Research And Implementation Of IEEE1588 And Synchronous Ethernet Technology

Because IP network is open,low cost,flexible networking,scalable size and other characteristics,so it has been very widely used.The future will be based on IP network evolution,therefore the existing many other technological system of the network will be IP transformation.However,since the IP network using the packet transmission,each node in the network,clock synchronization signal cannot be extracted directly from the traffic packets received to achieve the system synchronization.So,how to solve the timing and time synchronization in IP networks is a problem to be studied.Network Time Protocol(referred NTP)synchronization accuracy in milliseconds,cannot meet the high requirements for time synchronization applications.High precision timing GPS satellites,but there are siting difficulties in deployment and installation,maintenance difficulties and high construction cost disadvantage.At present on the packet network realizes the high precision time and frequency synchronization signal transmission,there are two kinds of feasible technology First,packet-based synchronization techniques,such as IEEE1588 standard defines the Precision Time Protocol(PTP);the second is based on the physical layer synchronization technology,such as Synchronous Ethernet(SyncE)technology.In this thesis,the PTP protocol,the clock model,network architecture and synchronization mechanisms defined in the IEEE1588 standard are analyzed in detail,but also on the synchronous Ethernet technology was studied.On the basis of analyzing the characteristics of these two technologies,the author thinks that IEEE1588 standard can make up for the synchronous Ethernet technology can only achieve frequency synchronization,can't realize the time synchronization.Synchronous Ethernet technology at the same time also can make up for the inadequacy of IEEE 1588 standard in terms of frequency synchronization.Therefore,in practical applications it can be used in conjunction with these two techniques.Because synchronous Ethernet technology is based on the physical layer synchronization technology,Ethernet transmit clock and receive clock can be chained together to achieve full network frequency synchronization,this article will focus on the study and implementation of standards in IEEE1588.Combined with a dedicated communications network project,this thesis describes the design and implementation of a clock synchronization module based on the IEEE 1588 standard and synchronous Ethernet technology.The clock synchronization module hardware platform uses a high-performance,low-power ARM processors and industry-leading support both IEEE1588 standard and synchronous Ethernet technology ACS9522T chip.Based on the hardware platform,the author carried out to establish cross-compiler development environment,embedded Linux system migration,the realization of the ACS9522T control program,writing the makefile file,implement the SPI interface driver and realization get UTC time from an external serial protocol handler,and so on.Finally,set up a local area network test environment,the module synchronization function,performance was verified.Results show that based on IEEE1588 standard clock synchronization module can realize the synchronization precision of nanosecond in Ethernet,at the same time reduce the connecting link between the master-slave clock synchronization module,as well as improve the message interaction between master-slave synchronization module frequency can improve the master-slave synchronization precision and speed up the convergence time.Through the study of this thesis,expand the IEEE1588 standard and synchronous Ethernet technology in the application of the network.Finally,this thesis points out the deficiency of the research and the direction of further work.