System-of-Systems Viewpoint for System Architecture Documentation

TL;DR

This paper evaluates a system-of-systems architecture documentation viewpoint to support integrated design and analysis, identifying gaps and proposing enhancements to improve comprehensiveness for constituent system concerns.

Contribution

It introduces a revised architecture documentation viewpoint with a Deployment Model to better address system interaction concerns in a system-of-systems context.

Findings

Expert review showed the viewpoint effectively answered most architect questions.

Identified a gap in the baseline viewpoint regarding software and network relationships.

Adding a Deployment Model improved coverage of interaction concerns.

Abstract

Context: The systems comprising a system of systems (SoS) are inde- pendently acquired, operated, and managed. Frequently, the architecture documentation of these existing systems addresses only a stand-alone perspective, and must be augmented to address concerns that arise in the integrated SoS. Objective: We evaluated an architecture documentation viewpoint to address the concerns of a SoS architect about a constituent system, to support SoS design and analysis involving that constituent system. Method: We performed an expert review of documentation produced by applying the viewpoint to a system, using the active review method. Results: The expert panel was able to used a view constructed using the baseline version of the viewpoint to answer questions related to all SoS architect concerns about a constituent system, except for questions concerning the interaction of the constituent system with the platform and network infrastructure. Conclusions: We found that the expert panel was unable to answer certain questions because the baseline version of the viewpoint had a gap in coverage related to relationship of software units of execution (e.g., processes or services) to computers and networks. The viewpoint was revised to add a Deployment Model to address these concerns, and is included in an appendix.