Cloud computing conceptual reference model identifies the major actors, their activities and functions in cloud computing.
Below figure 1 presents an overview of the NIST cloud reference architecture.
Figure 1 – The Conceptual Reference Model
As shown in Figure 1, the NIST cloud computing reference architecture defines five major actors: cloud consumer, cloud provider, cloud carrier, cloud auditor and cloud broker. Each actor is an entity (a person or an organization) that participates in a transaction or process and/or performs tasks in cloud computing.
Table 1 briefly lists the actors defined in the NIST cloud computing reference architecture. The general activities of the actors are discussed in further tutorial.
Actors in Cloud Computing
A person or organization that maintains a business relationship with, and uses service from, Cloud Providers.
A person, organization, or entity responsible for making a service available to interested parties.
A party that can conduct independent assessment of cloud services, information system operations, performance and security of the cloud implementation.
An entity that manages the use, performance and delivery of cloud services, and negotiates relationships between Cloud Providers and Cloud Consumers.
An intermediary that provides connectivity and transport of cloud services from Cloud Providers to Cloud Consumers.
Table 1 – Actors in Cloud Computing
Figure 2 illustrates the interactions among the actors. A cloud consumer may request cloud services from a cloud provider directly or via a cloud broker. A cloud auditor conducts independent audits and may contact the others to collect necessary information. The details will be discussed in the following sections and presented in increasing level of details in successive diagrams.
Figure 2 Interactions between the Actors in Cloud Computing
Usage Scenario 1: A cloud consumer may request service from a cloud broker instead of contacting a cloud provider directly. The cloud broker may create a new service by combining multiple services or by enhancing an existing service. In this example, the actual cloud providers are invisible to the cloud consumer and the cloud consumer interacts directly with the cloud broker.
Figure 3 Usage Scenario for Cloud Brokers
Usage Scenario 2: Cloud carriers provide the connectivity and transport of cloud services from cloud providers to cloud consumers. As illustrated in Figure 4, a cloud provider participates in and arranges for two unique service level agreements (SLAs), one with a cloud carrier (e.g. SLA2) and one with a cloud consumer (e.g. SLA1).
A cloud provider arranges service level agreements (SLAs) with a cloud carrier and may request dedicated and encrypted connections to ensure the cloud services are consumed at a consistent level according to the contractual obligations with the cloud consumers. In this case, the provider may specify its requirements on capability, flexibility and functionality in SLA2 in order to provide essential requirements in SLA1.
Figure 4 Usage Scenario for Cloud Carriers
Usage Scenario 3: For a cloud service, a cloud auditor conducts independent assessments of the operation and security of the cloud service implementation. The audit may involve interactions with both the Cloud Consumer and the Cloud Provider.