METHOD AND DEVICES FOR PACKET SELECTION

摘要

This invention relates to packet selection techniques that can be used in conjunction with a clock recovery mechanism to mitigate the effects of packet delay variation on timing messages exchanged over a packet network, particularly when seeking to synchronize the time of a clock in a slave device to that of a master clock. The packet selection techniques can assist in reducing the noise in the recovered clock signal at the slave device, allowing recovery to a higher quality. Embodiments of the invention provide techniques based on extracting timing packets that create a constant interval between the arrival of selected packets at the slave device and on extracting timing packets which are closest to making the interval between arrival of the selected packets equal to the interval between the departure of the packets.

主权项

1. A method of selecting packets transmitted from a first device to a second device over a packet network, the method including the steps of:
sending, from the first device to the second device, packets; recording the time of receipt of said packets according to a clock in the second device; repeatedly, for each of a plurality of groups of said packets:
determining an optimal inter-arrival time between successive packets at the second device;calculating, for each packet in said group, the inter-arrival time between the packet and the preceding packet;selecting the packet in said group which has an inter-arrival time which is the closest to the optimal inter-arrival time.