Employing configuration information to determine the role of a server in a coordinated timing network

• US 9,112,626 B2
• Filed: 10/22/2007
• Issued: 08/18/2015
• Est. Priority Date: 01/31/2007
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Carlson, Scott M., Crabtree, Donald, Dahlen, Dennis J., Sevigny, Denise M., Wierbowski, Judith A.
• Primary Examiner(s): Georgandellis, Andrew
• Assistant Examiner(s): FABBRI, ANTHONY E
• Application Number:
  US11/876,240
• Publication Number:
  US 20080183897A1
• Time in Patent Office: 2,857 Days
• Field of Search: 709/220
• US Class Current: 1/1
• CPC Class Codes: G06F 1/14 Time supervision arrangements, e.g. real time clock
• CPC Class Codes: G06F 15/16 Combinations of two or more digital computers each having at least an arithmetic unit, a program unit and a register, e.g. for a simultaneous processing of several programs coordinating program control therefor G06F9/52; in regulating and control system G05B
• CPC Class Codes: H04J 3/0635 Clock or time synchronisation in a network timer in protocols H04L69/28
• CPC Class Codes: H04J 3/0641 Change of the master or reference, e.g. take-over or failure of the master
• CPC Class Codes: H04J 3/0644 External master-clock
• CPC Class Codes: H04L 69/28 Timers or timing mechanisms used in protocols
• CPC Class Codes: H04L 9/40 Network security protocols

Abstract

A stratum-1 configuration for a timing network is defined. The stratum-1 configuration includes a single active stratum-1 server usable in ensuring that the servers in the network use the same primary reference time to synchronize their clocks. The servers in the network are synchronizing to the same root primary reference time and synchronization accuracy is not dependent on the quality of an external time source or of the existence of an external time source at the stratum-1 server.

Claims

1. A computer program product for facilitating management of a coordinated timing network, the computer program product comprising:

a non-transitory computer readable storage medium readable by a processor and storing instructions for execution by the processor for performing a method comprising;

obtaining, by a first server of one or more servers of a coordinated timing network, information indicating a configuration of the coordinated timing network, the indicated configuration comprising one or more roles for the one or more servers within the coordinated timing network, the coordinated timing network having a timing facility for clock synchronization, the coordinated timing network permitting only one server to be a stratum-1 server at any time, wherein a stratum-1 server is configured to provide coordinated server time for synchronization of the one or more servers of the coordinated timing network, said obtained information stored in one or more control blocks received by the first server, and said obtained information comprising information indicating for the first server a type of configuration of the coordinated timing network and including one or more server descriptors, wherein said indicated type of configuration indicates one type of configuration of a plurality of types of configurations, the plurality of types of configurations including (i) a first type of configuration indicating a null configuration in which a stratum-1 server is undefined and in which the included one or more server descriptors are invalid and (ii) at least one second type of configuration indicating which of the included one or more server descriptors are valid, wherein a valid server descriptor explicitly indicates a server of the one or more servers that has been pre-selected to assume the role of a stratum-1 server;

determining, by the first server, based on the indicated type of configuration, a role of the first server within the coordinated timing network; and

based on determining that the role of the first server is a stratum-1 server, providing coordinated server time for synchronization of the one or more servers;

or

based on determining that the role of the first server is not a stratum-1 server and based on there being a stratum-1 server, receiving coordinated server time from the stratum-1 server.

2. The computer program product of claim 1, wherein said at least one second type of configuration comprises a single server configuration, a dual server configuration and a triad configuration, wherein a triad configuration comprises an arbiter server in communication with an inactive stratum-1 server to determine whether the stratum-1 server has failed.

3. The computer program product of claim 1, wherein said indicated type of configuration indicates that the first server is in the null configuration and wherein the first server determines that its role is as an unsynchronized server.

4. The computer program product of claim 3, wherein the method further comprises the first server connecting to another server that has a non-null stratum-1 configuration, and wherein the first server in response to connecting becomes synchronized within the coordinated timing network.

5. The computer program product of claim 1, wherein said indicated type of configuration indicates that the first server is in a single server configuration in which a primary active server is defined and in which a server descriptor indicating the primary active server in the one or more control blocks is indicated as being valid, and wherein the first server determines based on its role as either a stratum-1 server or not a stratum-1 server that its role is either as the primary active server or as a secondary server that receives timing information from the primary active server.

