Contents

• Introduction• Why Cloud?• History of Cloud • Evolution of Cloud• Definition of Cloud• Cloud Models• Pros and Cons• Security Issues• Summary• References• Query

The spread of high-speed broadband

networks in developed countries, the

continual increase in computing power,

and the growth of the Internet have

changed the way in which society

manages information and information

services.

Why Cloud?

Imagine the absence of a power grid

throughout the nation, necessitating the

presence of a  generator in every home for

producing electricity. Well, why do we have

our computers filled with software we use

occasionally? Wouldn’t it be meaningful to

use software the same way we use

electricity – as and when we need it?This was the defining thought behind

cloud computing.

In 1960, J.C.R. Licklider is person who brought the idea of cloud computing to the forefront. In 1961, John McCarthy suggested in a speech at MIT that computing can be sold like a utility, like electricity/water. In 1997, Ramnath Chellappa – first known academic use of the term “Cloud Computing”

In 1999, Salesforce started delivering applications to users using a simple website. In 2002, Amazon started Amazon Web Services, providing services like storage, computation and even human intelligence. However, the launch of the Elastic Compute Cloud in 2006, open to everybody existed. In 2009, Google Apps, Microsoft Windows Azure, and companies like Oracle and HP have all joined the game.

Common Location Independent Online  Utility (that is available on) Demand simplifies the meaning of CLOUD -

(Chan, 2009).

The Cloud delivers a hosting environment that is immediate, flexible, elastic, scalable, secure, and available – while saving money, time and resources

• Instead of hosting apps and data on an individual desktop computer, everything is hosted in the "cloud"—an assemblage of computers and servers accessed via the Internet.

SaaS - 'Software as a Service', describes when users

'rent' or borrow online software instead of actually

purchasing and installing it on their own computers. 

Instead of selling you a copy of Microsoft Word for

$300, a cloud computing model would "rent" word

processing software to you through the Internet for

$5 a month. You would not install any special

software to your home machine to use this rented

online product. You simply use your modern web

browser to login from any web-enabled computer,

and you can access your word processing documents

in the same way that you would access your Gmail.

PaaS (Platform as a service), as the

name suggests, provides you

computing platforms which typically

includes operating system,

programming language execution

environment, database, web server

etc.

Examples : AWS Elastic Beanstalk,

Heroku, Force.com, Google App Engine.

IaaS(Infrastructure as a service), as the name

suggests, provides you the computing infrastructure,

physical or virtual machines and other resources like

virtual-machine disk image library, block and file-

based storage, firewalls, load balancers, IP addresses,

virtual local area networks etc.

Infrastructure as a Service (IaaS) describes one of the

three main methods of accessing cloud computing

based services. Organisations rent computing power

and disk space and access them from desktop PCs

through a private network or across the internet.

Examples : Amazon EC2, Windows Azure, Rackspace.

Public cloud -- The cloud infrastructure is made available to the general public or a large industry group and is owned by an organization selling cloud services.

Public cloud services may be free or offered on a pay-per-usage model.

BenefitsEasy and inexpensive set-up because

hardware, application and bandwidth costs are covered by the provider.

No wasted resources because you pay for what you use.

Examples Amazon Elastic Compute Cloud (EC2), IBM's Blue Cloud, Sun Cloud, Google AppEngine and Windows Azure Services Platform.

Private cloud -- The cloud infrastructure

is operated solely for an organization. It

may be managed by the organization

or a third party and may exist on

premise or off premise.

A private cloud can increase efficiency,

decrease costs and offer more security

than a public cloud.

Examples Eucalyptus, Elastra, VMware

and Windows Azure Services Platform.

Hybrid cloud -- The cloud infrastructure is a

composition of two or more clouds (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).

Government departments, universities, central

banks etc. often find this type of cloud useful.

Examples Google Apps for Government,

Microsoft Government Community Cloud

Community cloud -- The cloud infrastructure is shared by

several organizations and supports a specific community

that has shared concerns (e.g., mission, security

requirements, policy, and compliance considerations).

The goal of a community cloud is to have participating

organizations realize the benefits of a public cloud -- such

as multi-tenancy and a pay-as-you-go billing structure --

but with the added level of privacy, security and policy

compliance usually associated with a private cloud. The

community cloud can be either on-premises or off-

premises, and can be governed by the participating

organizations or by a third-party managed service

provider

Cloud computing requires an intricate interaction

with the hardware which is very essential to

ensure uptime of the application. It is very helpful

to divide the cloud model into two sections, one is

front end and other is backend.

They are connected via a network and mostly

internet is used for fulfilling the requirement. The

front side is the interface for the user and the

back end is the cloud section for the whole

system.

COMPLIANCE

COMPLIANCE

DATA MOBILITY

DATA MOBILITY

PRIVACY

PRIVACY

SERVICE LEVELS

SERVICE LEVELS

RISKS OF CLOUD

COMPUTING

Data Migration/Mobility

It is the process of moving or transferring

data, application from your machine to cloud

and vice-versa. Moving to the cloud or

between cloud environments presents the

usual IT issues, but the problems are

compounded by having data stored and

managed remotely, by external organizations

and often in multiple locations.

Cloud disaster recovery and backup options

have become more common, and some users

say they provide a higher level of protection

than traditional solutions -- at lower cost

Performance metrics How fast is the cloud server’s vCPU? How quickly do memory and disk respond? What is the actual network throughput?Naturally, cloud providers offer systems that are

different "sizes" with regard to power and price. Offerings typically have two key dimensions: CPU and memory (RAM).

Supplier’s own privacy & security policies. What are the supplier’s own procedures and policies? Do they include physical security? What about removal of data from premises on removable media? Does the supplier have an understanding of the role of the applicable privacy regulatory authorities, and procedures to respond to enquiries and complaints?

Privacy and data control issues are significant

in the context of cloud computing services.

Access controls Who will have access to the

data (including individuals or roles)? Are

there access audit trails? If there are

particular individuals who will have access to

significant amounts of data (for example,

database administrators) how is their access

monitored and managed? Are any

subcontractors involved? How is their access

controlled? Is data encrypted on disk? “in

flight”? Who holds access keys?

Secure Data Transfer

Secure Stored Data

Secure Software Interface

User Access Control

Data Separation

Cloud computing services often provide common business application online that are accessed from a web browser, while the software and data are stored on the servers.

Cloud computing is an umbrella term used to refer to Internet based development and services

Cloud computing defines virtual storage area which is provided by cloud providers and accessed by clients on demand and pay per use. Today, security is one of the most important factors in computing environment. Cloud service providers must provide trust worthy environment. End users must know about the awareness of security policy.

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comprehensive study on Cloud computing”,

International journal of Advanced Research in

Computer science and Software engineering, volume

2, issue 9, September 2012, ISSN: 2277 128X.

[2] Mladen A. Vouk, “Cloud computing – Issues,

Research and Implementations”, Journal of Computing

and Information technology, CIT 16, 2008, 4, 235-246.

[3] Anbalagan K., “Cloud computing”, National

seminar on Imminent Trends in Advanced Computing

and Technology – ITIACT’ 13, ISBN: 978-81-924922-3-

0.