Cloud computing model has gained tremendous popularity and it is utmost important to understand the service layers that defines it. Within
cloud computing model, there are three different service layers that are used to stipulate what is being provisioned:
Infrastructure as a Service (IaaS): Infrastructure as a Service (IaaS) is a model in which a business outsources the tools used to provision operations, including cloud storage, hardware, servers and networking components. The service provider wholly and solely possesses the equipment and is accountable for building, operating and maintaining it. The client normally pays on a per-use basis.
Platform as a Service (PaaS): This layer provides a platform for application development and creation. PaaS solutions are primarily development platforms for which the development tool itself is hosted in the Cloud Server and gained access to via a web browser. Through PaaS, developers can develop Web applications without any requirement to install any tools on their systems and then deploy those applications without any expert system management skills.
Software as a Service (SaaS): This layer of cloud can be defined as a software distribution model in which applications are hosted by the service provider and made accessible to the customers over a network, i.e. the Internet.