The document discusses cloud computing and defines it as the delivery of computing resources over the Internet. It describes the key characteristics of cloud computing including on-demand self-service, broad network access, resource pooling, rapid elasticity, and measured service. It also discusses the benefits of cloud computing such as cost savings, scalability, reliability, and simplified maintenance. Finally, it outlines the important components needed to build a dynamic cloud infrastructure including service management, asset management, virtualization, and energy efficiency.

1. CLOUD COMPUTING 15-1
LEARNING OBJECTIVES
At the end of this chapter you will be able to understand:
m Introduction
m Definition of Cloud Computing
p Characteristics of Cloud Computing
p Benefits of Cloud Computing
m Cloud Infrastructure
m Service Delivery Models (IAAS, PAAS and SAAS)
m Cloud Deployment Models/ Types of Cloud
m Pros and Cons of Cloud Computing
15.1. INTRODUCTION
The term “Cloud” refers to a Network or Internet. In other words we can say that Cloud is
something which is present at remote location. Cloud can provide services over network, i.e.,
on public networks or on private networks, i.e. WAN, LAN or VPN. The applications such as e-mail,
web conferencing, CRM all run in cloud.
The term cloud computing is used to refer a new paradigm of new technology. It is the delivery
of computing resources over the Internet. Instead of keeping data on your own hard drive we
use a service over the Internet at another location to store your information or use its applications.
When we store our photos online instead of on our home computer, use webmail, a social
networking site you are using a “Cloud computing” service (Fig. 15.1). If we are an organization,
and want to use an online invoicing service that service is a “Cloud computing” service.

2. 15-2 CLOUD COMPUTING
Fig. 15.1. Cloud Computing
Over the past decade cloud computing has interrupted almost every part of IT, Sales, marketing
and finance. Examples of cloud services include online file storage, social networking sites,
webmail and online business applications. Many companies are delivering services from the
cloud. Some notable examples as of July, 2014 include the following :
1. Google. It has a private cloud that uses for delivering many different services to its users
including email access, document applications, text translations, maps, web analytics and much
more.
2. Microsoft. It has Microsoft® Share-point® online service that allows for content and business
intelligence tools to be moved into the cloud and Microsoft currently makes its office applications
available in a cloud.
3. Salesforce.com. This is a Force.com development platform. This provides a simple user
interface and lets users log in, build an app and push it in the cloud.
4. Amazon EC2. The Amazon EC2 (Elastic Compute Cloud) lets the users configure and control
computing resources while running them on Amazon's environment.
5. AT&T. The AT&T allows access to virtual servers and manages the virtualization infrastructure.
This virtualization infrastructure includes network, server and storage.
15.2. DEFINITIONS OF CLOUD COMPUTING
The Cloud computing is delivery of computing services over Internet. It allows individuals and
businesses to use software and hardware that are managed by third parties at remote locations.
"Cloud Computing refers to manipulating, configuring, and accessing the applications
online. It offers online data storage, infrastructure and application."
We need not to install a piece of software on our local PC and this is how the cloud computing
overcomes platform dependency issues as shown in Fig. 15.2. Hence, the Cloud Computing is
making our business application mobile and collaborative.

3. CLOUD COMPUTING 15-3
Fig. 15.2. Cloud Computing.
"Cloud computing consists of hardware and software resources made available on the
Internet as managed third-party services. These services typically provide access to
advanced software applications and high-end networks of server computers."
"Cloud computing is a model for enabling convenient, on-demand network access to a
shared pool of configurable computing resources (e.g., networks, servers, storage,
applications, and services) that can be rapidly provisioned and released with minimal
management effort or service provider interaction. This cloud model promotes availability
and is composed of five essential characteristics, three service models and four deployment
models".
National Institute of Standards and Technology (NIST)
Cloud computing virtualizes systems by pooling and sharing resources. Systems and storage
can be provisioned as needed from a centralized infrastructure, costs are assessed on a metered
basis, multi-tenancy is enabled, and resources are scalable with agility.
"Cloud computing means on demand delivery of IT resources via the internet with pay-as-
you-go pricing. It provides a solution of IT infrastructure in low cost."
Finally in Cloud computing as shown in Fig. 15.3, a user experience and a business model:
1. Standardized offerings
2. Rapidly provisioned
3. Flexibly priced
4. Ease of access

4. 15-4 CLOUD COMPUTING
Fig. 15.3. Cloud Computing
An infrastructure management and services delivery method:
1. Virtualized resources
2. Managed as a single large resource
3. Delivering services with elastic scaling
Retail point of sale similar to Banking ATMs, Cloud is driven by:
1. Self-Service
2. Economies of scale
3. Technology advancement
15.2.1. Characteristics of cloud computing
The Cloud computing has a variety of characteristics described by NIST are as following as
shown in Fig. 15.4.
Fig. 15.4. Cloud Computing Characteristics.
"Cloud computing allows for the sharing and scalable deployment of services as needed
from almost any location and for which the customer can be billed based on actual usage."
1. On-demand self-service. A consumer can use computing capabilities such as server time
and network storage automatically without requiring human interaction with each service
provider.

