NIST Definition of Cloud Computing
Introduction to NIST
The National Institute of Standards and Technology (NIST) is a physical sciences laboratory and a non-regulatory agency of the U.S. Department of Commerce. Its mission is to promote innovation and industrial competitiveness by advancing measurement science, standards, and technology in ways that enhance economic security and improve our quality of life.
NIST Cloud Computing Definition
According to NIST Special Publication 800-145, cloud computing is defined as "a model for enabling ubiquitous, 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 is composed of five essential characteristics, three service models, and four deployment models, which provide a framework for understanding cloud computing as a concept and as a set of technologies.
Five Essential Characteristics of Cloud Computing
1. 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 provider. This characteristic empowers users to quickly obtain resources when needed, reducing dependency on IT personnel and accelerating implementation timelines.
2. 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, tablets, laptops, and workstations). This universal accessibility is one of cloud computing's most significant advantages, enabling remote work, global collaboration, and resource availability from virtually anywhere with internet connectivity.
3. 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). This pooling optimizes resource utilization and enables economies of scale.
4. Rapid Elasticity
Capabilities can be elastically provisioned and released, in some cases automatically, to scale rapidly outward and inward commensurate with demand. To the consumer, the capabilities available for provisioning often appear to be unlimited and can be appropriated in any quantity at any time. This elasticity allows organizations to handle variable workloads efficiently, scaling up during peaks and down during lulls to optimize costs.
5. 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. This pay-as-you-go model aligns costs with actual consumption and enables more predictable budgeting.
Three Service Models
1. Cloud Software as a Service (SaaS)
The capability provided to the consumer is to use the provider's applications running on a cloud infrastructure. The applications are accessible from various client devices through either a thin client interface, such as a web browser (e.g., web-based email), or a program interface. The consumer does not manage or control the underlying cloud infrastructure including network, servers, operating systems, storage, or even individual application capabilities, with the possible exception of limited user-specific application configuration settings. Popular examples include Microsoft Office 365, Google Workspace, Salesforce, and Dropbox.
2. Cloud Platform as a Service (PaaS)
The capability provided to the consumer is to deploy onto the cloud infrastructure consumer-created or acquired applications created using programming languages, libraries, services, and tools supported by the provider. The consumer does not manage or control the underlying cloud infrastructure including network, servers, operating systems, or storage, but has control over the deployed applications and possibly configuration settings for the application-hosting environment. Examples of PaaS include AWS Elastic Beanstalk, Google App Engine, Microsoft Azure App Service, and Heroku.
3. Cloud Infrastructure as a Service (IaaS)
The capability provided to the consumer is to provision processing, storage, networks, and other fundamental computing resources where the consumer is able to deploy and run arbitrary software, which can include operating systems and applications. The consumer does not manage or control the underlying cloud infrastructure but has control over operating systems, storage, and deployed applications; and possibly limited control of select networking components (e.g., host firewalls). Major IaaS providers include Amazon EC2, Microsoft Azure Virtual Machines, Google Compute Engine, and IBM Cloud Infrastructure.
Four Deployment Models
1. Private Cloud
The cloud infrastructure is provisioned for exclusive use by a single organization comprising multiple consumers (e.g., business units). It may be owned, managed, and operated by the organization, a third party, or some combination of them, and it may exist on or off premises. Private clouds offer enhanced security, compliance, and control but typically come with higher costs and more maintenance responsibilities than public clouds.
2. Community Cloud
The cloud infrastructure is provisioned for exclusive use by a specific community of consumers from organizations that have shared concerns (e.g., mission, security requirements, policy, and compliance considerations). It may be owned, managed, and operated by one or more of the organizations in the community, a third party, or some combination of them, and it may exist on or off premises. Community clouds are popular among organizations in regulated industries such as healthcare, finance, and government that need to comply with specific requirements.
3. Public Cloud
The cloud infrastructure is provisioned for open use by the general public. It may be owned, managed, and operated by a business, academic, or government organization, or some combination of them. It exists on the premises of the cloud provider. Public clouds offer maximum scalability and cost-efficiency through economies of scale but may present challenges related to data residency, compliance, and customizability.
4. Hybrid Cloud
The cloud infrastructure is a composition of two or more distinct cloud infrastructures (private, community, or public) that remain unique entities, but are bound together by standardized or proprietary technology that enables data and application portability (e.g., cloud bursting for load balancing between clouds). Hybrid clouds combine the benefits of different deployment models, allowing organizations to maintain sensitive data and critical applications in private clouds while leveraging the scalability and cost-efficiency of public clouds for less sensitive workloads.
Benefits of NIST's Definition
The NIST definition of cloud computing provides several important benefits to both providers and users of cloud services:
- Common Language: It establishes a standard terminology and set of concepts that help all stakeholders communicate effectively about cloud computing, reducing ambiguity and confusion in both technical and business discussions.
- Framework for Evaluation: It provides a structured approach for evaluating cloud services and offerings against standard characteristics, enabling more informed vendor selection and procurement decisions.
- Benchmarking: Organizations can use the NIST definition to benchmark their cloud implementations against industry standards, helping identify gaps and opportunities for improvement.
- Policy Development: It serves as a foundation for developing organizational policies related to cloud adoption and usage, helping ensure consistency and completeness in governance frameworks.
- Vendor Neutrality: The definition is vendor-neutral, focusing on characteristics rather than specific implementations, making it useful in a marketplace with diverse offerings from numerous providers.
- Educational Value: The clear, concise definition serves as an excellent educational tool for those new to cloud computing, helping them develop a solid understanding of fundamental concepts.
Relevance to Modern Organizations
NIST's framework remains exceptionally relevant for organizations navigating their cloud journeys. As cloud computing has matured from an emerging technology to a mainstream IT foundation, the standard has proven surprisingly durable and adaptable.
Organizations can use the NIST definition to clarify requirements for cloud services, develop cloud migration strategies, and evaluate different delivery options. It provides a common language that bridges gaps between technical teams, business units, and executive leadership, facilitating more effective collaboration and decision-making.
The definition has also influenced international standards development and regulatory frameworks impacting cloud computing, testament to its rigor and usefulness. Many countries have used NIST's definition as a basis for developing their own cloud computing policies and standards.
Conclusion
NIST's definition of cloud computing, as outlined in Special Publication 800-145, has become the de facto standard for defining cloud computing concepts worldwide. It provides a clear and comprehensive framework that helps organizations understand the fundamental characteristics, service models, and deployment models of cloud computing.
As cloud computing continues to evolve with new technologies such as edge computing, serverless architectures, and multi-cloud strategies, the NIST definition remains remarkably relevant, serving as a critical reference point for businesses, government agencies, and educational institutions navigating the complex cloud landscape.
The enduring value of this definition lies not in specific technical detailswhich inevitably changebut in its articulation of the essential principles that distinguish cloud computing from traditional IT models. By focusing on what cloud computing IS rather than merely HOW it is implemented, NIST created a standard that has proven resilient despite rapid technological change in the computing industry.
Organizations of all sizes continue to leverage this framework to inform their cloud strategies, evaluate vendor offerings, and develop policies that balance the benefits of cloud computing with considerations around security, compliance, cost, and performance.
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