Test Generation for a Protocol Specified in SDL with Complex Loops by Event-based EFSM Modeling

Test case generation for a network protocol by extended finite state machine (EFSM) based modeling is a well-known technique in formal methods in conformance testing. An input output based EFSM (IOEFSM) is a popular model for a protocol specified in the specification and description language (SDL) because an SDL process diagram is based on an input-driven EFSM. However, as an SDL specification may have a very complicated part such as complex nested loops, IOEFSM modeling may not be appropriate to represent such a complex SDL specification. This paper proposes a test generation method for a protocol specified in SDL using an event-based EFSM (EEFSM) for more exact modeling. It also shows the relations between an IOEFSM and an EEFSM, and their inter-conversion methods. Empirical results with a real network protocol, the service specific connection oriented protocol (SSCOP) showed the efficacy of the proposed method.