5. CLOUD COMPUTING 15-5
2. Broad network access. The capabilities are available over the network .They can accessed
through standard mechanisms by heterogeneous thin client platforms e.g., mobile phones, tablets,
laptops, and workstations.
3. Resource pooling.The provider's computing resources are pooled to serve multiple consumers
using a multi-tenant model. The different physical and virtual resources dynamically assigned
and reassigned according to consumer demand. There is a sense of location independence. The
customer generally has no control or knowledge over the exact location of the provided resources.
The may be able to specify location at a higher level of abstraction e.g., country, state or datacenter.
Examples of resources include storage, processing, memory, and network bandwidth.
4. Rapid elasticity. The capabilities can be elastically provisioned and released. In some cases
automatically to scale rapidly outward and inward commensurate with demand. To the consumer,
the capabilities available for provisioning often appear to be unlimited and can be appropriated
in any quantity at any time.
5. Measured service. Cloud systems automatically control and optimize resource. It leverage
the metering capability at some level of abstraction appropriate to the type of service e.g.,
storage, processing, bandwidth and active user accounts. Resource usage can be monitored,
controlled, and reported. It is provide transparency for both the provider and consumer of the
utilized service.
Apart of these five core features of cloud computing are on almost anybody’s list. We should
consider these additional features:
1. Lower costs. Because cloud networks operate at higher efficiencies and with greater
utilization, significant cost reductions are often encountered.
2. Ease of utilization. Depending upon the type of service being offered, you may find that
you do not require hardware or software licenses to implement your service.
3. Reliability. The scale of cloud computing networks and their ability to provide load
balancing and failover makes them highly reliable, often much more reliable than what
you can achieve in a single organization.
4. Outsourced IT management.A cloud computing deployment lets someone else manage
your computing infrastructure while you manage your business. In most instances, you
achieve considerable reductions in IT staffing costs.
5. Simplified maintenance and upgrade. Because the system is centralized, you can easily
apply patches and upgrades. This means your users always have access to the latest
software versions.
6. Quality of Service. The Quality of Service (QoS) is something that you can obtain
under contract from your vendor.
15.2.2. Benefits of Cloud Computing
The following are some of the possible benefits for those who offer cloud computing based
services and applications:
1. Cost savings. The companies can reduce their capital expenditures and use operational
expenditures for increasing their

6. 15-6 CLOUD COMPUTING
2. Computing capabilities. This is a lower barrier to entry and also requires fewer in houseIT
resources to provide system support.
3. Scalability. The companies can start with a small deployment and grow to a large
deployment fairly rapidly and then scale back if necessary. Also the flexibility of cloud
computing allows companies to use extra resources at peak times enabling them to satisfy
consumer demands.
4. Reliability. Services using multiple redundant sites can support business continuity and
disaster recovery.
5. Maintenance. Cloud service providers do the system maintenance, and access is through
APIs that do not require application installations onto PCs. It further reduces maintenance
requirements.
6. Mobile Accessible. Mobile workers have increased productivity due to systems accessible
in an infrastructure available from anywhere.
15.3. CLOUD AND DYNAMIC INFRASTRUCTURE
Cloud computing represents not a revolution but an evolution of existing enterprise computing
architectures dating back to the first instance of networked computing. The difference is that
today there are vast advances in virtualization in nearly every aspect of the data center. There
has also been an emergence of a dynamic understanding and need to control what, how, and
when the cloud provides services to the consumers of those services.
"This cloud dynamic paradigm must be able to intercept application and data traffic,
interpret the current context, and instruct the cloud infrastructure on how to most efficiently
deliver the request. These requirements include scalability, adaptability, extensibility and
manageability."
The world is smaller and flatter. The worldwide systems and infrastructure are reaching a
breaking point in following reasons.
1. The explosion of data, transactions and digitally-aware devices strains IT infrastructure
and operations.
2. The sudden increase growth in communications subscribers and services exposes
bandwidth limitations.
3. The supply inefficiencies and demand spikes tax energy and utility systems.
4. The networks, supply chains and borders face a proliferation of new risks and threats.
For the time being customer expectations and competitive pressures are increasing. According
to IBM the need for progress is clear.
1. In distributed computing environments, up to 85% of computing capacity sits idle.
2. Consumer product and retail industries lose about $40 billion annually, or 3.5 percent of
their sales, due to supply chain inefficiencies.
3. 70% on average is spent on maintaining current IT infrastructures versus adding new
capabilities.

