The Research Of Clock Synchronization Technology And Traffic Congestion Model On IEEE1588Network

The21st century is an information interaction age taken the network as the media, andnetwork influence on the development of science and technology. Time synchronization is aclassic topic of distributed system, with modern industrial field network system complexity,structure size, volume of continuous expansion, the global network of real-time puts forwardmore stringent requirements. Therefore, the research of high precision of network timesynchronization technology and theory has important significance and practical value. Basedon industrial Ethernet, this paper proposes a high ratio of IEEE1588protocol networkprecision clock synchronization technique and traffic-congestion forecast model of routingand scheduling strategy.First of all, detailed introduction high precise time synchronization protocol IEEE1588principle is given. IEEE1588message time stamp mark based on hardware and obtains theagreement with synchronous accuracy, high occupancy resources and advantages, such asfewer configurations. Based on thorough analysis theory basis, set up the hardware testplatform, platform by the ARM Cortex-M4kernel (STM32F407VGT6) and integratedcompatible IEEE1588agreement PHY chip (DP83848) composition. This paper deals withthe related hardware circuit composition, including main chip peripheral circuit, SWD debuginterface, the etheric WangKou, etc. Then, in the hardware basis complete LwIP protocolstack and PTP synchronization algorithm of software process design, including the PTPsystem initialization, message transceiver configuration, reading and writing time valuemodule, test signal configuration (1PPS signal, reference signal), etc.Secondly, considering the limited bandwidth, delay and the flow of mutual association,the greater the flow, the delay lags the more obvious; when flow close to saturation, delay willbecome very serious. According to the PTP local clock offset correction mechanism, thispaper proposed an adaptive routing algorithm based on through node flow congestion forecastmessage. The method based on least squares support vector machine on the discharge timeseries online regression estimate future period of time clock node network flow value, fromthis investigation clock node congestion degree index, so the choice of adaptability PTP sincethe minimum delay routing, improve the synchronous message delivery success rate, reducethe complex network of synchronous accuracy vulnerable data flow congestion hysteresiseffect.Finally, in setting up test platform of the Ethernet clock synchronization, through settingmultiple hops routing and with the aid of system PTP clock trigger configuration output1PPS signal and reference signal, the master-slave system synchronization accuracy between thetests, this paper was verified the effectiveness of the strategy. Test results show that by usingthe set of system and mechanism can make the Ethernet between the system clock in P2Pconditions, the accuracy of master-slave PTP is40ns; In5jumped50%unidirectionalbackground flow, the accuracy is better than300ns, achieving the expected goal.