1 Part 1: Fundamentals of the V-Modell

1.5 Project Execution

1.5.1 Acquirer/Supplier Interface

According to the V-Modell, is is possible to execute two V-Modell projects within the scope of system development: »System Development Project (Acquirer) and »System Development Project (Supplier). The V-Modell provides a specially adapted project execution strategy for these different project types (see paragraph »Project Execution Strategy ). Figure 15 shows an example for two different project execution strategies and the sequence of the corresponding »Decision Gate.

The V-Modell explicitly describes the »Interface between V-Modell Projects of the »Acquirer and of the »Supplier. An »Interface Product, which is developed outside the particular »V-Modell Project, is designated as »External Product in the V-Modell. Figure 15 shows the interface products which are exchanged between the V-Modell project of the acquirer and the supplier.

The V-Modell project of the acquirer develops a » Request for Proposal. This request for proposal includes the previously prepared »Requirements Specification and definitions regarding the content of the »Project Manual of the supplier. Based on the request for proposal, the V-Modell project of the potential supplier makes an » Offer. This offer includes the offer-relevant and contract-relevant parts of the »Project Manual and the »QA Manual of the potential supplier. If the acquirer accepts the offer, a » Contract will be concluded. This contract can be complemented by » Contract Addendum.

The »Project Status Reports inform the acquirer about project progress, project planning, project control measures, quality assurance and problem and change lists. The acquirer should be represented in the »Steering Committee and the »Change Control Board in order to ensure a direct coordination between acquirer and supplier.

The V-Modell project of the supplier sends interim products and end products as »Delivery to the acquirer. The V-Modell project of the acquirer provides a feedback to these interim and final deliveries by means of a »Statement of Acceptance. It is important that a statement of acceptance is only to be made for the decision gate »Acceptance Completed. The consequence is that the sole formal acceptance of development documents is not admissible. In general, the »User, who is represented by the acquirer, can only decide whether the supplier realized what has been required when the supplier delivers Software and Hardware respectively.

A supplier may act as acquirer with respect to a sub-supplier. The projects of the »Sub-Acquirer and the »Sub-Supplier will be processed in accordance with the V-Modell and connected via the already described »Acquirer/Supplier Interface.


Figure 15: Acquirer/Supplier Interface

If the system development project of the acquirer exceeds a certain magnitude, it should be subdivided into appropriate sub-projects. Even if these projects are executed within one company, this subdivision should also be conducted in accordance with the described acquirer/supplier interface. This is the only way to control the coordination between the projects adequately and to make corrections if required.