The overall functionality of the different parts of an enterprise is clearly indicated in its design architecture. When these parts are broken down further into manageable parts, and the interactions among these parts are defined, this will then make up the Enterprise Architecture. But then again, the need to separate the business of creating an Enterprise Architecture (Architecture-in-Design, AID) from the business of doing the actual work in an enterprise (Architecture-in-Operation, AIO) is presented in the four domain architecture or FDA.
There are a lot of different elements within the world of information systems and therefore grouping similar elements into domains will eventually result to an adequate coverage of the real world, a reasonable level of abstraction and realistically accessible and familiar concepts. Each domain is independent and driven by external factors therefore encompassing a traditional area of expertise that provides a unifying discipline for each model. The four domains of FDA are the following:
(a) Process Domain includes the procedures, processes, dependencies and business tools that are required to support different business functions. (b) Information / Knowledge Domain includes business rules and business data, their usage and interrelationships. Operational data, system data and metadata are also included in this domain type. (c) Infrastructure Domain includes system software and hardware, facilities and equipment, data storage sources, human interfaces and other underlying technologies that support the activities of other domains. (d) Organization Domain includes the people in the organization, their roles and responsibilities, organizational make-up as well as the underlying interrelationships between customers, suppliers, partners, allies and other stakeholders in the enterprise.