Introduction to Cloud Computing and Service Models

What is cloud computing?

Cloud Computing is a very comprehensive topic to understand and still in its infancy. It can be termed as the next evolution of computing. Cloud computing offers number of benefits to its users.

Depending upon the usage and advantages, there are several definitions of cloud computing. We can define cloud computing in a number of ways some of them are as follows:

1.  Cloud Computing is the use of multiple server computers via a digital network.

2.  Cloud Computing is an internet based computing environment where you pay only for resources that you use.

3.  Cloud computing is a technology which provides “Resource Optimization” where one can adjust the resource allocation by adding and removing resources dynamically to fit the need.

4.  National Institute of Standards and Technology (NIST) defined Cloud Computing as  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.


Key Cloud Characteristics:

• On-demand self-service

• Ubiquitous network access

• Location independent resource pooling

• Rapid elasticity

• Pay per use

There are three service models of Cloud Computing:

1.  Infrastructure as a Service (IaaS)

2.  Platform as a Service (PaaS)

3.  Software as a Service (SaaS)

These service models are not new to the IT world, the difference is only that cloud computing combines and integrate these approaches.

Infrastructure as a Service : Primary objective of an organization is to reduce time & money required to  procure, provision, and install new hardware systems. IaaS fulfills this primary objective i.e. equipment is outsourced to support operations. This is a provision model in which service provider is responsible for the housing, running and maintenance of the equipment.

Platform as a Service : PaaS provides computational resources through the platform such as Operating System. PaaS is built upon the principals of Infrastructure as a Service by providing an environment where applications can be built and deployed in a secure, rapid and high quality manner. The business needs Information Technology to rapidly develop, deploy, and maintain new applications to remain competitive and PaaS helps organizations in the same. PaaS eliminates the hardware dependency and capacity concerns. It also provides a simplified deployment model.

Software as a Service : SaaS is the most basic form of cloud computing. It includes implementation of specific business functions, customized business applications, etc. The major benefit of SaaS is that there is no licensing risk involved and neither there is any version compatibility issue. It reduces the hardware cost as well.  You pay for the software and the underlying infrastructure and does not require technical know-how. Typical examples of SaaS application software are ERP, CRM, Google Docs, etc. SaaS ensures lower capital, better cash flow and reduced IT support cost.

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