Form of internet-based computing that provides shared computer processing resources and data to computers and other devices on demand
The essential characteristics and service models of cloud computing necessitate the implementation of access control mechanisms to maintain system integrity and reduce exposure to malicious actors. The following diagram displays the scope of access control entailed with the various service models of cloud computing.
The highest-level categorization of cloud services as based on the type of computing capability that is provided. Any given cloud service may be categorized as one of three service models, namely Software as a Service (SaaS), Platform as a Service (PaaS), or Infrastructure as a Service (IaaS).
In 2012, the NIST published a document containing its synopsis and recommendations concerning cloud computing. That document contains the following diagram, which depicts public cloud infrastructure.
Cloud infrastructure is defined as the collection of hardware and software which collectively enable the five essential characteristics of cloud computing. Cloud infrastructure typically contains a physical layer – consisting of the actual computer hardware and its support systems (cooling, electricity, network connectivity, etc.) – and an abstraction layer consisting of software deployed across the physical layer, which manifests the five essential cloud characteristics.
The NIST specified three different service models for cloud computing services:
The NIST's definition details four different deployment models for cloud computing: