View DNDAF:OV-5a Functional Model Subview



OV-5a Functional Model Subview

Version & Date

1.6 See DNDAF Release History


The OV-5a subview is part of the DNDAF Operational View.

The Operational View-5a (OV-5a): Functional Model further defines the operation requirement scope to the desired level of operational activities or business functions. Through decomposition, the OV-5a focuses exclusively on “what must be done”, leaving “how it is done to be further developed in the Operational Process Model (OV-5b) and other supporting sub-views. The OV-5a describes the hierarchical relationships and dependencies among operational activities or business functions.

The objectives will not change. The methods can, and do, change frequently. The separation of “objective” (what) from “method” (how) allows modulated efficient change control.


The purpose of this sub-view is to describe the functions and their relationships, which are required in order to achieve the objective of the architecture project. This sub-view describes “what must be done” without prescribing “how it is to be done”, thus allowing the architect to potentially propose various valid solutions.


The objective and scope of the architecture project are initially described in the High-Level Concept of Operations Graphic (OV-1) and the Strategic Information Model (IV-1). In order to add detail to this objective within its related scope, it is necessary to describe the subordinate and related activities that are conducted in order to achieve this objective. Functions are composed of related activities with a common subject, which taken together achieve a specific aim. They describe what activities must be done to achieve the objective and are not concerned with the sequence of activities.

It is important to note that a function is not likely to change so long as the objective it supports does not change. However, how the function is implemented, i.e. the process, will likely change over time as new methods and new technologies are employed. The process sequence is based on the approach taken to accomplishing the objective. In other words, the way something is done may be dependant on the equipment used or the people involved, but its objective is not. The notion of activity is developed initially as “what” in the OV-5a and then further described as “how” in the OV-5b.

Given the diverse nature of the enterprise, the term function has many meanings, each relating to a specific dimension and perspective of the organization. Employed in the Operational View, the term function is intended to include what is commonly referred to as a business function, as well as what the operational community calls an operational activity; as their nature is the same but refers to different areas of the enterprise.



The Functional Model (OV-5a) is a decomposition model that describes subordinate and related activities that are conducted to achieve the objective of the architecture project. It describes what must be done and identifies the relationships between the activities.

Detailed Description

Functional Models are hierarchical in nature; that is, they begin with a single box that represents the overall activity and proceed successively to decompose the activity to the level required by the purpose of the architecture project. A Functional Model generally includes:

  • a diagram of the functions and sub-functions included in the model;
  • explanatory text for each diagram, which provides any required detail;
  • and a dictionary that defines all functions and terms used in the diagrams.

Although the notation is relatively simple, Functional Models can sometimes be quite complex. Detailed functional models are sometimes needed for analysis and discovery of issues, but only the higher levels, or abstractions of the higher levels, should be provided to decision-makers

Subview DADM Elements

The DADM entities and attributes provided below are the elements that this sub-view is responsible for creating:




  • graphical



  • p53 Figure 3.9.1 in DND/CF Architecture Framework (DNDAF)  Volume 2: DND/CF Views and Sub-Views


OV-2 and IV-1 are the prerequisites for this sub-view:

  • OV-2. The activities annotating an operational node in an OV-2 map to the activities described in an OV-5a.
  • IV-1. The IV-1 identifies those things which are within the scope of the architecture project and from which will be derived various activities which are of concern to the architecture project, both owned and of interest. Functions must related to at least one of the items identified in the Strategic Information Model or be deemed out of scope.


See DNDAF Subview Dependencies



From 2.10.2 in DND/CF Architecture Framework (DNDAF)  Volume 4: DND/CF User Guide

The OV-5a is equivalent to a Work Breakdown Structure (WBS). It defines and organizes the total scope of an operation using a hierarchical tree structure.

Starting from the highest level task (the root), then, decomposing it into the level of operational activities which are appropriate for level two. The first two levels of the WBS (the root, and the Level 2) define a set of operational activities that collectively and exclusively represent 100% of the operation scope.

The decomposition levels and the amount of detail shown on OV-5a should be aligned with the operational nodes that are responsible for conducting the operational activities (shown on corresponding OV-2). If there is any new information or changes regarding the operational activities, OV-2 should also be updated accordingly.

Other Frameworks

See also:


Category:Framework -> Specification
Category:Framework -> Subview



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