Application of Petri Nets in the Simulation and Fault Diagnosis of Digital Switches Signaling

Modeling and diagnosis of signaling faults in digital telecommunication switches is very important. Providing practical approaches to this issue can be effective in increasing the speed and security of traffic information in the telecommunications network. In this paper, the signaling of the NEAX digital switch, which is a commonly used switch in the Iran telecommunication network, is simulated using the concept of Petri Nets (PNs), and then based on this model, a new algebraic method is proposed for detecting fault signaling. Unlike most of the methods presented in this field, the method proposed in this paper, without using of the reachability graph, uses algebraic approaches to detect the faults. The low complexity of computations, the needles of observablity of transitions, possibility of fault detection both in places and transitions of PN are the advantages of this method. Here, for more illustration, signaling in a successful single-call mode and busy mode is simulated and faults such as incomplete sending of destination phone numbers are detected.