View NAF:Architecture Description

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Version & Date

See NAF.

Definition

A specification of a system of systems at a technical level which also provides the business context for the system of systems.

IEEE1471 describes an architectural description as a collection of products to document the architecture of a system. This is something of a circular definition (as product in this sense is an architectural product), and also assumes a technical system, whereas architectures complying with this metamodel describe an enterprise - i.e. the system of systems and the human processes they support.

Covered by NATO release conditions.

Comments

  • The comment made against ISO 42010 isn’t valid. ISO/IEC 42010 does not assume a technical system - the principles and rules apply to any type of system. The NAF definition of System only applies to technical systems and therefore cannot be applied to the enterprise. The definition of architecture description in ISO/IEC 42010 is also different since an architecture view is a product of an architecture viewpoint whereas in NAF it is a specification for an architecture view (architecture viewpoint in ISO/IEC 42010 terms).
  • Usual confusion between architecture (the real world thing) and architecture description - architectures complying with this metamodel describe - architectures don’t comply with NAF. NAF architecture descriptions, however, do.
  • NAF 3.1 is non-compliant with ISO/IEC 42010.
  • An architecture description is not always normative - how many examples are there of NATO systems built against a NAF architecture description? Virtually none since it will be the URD and SRD (requirement documents) that are contractual. An architecture description may simply be descriptive. The definition above shouldn’t therefore embed the application of the architecture description. ADs are probably more often used to describe than specify and obviously cannot be specifications if they are produced after the fact i.e. describing something that exists. If not all NAF ADs are specifications the definition is wrong.

System of Systems is used incorrectly here since from a classification (i.e a stereotype) aspect it is still of class or stereotype = System and therefore the notion that System referred to in ISO/IEC 42010 cannot represent an Enterprise but System of Systems can is wrong since a System of Systems is still a System - A System of Systems is an arrangement in the same way that Subsystem is - NOT a type or classification.. System can be substituted with no loss of meaning or accuracy. It is pretty clear therefore that System of Systems is used for marketing advantage and not technical or semantic accuracy.

This is a strange criticism of the ISO since NAF itself defines System as an artefact and part of the physical architecture.

References

•

  • p 365 of APPENDIX 5 TO ANNEX 1 TO AC/322-D(2007)0048. NATO Architecture Framework v3, CHAPTER 5

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