Research on link layer vulnerability of master-slave scheduling in industrial control network based on stochastic Petri net

With the development of modern industry, the network security problem of industrial control systems is becoming increasingly serious, and it is necessary to strengthen the research on the security vulnerability mechanism of industrial control networks. Aiming at the link layer vulnerability problem of industrial control networks based on the master-slave scheduling mechanism, a quantitative analysis method based on stochastic Petri nets (SPN) is introduced. Using the Markov Chain (MC) that is isomorphic to the SPN model, the steady-state probabilities of the final states of a industrial control system can be calculated by the mathematical tools of the isomorphic MC. Then the impact of key factors on the link layer vulnerability can be analyzed based on the trends of steady-state probabilities with respect to the variations of the different factors. The key transfer rate factors that affect the vulnerability of the link layer in the industrial control network are simulated, and the final steady-state probability quantitative results with respect to the variations of the transfer rate factors are obtained. The result indicates that the industrial control network link layer based on the master-slave scheduling mechanism has vulnerabilities. However, we can enhance the security of the industrial control system by improving the conversion rate of RTs waiting for the BC command words and the BC waiting for RT status words under the condition that economic costs permit, and reducing the data word transmission rate while meeting the requirements of actual system data transmission.