopted the technology .

1974,

the Federal Communication Commission (FCC)began allocating wireless spectrums for wirelesscommunication, and wireless companies beganintegrating radio packet data.

WIRELESS


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DATA COMMUNICATION CIRCUIT ARRANGEMENT


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Primary source -usually a

mainframecomputer with itsown set of localterminals and

peripheralequipment.

transmissionmedium - digital

information istransferred.

Data terminalequipment (DTE) -

the interfaceequipment used at

the station(between the host

and modem).

Datacommunicationsequipment (DCE) -

the equipment thatconverts digitalsignals to the

analog signals andinterfaces the data

terminal.

DATA COMMUNICATION CIRCUIT ARRANGEMENT


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Sender transmitted

Data is transmitted, on a single channel, one bit at a timeone after another

- Much faster than parallel because of way bits processed(e.g. USB and SATA drives)

Receiver received

Serial Transmission

101 0 0 1 1 0


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Receiverreceive

d

-each bit has its own piece of wire along which it travels

- often used to send data to a printer

Parallel Transmission

Sen

dertransm

itted

All bits are sent simultaneously

1

0

0

1

1

0

01


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Why Not use Parallel Instead of serial?

Due to inconsistencies on channelsdata arrives at different times

Because of the way it is transmittedpacket switching cannot be used

The above two points makes parallelslower than serial and requires higher

bandwidth.

Parallel transmissions are rarely usedanymore


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Synchronous Transmissionall data sent at once and no packet switching

Asynchronous TransmissionUses stop/ start bits

most common type of serial data transfer

Allows packet switching

Allows sharing of bandwidth (i.e. talk on phone

while another person is using internet)

Synchronous VS

AsynchronousTransmissions


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- simplex: One direction only

Transmission Direction


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Half Duplex Transmission

half duplex:

Both directions

but only onedirection at a

time


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Full Duplex Transmission

fullduplex:

send andreceive

bothdirectionsat once


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There are three basicconfigurations used to

connect computers theyare the

Bus

Ring

Star

NETWORK TOPOLOGIES


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Uses an empty data packet

called a token and a special

protocol called token ring.

Packets travel around the ring

in a clockwise direction.

Clients require an empty

token to transmit data.

Advantages

- no collisions because all

data travels in same direction.

Disadvantages

- fails if an individual node in

the network fails

Ring
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A bus is a form of Ethernet. Nodes linked by a cable known as the bus. Bus transmits in

both directions and uses CSMA/CD protocol

BUS TOPOLOGY

Advantages

- Easy to set up and maintain

failure of one node does not affect

network

Disadvantages

-Higher rate of data collision thanwith a bus network

-fails if there is any damage to the

bus


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All data is sent from one client

to another through the server.

Advantages

- If one client fails no other

clients are affected.

Disadvantages- If central file server fails the

network fails.

Star


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Network Hardware


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A network is a number of computers andperipheral devices connected together so

as to be able to communicate (i.e. transfer

data)Each device in a network is called a

node.

Terminals are data entry points whichcan also display.

What is a Network?


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LAN a network that connects computers in a limitedgeographical area.

MAN a backbone that connects LANs in a metropolitanarea such as a city and handles the bulk of communications

activity across that region.

WAN covers a large geographical area such as a city orcountry. Communication channels include telephone lines,Microwave, satellites, etc.

NETWORKS: categorized by size

NETWORK TOPOLOGIES


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NETWORK TOPOLOGIES

(categorizing by shape)


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Large networks can be separated into two or more smaller networks using a bridge.

This is done to increase speed and efficiency. This type of network is called a segmented

LAN and has largely been superseded by the use of switches which can transfer data

straight to a computer and thus avoid bottleneck jams which bridges were designed to

fix.

Bridge

Bridge


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Often used to connect a LAN with a WAN. Gateways join two or

More different networks together.

