Patent ID: 9363206
Filing Date: 2016-06-07
CPC Classification: H04J,H04L

Claim Text:
1. A method for selecting a passive port of a transparent clock node based on PTP, comprising: a port of a network device receiving an Announce packet transmitted from another network device, extracting a TLV field of the Announce packet, and obtaining clock identifier information, number-of-forwarding information and port identifier information carried in the TLV field, wherein the network device are provided with at least two ports; judging whether the port of the network device is a slave port; if it is judged that the port of the network device is not a slave port, comparing the number of forwarding carried in the TLV field received via the port of the network device with the number of forwarding carried in a TLV field received via the slave port of the network device, and if it is judged that the absolute value of the difference between the number of forwarding carried in the TLV field received via the port of the network device and the number of forwarding carried in the TLV field received via the slave port is 0 or 1, selecting a port with the lowest priority as the passive port; and if the port of the network device is a slave port or the absolute value of the said difference between the numbers of forwarding is not 0 or 1, updating clock identifier information of the network device and port identifier information of an Announce packet forwarding port of the network device into the TLV field of the received Announce packet respectively as clock identifier information and port identifier information, and forwarding the updated Announce packet via the Announce packet forwarding port after incrementing the number of forwarding of the Announce packet by one.