7. CLOUD COMPUTING 15-7
4. Explosion of information driving 54% growth in storage shipments every year.
5. 33% of consumers notified of a security breach will terminate their relationship with the
company they perceive as responsible.
"The opportunity for progress is clear. Handles over 50% of global Trades, 1.5M new
customers each month and $75M annual operating cost savings. We must move past today's
challenges to seize tomorrow's opportunities. It's time to start thinking differently about
infrastructure."
15.3.1. Cloud Infrastructure Components
The cloud infrastructure consists of servers, storage and network and management software and
deployment software and platform virtualization as shown in Fig. 15.5.
Fig. 15.5. Cloud Infrastructure Components
1. Hypervisor. Hypervisor is a firmware or low-level program that acts as a Virtual Machine
Manager. It allows sharing the single physical instance of cloud resources between several
tenants.
2. Management software. The management Software helps to maintain and configure the
infrastructure.
3. Deployment software. The deployment software helps to deploy and integrate the application
on the cloud.
4. Network. The network is the key component of cloud infrastructure. It allows connecting
cloud services over the Internet. It is also possible to deliver network as a utility over the Internet,
i.e., the consumer can customize the network route and protocol.
5. Server. The server helps to compute the resource sharing and offer other services such as
resource allocation and de-allocation, monitoring resources, security, etc.
6. Storage. The cloud uses distributed file system for storage purpose. If one of the storage
resources fails, then it can be extracted from another one which makes cloud computing more
reliable.
15.3.2. Infrastructural Constraints
The fundamental constraints that cloud infrastructure should implement are shown in the
following Fig. 15.6.

8. 15-8 CLOUD COMPUTING
Fig. 15.6. Infrastructural Constraints
1. Transparency. Since virtualization is the key to share resources in cloud environment. But it
is not possible to satisfy the demand with single resource or server. Therefore, there must be
transparency in resources, load balancing and application, so that we can scale them on demand.
2. Scalability. Scaling up an application delivery solution is not that easy as scaling up an
application because it involves configuration overhead or even re-architecting the network. So,
application delivery solution is needed to be scalable which will require the virtual infrastructure
such that resource can be provisioned and de-provisioned easily.
3. Monitoring. To achieve transparency and scalability, application solution delivery will need
to be capable of intelligent monitoring.
4. Security. The mega data center in the cloud should be securely architected. Also the control
node, an entry point in mega data center also needs to be secure.
15.3.3. Building a dynamic infrastructure
In this smarter world we need our infrastructure to drive us forward not hold us back. Infrastructure
that is instrumented, interconnected and intelligent. The infrastructure that brings together
business and IT to create new possibilities. We need a dynamic infrastructure that addressing
today's challenges and tomorrow's opportunities. It needs:
1. Improve service. It is not only ensuring high availability and quality of existing services, but
also meeting customer expectations for real-time, dynamic access to innovative new services.
2. Reduce cost. It is not just containing operational cost and complexity, but achieving
breakthrough productivity gains through virtualization, optimization, energy stewardship and
flexible sourcing.
3. Manage risk. It is Not only addressing today's security, resiliency, and compliance challenges,
but also preparing for the new risks posed by an even more connected and collaborative world.
So the dynamic infrastructure must be provide Service and asset management, virtualization,
energy efficiency, business resiliency, security and information infrastructure as shown in
Fig. 15.7.

9. CLOUD COMPUTING 15-9
Fig. 15.7. Building a Dynamic Infrastructure
1. Service management. The service management provides visibility, control and automation
across all the business and IT assets to deliver higher value services. It need to:
(a) Create an integrated, actionable and insightful view into critical metrics.
(b) Improve process discipline while remaining effective while systems grow.
(c) Improve quality and reduce costs through operational and workflow automation.
2. Asset management. Asset management maximizing the value of critical business and IT
assets over their lifecycle with industry tailored asset management solutions. It need to:
(a) Address all types of assets : production, delivery, transportation, facilities, infrastructure
and IT. Enforce best practices across the enterprise and reliable operations.
(b) Manage security policy compliance track hardware and software deployment.
(c) Manage audit, lease and software compliance exposures and combine inventory,
maintenance, contacting processes.
(d) Physical devices are becoming IP enabled - smart meter. Embedded IT improves asset
performance and remote monitoring and automation.
(e) Industry specific solutions for Nuclear Power, Utilities, Transportation, Life Sciences,
and Oil & Gas. Supporting infrastructure with Spatial and Linear Asset Management.
3. Virtualization. The leadership virtualization and consolidation solutions that reduce cost,
improve asset utilization and speed provisioning of new services. It need to:
(a) Reduce operating costs. Consolidate via virtualization to fewer systems simplify
management of the infrastructure and recapture floor space through consolidation.

