Cloud computing has five essential characteristics; On-demand self-service, broad network access, resource pooling, rapid elasticity, and measured service. It enables you to access a pool of computing resources, from everywhere, anytime. This means that you can use networks, servers, storage, applications, and services over the internet. The National Institute of Standards and Technology (NIST) defined the following five characteristics:
A consumer can buy computing capabilities, such as server time and network storage, without requiring human
interaction with the service provider. This is certainly the case in B2C scenarios, for example when you’re using cloud storage (Dropbox, GoogleDrive, iCloud) and you want to upgrade to more storage – you can simply buy more. You don’t need to go to a shop, see a service person etc. You just help yourself and get whatever you need. In complex enterprise software arrangements this is more complex, because vendors and customers have negotiated individual terms. However there is a trend towards more self-service and a demand for using public marketplaces.
Broad network access
Capabilities are available over the network. They are accessed through standard mechanisms that promote use by a varied range of client platforms (e.g., mobile phones, tablets, laptops, and workstations). This means you can practically use any device that can connect to the Internet.
Using a multi-tenant model, the provider’s computing resources are pooled to serve multiple consumers. Here, different physical and virtual resources are 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 the customer may be able to specify location at a higher level of abstraction (e.g., country, state, or datacenter). Often there are local regulations that require data to be processed and stored locally. Examples of resources include storage, processing, memory, and network bandwidth.
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. In essence, this means that the consumer can scale up or down, depending on what is needed. This is very interesting for business models that have high fluctuations due to peak times, e.g., streaming services like Netflix (People watching movies on certain days at certain times).
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 drives huge cost savings through better resource optimization. Besides that, it is critical in the prevention of down-time, which is a huge concern for many organizations.