Efficient test generation for army network protocols with conflicting timers

During the University of Delaware (UD´s) and CCNY´s (City College of the City University of New York) ongoing effort to generate conformance tests for the US Army network protocol MIL-STD 188-220, a significant obstacle has been addressed-when multiple timers are running simultaneously, a test sequence may become unrealizable if there are conflicting conditions based on the protocol´s timers. This problem, termed the conflicting timers problem, is handled in the hitherto generated tests by manually expanding a protocol´s extended FSM based on the set of conflicting timers, resulting in test sequences that are far from minimum-length. Similar inconsistencies, but based on arbitrary linear variables, are present in the extended FSMs modeling VHDL specifications. This paper presents an efficient solution to the conflicting timers problem that eliminates the redundancies of manual state expansion. CCNY´s inconsistency removal algorithms are applied to a new model for real-time protocols with multiple timers. The new model captures complex timing dependencies by using simple linear expressions. this modeling technique, combined with the CCNY´s inconsistency removal algorithms, is expected to significantly shorten the test sequences without compromising their fault coverage