A Petri net approach to the control unit of a broadband switching system

The traffic within the control unit of a broadband switching system is modelled by a stochastic Petri net. In particular, random switches included in this Petri net concept are applied to model the separation of signalling data according to the type of service requested by the subscribers, and the multiple use of the picture phone during a telephone session is modelled by correlated parallel paths in the Petri net model. The size and the complexity of the Petri net presented is independent of the number of processors of the control unit. The Petri net is analysed by evaluating the Markov chain equivalent to the net. In this connection for the evaluation of the entire control unit the decomposition of the transition rate matrix corresponding to the net is proposed. A performance measure associated with the switching delay is presented in order to show the applicability of the approach. Two configurations of the control unit are investigated and the results are presented graphically.