10. 15-10 CLOUD COMPUTING
(b) Manage availability in a 24/7 world. Increase availability and improve resiliency, manage
and secure data without affecting its availability.
(c) Improve system, network and application performance. Process more information in
real-time to make better business decisions and bring new services online quickly.
4. Energy Efficiency. It address energy, environment and sustainability challenges and
opportunities across your business and IT infrastructure. It need to:
(a) Reduce energy costs. Implement more energy efficient servers and storage.
(b) Increase IT utilization and efficiency, Improve service with increased flexibility and
resilience.
(c) Data center facilities: Extend the life of existing data centers. Rationalize data center
infrastructure across the company and design flexibility into my new data center
infrastructure.
(d) Energy management : Understand energy consumption. Produce reports to demonstrate
energy savings over time. Put policies in place to manage and control energy use.
(e) Environmental leadership : Comply with emerging stricter controls over energy
consumption, greenhouse gases, and disposal of hazardous substances. Align IT with
corporate sustainability initiatives to drive brand value.
5. Business Resiliency. It is maintaining continuous business and IT operations while rapidly
adapting and responding to risks and opportunities. The need:
(a) Effectively manage risk for key business services in a 24/7 world.
(b) Minimize impact of potentially disruptive events by determining the right resilience
strategy – by business process.
(c) Maintain business operations and services.
(d) Respond more effectively to unforeseen events. Deploy resilience for services, operations
and people.
(e) Assess business uptime needs against resiliency requirements.
(f) Ensure risk posture meets policies and regulations. Derive insight via dashboards, alerts
and reporting. Utilize mixed sources for resilience; in-house, out task,
6. Security. It is the end to end industry customized governance, risk management and
compliance solutions. It need to:
(a) Provide end-to-end risk management.
(b) Reduce the cost of security.
(c) Ensure secure service delivery.
(d) Respond with speed and agility.
7. Information infrastructure. It is helping businesses achieve information compliance,
availability, retention, and security objectives. It need:
(a) Maintain accurate, reliable, and complete information.
(b) Manage compliance as an organization-wide process.
(c) Meet service level commitments by design.
(d) Reduce disruptions, planned and unplanned.
(e) Reduce risk and cost of litigation and audit deficiency.

11. CLOUD COMPUTING 15-11
(f) Retain and manage business information efficiently.
(g) Reduce business and legal risk by purging expired data.
(h) Ensure the security of confidential data.
(i) Provide secure, policy-based access to information.
(j) Audit and report security breaches as required.
15.4. CLOUD SERVICE MODELS
Based on the services that the cloud provides mainly there are three types of cloud-computing
models: Infrastructure-as-a-Service (IaaS), Platform-as-a-Service (PaaS), and Software-as-a-
Service as shown in Fig.15.8.
Fig. 15.8. Cloud Service Models
"The cloud service models are Software as a Service (SaaS), Platform as a Service' (PaaS)
and Infrastructure as a Service (IaaS)."
1. Software as a Service (SaaS). The capability provided to the consumer is to use the provider's
applications running on a cloud infrastructure. There are several SaaS applications some of
them are listed below:
(a) Billing and Invoicing System
(b) Customer Relationship Management (CRM) applications
(c) Help Desk Applications
(d) Human Resource (HR) Solutions
Examples of SaaS offerings include :
(i) Google Apps. It offers Web-based email, calendar, document management, and web site
creation and management.
(ii) Microsoft Office 365. It offers Email, calendar, Office Web Apps, web conferencing
and file sharing.
(iii) NetSuite. It offers Business-management software applications that include accounting,
enterprise resource planning (ERP), inventory management, customer relationship
management (CRM) and e-Commerce .
(iv) Salesforce. CRM software application.
2. Platform as a Service (PaaS). PaaS offers the runtime environment for applications. It also
offers development & deployment tools, required to develop applications. PaaS has a feature of

12. 15-12 CLOUD COMPUTING
point-and-click tools that enables non-developers to create web applications.
Google's App Engine, Force.com is examples of PaaS offering vendors. Developer may log on
to these websites and use the built-in API to create web-based applications. Examples of PaaS
offerings include:
(a) Google App Engine. The platform is used to develop and run Java, Python and Go
applications on Google's infrastructure.
(b) Microsoft Windows Azure. It is on-demand compute and storage services as well as a
development and deployment platform for applications that run on Windows
(c) Salesforce Force.com. This platform is used to build and run applications and components
bought from App Exchange or custom applications.
(d) CloudBees. This is the platform to build, deploy, and manage Java applications.
3. Infrastructure as a Service (IaaS). The capability provided to the consumer is to provision
processing, storage, networks, and other fundamental computing resources where the consumer
is able to deploy and run arbitrary software, which can include operating systems and applications.
IaaS provides access to fundamental resources such as physical machines, virtual machines,
virtual storage, etc., Apart from these resources, the IaaS also offers:
(a) Virtual machine disk storage (b) Virtual local area network (VLANs)
(c) Load balancers (d) IP addresses
(e) Software bundles
All of the above resources are made available to end user via server virtualization. Moreover,
these resources are accessed by the customers as if they own them. Examples of IaaS offerings
include:
(i) Amazon Elastic Compute Cloud (EC2). Special virtual machines called Amazon
Machine Images (AMI), that can be deployed and run on the EC2 infrastructure Amazon
Simple Storage.
(ii) GoGrid Cloud Servers. Dynamically scalable computation and storage resources.
(iii) Rackspace Cloud Servers. Dynamically scalable computing, storage, and load-balancing
resources.
Some other service models are :
(a) Identity as a Service (IDaaS). Employees in a company require to login into system to
perform various tasks. These systems may be based on local server or cloud based. Following
are the problems that an employee might face:
(i) Remembering different username and password combinations for accessing multiple
servers.
(ii) If an employee leaves the company, it's required to ensure that each of the user's account
has been disabled. This increases workload on IT staff.
To solve above problems, a new technique emerged which is known as Identity as a Service
(IDaaS). Identity refers to set of attributes associated with something and make it recognizable.
All objects may have same attributes, but their identity cannot be the same. This unique identity
is assigned through unique identification attribute. There are several identity services that have