Gateway

Gateway


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Internetpublic/international network which is used to access information, e-shopping, e-

banking, email

Intranetprivate network (LAN or WAN) used to share resources in secure environment

uses web pages (HTML to view) and TCP/IP protocols (to make connection)

Extranetintranet that has been extended to include access to or from selected external organizations

such as customers, but not general public.

Note: Connections via leased lines, or network interconnections.

Internet, Intranet, Extranet


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Transmission Media

twisted pair telephone cable

coaxial cableThick black cable used for higher

bandwidth communications than twisted pair

(i.e. Optus cable)

fibre optic data transferred through pulses of

light. Extremely fast.

Non cable methods such as satelite,

microwave, wireless and bluetooth

More on internet
http://www.bettscomputers.com/transmissionmedia.htmhttp://www.bettscomputers.com/transmissionmedia.htm


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SERVERS: Help to manage the network and the resources of that network.On larger networks servers commonly have specialised tasks such as: File Servers:stores and manages files, Print Servers: manages printers and print jobs, MailServer: Manages email, Web Server: manages web access.

Routers: connects multiple networks and are protocol independent. can be

used in place of a switch or bridge.Switches: smart hubs which transmit packets to the destination port onlyHubs: like double adapters /power boards in the home except instead ofplugging in extension cords we are plugging in computers to allow them tocommunicate.

Network HardwareMore on Internet
http://bettscomputers.com/moodle/course/view.php?id=61http://bettscomputers.com/moodle/course/view.php?id=61


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- adding/removing users

- assigning users to printers

- giving users file access rights

- installation of software and sharing with users

- client installation and protocol assignment

- logon and logoff procedures

- network based applications

Some Network Administration Tasks


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Other Information Processesin Communication Systems

Collecting: phone as collection device with voice mail,EFTPOS terminal as a collection device for electronicbanking

processing: sending of attachments with e-mail, encoding

and decoding methods, including: analog data to analogsignal, digital data to analog signal, digital data to digitalsignal, analog data to digital signal, client-serverarchitecture: the client controls the user interface and theapplication logic server controls access to the database


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Collecting: The following are collection devices:ATMs for internetbanking, EFTPOS for stores, microphone and video camera for videoconferencing. Data can be analog or digital

Collecting


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Processing

Processing: Is the manipulation or changing

the data into a more useable format. The

processing may include changing the

appearance of the data, the file type orstorage options.


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Displaying

Displaying: How the information ismade available for the user to see


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Issues related toCommunication Systems

Messaging Systems (social context, Danger of Misinterpretation, PowerRelationships, Privacy and confidentiality, power relationships, electronic junkmail, information overload)

Internet (Internet trading, taxation, employment, nature of business, tradebarriers, censorship, child protection, internet banking, security, changing natureof work, branch closures and job losses, radio and video)

Telecommuting (work from home), blurring between work and home, morestress, advantagesand disadvantages)


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netiquette is etiquette/ manners on netMany people rely on messaging systems more

than spoken or face to face communication.written word only recipient miss out on (e.g. bodylanguage and voice inflection)privacy (employers have right to read e-mail at

work)Spam is overloading mailboxesWork/ information overload from ever growingnumber of emails

Issues relating to messaging systems

Issues relating to internet trading


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employment ramifications

Effect on trade barriers and taxationlaws

Phishing and security


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branch closures and job lossesdecreasing number of bank branchesjob losseschanging nature of worksecurity of banking details

Issues relating to internet banking


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Physical boundaries

telecommuting is working from home

virtual organisations

national trade barriers


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Acknowledgements

Slides 11-15 were originally created by Bob

Baker and have been modified by Graham

Betts

A number of slides have been adapted from a

slide show by Loretta Kocovska around 2001

especially the illustrations on slides 18,39,40,

41, 42 and 43

Serial Data Transmission


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Serial Data Transmission

Figure 4.2 shows the concept of serial

transmission.

