added-value processes (telecom just being one of them) and processes that produce SW component systems. Consequently, added-value development processes do not become model-driven by using UML. They only gain the ability to communicate with sub-contractor processes. The network system added-value process is divided between a standardization process and suppliers' development processes. Both processes deal with the added- value view of the system, the supplier selecting between standardized options and adding features and designs that are not defined by the standard model. Presently, both standard and supplier views are described in documents, using natural lan- guage text and intuitive pictures. Consequently, the translation from the standard view to a corresponding UML model is done in two steps by human interpretation of a large amount of documents. 3 In this scenario, it is an almost impossible task to guarantee that the UML model is an accurate realization of specified added values. However, by using AMLn both in the standardization process and suppliers devel- opment processes, a new scenario appears, where the added-value process becomes model-driven as well (see Fig. 1.7). Network design Telecom UML-model 2, AML-model 2, supplier SW & HW UML-model 2, SW & HW Developing the supplier view Model translation model 2 contractors AML->UML model_ model 1 Analyzing Developing Telecom market" standardization needs standard view Fig. 1.7 Models and model translations in the telecom development process As an example, we can look at the standard view of the ISDN network system: only the SS7 subsystem that supports control signalling in ISDN comprises about 2500 pages. If we add all other standards that describe the ISDN, we land at about 7000 pages (quite a few books) to interpret in order to fully understand this view. Still, this is not the only knowledge to be mas- tered by suppliers' designers. They have to know SDH, IP, ATM, TMN, etc., as well. 1 Introduction to Network System Modeling The scenario tells the follo