Data Communication and Computer Networking Part # 1

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Overview of Data CommunicationOverview of Data Communicationand Computer Networksand Computer Networks

JUNAID QADAR JUNAID QADAR MSC ELECTRONICS (PREV) MSC ELECTRONICS (PREV)

Department of Electronics Department of Electronics University of PeshawarUniversity of Peshawar

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OutlineOutline Data Communication OverviewData Communication Overview

DefinitionDefinition ComponentsComponents Protocols and standardsProtocols and standards

Network OverviewNetwork Overview ConnectivityConnectivity CategoriesCategories InternetworksInternetworks

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Motivations Motivations Efficient way to share resourcesEfficient way to share resources

Cost Cost –– less expensive less expensive Accessibility Accessibility –– easier easier

Efficient way to exchange informationEfficient way to exchange information Time Time –– faster faster Size Size –– bigger bigger Correctness Correctness –– more accurate more accurate

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Data Communication: Data Communication: DefinitionDefinition

Data Communication:Data Communication:

Transfer of data from one device to another via some form of transmission medium.

Transfer of data from one device to another via some form of transmission medium.

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Data CommunicationData Communication

Hi, how are you?

01010001

Hi, how are you?

UserComputer

you?

how

are

Hi,

you?

how

are

Hi,

01010001

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Components in CommunicationComponents in Communication

Hi, how are you?

5 Protocol

4 Medium

3 Receiver2 Sender

1 Message

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Data RepresentationData Representation NumbersNumbers

8/16/32 bit integers8/16/32 bit integers floating pointfloating point

TextText ASCII, UnicodeASCII, Unicode

ImagesImages Bit patterns, Graphics formats JPG/GIF/etcBit patterns, Graphics formats JPG/GIF/etc

Audio Audio →→ Samples of continuous signal Samples of continuous signal Video Video →→ Sequence of bitmap images Sequence of bitmap images

150

2

255

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Protocols and StandardsProtocols and Standards ProtocolProtocol

A set of rules governing data communicationsA set of rules governing data communications Syntax:Syntax: format of data block format of data block Semantics:Semantics: meaning of each section meaning of each section Timing:Timing: speed and sequencing speed and sequencing

StandardsStandards De factoDe facto (in practice) standards (in practice) standards

→→ not approved but widely adoptednot approved but widely adopted De jureDe jure (in law) standards (in law) standards

→→ approved by an organizationapproved by an organization

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Standards OrganizationsStandards Organizations Creation CommitteesCreation Committees

ISO, ITU-T, ANSI, IEEE, EIAISO, ITU-T, ANSI, IEEE, EIA ForumsForums Regulatory AgenciesRegulatory Agencies

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Direction of Data FlowDirection of Data Flow SimplexSimplex : One direction only: One direction only

Server Monitor

data flow

Keyboard

data flow

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Direction of Data FlowDirection of Data Flow Half Duplex:Half Duplex: Both directions, one at a time Both directions, one at a time

E.g., walkie-talkiesE.g., walkie-talkies

data flow at time 1

data flow at time 2

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Direction of Data FlowDirection of Data Flow Full DuplexFull Duplex : Both directions simultaneously: Both directions simultaneously

E.g., telephoneE.g., telephone

Can be emulated on a single communication link Can be emulated on a single communication link using various methodsusing various methods

data flow

data flow

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NetworksNetworks Network: Network: a set of devices connected by a set of devices connected by

media linksmedia links

Media Links

Printer

Workstation

Laptop

Scanner

Server

SD

iMac

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Types of ConnectionsTypes of Connections Point-to-pointPoint-to-point Multipoint (multidrop)Multipoint (multidrop)

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Point-To-Point ConnectionPoint-To-Point Connection

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Multipoint ConnectionMultipoint Connection

Wireless

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TopologyTopology Topology: physical or logical arrangement Topology: physical or logical arrangement

of devicesof devices MeshMesh StarStar BusBus RingRing HybridHybrid

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Fully Connected Mesh TopologyFully Connected Mesh Topology