Due to the sequential nature of the serial data

transmission, usually it takes longer time to

send this way.

Serialtransmission is used for long-distance

communications..

Figure 4 2: Serial data transmission


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Figure 4.2: Serial data transmission

A B

0 1 1 0

Clock4 T

T T T T

Figure 4.1: Serial data transmission

Parallel Data Transmission


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Parallel Data Transmission

All the bits of a code word are transferred

simultaneously and as a result, it is extremely

fast.

One wire for each bit of information to be

transmitted. This means a multi wire cable

must be used.

Used for short-distance communications and

within a computer

Figure 4 3: Parallel data transmission


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Figure 4.3: Parallel data transmission

MSB

A3

A

A2

A1

A0

LSB

A3

A2 B

A1

A0

0

Clock

T

0

1

1

The Differences between Serial and Parallel


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Transmission

Table 2 : The Differences between Serial and

Parallel Transmission.

Modes of Data Transmission
http://localhost/var/www/apps/conversion/tmp/scratch_6/Table%204.2.dochttp://localhost/var/www/apps/conversion/tmp/scratch_6/Table%204.2.dochttp://localhost/var/www/apps/conversion/tmp/scratch_6/Table%204.2.dochttp://localhost/var/www/apps/conversion/tmp/scratch_6/Table%204.2.doc


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Modes of Data Transmission

Modes of Data Transmission is the flow of

data between two points.

i. Simplex

ii. HalfDuplex

iii. Full Duplex

iv. Full Full Duplex

SIMPLEX


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SIMPLEX

Data flows in only one direction on the data

communication line (medium).

Examples are radio and television broadcasts.

They go from the TV station to your home

television

Simplex Transmission


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Simplex Transmission

Half-Duplex


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Half Duplex

Data flows in both directions but only one

direction at a time on the data communication

line.

For example, a conversation on walkie-talkies

is a half-duplex data flow. Each person takes

turns talking. If both talk at once - nothing

occurs!


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Half-Duplex Transmission (Walkie-Talkie)

Full-Duplex


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Full Duplex

Data flows in both directions simultaneously.

Modems are configured to flow data in both

directions.

Full duplex (FDX) operation requires 2

separate communication channels, so that

simultaneous 2 way communication can occur.

Full-Duplex transmission


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Full Duplex transmission

Full-Full Duplex


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Full Full Duplex

Data flows in both directions simultaneously

and in the same time received data.

Network Topology


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Network Topology

Main Types of Physical Topologies:

i. Star

ii. Bus

iii. Ring

iv. Mesh

v. Hybrid

Star Topology


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Designed with each node (file server,workstations, and peripherals) connecteddirectly to a central network hub, switch, or

concentrator . All computers are connected to a centralized

mainframe computer.

Consists of central host and all nodes areconnect to a host. The host will control theflow of communication in the network.

Star Topology


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Star Topology

Bus Topology


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All nodes (file server, workstations, and

peripherals) are connected to the linearcable.

That is consists of single central cable

(Backbone).

All nodes are sharing the backbone to

communicate with each other on the

network.

Bus Topology


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p gy

Ring Topology


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Each node connects to exactly two other

nodes, forming a single continuous pathway

for signals through each node - a ring.

Data travels from node to node, with eachnode along the way handling every packet.

A node failure or cable break might isolate

every node attached to the ring.

Ring Topology


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g p gy

Mesh topology


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p gy

Each node must not only capture and

disseminate its own data, but also serve as a

relayfor other nodes, that is, it must

collaborate to propagate the data in thenetwork.

The message propagates along a path, by

hopping from node to node until thedestination is reached.

Mesh Topology


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p gy

Hybrid Topology


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y p gy

A combination of topologies that do not exhibit thecharacteristics of any standard topology.

Connects network components by combining the features oftwo or more other topologies (such as star, bus, and ring).

The resulting hybrid topology exhibits features (and

limitations) of its comprising network components. Examplesof hybrid topologies include the star-wired ring and star-wiredbus.

