Cloud computing gives users network access to shared computing resources—such as servers, storage, networks, applications, and services—that can be provisioned and released on demand. Its flexibility can support faster deployment and more responsive use of capacity, but savings, security, and other benefits depend on how a particular service is implemented and used.
What is cloud computing?
The National Institute of Standards and Technology (NIST) defines cloud computing 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.” The definition comes from Peter Mell and Timothy Grance’s NIST SP 800-145, published in 2011.
In practical terms, cloud computing is a way to access computing capabilities over a network without having to own and manage every underlying resource yourself. It describes a model, not a single product or company. NIST’s definition gives organizations a framework for identifying whether a service has cloud characteristics; the label alone does not establish that a particular system is secure or appropriate.
How does cloud computing work?
NIST describes five essential characteristics that distinguish the cloud model. Together, they explain how cloud resources can be requested, shared, scaled, and monitored.
#1 Best Overall
- On-demand self-service: A user can provision capabilities such as server time or network storage without making a separate request to the provider for each allocation.
- Broad network access: Services are available over a network through standard access mechanisms and can be reached from different kinds of client devices.
- Resource pooling: A provider’s computing resources serve multiple consumers, with capacity assigned and reassigned as demand changes.
- Rapid elasticity: Resources can scale outward or inward in response to demand.
- Measured service: Usage is metered, monitored, controlled, and reported at a level suited to the service.
These characteristics explain the model’s flexibility: users can request capacity when needed, and providers can allocate pooled resources across demand. Metering can also make usage more visible. They do not, by themselves, establish that a service will cost less or perform better than another approach.
What are the main cloud service models?
Service models describe the kind of capability supplied. NIST identifies three:
Rank #2
| Model | What it provides |
|---|---|
| Software as a Service (SaaS) | Applications that users access as a service. |
| Platform as a Service (PaaS) | A platform on which users can develop or run applications. |
| Infrastructure as a Service (IaaS) | Computing infrastructure capabilities, such as processing, storage, or networking resources. |
The categories distinguish the type of service, not where or how it is deployed. NIST’s descriptions are set out in SP 800-145.
What are the cloud deployment models?
Deployment models describe how the cloud environment is arranged. NIST identifies four:
Do these 3 things before closing this tab:
1Fix the driver behind crashes, sound loss and screen glitches2Repair Windows errors before they cause bigger problems3Scan for outdated or missing drivers - takes under a minuteRank #3
- Public cloud: A cloud environment made available for use by the general public.
- Private cloud: A cloud environment for the exclusive use of one organization.
- Community cloud: An environment shared by organizations with common concerns.
- Hybrid cloud: A composition of two or more distinct cloud infrastructures that remain separate but are connected to enable data or application portability.
These are deployment arrangements, distinct from SaaS, PaaS, and IaaS, which describe service types. NIST’s publication provides the formal model definitions; a service’s marketing label alone may not tell you how closely its implementation matches them.
What are the potential benefits of cloud computing?
NIST named cost savings, energy savings, rapid deployment, and customer empowerment as potential benefits organizations may seek from cloud computing in its 2011 announcement, “NIST Cloud Computing Definition Aims to Improve Communications.” These are benefit categories, not a guarantee that every migration will deliver them or a quantified estimate of savings.
Flexible provisioning and scaling
On-demand self-service and rapid elasticity can let an organization provision capacity in response to demand and release it when it is no longer needed. That may reduce the delay involved in obtaining resources, while resource pooling lets providers allocate shared capacity across consumers. Whether this flexibility improves a particular workload depends on its needs and the service arrangement.
More visible resource use
Measured service makes usage available for monitoring and reporting. That visibility can help an organization understand how resources are being consumed. Metering alone does not ensure lower costs: the financial outcome depends on what is used and how the service is managed.
Best Value
Potential cost and energy savings
NIST lists cost and energy savings among the potential benefits organizations may seek. Its announcement does not supply a universal savings percentage, and the cloud model does not guarantee either result. Assessing them requires looking at the actual implementation and use case, rather than assuming that moving a workload to a service will automatically reduce expense or energy use.
Potentially faster deployment and greater customer empowerment
Self-service provisioning and rapid release can make it easier to obtain resources without a separate provider interaction for each request. NIST also names customer empowerment as a potential benefit. These outcomes depend on the service and how an organization uses it; the model’s characteristics do not quantify how much faster deployment will be in a given situation.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.How can you assess whether a service fits the cloud model?
NIST computer scientist Peter Mell said the definition gives agencies and companies “a tool to determine the extent to which the information technology implementations they are considering meet the cloud characteristics and models,” in the 2011 NIST announcement. For a practical comparison, consider:
- Which service model applies: SaaS, PaaS, or IaaS?
- Which deployment model applies: public, private, community, or hybrid?
- Can users provision and release resources on demand?
- Is the service accessible over a network through standard mechanisms?
- Are resources pooled and allocated according to demand?
- Is usage measured and reported?
These questions help identify cloud characteristics; they are not a substitute for examining a specific service’s security, cost, or fit for a workload. NIST’s definition can assist in evaluating security properties, but cloud adoption does not automatically make a system secure. The cited NIST material does not provide a detailed security responsibility matrix or a current vendor price comparison.
Quick wins for a faster PC:
Repair Windows errors before they cause bigger problemsFix Now →Fix the driver behind crashes, sound loss and screen glitchesFind Drivers →Quick Recap
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
