Levels and Types of Architectures

Architectures can be described at various levels. There are numerous types of architectures in use, each of which may be focussed on a particular theme, or on a specific function, or on an explicit set of systems. Some examples of architectures with a focus on a specific topic include: Operational; Programme; Security and Information. Some examples of architectures with specific purposes are: Integration; Problem Domain Definition; Design-Controlling. Some examples of architectures addressing a specific set of systems are: System of Systems and Product Line. Some practitioners regard each type of architecture as a viewpoint on to a single underlying architecture (i.e.: a single system could have both a security and an information architecture, etc.).

Generic Architecture Kinds

According to current practices in both civil and military domains, various architecture kinds can be considered. Among them:

• Strategic Architecture or Overarching Architecture: An enterprise- wide description of the future situation with limited detail. This description normally covers several programmes.

• Segment Architecture: A description of the construction with details necessary to guide a programme execution or architecting within a domain.

• Implemented Architecture: A description limited to the scope of a single project addressing implementation decisions.

• Baseline Architecture: The term “Baseline” qualifies an architecture kind rather than being an architecture kind as such. An architecture baseline is an architecture that has been formally agreed and that thereafter serves as the basis for further development.

• Reference Architecture: The term “Reference” qualifies an architecture kind rather than being an architecture kind as such. Reference architecture is an architecture that has been used as reference for development of other architecture for any other purpose.

Types of Architecture considered in TOGAF

TOGAF describes 3 main types of architectures which were initially aimed at developing information management systems:

• Business Architecture,

• Information Architecture which includes;

  • Application Architecture,

  • Data Architecture.

• Technology Architecture.

Note: According to ISO/IEC/IEEE 42010, it is better to talk about Business, Information System and Technological viewpoints.

Levels and Types of Architecture considered in NATO

Within NATO’s EA Policy architecture is described in terms of levels as well as types.¹ The three levels are:

1. Enterprise²

2. Capability³

3. Project⁴

The four types of architectures described in the policy are:

1. Business Architecture,

2. Information Architecture,

3. Application Architecture, and

4. Technology Architecture.

NATO architectures are dynamic in nature and are updated regularly to reflect changes in requirements and technology.

Details of NATO architecture levels and types are in Chapter 2.