Experiences in System-of-Systems-Wide Architecture Evaluation over Multiple Product Lines

Abstract

Software architecture evaluation, both for software products and software product lines, has become a mainstream activity in industry. Significant amount of practical experience exists in applying architecture evaluation in real projects. However, most of the methods and practices focus on evaluating individual products or product lines. In this paper, we study how to evaluate a system-of-systems consisting of several cooperating software product lines. In particular, the intent is to evaluate the system-of-systems-wide architecture for the ability to satisfy a new set of crosscutting requirements. We describe the experiences and practices of performing a system-of-systems-wide architecture evaluation in industry: the system-of-systems in question is a set of product lines whose products are used to create the All-IP 3G telecommunications network. The results indicate there are significant differences in evaluating the architecture of system-of-systems compared with traditional evaluations targeting single systems. The two main differences affecting architecture evaluation were the heterogeneity in the maturity levels of the individual systems, i.e., product lines, and the option that instead of simply evaluating each product line individually, responsibilities can be moved from one product line to another to satisfy the system-of-systems level requirements.