Maintaining a primary time server as the current time server in response to failure of time code receivers of the primary time server

• US 7,873,862 B2
• Filed: 10/21/2008
• Issued: 01/18/2011
• Est. Priority Date: 10/21/2008
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Crabtree, Donald, Cherniak, Stephen P., Hack, Michel H. T., Dahlen, Dennis J., Sevigny, Denise M., Carlson, Scott M., Dhondy, Noshir R., Wierbowski, Judith A.
• Primary Examiner(s): Bonzo; Bryce P
• Application Number:
  US12/255,348
• Publication Number:
  US 20100100761A1
• Time in Patent Office: 819 Days
• Field of Search: 714/4
• US Class Current: 714/4.1
• CPC Class Codes: H04J 3/0641 Change of the master or reference, e.g. take-over or failure of the master
• CPC Class Codes: H04L 12/6418 Hybrid transport

Abstract

A primary time server of a Coordinated Timing Network remains as current time server, even if time code information of the primary time server is unavailable. The primary time server receives the necessary or desired timing information from a secondary time server and uses that information to maintain time synchronization within the Coordinated Timing Network.

Claims

1. A computer program product to facilitate the providing of timing information to primary time servers of coordinated timing networks, the computer program product comprising:

a storage medium readable by a processing circuit and storing instructions for execution by the processing circuit for performing a method comprising;

obtaining by a primary time server of a coordinated timing network time code information from a secondary time server; and

employing by the primary time server the time code information from the secondary time server to provide time synchronization in the coordinated timing network, wherein the employing of the time code information from the secondary time server is in response to an indication that time code information of the primary time server is unavailable, and wherein the primary time server remains as current time server of the coordinated timing network, instead of having the secondary time server take over as the current time server.

2. The computer program product of claim 1, wherein the time code information includes pulse-per-second information.

3. The computer program product of claim 1, wherein the time code information includes network time protocol information.

4. The computer program product of claim 1, further comprising:

obtaining by the secondary time server the time code information using a time code receiver coupled to the secondary time server; and

forwarding at predefined intervals the time code information from the secondary time server to the primary time server.

5. The computer program product of claim 4, wherein the primary time server receives the time code information from the secondary time server absent a request for the time code information from the secondary time server.

6. The computer program product of claim 4, wherein the forwarding comprises using a secondary PPS information message command to provide the time code information to the primary time server.

7. The computer program product of claim 4, wherein the obtaining the time code information by the secondary time server comprises employing at least one of a Set PPS Information command or a Set PRT command to provide the time code information to the secondary time server.

8. The computer program product of claim 1, wherein the primary time server has associated therewith one or more time code receivers used to obtain time code information, and wherein the employing is in response to failure of the one or more time code receivers of the primary time server.

9. The computer program product of claim 8, wherein the secondary time server has a time code receiver associated therewith, and wherein the obtaining comprises:

using the time code receiver of the secondary time server to obtain the time code information of the secondary time server; and

providing the time code information of the secondary time server to the primary time server.

10. The computer program product of claim 1, wherein the time code information of the secondary time server comprises a pulse-per-second offset, and wherein the pulse-per-second offset is defined as a pulse-per-second offset at the secondary time server minus coordinated server time offset at the secondary time server.

11. A system of facilitating the providing of timing information to primary time servers of coordinated timing networks, said system comprising:

a primary time server of a coordinated timing network; and

a secondary time server of the coordinated timing network coupled to the primary time server, wherein the system is capable of performing a method comprising;

obtaining by the primary time server time code information from the secondary time server; and

employing by the primary time server the time code information from the secondary time server to provide time synchronization in the coordinated timing network, wherein the employing of the time code information from the secondary time server is in response to an indication that time code information of the primary time server is unavailable, and wherein the primary time server remains as current time server of the coordinated timing network, instead of having the secondary time server take over as the current time server.

12. The system of claim 11, further comprising:

obtaining by the secondary time server the time code information using a time code receiver coupled to the secondary time server; and

forwarding at predefined intervals the time code information from the secondary time server to the primary time server.

13. The system of claim 12, wherein the primary time server receives the time code information from the secondary time server absent a request for the time code information from the secondary time server.

14. The system of claim 12, wherein the forwarding comprises using a secondary PPS information message command to provide the time code information to the primary time server.

15. The system of claim 11, wherein the primary time server has associated therewith one or more time code receivers used to obtain time code information, and wherein the employing is in response to failure of the one or more time code receivers of the primary time server.

16. The system of claim 15, wherein the secondary time server has a time code receiver associated therewith, and wherein the obtaining comprises:

using the time code receiver of the secondary time server to obtain the time code information of the secondary time server; and

providing the time code information of the secondary time server to the primary time server.

17. The system of claim 11, wherein the time code information of the secondary time server comprises a pulse-per-second offset, and wherein the pulse-per-second offset is defined as a pulse-per-second offset at the secondary time server minus coordinated server time offset at the secondary time server.

18. A method of facilitating the providing of timing information to primary time servers of coordinated timing networks, said method comprising:

obtaining by a primary time server of a coordinated timing network time code information from a secondary time server; and

employing by the primary time server the time code information from the secondary time server to provide time synchronization in the coordinated timing network, wherein the employing of the time code information from the secondary time server is in response to an indication that time code information of the primary time server is unavailable, and wherein the primary time server remains as current time server of the coordinated timing network, instead of having the secondary time server take over as the current time server.

19. The method of claim 18, further comprising:

obtaining by the secondary time server the time code information using a time code receiver coupled to the secondary time server; and

forwarding at predefined intervals the time code information from the secondary time server to the primary time server.

20. The method of claim 18, wherein the time code information of the secondary time server comprises a pulse-per-second offset, and wherein the pulse-per-second offset is defined as a pulse-per-second offset at the secondary time server minus coordinated server time offset at the secondary time server.