13. CLOUD COMPUTING 15-13
been deployed to validate services such as validating web sites, transactions, transaction
participants, client, etc. Identity as a Service may include the following:
(i) Directory Services (ii) Federated Services
(iii) Registration (iv) Authentication Services
(v) Risk and Event monitoring (vi) Single sign-on services
(vii) Identity and Profile management
(b) Networks as a Service(NaaS). It allows us to access to network infrastructure directly and
securely. NaaS makes it possible to deploy custom routing protocols. NaaS uses virtualized
network infrastructure to provide network services to the consumer. It is the responsibility of
NaaS provider to maintain and manage the network resources which decreases the workload
from the consumer. Moreover, NaaS offers network as a utility. NaaS is also based on pay-per-use
model.
15.5. CLOUD DEPLOYMENT MODELS /TYPES OF CLOUD
The clouds come in different forms: public clouds, private clouds, hybrids clouds. It depending
on the type of data we are working with we will want to compare public, private and hybrid
clouds in terms of the different levels of security and management required.
15.5.1. Public Cloud
The public cloud allows systems and services to be easily accessible to general public (as shown
in Fig. 15.9) e.g., Google, Amazon, Microsoft offers cloud services via Internet.
Fig. 15.9. Public Cloud Deployment Model
Advantages. There are many benefits of deploying cloud as public cloud model:
1. Cost effective. Since public cloud share same resources with large number of consumer,
it has low cost.
2. Reliability. Since public cloud employs large number of resources from different locations,
if any of the resource fail, public cloud can employ another one.

14. 15-14 CLOUD COMPUTING
3. Flexibility. It is also very easy to integrate public cloud with private cloud, hence gives
consumers a flexible approach.
4. Location independence. Since public cloud services are delivered through Internet,
therefore ensures location independence.
5. Utility style costing. Public cloud is also based on pay-per-use model and resources are
accessible whenever consumer needs it.
6. High scalability. Cloud resources are made available on demand from a pool of resources,
i.e., they can be scaled up or down according the requirement.
Disadvantages. Here are the disadvantages of public cloud model:
1. Low security. In public cloud model, data is hosted off-site and resources are shared
publicly, therefore does not ensure higher level of security.
2. Less customizable. It is comparatively less customizable than private cloud.
15.5.2. Private cloud
The private cloud allows systems and services to be accessible within an organization as shown
in Fig. 15.10. The Private Cloud is operated only within a single organization. However It may
be managed internally or by third-party.
Fig. 15.10. Private Cloud Deployment Model
Advantages. There are many benefits of deploying cloud as private cloud model.
1. Higher security and privacy. Private cloud operations are not available to general public
and resources are shared from distinct pool of resources, therefore, ensures high security
and privacy.

15. CLOUD COMPUTING 15-15
2. More control. Private clouds have more control on its resources and hardware than
public cloud because it is accessed only within an organization.
3. Cost and energy efficiency. Private cloud resources are not as cost effective as public
clouds but they offer more efficiency than public cloud.
Disadvantages. Here are the disadvantages of using private cloud model:
1. Restricted area. Private cloud is only accessible locally and is very difficult to deploy
globally.
2. Inflexible pricing. In order to fulfill demand, purchasing new hardware is very costly.
3. Limited scalability. Private cloud can be scaled only within capacity of internal hosted
resources.
4. Additional skills. In order to maintain cloud deployment, organization requires more
skilled and expertise.
15.5.3. Hybrid Cloud
The hybrid cloud is a mixture of public and private cloud as shown in Fig. 15.11. Non-critical
activities are performed using public cloud while the critical activities are performed using
private cloud.
Fig. 15.11. Hybrid Cloud deployment Model
Advantages. There are many benefits of deploying cloud as hybrid cloud model.
1. Scalability. It offers both features of public cloud scalability and private cloud scalability.
2. Flexibility. It offers both secure resources and scalable public resources.
3. Cost efficiencies. Public cloud are more cost effective than private, therefore hybrid
cloud can have this saving.
4. Security. Private cloud in hybrid cloud ensures higher degree of security.
Disadvantages:
1. Networking issues. Networking becomes complex due to presence of private and public
cloud.
2. Security compliance. It is necessary to ensure that cloud services are compliant with
organization's security policies.
3. Infrastructural dependency. The hybrid cloud model is dependent on internal IT
infrastructure, therefore it is necessary to ensure redundancy across data centers.

