Cloud computing allows users to access software and store data over the internet rather than locally on individual computers. It provides various services through different deployment models including public, private, hybrid and community clouds. The main cloud service models are Infrastructure as a Service (IaaS), Platform as a Service (PaaS), and Software as a Service (SaaS). While cloud computing provides advantages like scalability, cost savings, and mobility, security of stored data is a primary concern that requires measures like access control, authentication, authorization and encryption.

1. CLOUD COMPUTING

2. What is Cloud?
• Everyone is talking about “the cloud”. But what does it mean?
• Nowadays, business applications are moving to the cloud. Looking
ahead, the next decade of cloud computing promises new ways to
collaborate everywhere, through mobile devices.
• Traditional business applications have always been very complicated
and expensive. The amount and variety of hardware and software
required to run them are difficult. You need a whole team of experts to
install, configure, test, run, secure and update them.

3. • Cloud-based apps can be up and running in days or weeks, and they
cost les. With a cloud app, you just open a browser, log in, customize
the app and start using it.
• Businesses are running all kinds of apps in the cloud, like Customer
Relationship Management (CRM), HR, accounting, and much more.
Some of the world’s largest companies moved their applications to the
cloud with salesforce.com
• As cloud computing grows in popularity, thousands of companies are
simply rebranding their non-cloud products and services as “cloud
computing.”

4. What is Cloud Computing?
• If you’re unsure about what cloud computing is, you are probably
among 99% of people that are already using cloud services, like online
banking and social networks, but don’t realize it.
• The “cloud computing” is a set of different types of hardware and
software that work collectively to deliver many aspects of computing
to the end-user as an online services.
• The cloud is not a “fad”. There are currently 2.1 billion people using
Facebook worldwide.
• Cloud computing offers platform independency, as the software is not
required to be installed locally on the PC. User just need mobile, tablet
and internet to use any software directly from Cloud.

5. History of Cloud Computing
• Before emerging the cloud computing, there was Client/Server
computing which is basically a centralized storage in which all the
software applications, all the data and all the controls are resided on
the server side.
• If a single user wants to access specific data or run a program, he/she
need to connect to the server and then gain appropriate access, and
then he/she can do his/her business.
• Then after, distributed computing came into picture, where all the
computers are networked together and share their resources when
needed.
• On the basis of above computing, there was emerged of cloud
computing concepts that later implemented.

6. • At around in 1961, John MacCharty suggested in a speech at MIT that
computing can be sold like a utility, just like a water or electricity. It
was a brilliant idea, but like all brilliant ideas, it was ahead of its time,
as for the next few decades, despite interest in the model, the
technology simply was not ready for it.
• But of course time has passed and the technology caught that idea and
after few years we mentioned that:
• In 1999, salesforce.com started delivering of applications to users
using a simple website. The applications were delivered to enterprises
over the internet, and this way the dream of computing sold as utility
were true.

7. • In 2002, Amazon started Web Services, providing services like
storage, computation and even human intelligence.
• In 2009, Google also started to provide cloud computing enterprise
applications.
• Of course, all the big players are present in the cloud computing
evolution, some were earlier, some were later. In 2009, Microsoft
launched Windows Azure, and companies like Oracle and HP have all
joined the game. This proves that today, cloud computing has become
mainstream.

8. Characteristics of Cloud Computing
• High availability and reliability:
Availability of servers is high and more reliable, because chances of
infrastructure failure are minimal.
• High Scalability:
Means “on-demand” provisioning of resources on a large scale, without
having engineers for peak loads.
• Multi-Sharing:
With the help of cloud computing, multiple users and applications can work
more efficiently with cost reductions by sharing infrastructure.

9. • Device and Location Independence:
Cloud computing enables the users to access systems using a web browser
regardless of their location or what device they use e.g. PC, mobile phone etc.
As infrastructure provided by a third-party and accessed via the internet, users
can connect from anywhere.
• Maintenance:
Maintenance of cloud computing applications is easier, since they do not need
to be installed on each user’s computer and can be accessed from different
places. So, it reduces the cost also.
• Low Cost:
By using cloud computing, the cost will be reduced because to take the
services of cloud computing, IT company need not to set its own infrastructure
and pay-as-per usage of resources.

10. • Services in pay-per-use mode:
Application Programming Interfaces (APIs) are provided to the users so that
they can access services on the cloud by using these APIs and pay the charges
as per the usage of services.

11. ADVANTAGES OF CLOUD
COMPUTING
• Lower cost computer for users:
In cloud, you don’t require a high-powered (and accordingly high-priced) computer to
run cloud computing’s web based applications because applications run on cloud not
on desktop PC or laptop.
• Lower IT infrastructure cost:
By using cloud computing, you need not to invest in larger numbers of more powerful
servers, you also need not to require the IT staff handling such powerful servers.
• Fewer maintenance cost:
The maintenance cost in cloud computing greatly reduces both hardware and software
maintenance for organizations of all sizes.
• Lower Software cost:
It reduces the software cost because you don’t need to purchase separate software
packages for each computer in the organization.

