Key takeaways
- Two definitions of architecture: fundamental properties of a system (ISO 42010) and a structure of components with their evolution principles.
- Four primary domains (Business, Data, Application, Technology); security, motivation, or governance may span them.
- Applications and their exchanges belong to Application Architecture; the infrastructure hosting them, to Technology Architecture.
- Logical and physical data assets and their management resources form Data Architecture.
- Solution Architecture: one focused activity and its IS/IT support, narrower than a Segment Architecture.
Two senses of the word 'architecture'
The TOGAF Standard keeps two definitions. The first, taken from ISO/IEC/IEEE 42010, speaks of the fundamental concepts or properties of a system in its environment, as shown in its elements, its relationships, and the principles of its design and evolution. The second, more practical, sees architecture as a structure of related components, together with the principles and guidelines that frame their design and evolution over time.
In both cases, architecture is not just a diagram: it includes the rules that guide future change. This is why principles appear throughout the ADM cycle.
The four domains, definition by definition
An Architecture Domain is the architectural area under consideration. The TOGAF Standard follows the tradition of splitting Enterprise Architecture into four primary domains; other domains, such as motivation, security, or governance, may span them.
- Business Architecture: a holistic, multi-dimensional representation of capabilities, end-to-end value delivery, information, and organization, linked to strategies, products, policies, initiatives, and stakeholders.
- Data Architecture: the structure of the major data types and sources, of logical and physical data assets, and of data management resources.
- Application Architecture: the structure and interactions of the applications that carry key business capabilities and manage data assets.
- Technology Architecture: the structure and interactions of technology services and technology components.
Classifying an element without hesitation
To decide, ask what the element describes. If it is an ability, a process, an organization, or a link to strategy, it is Business. If it is the nature, origin, or management of data, it is Data. If it is software, its services, and its exchanges with other software, it is Application. If it is the infrastructure running that software, it is Technology.
Two pairs come up often. An Application Component (for example a CRM) offers Application Services, such as 'view a customer's history'. A Technology Component (a server cluster) provides Technology Services, such as 'database hosting'. The Application Platform is the set of hardware and software components that provide the services applications use.
Solution Architecture and Digital Architecture
Solution Architecture describes one specific business operation or activity and how information systems support it. It is narrower than a Segment Architecture, which covers an area of the enterprise at program or portfolio level.
Digital Architecture is presented as an inclusive architecture: it combines Enterprise Architecture with disciplines such as data science, telecommunications and IoT, security, artificial intelligence, or robotics, in order to deliver operational services.
TERMS TO KNOW
The terms, in context.
- Architecture
- Fundamental properties of a system in its environment, or a structure of components with the principles of their design and evolution.
- Architecture Domain
- The architectural area considered; TOGAF retains four primary ones, which other domains may span.
- Business Architecture
- Holistic representation of capabilities, value delivery, information, and organization, and of their links to strategy.
- Data Architecture
- Structure of data types and sources, of logical and physical assets, and of data management resources.
- Application Architecture
- Structure and interactions of the applications that carry business capabilities and manage data.
- Technology Architecture
- Structure and interactions of technology services and components.
- Solution Architecture
- Description of a focused business operation and its IS/IT support.
- Digital Architecture
- Inclusive architecture combining EA with disciplines such as AI, IoT, or data science to deliver operational services.
- Application Component
- Modular, replaceable encapsulation of application functionality that exposes services through interfaces.
- Application Service
- A behavior that can be requested from an application, supporting one or more business services.
- Technology Component
- Infrastructure building block providing technology services to application or data components.
- Technology Service
- Technical capability providing the infrastructure needed to deliver applications.