Design of Telephony Services In Lotos

The purpose of this thesis is to design and validate a telephony system using the formal description language LOTOS and a series of tools provided by the Lotosphere Integrated Tool Environment, LITE. The starting point is a requirements document containing a series of informal specifications of services common to modern telephony systems. Special emphasis has been laid on choosing a design that simplifies the integration of additional telephone services in the specification. Most design decisions were thus taken with the purpose of creating an environment that could help different designers to develop distinct functionalities without the need for each one to be acquainted with other existing features in the system. To this end, the design was structured in a fashion that might enhance the extensibility of the system, as well as prevention and detection of incompatibilities between different features. A methodology is thus proposed for dealing with what is commonly known as the feature interaction problem for telephony systems