12. • Instant software updates:
Another software-related advantage in cloud computing is that users don’t need to face
with the choice between obsolete software and high upgrade cost. If the app is web-based,
updates happen automatically and are available next time when the user logs into the cloud.
• Increased computing power:
The execution capacity of cloud servers are very high. It processes the application
very fast.
• Unlimited storage capacity:
Cloud offers you a huge amount of storage capacity like 2000 GB or more than that if
required.

13. Disadvantages of Cloud Computing
• require a constant internet connection:
Cloud computing is impossible without internet connection. To access any
application and document, you need a constant internet connection. –Require
High Speed internet connection.
Similarly, a low-speed internet connection makes cloud computing painful at
best and often impossible. Web-based apps often require a lot of bandwidth to
download, as need to download large documents.
• Stored data might not be secure:
With cloud computing, all your data is stored in the cloud. That’s all well and
good, but how secure is the cloud? Can’t unauthorized users gain access to
your confidential data?

14. Cloud Deployment Model
• There are 4 cloud deployment models:
 Public Cloud
 Private Cloud
 Hybrid Cloud
 Community Cloud

15. Public Cloud
• Public Cloud allows systems and services to be easily accessible to
general public. The IT company like Google, Amazon and Microsoft
offers cloud services via internet.

16. • Here you can see this is cloud with some services:

17. Advantages and Disadvantages of Public
Cloud
Advantages
• Location independence
• Cost effective (same resource to
multiple users)
• Flexibility (smoothly integrate
with private cloud)
• High scalability
• Reliability
• Pay-per-use
Disadvantages
• Low security
• Less customozable

18. Private Cloud
• Private cloud allows system services to be accessible within an
organization. The Private Cloud is operated only within single
organization.
• A Private Cloud is a particular model of cloud computing that involves
a distinct and secure cloud based environment in which only the
specified client can operate.
• As with other cloud models, private clouds will provide computing
power as a service within a virtualized environment using an
underlying pool of physical computing resources.
• The cloud is only accessible by a single organization providing that
organization with greater control and privacy.

19. Advantages and Disadvantages of Private
Cloud
Advantages
• Enhanced security and privacy
(not available to general public)
• Improved reliability
• Improved performance
• Increased flexibility
• Total control
Disadvantages
• High priced
• Platform scaling
• Additional skill

20. • The Hybrid Cloud is the mixture of public and private cloud. Non-
critical activities are performed by public cloud while critical
activities are performed by private cloud.
Hybrid Cloud

21. Advantages and Disadvantages of Hybrid
Cloud
Advantages
• Scalable (provide public &
private)
• Flexible and secure
• Cost effective
Disadvantages
• Networking issues (presence of
private & public cloud)
• Security policy

22. • 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 by organizations or by
the third-party.
Community Cloud

23. Advantages and Disadvantages of
Community Cloud
Advantages
• Cost effective
• Sharing among organizations
• security
Disadvantages
• Might be excisable to other

24. Cloud Service Model
• Infrastructure as a Service (IaaS)
• Platform as a Service (PaaS)
• Software as a Service (SaaS)

25. Infrastructure as a Service (IaaS)
• IaaS is one of the layers of cloud computing platform wherein the
customer organization outsources its IT infrastructure such as servers,
networking, processing, storage, virtual machines and other resources.
Customers access these resources over internet i.e. cloud computing
platform, on a pay-per-use model. IaaS, earlier called Hardware as a
Service (HaaS).
• IT infrastructure was rented out for a specific periods of time, with
pre-hardware configuration. The client paid for the configuration and
time.
• IaaS is offered in three models: public, private and hybrid cloud.

26. Top Vendors who are providing IaaS
• Amazon AWS
• Google Compute Engine
• Windows Azure
• Rackspace Open Cloud
• HP Enterprise
• IBM

27. Advantages of IaaS Cloud Computing
• You can dynamically choose a CPU, memory and storage
configuration as per your needs.
• You easily access the vast computing power available on IaaS cloud
Platform.
• You can eliminate the need of investment used in IT hardware.
• IT infrastructure will be handled by the IaaS cloud computing platform
vendors.

28. Disadvantages of IaaS Cloud Computing
• IaaS cloud computing platform model is dependent on internet
availability.
• It is also dependent on the availability of virtualization services.
• IaaS cloud computing platform can limit the user privacy and
customization options.

29. Platform as a Service (PaaS)
• PaaS cloud computing platform is a developer programming platform
which is created for the programmer to develop, test, run and manage
the applications.
• Instead of ready-made applications or services, PaaS provides the
platform for developing such applications and services.
• No need to manage backups. This is handled by the PaaS cloud
provider.
• A developer is able to write the application as well as deploy it directly
into this layer easily.
• All the infrastructure to run the applications will be over the internet.

