Page 102 - Cloud computing: From paradigm to operation

1 Framework and requirements for cloud computing

10.2 Overview

Figure 10-1 provides an overview of the major elements of the CCRA – roles, cloud computing activities and
functional components, in a common configuration.
Figure 10-1 uses the graphical conventions introduced in clause 5. The boxes with continuous rounded edges
represent roles, the hexagons represent sub-roles, the rounded edged dotted boxes represent cloud
computing activities, and the square ones with bricks are functional components. The "L" shaped boxes
inside the service capabilities functional component represents the cloud service interfaces based on the
fundamental cloud capabilities types. In Figure 10-1, it is apparent that roles are collections of cloud
computing activities, and cloud computing activities themselves are implemented or realized by means of
functional components.
The proximity of the graphical elements representing roles to each other is meaningful, and represents close
interaction between roles assuming neighbouring roles. For example, the cloud service provider role is at
the centre of the diagram to emphasize that it interacts with all other roles. The same is true about the
positioning of the cloud computing activities inside a given role, as well as the relative positioning of
functional components inside a given activity. For example, the service capabilities functional component is
positioned above the resource abstraction and control functional component, to signal the dependency of
the former on the latter.

The cross-cutting aspects of auditability, availability, governance, interoperability, maintenance and
versioning, performance, portability, protection of personally identifiable information, regulatory,
resiliency, reversibility, security, and service levels and service level agreement are indicated by the
outermost box in Figure 10-1, which is intended to show that the cross-cutting aspects apply to all the other
elements in Figure 10-1 – roles, activities and functional components. As an example, the CSC:cloud service
user must have an identity, along with a set of credentials, which must be given to the user function
functional component when performing the use cloud service activity. The identity and the credentials are
presented to the access control functional component and authentication and authorization performed as
part of the provide services activity, invoking the appropriate security functional component capabilities
before the cloud service is provided to the CSC:cloud service user.
The service capabilities functional component of Figure 10-1 represents the implementation of the cloud
service itself.

10.2.1 Service capabilities functional component
The cloud service is offered via a service interface and can offer one or more of the cloud capabilities types,
represented by the "inverted L" shapes within the service capabilities functional component. The topmost L
shape represents the application capabilities type, while the next lower L shape represents the platform
capabilities type and the bottom L shape represents the infrastructure capabilities type.

The implication of the L shapes is that an application capabilities type can be implemented using the platform
capabilities type or not (at the choosing of the cloud service provider) and that the platform capabilities type
can be implemented using the infrastructure capabilities type or not.
For SaaS or CaaS cloud service categories, the service capabilities functional component contains the
application-specific software or the communication applications which are deployed onto the resource layer
in such a way that the service levels identified in the SLA are achieved.
For other cloud service categories, see cloud computing overview and vocabulary in Rec. ITU-T Y.3500 |
ISO/IEC 17788.

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