SCIENTIFIC FOUNDATIONS TO THE MULTILEVEL METHOD

Conformance testing of protocols is the process of checking whether an implementation under test conforms to the standards. In this paper we prove that the multilevel method (M method) [which splits the specifi cation graph into a basic subgraph and one or more higher level subgra ph(s)] is capable of diagnosing any number of faults in the higher lev el subgraph(s), if the basic subgraph is error-free, Heuristics for ob taining the basic subgraph and higher level subgraphs from the specifi cation graph are also given. The advantage of the M method is that it has error recovery and, in addition, it does not assume the presence o f reliable reset in the implementation under test. We additionally pro pose an incremental test sequence generation method, which produces a shorter test sequence and whose fault coverage is same as that of the hi method. Finally, we compare the M method with other fault detection and fault diagnostic methods.