Network Classification


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A network consists of two or more computers

that are linked in order to share resources

(such as printers and CDs), exchange files, or

allow electronic communications. The computers on a network may be linked

through cables, telephone lines, radio waves,

satellites, or infrared light beams.

LAN (Local Area Network)


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A group of computers connected within a building, single

floor, small company or a campus.

Useful for sharing resources like files, printers, games orother applications.

Most local area networks are built with relatively

inexpensive hardware such as Ethernet cables, network

adapters, and hubs. A LAN connects network devices over a relatively short

distance.

LAN Network
http://compnetworking.about.com/library/glossary/bldef-ethernet.htmhttp://compnetworking.about.com/cs/lanvlanwan/g/bldef_lan.htmhttp://compnetworking.about.com/cs/lanvlanwan/g/bldef_lan.htmhttp://compnetworking.about.com/library/glossary/bldef-ethernet.htm


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MAN (Metropolitan Area Network)


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A large computer network that usually spans a

city or a large campus.

Usually interconnects a number oflocal area

networks (LANs) using a high-capacitybackbone technology, such as fiber-optical

links, and provides up-link services to wide

area networks (or WAN) and the Internet.

Metropolitan Area Network
http://en.wikipedia.org/wiki/Local_area_networkhttp://en.wikipedia.org/wiki/Local_area_networkhttp://en.wikipedia.org/wiki/Wide_area_networkhttp://en.wikipedia.org/wiki/Wide_area_networkhttp://en.wikipedia.org/wiki/Internethttp://en.wikipedia.org/wiki/Internethttp://en.wikipedia.org/wiki/Wide_area_networkhttp://en.wikipedia.org/wiki/Wide_area_networkhttp://en.wikipedia.org/wiki/Local_area_networkhttp://en.wikipedia.org/wiki/Local_area_network


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WAN (Wide Area Network)


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Very large networks that interconnect smaller LAN networks,for a large geographic area like a country (i.e., any networkwhose communications links cross metropolitan, regional, ornational boundaries.). WANs are usually for privatecompanies; however, some built by internet service providers

connect LANs to the internet. WAN can use a combination of satellites, microwave, and link

and variety of computers from mainframes to terminals. A'node' on a WAN is a LAN

Wide Area Network


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GAN (Global area Network)


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GAN refers to any network that is composed

of different interconnected computer

networks (WANs) and also covers an unlimited

geographical area.

THE END
http://www.webopedia.com/TERM/N/network.htmlhttp://www.webopedia.com/TERM/W/wide_area_network_WAN.htmlhttp://www.webopedia.com/TERM/W/wide_area_network_WAN.htmlhttp://www.webopedia.com/TERM/N/network.html


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TOPICS MENU


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TOPICS MENU

Characteristics of Communication Systems

Examples of Communication Systems

Transmitting and Receiving

Other Information Processes

Issues Related To Communication Systems

Click on the topic of your choice

C i i T


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Communications Glossary

Communications Networking Glossary

Glossary of Networking terms at Clock.org

Communications Terms
http://bettscomputers.com/moodle/mod/glossary/view.php?id=76http://www.lantronix.com/learning/glossary.htmlhttp://www.clock.org/~jss/glossary/http://www.clock.org/~jss/glossary/http://www.lantronix.com/learning/glossary.htmlhttp://bettscomputers.com/moodle/mod/glossary/view.php?id=76


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Characteristics of

Communication Systems

Protocols

Handshaking

Speed of TransmissionError Checking

Communication Settings

Characteristics of Communication


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More Information

must be a Sender and ReceiverA protocol is a set of rules which governs the transfer of data between

computers. Protocols allow communication between computers and networks.Handshaking is used to establish which protocols to use. Handshaking

controls the flow of data between computers

protocols will determine the speed of transmission, error checking method,size of bytes, and whether synchronous or asynchronous

