Background and Introduction
What is an Architectural Framework?
In order to provide coherent and consistent models, it is necessary to have a “framework” which defines the different types of model that can be used, and how those models inter-relate. An Architectural Framework (AF) is a specification of how to organise and present architectural models. MODAF is a framework for MOD architectures, both in the business-space and the battle-space.
Views and Viewpoints
Because Enterprise Architecture is such an all-encompassing discipline, and because the enterprises it describes are often large, it can result in very complex models. To manage this complexity, an AF defines a standard set of model categories (sometimes called “Views” or “Viewpoints”) which each have a specific purpose and are often categorised by the domain they cover – e.g. operational / business, technical, etc. MODAF uses the term “Viewpoints” to denote these categories.
An AF defines a standard set of business and technical information about an enterprise (or aspects thereof). The purpose of the AF may be to identify elements of this information that will be mandatory to produce within the enterprise or to act as a guide to which types of information may be of most value in analysing aspects of an Enterprise Architecture. An AF usually takes the form of a set of standard of representations on the enterprise. MODAF uses the term “Views” to denote these representations, the various Views being grouped together within MODAF Viewpoints.
The following diagram demonstrates the importance of a model repository, based on the M3, as underpinning the various views that make up an architecture.
Architectural Framework Viewpoints provide consistent perspectives of an Architecture and they enable a user to articulate and analyse issues and requirements, and specify, design and validate solutions across a wide range of activities. The MODAF Viewpoints and their constituent Views are described in this document. The usage of these Views within key Communities of Interest are described in the MODAF Deskbooks.
This is further illustrated by the following diagram. The MODAF Viewpoints comprise the sides of the cube that contain the architecture model i.e. System Viewpoint, while the various Views (i.e. OV-2) by which a MODAF architecture is expressed can be regarded as being windows onto an underlying model.
Meta Model
For an Architectural Framework to be useful, the information described in each Viewpoint must be consistent, and integrated across the Viewpoints. To achieve this, MODAF has a Meta Model (M3) which provides a consistent “language” for describing architectures, and which describes the complete set of Architectural Elements and the relationships between them – within and across the Viewpoints.
This means that common information between the Viewpoints can be recorded once and re-used – either in the file used by the architectural tool, or in a repository. For example, a system first defined in SV-1 can be re-used by SV-3, StV-3, StV-5, etc., but the information about that system is stored only once in the underlying data set.
Ontology
An Ontology provides a standard structured dictionary for an Architecture. An Ontology provides a mechanism for ensuring that architectures can be related by allowing terms to be associated in meaning, thereby ensuring consistency across an enterprise and alignment with a business strategy.
The purpose of the MODAF Ontology is to provide a standard set of terminology and reference data to support the development and interchange of MODAF models. It is intended to be supplemented, within individual Architectures, by use of the AV-2 and StV-2 views, which provide Architecture-specific extensions to the MODAF Ontology.
Page version 1.1, dated 4th April 2007