Extensible Architecture Framework (xAF)

Extensible Architecture Framework (xAF)

The idea of developing an extensible framework has arisen in the fall of 2003 as a possible and challenging way of meeting the objective of the Generic Architecture Framework working group. This objective is to develop a generic architecture framework that is theoretically solid and practically useful.

The specific requirements for this framework are:

  1. The framework should be widely applicable, i.e. within the whole area of enterprise engineering (business definition, business system development, organisation development, ICT-applications development etc.).
  2. The concepts used in the framework should constitute a complete set, i.e. they must be necessary and sufficient for carrying out enterprise engineering projects successfully.
  3. The definition of each concept should be very precise, but should also leave room for customization within any sub area. The framework should not be a rigid standard.

The basic idea of xAF is that there is a root extensible framework (xAF0), on the basis of which other (extensible) frameworks can be defined as extensions of this root framework. Defining an xAFi as the extension of one or more existing xAFi’s is guided by strict extension rules. Two rules have been proposed, which seems to be sufficient: the specialisation rule and the integration rule. By applying these rules, one builds up a lattice of xAFi’s. Theoretically, it is possible then to reformulate any existing architecture framework as a particular xAFi in this lattice. This makes the xAF a universal basis for evaluating and comparing frameworks. But it also makes the xAF a method for developing one’s own framework in such a way that the developed framework satisfies high quality standards, and that it is easily comparable to existing frameworks.


The group of people that is carrying out the NAF-programme Generic Architecture Framework, calls itself the “xAF working group” (xAF-WG). According to the rules of the NAF, the xAF-WG consists of people from all three ‘blood groups’: academic institutions, architectures supplying companies, and architectures using companies. Currently, the xAF-WG consists of the following people:

  • Frank Baldinger (ING)
  • Jeroen van Beele (zelfstandig)
  • Wiel Bruls (IBM)
  • Jan Dietz (TU Delft)
  • Henk Gingnagel (Pink Roccade)
  • Hans Goedvolk (Capgemini)
  • Bart-Jan Hommes (Capgemini)
  • Jan Hoogervorst (Sogeti)
  • Wouter Mellink (KLM)
  • Karin Middeljans (Rijkswaterstaat)
  • Marleen Olde Hartmann (zelfstandig)
  • Martin Op ’t Land (Capgemini)
  • Roelof Rabbers (KPN)
  • Louis Stevens (Ordina)

The xAF-WG has bimestrial meetings in which the work of project groups is evaluated and in which decisions are made about projects (initiation, progress control, termination). The members of a project group are a sub set of the xAF-WG. The annual main event for presenting the progress of the xAF work is the LAC (Landelijk Architectuur Congres). All official publications of the xAF-WG are in English.


Publications can be found on the ‘Publicaties en Documenten‘ page under ‘Werkgroepen’So far, the working group has published the following documents:


Jan Dietz

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