Examples of protocols are: token ring, CSMA/CD, X.25, TCP/IP

Systems
http://www.bettscomputers.com/communications.htmhttp://www.bettscomputers.com/communications.htmhttp://www.bettscomputers.com/communications.htm


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5 Basic Components

Every communication system has 5 basic requirements

Data Source(where the data originates)

Transmitter (device used to transmit data)

Transmission Medium(cables or non cable)

Receiver (device used to receive data)

Destination(where the data will be placed)


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5 Basic Components

Transmission Media Speed


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Bandwidth:The amount of data which can be transmitted on amedium over a fixed amount of time (second). It is measured on Bits perSecond or Baud

Bits per Second (bps): A measure of transmissionspeed. The number of bits (0 0r 1) which can be transmitted in a second(more)

Baud Rate: Is a measure of how fast a change of state occurs(i.e. a change from 0 to 1) (more)

Transmission Media Speed
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This file has now been broken into four packets

PACKET

Packets

Transmissions are broken up into smaller

units or data transmissions called packets

PACKET PACKET PACKET

Example

A data file is divided into packets.

It does not matter what the transmission is. It could be Word

document, a PowerPoint or an MP3. Imagine this Green box

is a file for transfer


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Packets and OSI

After the file is divided into packets extrainformation is required to make sure it all goes

back together correctly. The OSI model helps

to look after this. The OSI model also provides much more

information which is included with each

package.

OSI 7 Layer Model


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More Information on OSI

OSI Open System InterconnectionOSI is not a protocol but a list of protocols

divided between 7 layers with each layer

having a different set of functions.Each packet is layered/packaged with

protocols from each of the layers as it is

processed.

The process of layering the protocols around

each package is called encapsulation. The final

encapsulated data packet is called a frame.

Originally Created by Bob Baker

Modified 2006

Graham Betts

Open Systems InterconnectionOriginally Created by Bob BakerModified 2006

Graham Betts
http://www.bettscomputers.com/osilayersmodel.htmhttp://www.bettscomputers.com/osilayersmodel.htm


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File

OSI Reference model

Layer 7 application

Layer 6 presentation

Layer 5 session

Layer 4 transport

Layer 3 network

Layer 2 data link

Layer 1 physical

Transmission Medium

File

Sender Receiver

File

Each file

is divided

into

packets The received

frame is then

unpacked

in theopposite order

Graham Betts

Each Packet

will

then be

Encapsulated

with

PROTOCOLS

The protocolsWill be added

systematically

Layer

By layer

The encapsulated

Packet is called

a frame


Modified 2006

Graham BettsServices Performed at Each Layer


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Layer 7 application


Layer 5 session Layer 4 transport

Layer 3 network

Layer 2 data link

Layer 1 physical

Identification, authentication

Format conversion

Set-up coordinate conversation

Ensures error-free transfer

Routing of data through network

Error control and synchronisation

Placing signals on the carrier

Graham Betts


Modified 2006

Graham Betts


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Examples of protocols

Layer 7 application


Layer 5 session

Layer 4 transport

Layer 3 network

Layer 2 data link

Layer 1 physical

E-mail, Web browser, Directory

POP, SMTP, FTP, HTTP, DNS

Sockets

TCP

IP

PPP, Ethernet, Token ring

100baseT

More on Protocols

Graham Betts


Modified 2006

Graham Betts
http://bettscomputers.com/moodle/mod/resource/view.php?id=653http://bettscomputers.com/moodle/mod/resource/view.php?id=653


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EncapsulationApplicationPresentation

Session

Transport

Network

Data Link

Physical

data

Device 1 Device 2

dataH6 T6

dataH5 T5

dataH4 T4

(packet)H3 data T3

H2 data T2

H1 data T1

carrier FRAME

Application

Presentation

Session

Transport

Network

Data Link

Physical

A typical frame DestinationAddress

Source

AddressData Padding CRCPreamble

FRAME FRAME FRAME

(Packet)

