This is a diagram containing four rounded rectangles, placed vertically above one another. From the top, the first one has the following text inside: cloud clients. Web browsers and web/mobile applications. This rectangle has a double ended arrow below it. Below this the next rectangle reads: Software as a Service (SaaS). Application accessible from Cloud clients. The next rectangle below it reads Platform as a Service (PaaS). Runtime environment, middleware and operating system. The final rectangle at the bottom reads: Infrastructure as a Service (IaaS). Virtual machines, servers, storage and networking.