MAINTAINING MESSAGE VERSIONS AT NODES IN A NETWORK

• US 20090063582A1
• Filed: 08/28/2007
• Published: 03/05/2009
• Est. Priority Date: 08/28/2007
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Bish, Thomas William, Anna, Gary, Dain, Joseph Whitney, Beeston, Ralph Thomas
• Granted Patent: US 8,856,206 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 3/038 Control and interface arrangements therefor, e.g. drivers or device-embedded control circuitry
• CPC Class Codes: G06Q 10/107 Computer-aided management of electronic mailing [e-mailing]
• CPC Class Codes: H04L 47/70 Admission control; Resource allocation
• CPC Class Codes: H04L 51/00 User-to-user messaging in packet-switching networks, transmitted according to store-and-forward or real-time protocols, e.g. e-mail
• CPC Class Codes: H04L 51/42 Mailbox-related aspects, e.g. synchronisation of mailboxes
• CPC Class Codes: H04L 69/24 Negotiation of communication capabilities
• CPC Class Codes: H04L 69/329 in the application layer [OSI layer 7]

Abstract

Provided are a method, system, and article of manufacture for maintaining message versions at nodes in a network. The nodes in the network maintain version information of nodes in the network. The version information for the nodes indicates a message version number of messages supported at the node. The nodes supporting one message version number can receive messages having that message version number. The nodes use the version information to determine whether there is at least one common message version number among the nodes The nodes supporting the at least one common message version number negotiate to join a quorum of the nodes having the at least one common message version number.

Claims

1. An article of manufacture comprising code implemented by nodes in a network to perform operations, the operations comprising:

maintaining version information of nodes in the network, wherein the version information for the nodes indicates a message version number of messages supported at the node, wherein the nodes supporting one message version number can receive messages having that message version number;

using the version information to determine whether there is at least one common message version number among the nodes; and

negotiating to join a quorum of the nodes having the at least one common message version number.

2. The article of manufacture of claim 1, wherein the nodes include node information indicating whether the nodes are in the quorum and in an offline or online state, wherein nodes in the offline state receive a subset of messages received by nodes in the online state, and wherein nodes in the online and offline states receive messages from other nodes negotiating to join the quorum, wherein the code performs transitioning node operations for a transitioning node comprising one of the nodes in the quorum, comprising:

transitioning to the offline state;

determining in the offline state whether the transitioning node has at least one message version number supported by the nodes in the quorum in the online and offline states in response to the transitioning node initiating an operation to return to the online state;

transitioning to the online state in the quorum in response to determining that the transitioning node supports one message version number that is common with respect to the other nodes in the quorum.

3. The article of manufacture of claim 2, wherein the transitioning node operations further comprise:

communicating information to the nodes in the quorum in the online and offline states indicating that the transitioning node is in the offline state in response to transitioning to the offline state;

communicating information to the nodes in the quorum in the online and offline states indicating that the transitioning node is in the online state in response to transitioning to the online state, wherein nodes receiving the communications on the state of the transitioning node update the node information for the transitioning node to indicate the offline or online state indicated in the communication.

4. The article of manufacture of claim 1, wherein the nodes include node information indicating whether the nodes are in the quorum and in an offline or online state, wherein the code performs joining node operations for a joining node that is not in the quorum, comprising:

determining whether the joining node supports at least one version number supported at all the nodes in the quorum in the offline and online states; and

joining the quorum in the online state in response to determining that the joining node supports the at least one version number supported at all the nodes in the quorum.

5. The article of manufacture of claim 4, wherein the joining node operations further comprise:

arbitrating to obtain permission to negotiate to join the quorum to serialize the joining nodes negotiations to join the quorum, wherein the operation of determining whether the joining node supports the at least one version number supported at all the nodes in the quorum is performed in response to obtaining permission to negotiate to join the quorum.

