Method and apparatus for synchronization of a master timebase with one or more slave timebases using indirect signalling of timing information

A method of synchronizing a slave device timebase to a master device timebase, comprising:

• determining whether the master device can send an indication of master transmission time representing a time of a transmission from the master device to the slave device such that the slave device can use the indication to determine the time of the transmission from the master device;
• if the indication is unavailable to the slave device, sending timing information from the slave device to the master device, the timing information representing the slave device timebase;
• and
• sending correction information from the master device to the slave device, the correction information representing a difference between the slave device timebase and the master device timebase, wherein the correction information is independent of a transmission time of a packet from the master device containing the correction information and independent of a transmission time of other packets from the master device to the slave device.

A method of synchronizing a slave device timebase of a slave device to a master device timebase of a master device, wherein the master device is a device configured such that application-level programs interacting with the master device are unable to include accurate time-of-sending information in packets directed to the slave device, and thus the master device is such that it does not transmit the time-of-sending information to the slave device in a form usable by the slave device to determine the time of the transmission from the master device, the method comprising:

• sending timing information from the slave device to the master device in a packet created by the slave device, the timing information representing the slave device timebase;
• receiving the packet at the master device;
• associating a received timestamp with the packet, the received timestamp corresponding to a time of receipt of the packet at the master device;
• comparing the received timestamp and the timing information to determine correction information representing a difference between the slave device timebase and the master device timebase;
• and
• providing the correction information to logic at the slave device for adjusting the slave device timebase, wherein the correction information is independent of the time-of-sending information.