The authors present a detailed study of four formal methods (T-, U-, D-, and W-methods) for generating test sequences for protocols. Applications of these methods to the NBS Class 4 Transport Protocol are discussed. An estimation of fault coverage of four protocol-test-sequence generation techniques using Monte Carlo simulation is also presented. The ability of a test sequence to decide whether a protocol implementation conforms to its specification heavily relies on the range of faults that it can capture. Conformance is defined at two levels, namely, weak and strong conformance. This study shows that a test sequence produced by T-method has a poor fault detection capability, whereas test sequences produced by U-, D-, and W-methods have comparable (superior to that for T-method) fault coverage on several classes of randomly generated machines used in this study. Also, some problems with a straightforward application of the four protocol-test-sequence generation methods to real-world communication protocols are pointed out.>

The authors present an estimation of fault coverage of four protocol test sequences generation techniques (T-, U-, D-, and W-methods) using Monte Carlo simulation on a simple protocol machine. The ability of a test sequence to decide whether a protocol implementation conforms to its specification heavily relies upon the range of faults that it can capture. This study shows that a test sequence produced by T-method has a poor fault detection capability whereas test sequences produced by U-, D- and W-methods have fault coverage comparable to each other and superior to that for T-method on several classes of randomly generated machines used.>

This paper presents results on the application of four protocol test sequence generation techniques (T-, U-, D-, and W-methods) to the NBS Class 4 transport protocol (TP4). The ability of a test sequence to decide whether a protocol implementation conforms to its specification depend on the range of faults that it can capture. The study shows that a test sequence produced by the T-method has a poor fault detection capability whereas test sequences produced by the U-, D- and W-methods have comparable (superior to that for T-method) fault coverage on several classes of randomly generated machines. The lengths of test sequences produced by the four methods tend to be different. The length of a test sequence produced by the T-method (W-method) is the smallest (largest). The length of a test sequence from the U-method is smaller than that for the D-method and lengths for both are greater than that for the T-method and less than that for the W-method.