Page 243 - How Cloud Computing Is Transforming Business and Why You Cant Afford to Be Left Behind

NIST DEFINITION O F C L O UD COMPUTING

may be able to specify location at a higher level of abstrac-
tion (e.g., country, state, or data center). Examples of re-
sources include storage, processing, memory, network
bandwidth, and virtual machines.

Rapid elasticity. Capabilities can be rapidly and elastically

provisioned, in some cases automatically, to quickly scale
out and rapidly released to quickly scale in. To the con-
sumer, the capabilities available for provisioning often ap-
pear to be unlimited and can be purchased in any quantity
at any time.

Measured service. Cloud systems automatically control and
optimize resource use by leveraging a metering capabil-

ity at some level of abstraction appropriate to the type
of service (e.g., storage, processing, bandwidth, and ac-
tive user accounts). Resource usage can be monitored,
controlled, and reported providing transparency for both
the provider and consumer of the utilized service.

Service Models

Cloud Software as a Service (SaaS). The capability provided

to the consumer is to use the provider’s applications run-
ning on a cloud infrastructure. The applications are ac-
cessible from various client devices through a thin client
interface such as a Web browser (e.g., Web-based e-mail).
The consumer does not manage or control the underly-
ing cloud infrastructure including network, servers, op-
erating systems, storage, or even individual application

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