1
Unit 1. Introduction to data commu
p p p p p
nications and networking
p p
1
NETWORKING FUNDAMENTALS p
UnitpStructure
1.0 Objectives
1.1 Introduction
1.2 Datap&pInformation
1.3 DatapCommunication
1.3.1 CharacteristicspofpDatapCommunication
1.3.2 ComponentspofpDatapCommunication
1.4 DatapRepresentation
1.5 DatapFlow
1.5.1.pSimplex
1.52.pHalfpDuplex
1.5.3.pFullpDuplex
1.6 ComputerpNetwork
1.6.1 Categoriespofpapnetwork
1.7 Protocol
1.7.1 ElementspofpapProtocol
1.8 StandardspInpNetworking
1.8.1 ConceptpofpStandard
1.8.2 StandardpOrganizationspinpfieldpofpNetworking
1.9 ReviewpQuestions
1.10 References
1.0 OBJECTIVES:
✓ Introduce the readers to data communication and
itspfundamentals
✓ Definepnetworks
✓ Definepprotocols
✓ Standardspinpnetworking
, 2
1.1 INTRODUCTION
pThispchapterpprovidespanpintroductionptopComputerpnetworkspand
coverspfundamentalptopicsplikepdata,pinformationptopthepdefinitionp
p
ofpcommunicationpandpcomputerpnetworks.
pThepmainpobjectivepofpdatapcommunicationpandpnetworkingpisptop
enablepseamlesspexchangepofpdatapbetweenpanyptwoppointspinpthe
pworld.
Thispexchangepofpdataptakespplacepoverpapcomputerpnetwork.
1.2 DATA & INFORMATION
p p
p Dataprefersp top thep rawp factsp thatp arep collectedp whilep information
refersptopprocessedpdatapthatpenablespusptoptakepdecisions.
pEx.pWhenp resultpofp apparticularp testp isp declaredp itp containspdatap
ofpallpstudents,pwhenpyoupfindpthepmarkspyouphavepscoredpyouphav
epthepinformationpthatpletspyoupknowpwhetherpyouphaveppassedporp
failed.
pThepwordpdataprefersptopanypinformationpwhichpisppresentedpinpapf
ormpthatpispagreedpandpacceptedpuponpbypispcreatorspandpusers.
1.3 DATA COMMUNICATION
p
pDatapCommunicationpispapprocesspofpexchangingpdataporpinforma
tion
pInpcasepofpcomputerpnetworkspthispexchangepispdonepbetweenp tw
opdevicespoverpaptransmissionpmedium.
pThispprocesspinvolvespapcommunicationpsystempwhichpispmadep u
ppofphardwarepandpsoftware.pThephardwareppartpinvolvespthepsend
erpandpreceiverpdevicespandpthepintermediatepdevicespthroughpwhi
chpthepdatappasses.pThepsoftwareppartpinvolvespcertainprulespwhic
hpspecifypwhatpisptopbepcommunicated,phowpitp isptopbepcommunica
tedpandpwhen.pItpispalsopcalledpaspapProtocol.
pThep followingp sectionsp describesp thep fundamentalpcharacteristi
cspthatparepimportantpforpthepeffectivepworkingpofp datapcommunica
tionpprocesspandpispfollowedpbypthepcomponentspthatpmakepuppapd
atapcommunicationspsystem.
, 3
1.3.1 CharacteristicspofpDatapCommunication
Thepeffectivenesspofpanypdatapcommunicationspsystempdependsp
uponpthepfollowingpfourpfundamentalpcharacteristics:
, 4
1. Delivery:pThepdatapshouldpbepdeliveredptopthepcorrectp destinatio
npandpcorrectpuser.
2. Accuracy:pThepcommunicationpsystempshouldpdeliverpthepdatapa
ccurately,pwithoutpintroducingpanyperrors.pThepdatapmaypgetpcorru
ptedpduringptransmissionpaffectingpthepaccuracypofpthepdeliveredpd
ata.
3. Timeliness:pAudiopandpVideopdataphasptopbepdeliveredpinpaptimely
pmannerpwithoutpanypdelay;psuchpapdatapdeliverypispcalledprealptim
eptransmissionpofpdata.
4. Jitter:pItpispthepvariationpinptheppacketparrivalptime.pUnevenpJitterpm
aypaffectptheptimelinesspofpdatapbeingptransmitted.
1.3.2 ComponentspofpDatapCommunication
Ap Datap Communicationp systemp hasp fivep componentsp asp s
hownpinpthepdiagrampbelow:
Fig.pComponentspofpapDatapCommunicationpSystem
1. Message
Messagepispthep informationp top bep communicatedpbypthep senderptopth
epreceiver.
2. Sender
Thep senderp isp anyp devicep thatp isp capablep ofp sendingp thep datap(
message).
3. Receiver
Thepreceiverpispapdevicepthatpthepsenderpwantsptopcommunicatepthepd
atap(message).
4. TransmissionpMedium
Itpisptheppathpbypwhichpthepmessageptravelspfrompsenderptopreceiver.pIt
pcanpbepwiredporpwirelesspandpmanypsubtypespinpboth.
