Abstract
The article improves the efficiency of counteracting unauthorised access by using algorithms and a protocol for monitoring information security in fibre-optic transmission systems and access networks with the help of the proposed software, which functions as part of a combined (hardware and software) method of protecting optical information flows in FOCLs. The principles of building network protocols are investigated. The functionality of the developed algorithms and the protocol for monitoring the information security of fibre-optic transmission systems is substantiated. The algorithms for stopping and restoring the transmission mode for the subscriber and linear sections of the optical network based on GPON and GEPON technologies, as well as the protocol for monitoring the information security of fibre-optic transmission systems are developed. The practical significance of the work is to improve information security through the use of a combined security control tool that operates on the basis of the developed algorithms and the information security control protocol.