16. 15-16 CLOUD COMPUTING
15.5.4. Community Cloud
The community cloud allows system and services to be accessible by group of organizations. It
shares the infrastructure between several organizations from a specific community. It may be
managed internally or by the third-party as shown in Fig. 5.12.
Fig. 15.12. Community Cloud Deployment Model
Advantages: There are many benefits of deploying cloud as community cloud model.
1. Cost effective. Community cloud offers same advantage as that of private cloud at low
cost.
2. Sharing between organizations. Community cloud provides an infrastructure to share
cloud resources and capabilities among several organizations.
3. Security. Community cloud is comparatively more secure than the public cloud.
Disadvantages :
1. Since all data is housed at one location, one must be careful in storing data in community
cloud because it might be accessible by others.
2. It is also challenging to allocate responsibilities of governance, security and cost.
15.6. PROS AND CONS OF CLOUD COMPUTING
Cloud computing offers numerous advantages both to end users and businesses of all sizes. The
obvious huge advantage is that we no more have to support the infrastructure or have the
knowledge necessary to develop and maintain the infrastructure, development environment or
application, as were things up until recently.

17. CLOUD COMPUTING 15-17
"The burden has been lifted and someone else is taking care of all that. Businesses are
now able to focus on their core business by outsourcing all the hassle of IT infrastructure.
Some of the most important advantages of cloud computing and discuss them in more
detail".
Pros of cloud computing. The Pros of cloud computing are as following:
1. Cost efficiency. This is the biggest advantage of cloud computing, achieved by the elimination
of the investment in stand-alone software or servers. By leveraging cloud's capabilities, companies
can save on licensing fees and at the same time eliminate overhead charges such as the cost of
data storage, software updates, management etc. The cloud is in general available at much
cheaper rates than traditional approaches and can significantly lower the overall IT expenses.
At the same time, convenient and scalable charging models have emerged (such as one-time-payment
and pay-as-you-go), making the cloud even more attractive.
2. Convenience and continuous availability. Public clouds offer services that are available
wherever the end user might be located. This approach enables easy access to information and
accommodates the needs of users in different time zones and geographic locations. As a side
benefit, collaboration booms since it is now easier than ever to access, view and modify shared
documents and files.
3. Increased storage capacity. The cloud can accommodate and store much more data compared
to a personal computer and in a way offers almost unlimited storage capacity. It eliminates
worries about running out of storage space and at the same time It spares businesses the need to
upgrade their computer hardware, further reducing the overall IT cost.
4. Backup and recovery. The process of backing up and recovering data is simplified since
those now reside on the cloud and not on a physical device. The various cloud providers offer
reliable and flexible backup/recovery solutions. In some cases, the cloud itself is used solely as
a backup repository of the data located in local computers.
5. Cloud is environmentally friendly. The cloud is in general more efficient than the typical
IT infrastructure and It takes fewer resources to compute, thus saving energy.
For example, when servers are not used, the infrastructure normally scales down, freeing up
resources and consuming less power. At any moment, only the resources that are truly needed
are consumed by the system.
6. Resiliency and redundancy. A cloud deployment is usually built on a robust architecture
thus providing resiliency and redundancy to its users. The cloud offers automatic failover between
hardware platforms out of the box, while disaster recovery services are also often included.
7. Scalability and performance. A cloud system can be up and running in a very short period,
making quick deployment a key benefit. On the same aspect, the introduction of a new user in
the system happens instantaneously, eliminating waiting periods.
8. Device diversity and location independence. Cloud computing services can be accessed
via a plethora of electronic devices that are able to have access to the internet. These devices
include not only the traditional PCs, but also smart phones, tablets etc. With the cloud, the
"Bring your own device" (BYOD) policy can be easily adopted, permitting employees to bring
personally owned mobile devices to their workplace.

