Petri net model of protocol conversion for CTF service: Its universal coupling criteria and property analysis

摘要

Protocol conversion is a critical issue requiring much research attention. In this paper, the protocol conversion methodology proposed originally by Green is extended with the Petri nets theory to study application layer protocol conversion among more than two interfaces. The click-to-fax (CTF) service based on the Internet intelligent network (IIN) model is taken as an example to illustrate the extended part. A two-step Petri net modelling method is proposed, which is easier compared to constructing the overall model directly in just one step. Universal coupling criteria of Petri net model of protocol conversion (PNPC) are abstracted. The PNPC of CTF service is analysed using analytical techniques of Petri nets, which are proved to be effective in finding and eliminating potential bugs. The necessity of the concept of service layer is also emphasized.