Study On Network Clock Synchronization

The clock synchronization on network is an important research field in the distributed system, which is the foundation of many key application based on network. Clock synchronization includes logical clock synchronization and physical clock synchronization. Logical clock synchronization means that it is not always necessary for all the processes to keep on concurrent time if the sequence of the events happened in the distributed system can be consistent. Physical clock synchronization includes external clock synchronization and internal clock synchronization. External clock synchronization is to keep the clock of a system concurrent with a standard clock that is not in the same one with some algorithm. Internal synchronization is to maintain the difference between two clocks be bounded in a fixed range. Based on the detailed analysis of NTP (Network Time Protocol), the mathematical model of physical clock and its principle of vibration are introduced firstly. Then, the corresponding clock synchronization model and the algorithm of clock leader election when there are more than one time source in the network is proposed. And we make a lot of analysis and design in detail on clock synchronization process,selection of time stamps and clock correction. After that, with constructed message, large amount of experimental data is put forward and proofed that the network clock synchronization system designed in this thesis is feasible and in high accuracy.