The “National Institute of Standards and Technology” or NIST definition which states, “cloud computing is 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.”

Essential Characteristics

The NIST definition lists five “essential characteristics” of cloud computing

Service Models

NIST also lists three “service models” which define the services that are being offered in the cloud

This categorization of these services is not meant to define a common standard but are intended more as a general guideline to get everyone on the same page. It is worthwhile to note that there’s always overlap between the service models.

Deployment Models

NIST also defines four “deployment models”, which essential defines how and where the cloud infrastructure is built

Together these models categorize ways to deliver cloud services. The definition is intended to make it easier to compare cloud services and deployment strategies. It also provides a baseline for discussion about cloud computing and how to best use cloud computing.