Research On Networking Technology Of Time Synchronous Network Based On PTP Protocol

As a mature high-precision timing technology,time synchronization technology based on the PTP protocol(Precision Time Protocol)is widely used in telecommunication networks.The PTP protocol implemented on the basis of existing network equipment to improve the time synchronization accuracy,contributes to the development of time synchronization networks.However,with the generation of new services and the increase of time synchronization requirements,a l arge amount of time-consuming terminal equipment needs to access the time synchronization network to obtain reliable time,which poses greater challenges to the overall performance of the time synchronization network.Based on the above problems,this thesis conducts research from the level of network planning,mainly solving the following two problems:(1)how to set the master clock in a reasonable position of the network,(2)how to design a reasonable time synchronization signal transmission path.In order to solve the problem of setting the location of the master clock reasonably,this thesis proposes a clustering-based partitioning algorithm,which takes into account the construction cost and synchronization performance of the time synchronization network,and improves the time synchronization accuracy of the clock nodes.On the premise of meeting the PTP protocol networking principle,the clustering-based domain division algorithm calculates the optimal master clock distribution scheme in the network,including the number and the location of master clocks,and the division of the network.The specific scheme is as follows:First,according to the clustering principle,a master clock selection strategy is proposed,which considers the node heat and the distance between nodes,and calculates the ranking of all nodes in the network that may become the master clock.Secondly,the strategy of tracing the source from the clock nodes is formulated to ensure that all clocks are divided into corresponding PTP subdomains.Finally,from the aspects of network scale and cost,calculate the most suitable networking scheme for the network.Aiming at the problem of designing a reasonable time synchronization signal transmission path,this thesis proposes a routing algorithm based on the path evaluation mechanism,which solves the problem of bidirectional routing and reduces the time error caused by bidirectional asymmetry.The specific solution is as follows:Aiming at the problem of selecting the route for sending the synchronization request signal from the master clock to the slave clock,this thesis proposes a routing strategy based on the routing evaluation table,which can select the optimal route with the goal of the shortest path.To address the problem of routing the delay request signal from the slave clock to the master clock,this thesis proposes a comprehensive path evaluation strategy based on the entropy method,which comprehensively evaluates the differences between the delay request signal path and synchronization request signal path in terms of link length and hop count,and selects the comprehensive evaluation of the optimal routing scheme.In conclusion,the thesis proposes a clustering-based domain algorithm and a path-scoring-based routing algorithm,aiming at solving the problems of how to set up the master clock in a reasonable position on the network and how to design a reasonable time synchronization signal transmission path.These two algorithms shrink the network scale,reduce the time error caused by two-way asymmetry,thereby improve the overall performance of the PTP-based time synchronization network.