30. Top Vendors who are providing PaaS
• Google Apps Engine (GAE)
• Salesdorce.com
• Windows Azure
• AppFog
• Openshift
• IBM Blue Mix
• AWS

31. Advantages of PaaS Cloud Computing
• Simplified development:
Developers can focus on development and innovation without worrying about the
infrastructure.
• Lower price:
No requirements of up-front investment in hardware and software. Developers only
need a PC and an internet connection to start building applications.
• Instant community:
PaaS vendors frequently provides online communities where developer can get ideas,
share experiences and seek advice from others.
• Scalability:
Applications deployed can scale from one to thousands of users without any change
to the applications.

32. Disadvantages of PaaS Cloud Computing
• Vendor lock-in:
One have to write the applications according to the platform provided by PaaS
vendor. So migration of an application to another PaaS vendor would be a
problem.
• Data privacy:
Corporate data, whether it can be critical or not, will be private. So if it is not
located within the walls of the company there can be a risk in terms of privacy
of data.
• Integration with the rest of the systems applications:
It may happen that some applications are local and some are in cloud. So there
will be chances of increased complexity when we want to use data which is in
the cloud with the local data.

33. Software as a Service (SaaS)
• Software as a Service (or SaaS) is a way of delivering applications
over the internet – as a service. Instead of installing and maintaining
software, you simply access it via the internet, you can free yourself
from complex software and hardware management. SaaS is one of
three main category of cloud computing services.
• SaaS remove the need for client to install and run the application on
their own computer or laptop. This eliminate the expense of hardware
and maintenance, as well as software licensing, installation and
support.

34. Characteristics of SaaS
• SaaS makes the software available over the internet.
• The software applications are maintained by the vendor.
• The license to the software may be subscription based or usage based.
• SaaS applications are cost-effective since they do not require any
maintenance at user side.
• They are available on demand.
• They can be scaled up or down on demand.
• They are automatically upgraded and updated.
• All users run the same version of the software.

35. Advantages of SaaS Cloud Computing
• Flexible payments:
Rather than purchasing software to install, or additional hardware to support it,
customers subscribe to a SaaS offering. Generally, they pay for this service on
a monthly basis using a pay-as-you-go model.
• Efficient use of software licenses:
The customer can have single license for multiple computers running at
different locations which reduces the licensing cost. Also, there is no
requirement for license servers because the software runs in the provider’s
infrastructure.
• Scalable usage:
Cloud services like SaaS offer high scalability, which gives customers the
option to access more, or fewer services or features on-demand.

36. • Automatic updates:
Rather than purchasing a new software, customers can rely on a SaaS provier
to automatically perform updates and patch management. This further reduces
the burden on in-house IT staff.
• Accessibility and persistence:
Since SaaS applications are delivered over the internet, users can access them
from any internet-enabled device and location.
• Platform responsibilities managed by providers:
All platform responsibilities such as backups, system maintenance, security,
hardware refresh, power management, etc. are performed by the cloud
provider. The customer does not need to bother about them.

37. Disadvantages of SaaS Cloud Computing
• Browser based risks:
If the customer visits malicious website so browser becomes infected, and
with that it’s chance to lose customer’s data.
To avoid such risks, the customer can use multiple browsers and dedicate a
specific browser to access SaaS applications or can use virtual desktop while
accessing the SaaS applications.
• Network dependence:
The SaaS application can be delivered only when network is continuously
available.

38. Cloud Computing Security
• Security in cloud computing is a major concern. Data in cloud should be
stored in encrypted form.
• Cloud computing security or, more simply, cloud security refers to a broad
set of policies, technologies, and controls deployed to protect data,
applications, and the associated infrastructure of cloud computing. It is a
sub-domain of computer security, and more broadly, information security.
• In cloud computing, there have a Data Center where clients’ data are stored,
and that data have a back up also, so in case if there is any earthquake or
natural disasters, client’s data are stored in other data center.
• If 1 data center is in India, then another backup data center will be in USA.

39. Security Associated with the Cloud
• Security concerns associated with cloud computing falls into two broad
categories: security issues faced by cloud providers (organizations
providing software-, platform-, or infrastructure-as-a-service via the cloud)
and security issues faced by their customers (companies or organizations
who host applications or store data on the cloud). The responsibility is
shared, however. The provider must ensure that their infrastructure is secure
and that their client’s data and applications are protected, while the user
must take measures to fortify their application and use strong passwords and
authentication measures.
• Encryption helps to protect data from being compromised. It protects data
that is being transferred as well as data stored in the cloud. Although
encryption helps to protect data from any unauthorized access, it does not
prevent data loss.

40. Since all the data is transferred using internet, data security is of major
concern in the cloud. Here are key mechanisms for protecting data.
• Access Control
Access control methods ensure that authorized users access the data and the
system.
• Auditing
In cloud computing, auditing is done automatically.
• Authentication
Cloud computing is changing the way we interact with devices, software, data
and processes. Identity management and authentication form the basis for
security whether in the cloud or on the local network.
• Authorization
Authorization is normally used in authentication for user identity verification.

41. Top Security Concerns for Cloud-based
Services
Data breaches
Hijacking of accounts
Insider threat
Malware injection
Insecure APIs
Denial of service attacks
Data loss
abuse of cloud services