There are mainly four models of cloud computing:
- Infrastructure as a Service (IaaS)
- Platform as a Service (PaaS)
- Software as a Service (SaaS)
- Network as a Service (Naas)
Infrastructure as a Service (IaaS): This is the most basic cloud-service model, which provides the user with virtual infrastructure, for example servers and data storage space. Virtualization plays a major role in this mode, by allowing IaaS-cloud providers to supply resources on-demand extracting them from their large pools installed in data centers.
Platform as a Service (PaaS): In this model, cloud providers deliver to the user development environment services where the user can develop and run in-house built applications. The services might include an operating system, a programming language execution environment, databases and web servers.
Software as a Service (SaaS): In this model, the cloud provides the user with access to already developer applications that are running in the cloud. The access is achieved by cloud clients and the cloud users do not manage the infrastructure where the application resides, eliminating with this the way the need to install and run the application on the cloud user’s own computers.
Network as a Service (Naas): The least common model, where the user is provided with network connectivity services, such as VPN and bandwidth on demand.
But we are study only three services(first three).
