The Analysis And Research On Circuit Emulation Service Over Packet

In this paper, a technology of circuit emulation service over packet(CESoP) is introduced. Along with the evolution of the communication networks and amalgamation of different categories of network, transmission and switching based on data packets will be the dominate way in the Next Generation Network(NGN).In the other hand,NGN is not built overnight. Traditional Time Division Multiplex (TDM) network will still be exist in a long time. So it is quite necessary to support TDM service in next generation packet switch network.Time Division Multiplex over Packet Switch Network (TDMoPSN) protocol set down by Internet Engineering Task Force (IETF) is introduced,including universal reference model,protocol stack reference model and time synchronization reference model. Then two different ways of implement of CES,structured and unstructured circuit emulation service, are analyzed.Constant Bit Rate and precise synchronization are two preconditions of TDM service. With the increase of the transmission rate in packet switch network,synchronization is becomes the bottleneck of CES. Based on the pro-research project"Research on key technology of transmitting and recovery of network clock over packet-switched network", this paper focuses on the strategy of how to recover the TDM service clock through packet switched networks. A service clock recovery method based on the research of PTP protocol is put forward. Both analysis and simulation show that this method has been well designed.