Algorithmic generation of protocol conformance tests

With the recent expansion of data communications networks, computers and terminals from different manufacturers must be interconnected. Before being connected to the network, these interacting elements should be tested to ensure that they conform to the network's protocol specifications. We describe an algorithmic method (which is based on unique input/output sequences and Rural Postman tours) for generating conformance-test sequences that require minimum cost (i.e., run time) and completely cover the state transitions defined by the protocol specification. The technique, which has been implemented as the POSTMAN software package, has been widely used in AT&T Bell Laboratories to generate protocol-conformance tests. This approach can be used to generate tests for valid, inopportune, and illegal messages; for error recovery; and for window-flow-control procedures (see Sherif and Uyar
¹
).