Cloud Computing Reference Architecture

The cloud computing reference architecture is a practical plan for a system with a distinct range of operations. It fulfills specific system requirements through carefully crafted architectural schemes to ensure quality and consistency over the course of system development and delivery projects.

The Conceptual Reference Model

The figure below illustrates the National Institute of Standards and Technology (NIST) cloud computing reference architecture. It shows the five main participants in the cloud computing environment and the roles they play.

NIST Cloud Computing Refernce Architecture

NIST Cloud Computing Refernce Architecture

The diagram depicts a generic high-level architecture and is intended to simplify the comprehension of the requirements, usages, features and principles of cloud computing:

Actors in Cloud Computing

The NIST cloud computing architecture defines five major actors:

  • Cloud consumer
  • Cloud provider
  • Cloud carrier
  • Cloud auditor
  • Cloud broker

Each participant is either an individual or an entity that participates in a transaction or process and/or performs various tasks within the cloud system.

The figure below shows the interactions between the actors. As implied, cloud consumers may request services directly from providers or through brokers while auditors may collect relevant information from any of the three aforementioned parties in efforts to conduct independent audits.

Interactions between the actors in cloud computing

Interactions between the actors in cloud computing

The following table, briefly, lists the functions of each participant depicted in the NIST cloud computing reference architecture.

Actor Definition
Cloud Consumer A person or organization that maintains a business relationship with and uses service form cloud providers
Cloud Provider A person, organization, or entity responsible for making a service available to interested parties.
Cloud Auditor A party that can conduct independent assessment of cloud services, information system operations, performance and security of the cloud implementation
Cloud Broker An entity that manages the use, performance and delivery of cloud services, and negotiates relationships between Cloud Providers and Cloud Consumers
Cloud Carrier An intermediary that provides connectivity and transport of cloud services from Cloud Providers to Cloud Consumers

Now, let us understand each actor in detail.

Cloud Consumer

A cloud consumer is the primary stakeholder for the cloud computing service. A cloud consumer may be an individual or an organization.

After browsing the cloud service catalogs from a cloud provider, requests the service applicable to their business processes, sign service-level agreements (SLAs) or contracts with the provider, and use the service(s) for which they are billed on a pay-per-use basis.

Cloud SLAs stipulate the technical performance commitments between the provider and the client/customer and cover particular aspects of the service concerning issues such as the availability and quality of service, security measures, client obligations, and remedies and quality of service, security measures, client obligations, and remedies for performance letdowns.

Normally, a cloud provider’s pricing policy and SLAa are non-negotiable, unless the customer anticipates heavy data usage and might not be in a position to negotiate for better contracts.

Cloud Provider

A cloud provider is the entity in charge of rendering cloud services to interested clients.

A cloud provider procures and controls the computing infrastructure necessary for providing the services. Cloud providers manage the cloud hardware and software components through network access.

As shown in the figure below, a Cloud Provider’s activities can be described in five major areas.

Cloud provider activities

Cloud provider activities

Cloud Auditor

A cloud auditor is the entity that can perform objective examinations of cloud services in conformity with IT standards.

Cloud auditor assess the services delivered by a cloud provider regarding the adherence to security and privacy protocols, quality service performance, and so on.

Cloud Broker

Cloud Brokers are companies that foster relationships between a cloud provider and the client. They facilitate the use, performance and delivery of cloud services. Usually, when clients are not sure which cloud providers or services to acquire, they hire brokers to make recommendations.

In general, a cloud broker provides the following three types of services:

1. Service intermediation

A cloud broker improves services by refining some specific characteristics and providing value-added features to cloud consumers. These features include the managing of client access to cloud services, identity management, performance reporting, enhanced security, and so on.

2. Service aggregation

A cloud broker merges numerous facilities into on or more new service by providing data integration and ensuring secure data migration between the cloud consumer and the cloud provider.

3. Service arbitrage

Service arbitrage is analogous to service aggregation, but with service arbitrage, the cloud broker has the flexibility to integrate services from multiple cloud providers.

Cloud Carrier

A cloud carrier acts as a go-between that provides network access and transference of cloud services between cloud consumers and cloud providers through network and telecommunication devices such as personal computers, cellphones, tables, and so on.