I created the diagram above to give you a visual representation of the levels of service provided by each service model. There are a few things I should point out in this representation.
- For each service model, management is a part of the service provided by the cloud service provider. In larger organizations, you will still require management functions to manage multiple services, service models and on-premise applications and systems.
- If you purchase an infrastructure service from a cloud service provider, then you would build on top of that your applications and services and if you require a development platform, you would build this on the infrastructure service as well.
- If you purchase a platform service, then it includes the required infrastructure service to support this platform.
- If you purchase an application (software) service, then the service includes all of the infrastructure and platform services to support your application.
- Business process systems facilitate the development of business processes, including business process inventory, definition, development, deployment, management and measurement.
- And finally, probably the most interesting part is the Services layer. Services (Web Services or Business Services) are reusable technical components made available internally and/or externally to be consumed or used to create new business processes or applications. Creating these reusable functions enables the business to be less reliant upon IT to modify existing systems in order to provide new functionality. A new application can be created, using a service which utilizes the existing applications to provide this new business functionality in the SaaS and/or BaaS layer. This is the meaning of the Services layer represented in the diagram above, it is Web or Business Services which are reusable technical components, not the general term ‘cloud services’.