Graham Betts

Error Checking Methods


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Parity bit check Check sum

* data transmitted in blocks, each block addedto give a total checksum

* used in X Modem protocol

Cycle redundancy check

Error Checking Methods

More on internet


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HSC Topic 3.3

Examples of Communication

Systems


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Examples of Communication Systems

- E-mail- Voice Mail - Fax- Smart Phone - Instant Messaging- Telecommuting - Video-conferencing- Groupware - Telephony

- E-Commerce - The Internet- Bulletin board system - The Web- Global positioning system


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HSC Topic 3.4

Transmitting and Receivingin Communication Systems

Communication concepts

(transmission of data, protocols and handshaking, networks, LANs andWANs,Topologies, Network Access Methods)

Network Hardware (NICs, Servers, Routers and Switches, Bridges and gateways, Hubs, Transmission

media

Network Software

NOSs, Network Operating System Tasks, Logon and Logoff Procedures, Intranets andExtranets


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Any transmission May be:

analog or digital

Serial or parallel

Communication Concepts

l


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Sender transmitted

Data is transmitted, on a single channel, one bit at a timeone after another

- Much faster than parallel because of way bits processed(e.g. USB and SATA drives)

Receiver received

Serial Transmission

101 0 0 1 1 0

Parallel Transmission


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Receiverreceiv

ed

-each bit has its own piece of wire along which it travels- often used to send data to a printer

Send

ertransmitted

All bits are sent simultaneously

1

0

01

1

0

0

1

Why Not use Parallel Instead of serial?


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Due to inconsistencies on channels data arrives atdifferent times

Because of the way it is transmitted packet switching

cannot be used

The above two points makes parallel slower than

serial and requires higher bandwidth.

Parallel transmissions are rarely used anymore

Synchronous Vs

A h T i i


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Synchronous Transmissionall data sent at once and no packet switching

Asynchronous TransmissionUses stop/ start bits

most common type of serial data transfer

Allows packet switching

Allows sharing of bandwidth (i.e. talk on phone

while another person is using internet)

AsynchronousTransmissions



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- simplex: One direction only


Half Duplex Transmission


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half duplex: Both

directions but

only one

direction at a

time

Full Duplex Transmission


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full duplex:

send and

receive bothdirections at

once

3 Common Protocols


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Ethernet (Ethernet Network)

-Carrier Sense Multiple Access/Collision Detection (CSMA/CD)

-TCP/IP

3 Common Protocols


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Ethernet

Developed at Xerox in 1976.

First protocol approved as an industrystandard protocol 1983

LAN protocol used on bus and star

Most popular LAN protocol

Inexpensive

Carrier Sense Multiple Access/Collision


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Carrier Sense Multiple Access/Collision

Detection (CSMA/CD)

- Used on bus networks to avoid data

collisions.

TCP/IP


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Developed in 1973 for use on theARPANET which was a defense forceresearch network.

-Adopted in 1983 as the Internet standard.all hosts on the Internet are required touse TCP/IP.

- Allows transfer of data using packetswitching

TCP/IP


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LANs Vs WANs

LANis local Area network which is anetwork confined to a small geographic area

which is a building or a group of buildings.

WANis wide area network which is anetwork spread over a large geographic area.

The largest WAN is the internet.


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Examples of LANS

3 different types of LANS are:

Ring

BusStar

Uses an empty data packet

called a token and a specialRing


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protocol called token ring.

Packets travel around the ring

in a clockwise direction.

Clients require an emptytoken to transmit data.

Advantages

- no collisions because all

data travels in same direction.

Disadvantages

- fails if an individual node in

the network fails

Ring

BUS TOPOLOGY
http://bettscomputers.com/moodle/course/view.php?id=10


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A bus is a form of Ethernet. Nodes linked by a cable known as the bus. Bus transmits in

both directions and uses CSMA/CD protocol

Advantages

- Easy to set up and maintainfailure of one node does not affect

network

Disadvantages

-Higher rate of data collision thanwith a bus network

-fails if there is any damage to the

bus

Star


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All data is sent from one client

to another through the server.

