Managing software evolution with the service concept

Software-intensive systems evolve. Properties embedded in them seldom benefit from this, as the modifications needed for supporting new features do not always match with software structures that originally constitute the system. This results in special cases and exceptions for intended abstractions, and consequently creates problems for the future evolution of the system. In order to improve the facilities that enable the management of the evolution of telecommunications system software, we have introduced the notion of services. The purpose of the service concept is to enable an abstract description of conceptual properties of the system disregarding their final relation to underlying software components of the implementation. Therefore, services provide a view of the system where the focus can be shifted from individual implementation components to their collaboration at varying levels of abstraction. Based on this collaboration, we then define a virtual architecture that helps in managing software evolution. We introduce the basic notion of services, and present experiences on employing the concept in practice.