Using Semicontrollable Interfaces In Testing Army Communications Protocols: Application To Mil-Std 188-220b

Testing Army communications protocols is considered for a testing environment where tester has limited degrees of controllability on applying inputs to an Implementation Under Test. The inputs fall into three categories: directly controllable, semicontrollable, or uncontrollable. A graph conversion algorithm is presented to utilize the semicontrollable inputs, thereby increasing the number of testable transitions. The research was motivated while generating tests for MIL-STD 188-220B. The number of testable transitions for 188-220B Class A--Type 1 Datalink Service module is approximately 200 without utilizing semicontrollable inputs. These 200 account for only 30% of the transitions defined in the protocol specification. The presented methodology makes it possible to increase the number of testable transitions to over 700. Combined with our previous work on testing protocols with timing constraints, the methodology allows us to generate tests free of interruptions due to timeouts, and covering more than 95% of the defined transitions in 188-220B's Type 1 Datalink Layer

Generation Of Realizable Conformance Tests Under Timing Constraints

An optimization method is introduced for generating minimum-length test sequences taking into account timing constraints for FSM models of communication protocols. Due to active timers in many of today's protocols, the number of consecutive self-loops that can be traversed in a given state before a timeout occurs is limited. An example of a protocol where this constraint occurs is MIL-STD 188-220B. A test sequence that does not consider timing constraints will likely be unrealizable in a test laboratory, thereby potentially resulting in the incorrect failing of valid implementations. The solution uses a series of augmentations for a protocol 's directed graph representation. The resulting test sequence is proven to be of minimum-length while not exceeding the tolerable limit of consecutive self-loops at each state. Although UIO sequences are used for state verification method, the results also are applicable to test generation that uses distinguishing or characterizing sequences

Formal Design And Testing Of Army Communication Protocols Based On Estelle

This paper describes the Estelle specification of MILSTD 188-220A [7] Intranet Layer as well as a methodology for generating test sequences for checking the conformance of a protocol implementation to its specification. The methodology for deriving test cases from Estelle specification, which serves as input to test generation techniques, is presented. A Chinese postman tour [1] is used to determine a minimum-cost tour of the transition graph for various transition types. Finally, the paper discusses several controllability and optimization issues that need to be addressed in test cases generation for intranet and datalink layers of MIL-STD 188-220A. 1 Introduction One of the University of Delaware's (UD) major contributions to the ATIRP is the study of formal specification languages in the specification and testing of Army communication protocols. In 1989, Estelle was approved as one of two ISO International Standard Formal Description Techniques (FDT) for the specification of compu..

A Technique to Generate Feasible Tests for Communications Systems with Multiple Timers

We present a new model for testing real-time protocols with multiple timers, which captures complex timing dependencies by using simple linear expressions involving timerrelated variables. This new modeling technique, combined with the algorithms to eliminate inconsistencies, allows generation of feasible test sequences without compromising their fault coverage. The model is specifically designed for testing to avoid performing full reachability analysis, and to control the growth of the number of test scenarios. Based on extended finite state machines, it is applicable to languages such as SDL, VHDL, and Estelle. The technique models a realistic testing framework in which each I/O exchange takes a certain time to realize and timers can be arbitrarily started or stopped. A software tool implementing this technique is used to generate test cases for the US Army wireless standard MIL-STD 188-220