Patent ID: 8995473
Filing Date: 2015-03-31
Classification: H04J

Abstract:
1. A method performed in a master clock node in a network of nodes having the master clock node with a local clock and a plurality of slave clock nodes each with a local clock, the slave clock nodes being in a ring topology from the master clock node and back to the master clock node, the method to synchronize the slave clock nodes of the network to the master clock node and to compensate for phase alignment offsets of the slave clock nodes, the method comprising: creating a timing packet that includes within the timing packet a time stamp based on an obtained time; sending the timing packet including the time stamp from a master port of the master clock node to a first slave clock node of the ring topology, each slave clock node having a slave port to receive a timing packet from one network node and a master port to transmit a timing packet to another network node; receiving a timing packet from a last slave clock node of the ring topology at a slave port of the master clock node, wherein the last slave clock node is a different slave clock node than the first slave clock node; determining a phase alignment offset of the slave clock nodes by comparing a recovered time from the received timing packet, which was received from the last slave clock node of the ring topology, with a time of the local clock of the master clock node; determining a phase correction value for the slave clock nodes based on the determined phase alignment offset; and sending a phase correction packet including the phase correction value from the master clock node to the plurality of slave clock nodes.