Cloud as a Service is a broad collection of cloud computing services offered by cloud providers. Cloud services are offered by integrating applications, servers, networks, and services that can be instantly provisioned based on demand to end users. Cloud as a Service is offered by pooling of resources among multiple users and are usually offered as metered services.
These services can be easily scaled up or scaled down in response to demand peaks and troughs. In Cloud as a Service, all the operations related to back-end are managed by vendors and the end users are required to pay for utilities including bandwidth, memory, and processing time just to name a few.
Cloud-based services are experiencing exponential growth because these are easily accessible and scalable. Redundancy of cloud services is an important attribute to make them highly desirable for commercial enterprises.
Cloud as a Service is provided to individuals or organizations by cloud providers in the form of utility based computing facilities. Therefore these are also sometimes referred to as utility computing providers. Generally, their services fall into three basic categories. These are
Infrastructure as a Service (IaaS),
Software as a Service (SaaS), and
Platform as a Service (PaaS).