Unit 1. Introduction to data commu
p p p p p
nications and networking
p p
1
NETWORKING FUNDAMENTALS p
UnitpStructure
1.0 Objectives
1.1 Introduction
1.2 Datap&pInformation
1.3 DatapCommunication
1.3.1 CharacteristicspofpDatapCommunication
1.3.2 ComponentspofpDatapCommunication
1.4 DatapRepresentation
1.5 DatapFlow
1.5.1.pSimplex
1.52.pHalfpDuplex
1.5.3.pFullpDuplex
1.6 ComputerpNetwork
1.6.1 Categoriespofpapnetwork
1.7 Protocol
1.7.1 ElementspofpapProtocol
1.8 StandardspInpNetworking
1.8.1 ConceptpofpStandard
1.8.2 StandardpOrganizationspinpfieldpofpNetworking
1.9 ReviewpQuestions
1.10 References
1.0 OBJECTIVES:
✓ Introduce the readers to data communication and
itspfundamentals
✓ Definepnetworks
✓ Definepprotocols
✓ Standardspinpnetworking
, 2
1.1 INTRODUCTION
pThispchapterpprovidespanpintroductionptopComputerpnetworkspand
coverspfundamentalptopicsplikepdata,pinformationptopthepdefinitionp
p
ofpcommunicationpandpcomputerpnetworks.
pThepmainpobjectivepofpdatapcommunicationpandpnetworkingpisptop
enablepseamlesspexchangepofpdatapbetweenpanyptwoppointspinpthe
pworld.
Thispexchangepofpdataptakespplacepoverpapcomputerpnetwork.
1.2 DATA & INFORMATION
p p
p Dataprefersp top thep rawp factsp thatp arep collectedp whilep information
refersptopprocessedpdatapthatpenablespusptoptakepdecisions.
pEx.pWhenp resultpofp apparticularp testp isp declaredp itp containspdatap
ofpallpstudents,pwhenpyoupfindpthepmarkspyouphavepscoredpyouphav
epthepinformationpthatpletspyoupknowpwhetherpyouphaveppassedporp
failed.
pThepwordpdataprefersptopanypinformationpwhichpisppresentedpinpapf
ormpthatpispagreedpandpacceptedpuponpbypispcreatorspandpusers.
1.3 DATA COMMUNICATION
p
pDatapCommunicationpispapprocesspofpexchangingpdataporpinforma
tion
pInpcasepofpcomputerpnetworkspthispexchangepispdonepbetweenp tw
opdevicespoverpaptransmissionpmedium.
pThispprocesspinvolvespapcommunicationpsystempwhichpispmadep u
ppofphardwarepandpsoftware.pThephardwareppartpinvolvespthepsend
erpandpreceiverpdevicespandpthepintermediatepdevicespthroughpwhi
chpthepdatappasses.pThepsoftwareppartpinvolvespcertainprulespwhic
hpspecifypwhatpisptopbepcommunicated,phowpitp isptopbepcommunica
tedpandpwhen.pItpispalsopcalledpaspapProtocol.
pThep followingp sectionsp describesp thep fundamentalpcharacteristi
cspthatparepimportantpforpthepeffectivepworkingpofp datapcommunica
tionpprocesspandpispfollowedpbypthepcomponentspthatpmakepuppapd
atapcommunicationspsystem.
, 3
1.3.1 CharacteristicspofpDatapCommunication
Thepeffectivenesspofpanypdatapcommunicationspsystempdependsp
uponpthepfollowingpfourpfundamentalpcharacteristics:
, 4
1. Delivery:pThepdatapshouldpbepdeliveredptopthepcorrectp destinatio
npandpcorrectpuser.
2. Accuracy:pThepcommunicationpsystempshouldpdeliverpthepdatapa
ccurately,pwithoutpintroducingpanyperrors.pThepdatapmaypgetpcorru
ptedpduringptransmissionpaffectingpthepaccuracypofpthepdeliveredpd
ata.
3. Timeliness:pAudiopandpVideopdataphasptopbepdeliveredpinpaptimely
pmannerpwithoutpanypdelay;psuchpapdatapdeliverypispcalledprealptim
eptransmissionpofpdata.
4. Jitter:pItpispthepvariationpinptheppacketparrivalptime.pUnevenpJitterpm
aypaffectptheptimelinesspofpdatapbeingptransmitted.
1.3.2 ComponentspofpDatapCommunication
Ap Datap Communicationp systemp hasp fivep componentsp asp s
hownpinpthepdiagrampbelow:
Fig.pComponentspofpapDatapCommunicationpSystem
1. Message
Messagepispthep informationp top bep communicatedpbypthep senderptopth
epreceiver.
2. Sender
Thep senderp isp anyp devicep thatp isp capablep ofp sendingp thep datap(
message).
3. Receiver
Thepreceiverpispapdevicepthatpthepsenderpwantsptopcommunicatepthepd
atap(message).
4. TransmissionpMedium
Itpisptheppathpbypwhichpthepmessageptravelspfrompsenderptopreceiver.pIt
pcanpbepwiredporpwirelesspandpmanypsubtypespinpboth.
