ISO/IEC describes cloud computing systems from four distinct viewpoints:
- User view: The system context, the parties, the roles, the sub-roles, and the cloud computing activities
- Functional view: The functions necessary for the support of cloud computing activities
- Implementation view: The functions necessary for the implementation of a cloud service within service parts and/or infrastructure parts
- Deployment view: How the functions of a cloud service are technically implemented within already existing infrastructure elements or within new elements to be introduced in this infrastructure
The four distinct functional layers defined in the ISO/IEC 17789 CCRA are:
- User layer: Functional components that support the cloud computing activities of cloud service customers and cloud service partners
- Access layer: Includes functional components that facilitate function distribution and interconnection
- Service layer: Includes functional components that provide the cloud services themselves plus related administration and business capabilities, and the orchestration capabilities necessary to realize them
- Resource layer: Includes the functional components that represent the resources needed to implement the cloud computing system
Not all layers or functional components are necessarily instantiated in a specific cloud computing system. The multilayer functions include functional components that provide capabilities that are used across multiple functional layers. These include:
- development support
- integration
- security systems
- operational support systems
- business support systems
ISO/IEC 17789 cloud computing reference architecture defines three roles namely:
- Cloud service customer (CSC): A party that is in a business relationship for the purpose of using cloud services.
- Cloud service provider (CSP): A party that makes cloud services available.
- Cloud service partner (CSN): A party that is engaged in support of, or auxiliary to, activities of either the cloud service provider or the cloud service customer, or both. Cloud service broker and cloud auditor both fall under this ISO/IEC 17789 role.
These “roles” loosely align with the NIST reference architecture “actors.” The ISO/IEC 17789 standard also defines sub-roles that are used to categorize the activities managed under a given role.
