Cloud Computing

Cloud Computing

Cloud computing is a model for enabling convenient, on-demand network access to a shared pool of configurable computing resources (e.g., networks, servers, storage, applications, and services) that can be rapidly provisioned and released with minimal management effort or service provider interaction. This cloud model promotes availability and is composed of five essential characteristics (On-demand self-service, Broad network access, Resource pooling, Rapid elasticity, Measured Service); three service models (Cloud Software as a Service (SaaS), Cloud Platform as a Service (PaaS), Cloud Infrastructure as a Service (IaaS)); and, four deployment models (Private cloud, Community cloud, Public cloud, Hybrid cloud). Key enabling technologies include: (1) fast wide-area networks, (2) powerful, inexpensive server computers, and (3) high-performance virtualization for commodity hardware.
The Cloud Computing model offers the promise of massive cost savings combined with increased IT agility. It is considered critical that government and industry begin adoption of this technology in response to difficult economic constraints. However, cloud computing technology challenges many traditional approaches to datacenter and enterprise application design and management. Cloud computing is currently being used; however, security, interoperability, and portability are cited as major barriers to broader adoption.
The long term goal is to provide thought leadership and guidance around the cloud computing paradigm to catalyze its use within industry and government. NIST aims to shorten the adoption cycle, which will enable near-term cost savings and increased ability to quickly create and deploy enterprise applications. NIST aims to foster cloud computing systems and practices that support interoperability, portability, and security requirements that are appropriate and achievable for important usage scenarios.


The NIST Definition of Cloud Computing
Authors: Peter Mell and Tim Grance
Version 15, 10-7-09
National Institute of Standards and Technology, Information Technology Laboratory
Note 1: Cloud computing is still an evolving paradigm. Its definitions, use cases, underlying
technologies, issues, risks, and benefits will be refined in a spirited debate by the public and
private sectors. These definitions, attributes, and characteristics will evolve and change over time.
Note 2: The cloud computing industry represents a large ecosystem of many models, vendors,
and market niches. This definition attempts to encompass all of the various cloud approaches.
Definition of Cloud Computing:
Cloud computing is a model for enabling convenient, on-demand network access to a shared
pool of configurable computing resources (e.g., networks, servers, storage, applications, and
services) that can be rapidly provisioned and released with minimal management effort or
service provider interaction. This cloud model promotes availability and is composed of five
essential characteristics, three service models, and four deployment models.
Essential Characteristics:
On-demand self-service. A consumer can unilaterally provision computing capabilities,
such as server time and network storage, as needed automatically without
requiring human interaction with each service’s provider.
Broad network access. Capabilities are available over the network and accessed through
standard mechanisms that promote use by heterogeneous thin or thick client
platforms (e.g., mobile phones, laptops, and PDAs).
Resource pooling. The provider’s computing resources are pooled to serve multiple
consumers using a multi-tenant model, with different physical and virtual
resources dynamically assigned and reassigned according to consumer demand.
There is a sense of location independence in that the customer generally has no
control or knowledge over the exact location of the provided resources but may be
able to specify location at a higher level of abstraction (e.g., country, state, or
datacenter). Examples of resources 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
consumer, the capabilities available for provisioning often appear 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 capability at some level of abstraction appropriate to the
type of service (e.g., storage, processing, bandwidth, and active user accounts).
Resource usage can be monitored, controlled, and reported providing
transparency for both the provider and consumer of the utilized service.