| With the development of communication technologies and the growing of new communication business, the entire electric power communication network operation and maintenance are becoming increasingly important. Traditional "trial-use" as the main features of anti-accident exercise has made some contribution to the safety of electric power communications network, but there are many defects. In order to improve efficiency to deal with the accident, to overcome detects of traditional anti-accident exercise, it is necessary to simulate the real electric power communication network, which can be basic to the research and development of the electric power communication network operation and maintenance. And it is known that electric power communication network is based on synchronization. At present, a large number of electric power communication networks are using SDH. Therefore to simulate electric power communication networks, we must study the simulation of SDH network synchronization. In this dissertation, there is an overview of clock synchronization status and the background and significance of the research.It describes SDH transmission principles, including the SDH frame structure. This dissertation highlights the logic of SDH prototype parts and functions, details of the SDH synchronization mechanisms.It also does some research on several classical clock synchronization algorithms and comparison. Finally, with the combination of SDH transmission principles and communication simulation status, this dissertation proposes the simulation of SDH network synchronization.It discusses SDH synchronization between the prototype and the prototype's internal synchronization, proposes a asymmetric adaptive clock synchronization algorithm.The algorithm changes the symmetric network structure into asymmetric structure,and selects a reference clock node through calculation of parameters.In the end,the entire system manages to achieve clock synchronization by adjusting clock. |
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