The cloud service model covers four platforms. Each platform provides a separate IT-Service. Following chart shows the structure of the model.

IaaS function - At the lowest layer the IT services of basic infrastructure are located. This platform is reserved for the IT-specialists in the field of provisioning for IT operations and IT service. This usually covers CPU and storage functionality on virtualized servers and networks with a high degree of standardization and an intelligent system management for operation. The customer usually rents the storage capacity and processor power of the server. IaaS users benefit from flexibility and elasticity in data storage and its payment based on the pay-as-you go concept.


PaaS function – the development platform is based in the next layer of the service model.. PaaS describes services (Middleware) for the application platform. PaaS evolved as support for developers in the sense it eliminates the burden of generating and maintaining infrastructure on-site and shortens the development time with a great number of real-time available tools and scalable services (Keesookpuna, 2011, p. 7) .

Software for database, workflow-tools etc. is available, depending on the vendor, in order to develop, produces and delivers their applications.


SaaS function – the third layer of the service model covers the applications. These services are aimed at the user. Business applications are provided as standardized services from a service provider. Importantly, for the user the benefit is the temporary use of standard applications without having to establish or operate such services.

SaaS is based on the concept of multitenancy where a single instance of the software can service different clients simultaneously (Keesookpuna, 2011, p. 4).


BPaaS tasks – Is the latest layer in the definition of the service modules. BpaaS coveres various applications and the workflow to carry out a whole business process as a service-