On-Demand self service
It is one of the essential characteristic of cloud that allows user to receive the services such as computing resources, server time and network storage automatically without direct interaction with the service provider. The applications and resources can be assigned and removed within minutes using cloud catalogs. Some of the popular on demand self service providers are AWS (Amazon Web Services), Google, Microsoft, IBM, Salseforce.com.
Broad network access
This is another essential aspect that is available over the network. They are accessed by using standard mechanisms in thick or thin client platforms.
Location independent resource pooling
The service provider’s resources are pooled in order to serve multiple consumers. There is a sense of location independence as the customer has no control over location where the resources are provided. Consumers need not worry about how the cloud allocates the provided resources.
The definition of elasticity is the ability to scale the resources up and down as required. The storage on cloud seems to be unlimited for the client. The consumer can use as much as he needs at any time.
Another essential attribute is that the resources can be measured, controlled and reported. This provides transparency for both provider and consumer of the used service. Metering capability is used to control and optimize resource use.