The document discusses key aspects of cloud computing including characteristics, service models, and deployment models. It describes the essential characteristics of cloud computing as on-demand self-service, broad network access, resource pooling, rapid elasticity, and measured service. The three main service models are outlined as Software as a Service (SaaS), Platform as a Service (PaaS), and Infrastructure as a Service (IaaS). Finally, the four main deployment models of private cloud, community cloud, public cloud, and hybrid cloud are summarized.

1. The recentdevelopmentsinthe technologyindustryhasbeenextremelyimperativeinoffering
contemporarysolutionstovariousbusinessproblems.Inthe lastdecade,manytechnologieswere
introducedasa resultof thistrendof movingtowardsthe digital transformation. While ameliorating
the tough timesfacedbybusinesses,these advancementsalsobroughtstabilityinthem.The most
promisingadvancementsinclude IoT,AI,andCloudComputingetc.Frombusinessesperspective,
Cloudcomputingismostproficientaninstrumental. AccordingtoNational Institute of Standardsand
Technology(NIST),“itisamodel thatallow suitable,ondemandnetworkaccesstoa sharedpool of
configurable computingresourcesthatcan be rapidlyprovisionedandreleasedwithslight
managementeffortorservice providerinteraction”.
Cloudenvironmentsare basicallycomposedof three importantfactorsincludingcloudproviders,
cloudcustomers,andendusers.Firstly,cloudprovidersoffertheirresourcesinthe formof services
usingtheirinfrastructuresbasedonpay-per-use model.Secondly,cloudservicesare purchasedby
cloudconsumersforhostingandrunningtheirapplicationsorservices.Finally,serviceshostedby
cloudprovidersandofferedbycloudconsumersare providedtothe endusers.The endcustomers
use the cloudserviceseitherdirectlyprovidedbythe cloudprovidersorindirectlyofferedbythe
cloudconsumers.
Cloud Computing Essential Characteristics
In General,cloudcomputingcanbe characterizedintofive essential elementsincluding On-demand
self-service, Broadnetworkaccess,Resource pooling,Rapidelasticity,andMeasuredService
 On-demandself-service
For a particulartime-slotandinstatenousrequirementof the computingresourceslike network
storage,software use,andCPUtime,the endusercan get these resourcesautomaticallywithout
gettingintouchwiththe service providers.
 Broad network access
Numberof clientscanuse these resources,deliveredthroughnetworking,onmultiple platforms
available atthe customer’s location includingmobile,laptops.
 Resource Pooling
Accordingto the demandof the enduser,the computingresourcesprovidedbythe cloud
service providersare “pooledtogether”toserve multiple userswiththe helpof virtualization
model ormulti-tenancy.Asaresult,the physical computingresourcesare notshownto
consumerwhodon’thave any knowledge andaren’taware of the originalities,formationand
site of these resources.
 Rapid elasticity
The computingresourcesprovided tothe endusersbythe service providersare immediate
rather thanintermittenti.e.,consumerscannotscale upor downthese resourcesaccordingto
the requirements.
 MeasuredService
In case of sharedcomputingresourcesamongvariousconsumers,the cloudinfrastructureis
prudentenoughtoestimate the consumptionof resourcesbyeachuserthroughitsmetering
capabilities.

2. Cloud Computing Service Model
The CloudSPImodel isnormallyassociatedwiththree servicesincludingSaaS,PaaSand IaaS.Based
on the resourcesmade available tothe endusers,the three servicescanbe differentiated.The stack
of three abstractlayersincludinginfrastructure,platformandapplicationcanbe usedtorepresent
CloudComputinginfrastructure,where the bottomlayerprovideitsresourcesasservice tothe layer
above it.
 Software-as-s-service
Software’savailable onlinelikeDrop-Box,Facebook,andGoogle-Drive etc.canbe accessedbe the
consumersinsteadof installingthemontheirworkstations.
 Platform-as-a-Service
A platformismade available forthe programmersanddeveloperswheretheycancode and deploy
Cloudapplicationsconvenientlywithoutworryingaboutthe capacityof the applications.For
instance,MicrosoftAzure,andGoogle Appengine.
 Infrastructure-as-a-Service
Accordingto the requirementsof the application,computingresourcesinthe formof virtual
machine are providedwithpricesbasedonthe requirement.Moreover,the consumersare provided
withstorage and networkinfrastructuresaswell.OpenStack,Flexiscale,andAmazonEC2are some
examplesof Infrastructure-as-service.
Cloud Computing Deployment Model
Recently,fourtypesof deploymenthasbecome increasinglypopularamongthe CloudCommunity
includingPrivate cloud,Communitycloud,Publiccloud,andHybridcloud.
 Private cloud
Thisinfrastructure isusedsolelyinone organizationandmanagedbythe organizationitself orbya
third-party. Itcouldbe locatedbothon or off premise. There are multiple benefitsforsettingup
private cloudforan organization.Companieswheresecurityanddataprivacyare vital,private cloud
infrastructure become indispensable andanideal option. Moreover,itdecisivelyoptimize and
enhance the utilizationof onhandresources.Inadditiontothis,itiscost effectivecomparedtothe
cost involvedfortransferringdatafromlocal IT infrastructure toPublicCloud. Finally,universities
and researchcentersprefertohave private cloudforresearchworkand deliveringlectures.
 CommunityCloud
One of the dominantcommutingdeploymentmodelsinwhichmanyorganizationswithidentical
needs,problemsandpoliciesmake acoalitionanddevelopandshare commoncloudinfrastructure.
Thisinfrastructure canbe managedbya third-party or byany of the organizationfromthe group.
 PublicCloud
It isthe propertyof cloudservice providerswhocanhave hisownpoliciesandfull rightsforprofit,
costingand chargingto the general publiccloudusers.Some commonexamplesinclude Google App
Engine,Force.Com,andAmazonEC2.
 Hybrid Cloud
Two or more cloudsare combinedtogethertoforma HybridCloudinfrastructure.Standardized
techniquesare usedforembeddingtwocloudswhichallowsapplicationsanddataportability.This
model ispreferredbythe companieswhere peripheral businessfunctionsare transferredontothe
cloudand primarytasksare managedon-premisesusingprivate cloudinfrastructure.Asaresult,the

3. core competencesare enhancedandresourcesare optimized.However,thereare certaindrawbacks
relatedtohybridcloud,thatwill be addressedinlatersections.