An object oriented approach for structuring ISDN call processing software

In 1989 a pilot project was started at Siemens to gain experience concerning the applicability of object oriented techniques (OOT) in the field of switching system software. In this pilot project an ISDN prototype switch was implemented applying both the principles of object oriented design and the programming language Object-CHILL, an object oriented extension of CHILL. The authors deal with the results reached so far within this project. In this context three subjects are considered in more detail: the influence of OOT on the software development process, the resulting structure of the ISDN call processing software and the impact of OOT on the tool set. In general many of the advantages claimed to be associated with object orientation in other application fields could be confirmed for switching system software