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CLOUD COMPUTING. CONTENTS. Definition Of Cloud Computing Characteristics Of A Cloud Service Service Models Types Of Cloud Computing Advantages and disadvantages of cloud computing. WHAT IS CLOUD COMPUTING?. DEFINITION :
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CONTENTS • Definition Of Cloud Computing • Characteristics Of A Cloud Service • Service Models • Types Of Cloud Computing • Advantages and disadvantages of cloud computing
WHAT IS CLOUD COMPUTING? DEFINITION: • Cloud computing is an emerging paradigm in the computer industry where the computing is moved to a cloud of computers. • Cloud is a term used as a metaphor for the wide area networks (like internet) or any such large networked environment. It came partly from the cloud-like symbol used to represent the complexities of the networks in the schematic diagrams. • It represents all the complexities of the network which may include everything from cables, routers, servers, data centers and all such other devices.
CHARACTERISTICS OF A CLOUD SERVICE • The characteristics of a cloud service is that it is normally: • Accessed via the internet • Paid by need and use • Adjusted up and down as needed and • Delivered from a platform of pooled computer resources
SERVICE MODELS: The above literature apply to all clouds but each cloud provides users with services at a different level of abstraction, which is referred to as a service model in the definition. The three most common service models are:
SERVICE MODELS: 1.SOFTWARE AS A SERVICE (SAAS): • This is where users simply make use of a web-browser to access software that others have developed and offer as a service over the web. • At the SaaS level, users do not have control or access to the underlying infrastructure being used to host the software. EXAMPLE: Salesforce’s Customer Relationship Management software and Google Docs are popular examples that use the SaaS model of cloud computing.
SERVICE MODELS: 2. PLATFORM AS A SERVICE (PAAS): • This is where applications are developed using a set of programming languages and tools that are supported by the PaaS provider. • PaaS provides users with a high level of abstraction that allows them to focus on developing their applications and not worry about the underlying infrastructure, Just like the SaaS model. EXAMPLE: Google App Engine and Microsoft Azure are popular PaaS examples.
SERVICE MODELS: 3. INFRASTRUCTURE AS A SERVICE (IAAS): • This is where users acquire computing resources such as processing power, memory and storage from an IaaS provider and use the resources to deploy and run their applications. • In contrast to the PaaS model, the IaaS model is a low level of abstraction that allows users to access the underlying infrastructure through the use of virtual machines. • IaaS gives users more flexibility than PaaS • However, flexibility comes with a cost and users are responsible for updating and patching the operating system at the IaaS level. EXAMPLE: Amazon Web Services’ EC2 and S3 are popular IaaS examples.
TYPES OF CLOUD COMPUTING The service models described in the definition are deployed in clouds, but there are different types of clouds depending on who owns and uses them. This is referred to as a cloud deployment model in the definition and the four types of cloud computing are:
TYPES OF CLOUD COMPUTING 1. PRIVATE CLOUD: • A cloud that is used exclusively by one organization. • The cloud may be operated by the organization itself or a third party. EXAMPLE: The St Andrews Cloud Computing Co-laboratory and Concur Technologies are example organisations that have private clouds.
TYPES OF CLOUD COMPUTING 2. PUBLIC CLOUD: • A cloud that can be used (for a fee) by the general public. • Public clouds require significant investment and are usually owned by large corporations. EXAMPLE: such as Microsoft, Google or Amazon.
TYPES OF CLOUD COMPUTING 3. COMMUNITY CLOUD: • A cloud that is shared by several organisations and is usually setup for their specific requirements. • The Open Cirrus cloud test bed could be regarded as a community cloud that aims to support research in cloud computing . EXAMPLE: all Government organizations within the state of Pakistan may share computing infrastructure on the cloud to manage data related to citizens residing in Pakistan.
TYPES OF CLOUD COMPUTING 4. HYBRID CLOUD: • A cloud that is setup using a mixture of the above three deployment models. • Each cloud in a hybrid cloud could be independently managed but applications and data would be allowed to move across the hybrid cloud. • Hybrid clouds allow cloud bursting to take place, which is where a private cloud can burst-out to a public cloud when it requires more resources. EXAMPLE: Sales force cloud computing for high/peak load requirements.
ADVANTAGES AND DISADVANTAGES ADVANTAGES: • Low –or no –start-up costs • Payment according to need/use • Great flexibility in relation to fast up-and downscaling of resource needs • Possibility of full service with maintenance • Easier (and cheaper) access to new software versions
CONT’D DISADVANTAGES: • Financial trade-off is necessary –it might be more expensive over time than an in-house solution • Lack of control on operation and development • Costs of data traffic to and from the solution • Data security and return of data upon termination
REFERENCES Neil Robinson, Lorenzo Valeri, Jonathan Cave & Tony Starkey (RAND Europe) Hans Graux (time.lex) Sadie Creese & Paul Hopkins (University of Warwick) 30 November 2010 Prepared for Unit F.5, Directorate-General Information Society and Media, European Commission http://cordis.europa.eu/fp7/ict/security/docs/the-cloud-understanding-security-privacy-trust-challenges-2010_en.pdf Ali Khajeh-HosseiniCloud Computing Co-laboratory School of Computer ScienceUniversity of St AndrewsSt Andrews, UK akh@cs.st-andrews.ac.uk http://www.itretsforum.dk/uploads/media/Drafting_Cloud_Computing_Contracts_by_Niels_Chr_Ellegaard.pdf