Protocol modeling for conformance testing: Case study for the ISDN LAPD protocol

In this paper, we present a generic approach for modeling a communications protocol with state transitions and window and timer mechanisms, and for generating conformance test sequences automatically. Based on this model, minimum-cost (i.e., minimum run time) conformance test sequences can be generated by using a method based on unique input/output sequences and the Rural Chinese Postman tours. As a case study, this method is applied to the Integrated Services Digital Network link-access protocol on the D channel.