An approach to dynamic protocol testing

Protocol conformance testing aims at checking if a protocol implementation conforms to the standard (or specification) it is supposed to support. The results of testing can be classified into global verdict showing the tested system is either error-free or faulty, and local verdict indicating whether each element (e.g., a transition in the FSM) of the system is implemented correctly or not. In reality, the conventional protocol test procedure may give wrong local verdicts in the initial stages of testing because the procedure uses predetermined test sequence. In this paper, we propose a dynamic procedure for protocol testing using Test Sequence Tree (TST). The procedure allows us to get local verdicts more correctly than the conventional methods. The TST is reconfigured dynamically to obtain accurate verdicts for the untested elements by feedback of the local verdicts of the tested elements. The proposed technique was tested on the ITU-T Q.2931 signalling protocol. Our results showed that the fault coverage of our test procedure is better than the conventional methods. An extension of the proposed dynamic testing technique to the nondeterministic FSM is also discussed.