Measure and improve clock synchronization using combination of transparent and boundary clocks

Patent metadata

Field	Value
Publication number	US-10484163-B2
Application number	US-201715782915-A
Country	US
Kind code	B2
Filing date	Oct 13, 2017
Priority date	Oct 13, 2017
Publication date	Nov 19, 2019
Grant date	Nov 19, 2019

Abstract

The present technology improves synchronization of a slave node with a master node in a network using PTP packets in which the slave node is coupled to the working master node through at least one boundary node. The technology establishes a synchronization communication session between the boundary node and the slave node in which the synchronization communication session is configured to measure a first timing delay from the boundary node to the slave node, and establishes a transparent communication session between the master node and the slave node through the boundary timing node in which the transparent communication session configured to measure a second timing delay from the master node to the slave node. Using the sessions, the technology adjusts a timing delay correction factor according to the first timing delay and the second timing delay, and synchronizes the slave node with the master node according to the correction factor.

First claim

What is claimed is:

1. A network time synchronization management system comprising:
a computing device in communication with a communication network comprising a slave node coupled to a working master node through at least one boundary node, the computing device comprising at least one non-transitory computer readable medium comprising instructions stored thereon that when executed are effective to cause at least one processor to:
receive a request to synchronize the slave node with the working master node;
establish a first communication session between the boundary node and the slave node, the first communication session configured to measure a first timing delay from the boundary node to the slave node;
establish a second communication session between the working master node and the slave node through the boundary node, the second communication session configured to measure a second timing delay from the working master node to the slave node;
adjust a timing delay correction factor according to the first timing delay and the second timing delay; and
synchronize the slave node with the working master node according to the adjusted timing delay correction factor;
wherein the first and second communications sessions are different from each other.

2. The network time synchronization management system of claim 1 , wherein the instructions are further executed to display the adjusted timing delay correction factor on a display.

3. The network time synchronization management system of claim 1 , wherein the request is received according to at least one of a manual request and at one of a plurality of automated requests issued at ongoing intervals.

4. The network time synchronization management system of claim 1 , wherein the instructions are further executed to:
identify a plurality of available master nodes in the communication network;
establish the first and second communication sessions, adjust the timing delay correction factor, and synchronize the slave node on each of the available master nodes; and
select one of the available master nodes to be the working master node based upon the adjusted timing delay correction factor determined for each available master node.

5. The network time synchronization management system of claim 4 , wherein the instructions are further executed to receive the request from a plurality of slave nodes, wherein the slave nodes conduct an arbitration process to select one of the available master nodes to be the working master node.

6. The network time synchronization management system of claim 5 , wherein the first and second communication sessions conform to an IEEE 1588 protocol, wherein the slave nodes are executed to conduct the arbitration process using a telemetry message conveyed among the slave nodes.

7. The network time synchronization management system of claim 1 , wherein the request is received as a result of a trigger event from a communication channel through the slave node.

8. A network time synchronization management method comprising:
receiving, by at least one processor that executes instructions stored in at least one memory, a request to synchronize a slave node with a working master node, the slave node coupled to the working master node through at least one boundary node;
establishing, using the instructions, a first communication session between the boundary node and the slave node, the first communication session configured to measure a first timing delay from the boundary node to the slave node;
establishing, using the instructions, a second communication session between the working master node and the slave node through the boundary timing node, the second communication session configured to measure a second timing delay from the working master node to the slave node;
adjusting, using the instructions, a timing delay correction factor according to the first timing delay and the second timing delay; and
synchronizing, using the instructions, the slave node with the working master node according to the adjusted timing delay correction factor;
wherein the first and second communications sessions are different from each other.

9. The network time synchronization management method of claim 8 , further comprising receiving the request according to at least one of a manual request and one of a plurality of requests automatically issued at ongoing intervals.

10. The network time synchronization management method of claim 8 , further comprising:
identifying a plurality of available master nodes;
establishing the first and second communication sessions, adjust the timing delay correction factor, and synchronize the slave node on each of the available master nodes; and
selecting one of the available master nodes to be the working master node based upon the adjusted timing delay correction factor determined for each available master node.

11. The network time synchronization management method of claim 10 , further comprising transmitting the request by a plurality of slave nodes, wherein the slave nodes conduct an arbitration process to select one of the available master nodes to be the working master node.

12. The network time synchronization management method of claim 11 , further comprising conducting, by the slave nodes, the arbitration process using a telemetry message conveyed among the slave nodes, wherein the first and second communication sessions conform to an IEEE 1588 protocol.

13. The network time synchronization management method of claim 8 , further comprising receiving the request as a result of a trigger event from a communication channel through the slave node.

14. A computer-readable storage device storing instructions which, when executed by a processor, cause the processor to perform operations comprising:
receiving a request to synchronize a slave node with a working master node, the slave node coupled to the working master node through at least one boundary node;
establishing a first communication session between the boundary node and the slave node, the first communication session configured to measure a first timing delay from the boundary node to the slave node;
establishing a second communication session between the working master node and the slave node through the boundary node, the second communication session configured to measure a second timing delay from the working master node to the slave node;
adjusting a timing delay correction factor according to the first timing delay and the second timing delay; and
synchronizing the slave node with the working master node according to the adjusted timing delay correction factor;
wherein the first and second communications sessions are different from each other.

15. The instructions of claim 14 , further comprising displaying the adjusted timing delay correction factor on a display.

16. The instructions of claim 14 , further comprising receiving the request according to at least one of a manual request and at one of a plurality of automated requests issued at ongoing intervals.

17. The instructions of claim 14 , further comprising:
identifying a plurality of available master nodes in the communication network;
establishing the first and second communication sessions, adjust the timing delay correction factor, and synchronize the slave node on each of the available master nodes; and
selecting one of the available master nodes to be the working master node based upon the adjusted timing delay correction factor determined for each available master node.

18. The instructions of claim 17 , further comprising trans

Assignees

• Cisco Tech Inc

Inventors

• Tanwar Anshul
• Garg Vineet Kumar
• Krishna N N V Hari

Classifications

• H04J3/0673 Primary

  using intermediate nodes, e.g. modification of a received timestamp before further transmission to the next packet node, e.g. including internal delay time or residence time into the packet · CPC title

• H04J3/0667

  Bidirectional timestamps, e.g. NTP or PTP for compensation of clock drift and for compensation of propagation delays (arrangements for monitoring round trip delays in packet switching networks H04L43/0864) · CPC title

• H04J3/0641

  Change of the master or reference, e.g. take-over or failure of the master · CPC title

• H04L7/0033 Primary

  Correction by delay · CPC title