Various models are available depending on the services required. Software as a Service (SaaS) is the term used to describe applications installed and running on servers belonging to a third-party provider. In many cases, the applications are operated via a browser. In addition, all the data relating to the applications is stored at the provider’s computer centres. Platform as a Service (PaaS) makes a cloud-based development or production environment available to users for their own applications. Finally, Infrastructure as a Service (IaaS) provides users with virtual computer resources such as computing power, hard drive storage or server environments.
A differentiation is made between private and public cloud services depending on where they are operated and how they are accessed. The public cloud makes services available to users over the public Internet. A private cloud, on the other hand, provides access to abstracted IT infrastructures on distinct hardware within certain types of organisation. Various combination models are also available, such as hybrid, virtual private or community cloud computing.
A typical application for the technology described above is the cloud telephone system. It offers users the standard features of a telephone system without the need for any local software or hardware. The only prerequisite for using network telephone services is a sufficiently fast Internet connection. Telephone systems of this kind are easily scalable and can be used from any location with Internet access.