Model-Based Scalability Estimation in Inception-Phase Software Architecture.

Scalability is one of the crucial nonfunctional requirements that must be evaluated in the Inception Phase of the Rational Unified Process [9]. This is the phase in which the least information is generally available to form a principled evaluation. We demonstrate how an estimate of user scalability can be formed using sequence diagrams of the common user scenarios, together with experimentation (ranging from simple timing measurements to more complex architectural prototypes), published study data, and performance data from baseline systems. Despite being quite inexpensive, the techniques used by our team enabled us to identify and guide corrective actions for major bottlenecks before they became serious design flaws in the Elaboration and Construction phases of the Unified Process. The same techniques also allowed us to quickly evaluate the effects of high-level architecture and technology alternatives on user scalability and response time. [ABSTRACT FROM AUTHOR]