Specification quality [formal SDL and signalling]

The paper reports on some of the initiatives within BT to take advantage of formal specification and description language (SDL) and the improved quality of their signalling specifications. In particular it deals with the specification and modelling parts of BT´s Signalling System No.7 (C7) network and its verification against requirements through simulation. The use of simulation also allows the company to interwork one specification with another ensuring that the specifications are complete, unambiguous and self consistent. Furthermore, it indicates other advantages BT gains from high quality SDL specifications, in particular the use of SDL as part of rapid product development and semiautomatic test generation