18. 15-18 CLOUD COMPUTING
Cons of cloud computing. The cons of cloud computing are as following :
"As made cloud computing is a tool that offers enormous benefits to its adopters. However
being a tool it also comes with its set of problems and inefficiencies."
1. Security issues. How safe is your data ? Cloud computing means Internet computing. So we
should not be using cloud computing applications that involve using or storing data that we are
not comfortable having on the Internet. That being said, established, reliable cloud computing
vendors will have the latest, most sophisticated data security systems possible as they want your
business and realize that data security is a big concern.
2. Dependency. One of the major disadvantages of cloud computing is the implicit dependency
on the provider. This is what the industry calls vendor lock-in since it is difficult, and sometimes
impossible, to migrate from a provider once we have rolled with him. If a user wishes to switch
to some other provider, then it can be really painful and cumbersome to transfer huge data from
the old provider to the new one. This is another reason why we should carefully and thoroughly
contemplate all options when picking a vendor.
3. Technical difficulties and downtime. Certainly the smaller business will enjoy not having
to deal with the daily technical issues and will prefer handing those to an established IT company,
however we should keep in mind that all systems might face dysfunctions from time to time.
Outage and downtime is possible even to the best cloud service providers, as the past has shown.
4. Limited control. Since the applications and services run on remote, third party virtual
environments, companies and users have limited control over the function and execution of the
hardware and software. Moreover, since remote software is being used it usually lacks the
features of an application running locally.
5. Inflexibility. Be careful when we are choosing a cloud computing vendor that we are not
locking your business into using their proprietary applications or formats. We can not insert a
document created in another application into a Google Doc spreadsheet. Also make sure that we
can add and subtract cloud computing users as necessary as your business grows or contracts.
6. Increased weakness. Related to the security and privacy mentioned before, note that cloud
based solutions are exposed on the public internet and are thus a more vulnerable target for
malicious users and hackers. Nothing on the Internet is completely secured and even the biggest
players suffer from serious attacks and security breaches. Due to the interdependency of the
system if there is a compromise one of the machines that data is stored, there might be a leakage
of personal information to the world.
POINT TO REMEMBER
1. Cloud computing refers to the delivery of computing resources over the Internet
2. The examples of cloud services include online file storage, social networking sites,
webmail, and online business applications
3. The IaaS capability provided to the consumer is to provision processing, storage, networks
and other fundamental computing resources where the consumer is able to deploy and
run arbitrary software which can include operating systems and applications.

19. CLOUD COMPUTING 15-19
4. The PaaS capability provided to the consumer is to deploy onto the cloud infrastructure
consumer-created or acquired applications created using programming languages, libraries,
services and tools supported by the provider
5. The SaaS capability provided to the consumer is to use the provider's applications running
on a cloud infrastructure.
6. The private cloud is cloud infrastructure dedicated to a particular organization. It allows
businesses to host applications in the cloud while addressing concerns regarding data
security and control which is often lacking in a public cloud environment
7. A community cloud serves a group of cloud consumers which have shared concerns such
as mission objectives, security, privacy and compliance policy, rather than serving a single
organization as does a private cloud.
8. The cloud infrastructure is provisioned for open use by the general public. It may be
owned, managed, and operated by a business, academic or government organization or
some combination of them.
9.. The hybrid clouds are a composition of two or more clouds private, community or public
that remain unique entities but are bound together offering the advantages of multiple
deployment models
KEY TERMS
 National Institute for Standards and Technology (NIST)
 Cloud Infrastructure
 Service Delivery Models
 Cloud Deployment Models
 Infrastructure as a Service (IaaS)
m Platform as a Service (PaaS)
m Software as a Service (SaaS)
m Public clouds
m Private clouds
m Community Clouds
m Hybrids clouds
SOLVED QUESTION
Q. 1. What is cloud computing?
Ans. Cloud computing is the delivery of computing services over the Internet. Whether they
realize it or not many people use cloud computing services for their own personal needs. For
example, many people use social networking sites or webmail, and these are cloud services.
Photographs that people once kept on their own computers are now being stored on servers
owned by third parties. These are also examples of cloud services. Cloud services are popular
because people can access their e-mail, social networking site or photo service from anywhere
in the world, at any time, at minimal or no charge.
Q. 2. Why are organizations interested in cloud computing?
Ans. Cloud computing can significantly reduce the cost and complexity of owning and operating
computers and networks. If an organization uses a cloud provider, it does not need to spend

