Cloud computing is the use of various services, such as software development platforms, servers, storage, and software, over the Internet, often referred to as the Cloud. The Cloud Computing environment can consist of multiple types of clouds based on their deployment and usage.

It provides the various services in different manner as per the requirement of user.

Infrastructure as a Service (IaaS): It is the foundation of cloud services that provides services with server hardware, storage, bandwidth and other fundamental computing resources on pay per use basis. It provides access to shared resources on need basis, without revealing details like location and hardware to clients.

Software as a Service (SaaS): It includes a complete software offering on the cloud. Person can use the software application on cloud as per the requirement and charges have to pay on the basis of use. SaaS is a model where there user is not required to install and run an application on his computer. User need not to bear software maintenance and support but users relinquish control over software versions and requirements.

Platform as a Service (PaaS): It provides clients with access to the basic operating software and optional services to develop and use software applications (e.g. databas e access and payment service) without the need to buy and manage the underlying computing infrastructure. For example, Google App Engine allows clients to run their web applications on Google’s infrastructure.

Network as a Service (NaaS): It is a category of cloud services where the capability provided to the cloud service user is to use network/transport connecting services. NaaS involves optimization of resource allocation by considering network and computing resources as a whole. Some of the examples are: Virtual Private Network, Mobile Network Virtualization etc.

Communication as a Service (CaaS): CaaS is an outsourced enterprise communication solution that can be leased from a single vender. The CaaS vendor is responsible for all hardware and software management and offers guaranteed Quality of Service. It  allows businesses to selectively deploy communication devices and modes on a pay-as you-go, as-needed basis. This approach eliminates the large capital investments. Examples are: Voice over IP (VoIP), Instant Messaging (IM), Collaboration and Video conferencing application using fixed and mobile devices.