Generating a Model of a Communication Protocol from Test Data

Abstract: Model-based techniques for verification and validation require a model of the systemunder test (SUT). However, most communication systems lack a complete, correctmodel. One approach for generating a model of a system is to infer the model byobserving its external behavior. This approach is useful when the source code of thesystem is not available, e.g., third party components. Regular inference techniques areable to infer a finite state machine model of a system by observing its externalbehavior. In this master thesis we consider the models inferred by regular inferencetechniques of a certain kind of systems: communication protocol entities. Suchentities interact by sending and receiving messages consisting of a message type and anumber of parameters, each of which potentially can take on a large number of values.This may cause a model of a communication protocol entity inferred by regularinference, to be very large. Since regular inference creates a model from the observedbehavior of a communication protocol entity, the model may be very different from adesigner's model of the system's source code. This master thesis presents a novel approach to transform the inferred model ofcommunication protocols to a new formalism in a sense that it is more compact andit has a similar partitioning of an entity's behavior into control states as in a designer'smodel of the protocol. We have applied our approach to an executable specificationof the Mobile Arts Advanced Mobile Location Center (A-MLC) protocol andevaluated the results.