20. 15-20 CLOUD COMPUTING
money on information technology infrastructure, or buy hardware or software licenses. Cloud
services can often be customized and flexible to use, and providers can offer advanced services
that an individual company might not have the money or expertise to develop.
Q. 3. What are the properties of Cloud Computing?
Ans. There are six key properties of cloud computing: Cloud computing is
(a) User-centric (b) Task-centric
(c) Powerful (d) Accessible
(e) Intelligent (f) Programmable
Q.4. What are the pros and cons of Cloud Computing?
Ans. The pros and cons of cloud computing are as following:
Pros:
(a) Lower-cost computers for users (b) Improved performance
(c) Lower it infrastructure costs (d) Fewer maintenance issues
(e) Lower software costs (f) Instant software updates
(g) Increased computing power (h) Unlimited storage capacity
(i) Increased data safety
(j) Improved compatibility between operating systems
(k) Improved document format compatibility
(l) Easier group collaboration
(m) Universal access to documents
(n) Latest version availability
(o) Removes the tether to specific devices
Cons:
(a) Requires a constant internet connection
(b) Does not work well with low-speed connections
(c) Can be slow
(d) Features might be limited
(e) Stored data might not be secure
(f) If the cloud loses your data you are screwed
Q. 5. Who get benefits from cloud computing?
Ans. The following get benefits :
(a) Collaborators (b) road warriors
(c) cost-conscious users (d) cost-conscious
(e) IT departments (f) users with increasing needs
Q. 6. List the companies who offer cloud service development?
Ans. The companies who offer cloud service are:
(a) Amazon (b) Google App Engine
(c) IBM (d) Salesforce.com
Q. 7. Explain the cloud computing deployment model.
Ans. The National Institute of Standards and Technology (NIST) is emerging as the preferred
provider of the real definition of cloud computing and the distribution models. To deploy cloud

21. CLOUD COMPUTING 15-21
computing, the US National Institute of Standards and Technology (NIST) listed 4 models.
(a) Private cloud. A cloud infrastructure is operated only for a single organization. In other
words the proprietary network or the data center supplies hosted services to a certain
group of people.
(b) Community cloud. The cloud infrastructure is shared by several organizations with
common concerns like mission, security requirements, policy, compliance considerations
etc. is known as community cloud.
(c) Public cloud. The cloud infrastructure is provisioned for open use by the general public.
It may be owned, managed, and operated by a business, academic, or government
organization, or some combination of them. It exists on the premises of the cloud provider.
(d) Hybrid cloud. The cloud infrastructure is a composition of two or more distinct cloud
infrastructures such as private, community, or public that remain unique entities, but are
bound together by standardized or proprietary technology that enables data and application
portability e.g., cloud bursting for load balancing between clouds."
Q. 8. Explain the different Cloud Service Models.
Ans. Cloud Computing is in its simplest form, an image for the Internet and the process of
delivering applications and services through it. Cloud computing within this image there are a
number of services that are delivered via the Internet. These include Software as a Service
(SaaS), Platform as a Service' (PaaS) and Infrastructure as a Service' (IaaS).
(a) Software as a Service (SaaS). The capability provided to the consumer is to use the
provider's applications running on a cloud infrastructure.
(b) Platform as a Service (PaaS). The capability provided to the consumer is to deploy
onto the cloud infrastructure consumer-created or acquired applications created using
programming languages, libraries, services, and tools supported by the provider.
(c) Infrastructure as a Service (IaaS). The capability provided to the consumer is to
provision processing, storage, networks, and other fundamental computing resources where
the consumer is able to deploy and run arbitrary software, which can include operating
systems and applications.
MULTIPLE CHOICE QUESTIONS
1. What is Cloud Computing replacing?
(a) Corporate data centers (b) Expensive personal computer hardware
(c) Expensive software upgrades (d) All of the above
2. What is the number one concern about cloud computing?
(a) Too expensive (b) Security concerns
(c) Too many platforms
3. Which of these companies is not a leader in cloud computing?
(a) Google (b) Amazon
(c) Blackboard (d) Microsoft
4. Google Docs is a type of cloud computing
(a)True (b) False

22. 15-22 CLOUD COMPUTING
5. Which one of these is not a cloud computing pricing model?
(a) Free (b) Pay Per Use
(c) Subscription (d) Ladder Perpetual License
6. Which of these is not a major type of cloud computing usage?
(a) Hardware as a Service (b) Platform as a Service
(c) Software as a Service (d) Infrastructure as a Service
7. An Internet connection is necessary for cloud computing interaction.
(a) True (b) False
8. Which is not a major cloud computing platform?
(a) Google 101 (b) IBM Deep blue
(c) Microsoft Azure (d) Amazon EC2
9. Cloud in cloud computing represents what?
(a) Wireless (b) Hard drives
(c) People (d) Internet
10. Which of these should a company consider before implementing cloud computing
technology?
(a) Employee satisfaction (b) Potential cost reduction
(c) Information sensitivity (d) All of the above
ANSWER
1. (d) 2. (b) 3. (c) 4. (a) 5. (d)
6. (a) 7. (a) 8. (b) 9. (d) 10. (d)
UNSOLVED QUESTIONS
1. What is the meaning and definitions of cloud computing? Explain with suitable examples.
2. Explain the characteristics of Cloud Computing.
3. Explain cloud computing deployment model.
4. Describe the cloud infrastructure with suitable diagram.
5. Discuss about the pros and cons of cloud computing.
6. Explain the cloud service development.
7. Explain the types of cloud service development in detail.