6. The computer program product of claim 5, wherein the one or more control blocks comprise a stratum-1 configuration information block received by the first server across the coordinated timing network, wherein the first server maintains the stratum-1 configuration information block, and wherein the determining is based on information in the stratum-1 configuration information block maintained at the first server.

7. The computer program product of claim 1, wherein said indicated type of configuration indicates that the first server is in a dual server configuration in which a primary server and an alternate server are defined and in which server descriptors indicating the primary server and the alternate server in the one or more control blocks are indicated as being valid, and wherein the first server further determines that its role is as the primary server, the alternate server or as a server that is neither the primary or alternate server.

8. The computer program product of claim 7, wherein the one or more control blocks comprise a stratum-1 configuration information block received by the first server across the coordinated timing network, wherein the first server maintains the stratum-1 configuration information block, and wherein the determining is based on information in the stratum-1 configuration information block maintained at the first server.

9. The computer program product of claim 1, wherein said indicated type of configuration indicates that the first server is in a triad configuration in which a primary server, an alternate server and an arbiter server are defined and in which server descriptors indicating the primary server, the alternate server, and the arbiter server in the one or more control blocks are indicated as being valid, and wherein the first server further determines that its role is as the primary server, the alternate server, the arbiter server, or as a server that is not the primary server, alternate server, or arbiter server.

10. The computer program product of claim 9, wherein the one or more control blocks comprise a stratum-1 configuration information block received by the first server across the coordinated timing network, wherein the first server maintains the stratum-1 configuration information block, and wherein the determining is based on information in the stratum-1 configuration information block maintained at the first server.

11. The computer program product of claim 1, wherein the method further comprises performing an action by the first server based on its determined role in the coordinated timing network, in response to an occurrence of a condition.

12. The computer program product of claim 11, wherein the condition is a failure of the stratum-1 server in a dual configuration or a triad configuration, and wherein the first server takes over as stratum-1 server for the failed stratum-1 server.

13. The computer program product of claim 1, wherein the first server is in network communications with a primary active server via a Coordinated Timing Network configured to maintain time synchronization, the first server receiving Server Time Protocol messages by way of said Coordinated Timing Network.

14. A computer system for facilitating management of a coordinated timing network, the computer system comprising:

a memory; and

a processor in communications with the memory, wherein the computer system is configured to perform a method, said method comprising;

obtaining, by a first server of one or more servers of a coordinated timing network, information indicating a configuration of the coordinated timing network, the indicated configuration comprising one or more roles for the one or more servers within the coordinated timing network, the coordinated timing network having a timing facility for clock synchronization, the coordinated timing network permitting only one server to be a stratum-1 server at any time, wherein a stratum-1 server is configured to provide coordinated server time for synchronization of the one or more servers of the coordinated timing network, said obtained information stored in one or more control blocks received by the first server, and said obtained information comprising information which indicates for the first server a type of configuration of the coordinated timing network and including one or more server descriptors, wherein said indicated type of configuration indicates one type of configuration of a plurality of types of configurations, the plurality of types of configurations including (i) a first type of configuration indicating a null configuration in which a stratum-1 server is undefined and in which the included one or more server descriptors are invalid, and (ii) at least one second type of configuration indicating which of the included one or more server descriptors are valid, wherein a valid server descriptor explicitly indicates a server of the one or more servers that has been pre-selected to assume the role of a stratum-1 server;

determining, by the first server, based on the indicated type of configuration a role of the first server within the coordinated timing network; and

based on determining that the role of the first server is a stratum-1 server, providing coordinated server time for synchronization of the one or more servers;

or

based on determining that the role of the first server is not a stratum-1 server and based on there being a stratum-1 server, receiving coordinated server time from the stratum-1 server.

15. The computer system of claim 14, wherein said indicated type of configuration indicates that the first server is in the null configuration, and wherein the first server determines that its role is as an unsynchronized server.

16. The computer system of claim 15, wherein the first server connects to another server that has a non-null stratum-1 configuration, and wherein the first server in response to connecting becomes synchronized within the coordinated timing network.

