Research And Implementation Of Remote Experiment Communication Mechanism Based On MQTT

The rapid development of digital information technology has brought development opportunities for remote experimental education.However,because of the imperfect remote experimental communication mechanism,the real-time and reliability of message transmission during experimental communication process is poor,the network and instrument safety control is insufficient and the ability to deal with concurrent access to large-scale users is lack,which has led to the inability of remote experiments to be open to the public in all aspects and seriously hindered the further sharing of experimental teaching resources and the improvement of students' practical ability.In view of this,this article uses the advantages of fast,lightweight,low-power,low-latency and low-bandwidth of message queue telemetry transmission(MQTT)technology to conduct research on remote experimental communication mechanism based on MQTT,designs and implements a remote experimental communication system based on this mechanism.The main research contents of this topic are as follows.(1)Research on the concurrent access mechanism of instrument and user.The EMQ message server cluster based on MQTT is built to improve the transfer,processing and concurrency ability of communication message.The experimental communication topics are designed to ensure the independence of each group communication.Combine embedded gateway and WebSocket to reduce the computing resources and network traffic of the instrument and Web client.(2)Research on real-time reliable message transmission mechanism.According to the requirements of remote experimental communication data transmission,the message transmission mechanism under three QoS levels of MQTT is studied.The corresponding communication service quality assurance is provided for different experimental application scenarios.At the same time,the message sequence control mechanism is studied to ensure the order of communication messages when the network is unstable.(3)Research on security control mechanism of network communication.The transmission layer adopts SSL/TLS protocol to implement the encryption and trusted connection of MQTT communication.The application layer adopts the education electronic identity(E2ID)to ensure the real-name security control of the user,at the same time,the user access control list is designed to implement the dynamic management of user access and instrument operation authorization.(4)Research on the safety and guarantee mechanism of experimental instruments.The wills message protection,communication connection detection and experimental safety threshold management are established to ensure the safety of the instrument when the experimental communication fails.At the same time,the communication self-healing and fault alarm mechanism is designed to automatically switch the communication line and attempt to reconstruct the experimental communication function when the communication is disconnected.Finally,the performance of the communication system based on the proposed distance experimental communication mechanism is tested under the environment where simulating real-time concurrent access of large-scale user.The test results show that the proposed mechanism can not only satisfies the high concurrency requirement of the experimental communication,but also effectively ensure the real-time and reliable transmission and security control of the message,which greatly improve the interactive effect of the experimental operation and promote the opening of the experimental platform.The put forward distance experimental communication mechanism has high application value.