Advantages

- If one client fails no other

clients are affected.

Disadvantages

- If central file server fails thenetwork fails.


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Network Hardware

What is a Network?


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A network is a number of computers andperipheral devices connected together so

as to be able to communicate (i.e. transfer

data)Each device in a network is called a

node.

Terminals are data entry points whichcan also display.



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LAN a network that connects computers in a limitedgeographical area.

MAN a backbone that connects LANs in a metropolitanarea such as a city and handles the bulk of communicationsactivity across that region.

WAN covers a large geographical area such as a city orcountry. Communication channels include telephone lines,Microwave, satellites, etc.


NETWORK TOPOLOGIES(categorizing by shape)


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(categorizing by shape)

Bridge


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Large networks can be separated into two or more smaller networks using a bridge.

This is done to increase speed and efficiency. This type of network is called a segmentedLAN and has largely been superseded by the use of switches which can transfer data

straight to a computer and thus avoid bottleneck jams which bridges were designed to

fix.

Bridge

Bridge

Gateway


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Often used to connect a LAN with a WAN. Gateways join two or

More different networks together.

Gateway

Internet

Internet, Intranet, Extranet


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Internetpublic/international network which is used to access information, e-shopping, e-

banking, email

Intranetprivate network (LAN or WAN) used to share resources in secure environment

uses web pages (HTML to view) and TCP/IP protocols (to make connection)

Extranetintranet that has been extended to include access to or from selected external organizations

such as customers, but not general public.

Note: Connections via leased lines, or network interconnections.

Transmission Media
http://www.bettscomputers.com/transmissionmedia.htm


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twisted pair telephone cable coaxial cableThick black cable used for higher

bandwidth communications than twisted pair

(i.e. Optus cable) fibre optic data transferred through pulses of

light. Extremely fast.

Non cable methods such as satelite,microwave, wireless and bluetooth

More on internet

Network HardwareMore on Internet
http://www.bettscomputers.com/transmissionmedia.htmhttp://www.bettscomputers.com/transmissionmedia.htmhttp://bettscomputers.com/moodle/course/view.php?id=61http://bettscomputers.com/moodle/course/view.php?id=61


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SERVERS: Help to manage the network and the resources of that network.On larger networks servers commonly have specialised tasks such as: File Servers:stores and manages files, Print Servers: manages printers and print jobs, MailServer: Manages email, Web Server: manages web access.

Routers: connects multiple networks and are protocol independent. can beused in place of a switch or bridge.

Switches: smart hubs which transmit packets to the destination port onlyHubs: like double adapters /power boards in the home except instead ofplugging in extension cords we are plugging in computers to allow them tocommunicate.

More on Internet

Some Network Administration

T k


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- adding/removing users

- assigning users to printers

- giving users file access rights

- installation of software and sharing with users

- client installation and protocol assignment- logon and logoff procedures

- network based applications

Tasks


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Other Information Processesin Communication Systems

Collecting: phone as collection device with voice mail,EFTPOS terminal as a collection device for electronicbanking

processing: sending of attachments with e-mail, encodingand decoding methods, including: analog data to analog

signal, digital data to analog signal, digital data to digitalsignal, analog data to digital signal, client-serverarchitecture: the client controls the user interface and theapplication logic server controls access to the database

Collecting


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Collecting: The following are collection devices:ATMs for internetbanking, EFTPOS for stores, microphone and video camera for videoconferencing. Data can be analog or digital

g

P i


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Processing

Processing: Is the manipulation or changingthe data into a more useable format. The

processing may include changing the

appearance of the data, the file type orstorage options.

