Synchronizing Computer Clocks Using a Local Area Network
NATIONAL INST OF STANDARDS AND TECHNOLOGY BOULDER CO TIME AND FREQUENCY DIV
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We have completed the first tests of a method to synchronize the clocks of networked computers to the NIST time scale. The method uses a server computer to disseminate the time to other clients on the same local-area network. The server is synchronized to NIST using the ACTS protocol over a dial-up telephone line. The software in both the server and the clients constructs a statistical model of the performance of the local clock and of the calibration channel, and the parameters of this model are used to adjust the time of the local clock and the interval between calibration requests in a statistically optimum way. The algorithm maximizes the time between calibrations while at the same time keeping the time of the local clock correct within a specified tolerance. The method can be extended to synchronize computers linked over wide-area networks, and an experiment to test the performance of the algorithms over such networks is being planned.
- Computer Systems
- Test Facilities, Equipment and Methods