17. The computer system of claim 14, wherein said indicated type of configuration indicates that the first server is in a single server configuration in which a primary active server is defined and in which a server descriptor indicating the primary active server in the one or more control blocks is indicated as being valid, and wherein the first server determines based on its role as either a stratum-1 server or not a stratum-1 server that its role is either as the primary active server or as a secondary server that receives timing information from the primary active server.

18. The computer system of claim 14, wherein said indicated type of configuration indicates that the first server is in a dual server configuration in which a primary server and an alternate server are defined and in which server descriptors indicating the primary server and the alternate server in the one or more control blocks are indicated as being valid, and wherein the first server further determines that its role is as the primary server, the alternate server or as a server that is neither the primary or alternate server.

19. The computer system of claim 14, wherein said indicated type of configuration indicates that the first server is in a triad configuration in which a primary server, an alternate server and an arbiter server are defined and in which server descriptors indicating the primary server, the alternate server, and the arbiter server in the one or more control blocks are indicated as being valid, and wherein the first server further determines that its role is as the primary server, the alternate server, the arbiter server, or as a server that is not the primary server, alternate server, or arbiter server.

20. The computer system of claim 14, wherein the first server performs an action based on its determined role in the coordinated timing network, in response to an occurrence of a condition.

21. The computer system of claim 14, wherein the first server is in network communications with a primary active server via a Coordinated Timing Network configured to maintain time synchronization, the first server receiving Server Time Protocol messages by way of said Coordinated Timing Network.

22. A method to facilitate management of a coordinated timing network, said method comprising:

obtaining, by a first server of one or more servers of a coordinated timing network, information indicating a configuration of the coordinated timing network, the indicated configuration comprising one or more roles for the one or more servers within the coordinated timing network, the coordinated timing network having a timing facility for clock synchronization, the coordinated timing network permitting only one server to be a stratum-1 server at any time, wherein a stratum-1 server is configured to provide coordinated server time for synchronization of the one or more servers of the coordinated timing network, said obtained information stored in one or more control blocks received by the first server, and said obtained information comprising information which indicates for the first server a type of configuration of the coordinated timing network and including one or more server descriptors, wherein said indicated type of configuration indicates one type of configuration of a plurality of types of configurations, the plurality of types of configurations including (i) a first type of configuration indicating a null configuration in which a stratum-1 server is undefined and in which the included one or more server descriptors are invalid, and (ii) at least one second type of configuration indicating which of the included one or more server descriptors are valid, wherein a valid server descriptor explicitly indicates a server of the one or more servers that has been pre-selected to assume the role of a stratum-1 server;

determining, by the first server, based on the indicated type of configuration a role of the first server within the coordinated timing network; and

based on determining that the role of the first server is a stratum-1 server, providing coordinated server time for synchronization of the one or more servers;

or

based on determining that the role of the first server is not a stratum-1 server and based on there being a stratum-1 server, receiving coordinated server time from the stratum-1 server.

23. The method of claim 22, wherein said indicated type of configuration indicates that the first server is in the null configuration and wherein the first server determines that its role is as an unsynchronized server.

24. The method of claim 22, wherein said indicated type of configuration indicates that the first server is in a single server configuration in which a primary active server is defined and in which a server descriptor indicating the primary active server in the one or more control blocks is indicated as being valid, and wherein the first server determines based on its role as either a stratum-1 server or not a stratum-1 server that its role is either as the primary active server or as a secondary server that receives timing information from the primary active server.

25. The method of claim 22, wherein said indicated type of configuration indicates that the first server is in a dual server configuration in which a primary server and an alternate server are defined and in which server descriptors indicating the primary server and the alternate server in the one or more control blocks are indicated as being valid, and wherein the first server further determines that its role is as the primary server, the alternate server or as a server that is neither the primary or alternate server.

26. The method of claim 22, wherein said indicated type of configuration indicates that the first server is in a triad configuration in which a primary server, an alternate server and an arbiter server are defined and in which server descriptors indicating the primary server, the alternate server, and the arbiter server in the one or more control blocks are indicated as being valid, and wherein the first server further determines that its role is as the primary server, the alternate server, the arbiter server, or as a server that is not the primary server, alternate server, or arbiter server.