Industrial Automatic Control Systems and Controllers Annotation << Back Model of Evaluation the Infl uence of Logical Link Control Sublayer on the Characteristics of the Heterogeneous Local Communication Network with Combined Access Protocol E.B. Gezalov In the article the local communication network, heterogeneous on the intensity of the incoming message flow and the type of messages, with the combined access protocol. The logical link control sublayer of the network under consideration implements the protocol option «Service without connection with a confi rming response». The model of the considered local network in discrete time is developed, allowing to evaluate the infl uence of the processes occurring on the sublevel of control by the logical link of the network on its characteristics. In order to assess the influence of the logical link control sublayer on the characteristics of a heterogeneous local network with a combined access protocol, the average delay time of the speech frame, video frame and data frame is analyzed. The results of the analysis and the nature of the change in the average delay time of the speech frame, video frame and data frame in the local network in confi rm the adequacy of the developed network model to the physical processes occurring at the logical link control sublayer. It is established that by varying the processing speed of data in network stations and the probability of blocking the receiving buffer of stations with changing external traffic, it is possible to minimize the average delay time of messages and select the type of the element base station corresponding to the best network variant. Keywords: heterogeneous local area network; combined access protocol; logical link control sublayer; medium access control sublayer; buffer; frame; time window; service interval. Contacts: E-mail: gelchin_63@mail.ru Pp. 47-55.