Di l i


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Displaying

Displaying: How the information is

made available for the user to see


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Issues related to

Communication Systems

Messaging Systems (social context, Danger of Misinterpretation, PowerRelationships, Privacy and confidentiality, power relationships, electronic junkmail, information overload)

Internet (Internet trading, taxation, employment, nature of business, tradebarriers, censorship, child protection, internet banking, security, changing nature

of work, branch closures and job losses, radio and video)

Telecommuting (work from home), blurring between work and home, morestress, advantagesand disadvantages)

Issues relating to messaging

t


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netiquette is etiquette/ manners on netMany people rely on messaging systems morethan spoken or face to face communication.

written word only recipient miss out on (e.g. bodylanguage and voice inflection)privacy (employers have right to read e-mail atwork)Spam is overloading mailboxesWork/ information overload from ever growingnumber of emails

systems



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employment ramifications

Effect on trade barriers and taxationlaws

Phishing and security

Issues relating to internet

banking


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branch closures and job lossesdecreasing number of bank branches

job losseschanging nature of worksecurity of banking details

banking

Physical boundaries


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Physical boundaries

telecommuting is working from home virtual organisations

national trade barriers

Acknowledgements


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Acknowledgements

Slides 11-15 were originally created by BobBaker and have been modified by Graham

Betts

A number of slides have been adapted from aslide show by Loretta Kocovska around 2001

especially the illustrations on slides 18,39,40,

41, 42 and 43


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a tour of new features

introducing

POWERPOINT 2010

EnhancingYour Presentation


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We have features for every step of the way

Author YourPresentation

Enrich YourPresentation

Deliver YourPresentation


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Author Your Presentation

Design, organize, and collaborate

Getting Startedwith Templates


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Use sample templatesto kick-off

your presentation and focus on the

content (youre viewing one right

now!)

You dont have to start from scratch.

If you need help with a status report

or ideas for a photo album, look no

further.

Too much information?


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Org

anizewith

Sections

Divide and conquer a large presentation by organizing your

presentation with sections.

You can name, print, and

apply effects to an entire

section easily.


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Simultaneous edits on one single document.

No more waiting your turn or managing

multiple versions.

Its about team work, and co-authoringwill

get you there.

Collaboration


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Enrich Your Presentation

Stylize, edit, and animate your media


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Its not just about the visuals, but strengthening

YOUR MESSAGE.

New Picture Effects


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Picture Color, Corrections, Artistic Effects,

and Background Removal allow you to customize images for your story

Animate This


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Check out this animation:

With the Animation Painteryou can re-create the same animation with one click

Video Perfect


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You can do a lot more with videos in

PowerPoint 2010.

Videos can be embedded in your

presentation. Thats right, no more

lost videos!

Also, you can recolor the entire video

or apply a video style easily. Your

videos will look great!

Want to jump to a


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bookmark in your video?

Hover over the video andyoull be pleasantly surprised.

Did we mention you can add

bookmarks, includefades, and

trimyour videos now?

Exciting new transitions


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What about the beautiful transitionsyouve been seeing?

They are new too.


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Deliver Your Presentation

Broadcast and compress for seamless delivery

BROADCAST IT


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Show and tell your presentation with

Broadcast Slide Show

Share your presentation in real-time with

anyone with a browser, directly from

PowerPoint.

Youll never have to say, Next slide, please

again!

BROADCAST IT


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Record your presentation with

Create a Videoand capture narrations,

animations, media, and much more.

Upload, embed, and share away!

Spread the Message!


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For a media-rich presentation, you

can Optimize for Compatibility

orCompress Media to share your

presentation reliably without

exploding your inbox

Package your presentation

for easy sharing


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?

But wait

Theres More!

View your slides from anywhere!

AccessAnywhere


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Check out the

PowerPoint Web App

Access slides wherever you are


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Whats Your Message?POWERPOINT 2010

DATA COMM CHAPTER 4.pptx

Documents

Transcript of DATA COMM CHAPTER 4.pptx