Аннотация:This article is about developing a test coverage generation system for testing network devices that implements network protocols, using the AFDX (Avionics Full- Duplex Switched Ethernet) protocol as an example. When network devices are in developing, it is necessary to carry out functional testing of the correctness of the implementation of network protocols for compliance with the speci cation. The paper considers methods for generating test coverages based on nite and extended nite machines. A review was carried out, which considered the following methods for generating test coverage: the RETGA method, the method of input and output sequences, and the method of counting states. As a network device implementing the AFDX protocol, the model implemented in the system is used, which receives a set of network tra c as input. To perform evaluation, an algorithm was developed for translating test sequences into a set of input and output network traffic.