Maintaining switching software viability

The need for a continuous flow of new functionality in a switch necessitates an approach of focused restructure-periodic maintenance of limited sections of software. Executing a program of focused restructure has historically been a non-precise undertaking for switching systems. This paper describes an approach for establishing more formal guidelines for identifying switching system software that is more likely to contain faults and is hence a candidate for focused restructure. The software architecture-based analysis (SABA) methodology is described. This methodology enlightens the common black box perspective of a large software system with gray box details, applies a dynamic, sophisticated statistical analysis, and produces an expert discrimination of critical software components within their software architecture. Finally, a joint trial of Bellcore's SABA to a large AT&T digital switching system is used to illustrate the approach.