What is Cloud Computing?
The National Institute of Standards and Technology; or NIST, an agency of the U.S. Department of Commerce founded in 1901 as the nation’s first federal physical science research laboratory; and whose mission is to promote U.S. innovation and industrial competitiveness by advancing measurement science, standards and technology, has developed the following working 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.
The 5 Essential Characteristics of Cloud Computing
The 5 essential characteristics of a Cloud Computing deliverable are:
- On-demand Self-Service – where a customer can unilaterally provision computing capabilities such as user access, server time and network storage as needed automatically without requiring human interaction with individual service providers.
- Broad Network Access – where capabilities are available over the network and accessed through standard mechanisms that promote use by heterogeneous thin or thick client platforms such as mobile phones, desktops, laptops and PDAs.
- Resource Pooling – where the provider’s computing resources are pooled to serve multiple customers in a multi-tenant model, with different physical and virtual resources dynamically assigned and reassigned according to 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 such as a country, state, or datacenter. Examples of these pooled resources include storage, processing, memory, network bandwidth, and virtual machines.
- Rapid Elasticity – where capabilities can be rapidly and elastically provisioned; in some cases automatically, to quickly scale out and rapidly released to quickly scale in. To the customer, the capabilities available for provisioning often appear to be unlimited and can be purchased in any quantity at any time.
- Measured Service – where Cloud systems automatically control and optimize resource use by leveraging a metering capability at some level of abstraction appropriate to the type of service, such as storage, processing, bandwidth, and active user accounts. Resource usage can be monitored, controlled, and reported, providing transparency for both the provider and customer of the utilized service.