System And Method For Monitoring Network Synchronization

• US 20150071308A1
• Filed: 09/10/2013
• Published: 03/12/2015
• Est. Priority Date: 09/10/2013
• Status: Active Grant

• Current Assignee: Keysight Technologies Singapore (Holdings) Pte. Limited. (Keysight Technologies, Inc.)
• Original Assignee: ANUE Systems (Keysight Technologies, Inc.)
• Inventors: Webb, Charles A. III, Karnes, Joshua D., Nutt, Jason C., Mackenzie, Simon A.
• Granted Patent: US 9,491,727 B2
• Time in Patent Office: Days
• US Class Current: 370/503
• CPC Class Codes: H04J 3/0661 using timestamps
• CPC Class Codes: H04J 3/14 Monitoring arrangements for SDH/SONET rings H04J3/085
• CPC Class Codes: H04W 56/0035 detecting errors in frequency or phase

Abstract

Systems and methods are disclosed for monitoring network synchronization. The disclosed embodiments utilize time window snapshots to capture network time information and compare the captured time information against time reference information to determine network time errors. These network time errors can then be analyzed with respect to selected operating parameters and tolerances to determine network synchronization errors and to generate alarms. Certain embodiments are configured to capture time information data and to analyze this captured data locally to determine time error data. Certain other embodiments are configured to utilize multiple capture devices and to transmit time error data to a central snapshot synchronization monitor. The central snapshot synchronization monitor can also communicate control information to the capture devices to control the snapshot time windows. In addition, synchronization errors can be used as trigger events to cause additional capture of time information by other capture devices.

Claims

1. A method for monitoring network synchronization, comprising:

capturing time information for a first time period associated with a network being monitored;

comparing the captured time information for the first time period to time reference information to determine a first synchronization metric for the first time period;

analyzing the first synchronization metric with respect to a second synchronization metric to determine if a synchronization error is present with respect to the network being monitored; and

outputting a synchronization error alarm if a synchronization error is determined to be present.

2. The method of claim 1, wherein the capturing step during the first time period comprises:

capturing packets associated with a packet flow within the network being monitored;

recording time stamps associated with arrival times for the captured packets, the time stamps providing the time reference information for the comparing step; and

analyzing the packets to identify timing information contained within the packets, the identified time information providing the captured time information for the first time period for the comparing step.

3. The method of claim 1, wherein the captured time information comprises time information generated by a network node within the network being monitored.

4. The method of claim 3, wherein the network node comprises a mobile base station configured to communicate with a plurality of mobile handsets, and wherein the generated time information comprises time-of-day information generated by the mobile base station.

5. The method of claim 3, wherein the generated time information comprises a clock signal generated by the network node.

6. The method of claim 1, wherein the second synchronization metric is associated with time information captured from one or more previous time periods prior to the first time period.

7. The method of claim 1, wherein the second synchronization metric comprises one or more predefined threshold values.

8. The method of claim 7, wherein the one or more predefined threshold values comprises a threshold time error difference between the captured time information and the time reference information.

9. The method of claim 1, wherein the time reference information is based upon time information from at least one of a satellite positioning system or a network-based timing protocol clock.

10. The method of claim 1, wherein the synchronization error alarm comprises a trigger event associated with a first network node, and further comprising capturing time information within additional time periods for at least one additional network node based upon the trigger event.

11. The method of claim 1, wherein the capturing and comparing steps are performed by a plurality of capture devices coupled to different monitoring points for the network being monitored, wherein the method further comprises transmitting time data associated with the first synchronization metric from the plurality of capture devices to a central synchronization monitor, and wherein the central synchronization monitor performs the analyzing and outputting steps.

12. The method of claim 11, further comprising applying one or more data reduction techniques to the time data prior to transmitting the time data.

13. The method of claim 12, wherein data reduction techniques comprise at least one of a data compression technique or a hash algorithm.

14. The method of claim 11, further comprising communicating control information from the central synchronization monitor to the plurality of capture devices to determine the first time period.

15. The method of claim 11, wherein the synchronization error comprises a synchronization impairment introduced by one or more network components associated with the monitoring points.

16. A system for monitoring network synchronization, comprising:

a snapshot window control block configured to output snapshot control signals;

a snapshot capture block configured to capture time information from a network being monitored for a first time period based upon the snapshot control signals;

a time synchronization comparator configured to compare the captured time information for the first time period to time reference information to determine a first synchronization metric for the first time period;

a synchronization analysis block configured to analyze the first synchronization metric with respect to a second synchronization metric to determine if a synchronization error is present with respect to the network being monitored; and

a data output block configured to output a synchronization error alarm if a synchronization error is determined to be present.

17. The system of claim 16, wherein the snapshot capture block is configured to capture packets associated with a packet flow within the network being monitored, and wherein the snapshot capture block comprises a time stamp block configured to generate time stamps associated with arrival times for the captured packets to provide the time reference information for the time synchronization comparator.

18. The system of claim 17, further comprising a network time information extractor configured to identify timing information contained within the captured packets, the identified time information providing the captured time information for the first time period for the time synchronization comparator.

19. The system of claim 16, wherein the captured time information comprises time information generated by a network node within the network being monitored.

20. The system of claim 19, wherein the generated time information comprises at least one of a clock signal generated by the network node or time-of-day information generated by the network node.

21. The system of claim 16, wherein the second synchronization metric is associated with time information captured from one or more previous time periods prior to the first time period.

22. The system of claim 16, wherein the second synchronization metric comprises one or more predefined threshold values.

23. The system of claim 22, wherein the one or more predefined threshold values comprises a threshold time error difference between the captured time information and the time reference information.

24. The system of claim 16, wherein the time reference information is based upon time information from at least one of a satellite positioning system or a network-based timing protocol clock.

25. The system of claim 16, wherein the synchronization error alarm comprises a trigger event associated with a first network node, and further comprising a snapshot window controller configured to forward snapshot window controls to cause time information to be captured within additional time periods for at least one additional network node based upon the trigger event.

26. The system of claim 16, wherein the synchronization analysis block and the data output block are within a central synchronization monitor coupled to a capture device having the snapshot window control block, the snapshot capture block, and the time synchronization comparator, and wherein the capture device is configured to transmit time data associated with the first synchronization metric to the central synchronization monitor.

27. The system of claim 26, further comprising one or more additional capture devices also comprising a snapshot window control block, a snapshot capture block, and a comparator, and wherein each of the capture devices is coupled to a different monitoring point and is configured to transmit time data associated with the first synchronization metric to the central synchronization monitor.

28. The system of claim 27, wherein each of the capture devices is further configured to apply one or more data reduction techniques to the time data prior to transmitting the time data.

29. The system of claim 27, wherein the central synchronization monitor is further configured to communicate control information to each of the capture devices to determine the first time period.

30. The system of claim 27, wherein the synchronization error comprises a synchronization impairment introduced by one or more network components associated with the monitoring points.