SYSTEMS AND METHODS OF CLOCK SYNCHRONIZATION BETWEEN DEVICES ON A NETWORK

摘要

An exemplary method of synchronizing a master clock and a slave clock comprises transmitting a plurality of packets between a master device and a slave device, calculating a first skew between a first pair of the plurality of packets at the slave device and a second skew between the first pair at the master device, calculating a ratio between the first skew and the second skew, providing a slave clock frequency correction to the slave device, calculating a first packet trip delay using a time that the master device initiates sending a packet to the slave device, a time the master device receives a response from the slave device, a corrected time the slave device receives the packet, and a corrected time the slave device initiates sending the response, calculating a first offset based on the first packet trip delay, and providing the first offset to the slave device.

主权项

1. A method of synchronizing a master clock and a slave clock, the method comprising:
transmitting a first packet and a second packet from a master device with a master clock to a slave device with a slave clock; determining a first time when the master device sends the first packet and a second time when the master device sends the second packet; determining a third time when the slave device receives the first packet and a fourth time when the slave device receives the second packet; determining a fifth time when the slave device sends a third packet to the master device and a sixth time when the slave device sends a fourth packet to the master device; determining a seventh time when the master device receives the third packet and an eighth time when the master device receives the fourth packet; calculating a first skew based on a difference between the second time and the first time, and a second skew based on a difference between the fourth time and the third time; calculating a third skew based on a difference between the eighth time and the seventh time, and a fourth skew based on a difference between the sixth time and the fifth time; calculating an RMS ratio based on the first skew and the second skew; calculating an RSM ratio based on the third skew and the fourth skew; comparing the RMS ratio to the RSM ratio; based on whether the comparison of the RMS ratio and the RSM ratio satisfies a condition, determining whether to trust a packet trip delay; calculating the packet trip delay either based on the first time, the third time, a time that the slave device initiates sending a response to the first packet, and a time that the master device receives the response to the first packet from the slave device, or based on the second time, the fourth time, a time that the slave device initiates sending a response to the second packet, and a time that the master device receives the response to the second packet from the slave device; calculating an offset between the master clock and the slave clock based on the packet trip delay; and providing the offset to the slave device to enable the slave device to make a correction to the slave clock.