A

CB

D

E

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Fully Connected Mesh TopologyFully Connected Mesh Topology

2020

Fully Connected Mesh TopologyFully Connected Mesh Topology Pros:

Dedicated links Robustness Privacy Easy to identify fault

Cons: A lot of cabling I/O ports Difficult to move

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Star TopologyStar Topology

Hub

A D

B CDrop

Drop

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Star TopologyStar Topology

Switch

A D

B C

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Star TopologyStar Topology

Hub

A D

B C

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Star TopologyStar Topology Pros:

One I/O port per device

Little cabling Easy to install Robustness Easy to identify fault

Cons: Single point of failure More cabling still

required

Hub

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Bus TopologyBus Topology

Dropline

Tap

Terminator

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Bus TopologyBus Topology

A B C D

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Bus TopologyBus Topology

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Bus TopologyBus Topology Pros:

Little cabling Easy to install

Cons: Difficult to modify Difficult to isolate fault Break in the bus cable

stops all transmission

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Ring TopologyRing Topology

A

B

C

D

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Ring TopologyRing Topology

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Ring TopologyRing Topology

Pros: Easy to install Easy to identify fault

Cons: Delay in large ring Break in the ring stops all

transmission

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Hybrid TopologiesHybrid Topologies

A C TA C T

1 0 M 1 0 0 M

1 2 3 4

1 3 1 4 1 5 1 6

5 6 7 8

1 7 1 8 1 9 2 0

9 1 0 1 1 1 2

2 1 2 2 2 3 2 4

U P L I N K

1 2 3 4 5 6 7 8 9 1 0 1 1 1 2

1 3 1 4 1 5 1 6 1 7 1 8 1 9 2 0 2 1 2 2 2 3 2 4

C O LC O L

P W R

S W I T C H

A C TA C T

1 0 M 1 0 0 M

1 2 3 4

1 3 1 4 1 5 1 6

5 6 7 8

1 7 1 8 1 9 2 0

9 1 0 1 1 1 2

2 1 2 2 2 3 2 4

U P L I N K

1 2 3 4 5 6 7 8 9 1 0 1 1 1 2

1 3 1 4 1 5 1 6 1 7 1 8 1 9 2 0 2 1 2 2 2 3 2 4

C O LC O L

P W R

S W I T C H

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Network CategoriesNetwork Categories Local Area Network (LAN)Local Area Network (LAN) Wide Area Network (WAN)Wide Area Network (WAN) Metropolitan Area Network (MAN)Metropolitan Area Network (MAN)

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Local Area NetworksLocal Area Networks Network in a single office, building, or Network in a single office, building, or

campuscampus

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Wide Area NetworksWide Area Networks Network providing long-distance communication Network providing long-distance communication

over a country, a continent, or the whole worldover a country, a continent, or the whole world

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Metropolitan Area NetworksMetropolitan Area Networks Network extended over an entire cityNetwork extended over an entire city

Bangkhen Kampangsaen

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Network of NetworksNetwork of Networks

Company A

Company D

Network Interface Card (NIC)

Company B

Company C

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InternetworkingInternetworking How to allow devices from different How to allow devices from different

standards to communicatestandards to communicate Gateways/routersGateways/routers – devices capable of – devices capable of

communicating in several standardscommunicating in several standards

These become "These become "network of networksnetwork of networks""

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InternetworksInternetworks Two or more networks connected become Two or more networks connected become

an an internetworkinternetwork, or , or internetinternet

Example: Example: The InternetThe Internet

Network1 Network2

Gateway

Network3

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The InternetThe Internet The largest internetwork (network of networks) in The largest internetwork (network of networks) in

the worldthe world Devices communicating with TCP/IP protocol Devices communicating with TCP/IP protocol

suitesuite

UCLA

Stanford

UC Santa Barbara

U. of Utah

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SummarySummary Data communicationData communication

Protocols and standardsProtocols and standards Computer networksComputer networks

TopologiesTopologies LAN/MAN/WANLAN/MAN/WAN

Internetworks (networks of networks)Internetworks (networks of networks)

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THANKSTHANKS????????????