The Design And Inplementation Of Time Synchronization In Packet Transport Network

The fast development of IP Service helps to promote the technical innovation of transport network. Traditional SDH/MSTP will be replaced by new transport network technology represented by PTN. However, network construction must take the existing resource into account. So the coexistence of multiservice transport platform and packet transport network will be quite common. One of the important research content of this paper is key technologies in the hybrid network, including time synchronization and end to end OAM. Besides, as a matured access solution, multiservice access platform (MSAP) will be remained in packet transport network. The other research content of this paper is the network protection in MSAP.First, this paper shows the design scheme of a FE-E1Protocol Converters which supports IEEE1588v2function. By implementing the boundary clock functionality and realizing a specially designed algorithm, the Protocol Converter can overcome the disadvantage caused by a TDM link in time synchronization and remarkably increase the precision. The whole system has already been realized in FPGA. As a supplement to time synchronization, a frequency synchronization technique called frequency compensated clock is also introduced.Then, this paper analyzes the mechanism of OAM interworking between different networks. By researching and summarizing the current solutions, an improved gateway scheme has been designed, which can provide a reference for the end to end management between PTN and MSTP.Finally, in order to improve the survivability of access layer of PTN, a network protection scheme of multiservice access platform is designed, including the technical principle and implementation method.