6. The article of manufacture of claim 5, wherein the code performs offline node operations for an offline node that is in the offline state in the quorum, comprising:

determining whether the offline node supports at least one version number supported at all the nodes in the quorum in the offline and online states; and

returning to the online state in response to determining that the offline node supports the at least one version number supported at all the nodes in the quorum, wherein the offline node does not need to arbitrate to obtain exclusive access to return to the online state.

7. The article of manufacture of claim 4, wherein the code performs updating node operations for an updating node in the quorum, comprising:

transitioning to exit the quorum in response to initiating an operation to update to support an update message version number;

applying the update message version number to the updating node in response to the updating node transitioning to exit the quorum; and

performing the operations of the joining node to rejoin the quorum in response to updating to the update message version number.

8. The article of manufacture of claim 7, wherein the updating node operations further comprise:

determining whether the update message version number is supported by the nodes in the quorum in the offline and online state before applying the update to the update message version number, wherein the updating node exits the quorum to apply the update in response to determining that the update message version number is supported by the nodes in the quorum; and

communicating a message to a user of the node that the update message version number of the update is not supported by the nodes in the quorum to enable the user to select to apply or not apply the update to the update message version number at the updating node.

9. The article of manufacture of claim 1, wherein the code performs operations as a sending node to send a selected message to a receiving node, comprising:

maintaining at least one message table, wherein each message table is associated with one of the message version numbers, wherein each message table indicates a message specific version number for each supported message indicated in the message table;

initiating an operation to send a selected message to a receiving node;

determining from the version information, a common message version number supported by both the sending and receiving nodes;

determining from the message table associated with the determined highest message version number the message specific version number for the selected message; and

transmitting the determined message specific version of the message to the receiving node.

10. The article of manufacture of claim 9, wherein the sending node transmits different message specific versions of the selected message to different receiving nodes in the quorum if the different receiving nodes support different message version numbers also supported by the sending node that are associated with message tables providing different message specific version numbers for the selected message.

11. A system, comprising:

a plurality of nodes that communicate over a network, wherein each node includes;

version information indicating a message version number of messages supported at the nodes in the network, wherein the nodes supporting one message version number can receive messages having that message version number;

a message manager to perform operations, the operations comprising;

using the version information to determine whether there is at least one common message version number among the nodes; and

negotiating to join a quorum of the nodes having the at least one common message version number.

12. The system of claim 11, wherein the nodes include node information indicating whether the nodes are in the quorum and in an offline or online state, wherein nodes in the offline state receive a subset of messages received by nodes in the online state, and wherein nodes in the online and offline states receive messages from other nodes negotiating to join the quorum, wherein the message manager performs operations as a transitioning node comprising one of the nodes in the quorum, comprising:

transitioning to the offline state;

determining, in the offline state, whether the transitioning node has at least one message version number supported by the nodes in the quorum in the online and offline states in response to the transitioning node initiating an operation to return to the online state;

transitioning to the online state in the quorum in response to determining that the transitioning node supports one message version number that is common with respect to the other nodes in the quorum.

13. The system of claim 11, wherein the nodes include node information indicating whether the nodes are in the quorum and in an offline or online state, wherein the message manager performs operations as a joining node that is not in the quorum, comprising:

determining whether the joining node supports at least one version number supported at all the nodes in the quorum in the offline and online states; and

joining the quorum in the online state in response to determining that the joining node supports the at least one version number supported at all the nodes in the quorum.

14. The system of claim 13, wherein the message manager operations as the joining node further comprises:

arbitrating to obtain permission to negotiate to join the quorum to serialize the joining nodes negotiations to join the quorum, wherein the operation of determining whether the joining node supports the at least one version number supported at all the nodes in the quorum is performed in response to obtaining permission to negotiate to join the quorum.

15. The system of claim 14, wherein the message manager performs operations as an offline node in the offline state in the quorum comprising:

determining the offline node supports at least one version number supported at all the nodes in the quorum in the offline and online states; and

returning to the online state in response to determining that the offline node supports the at least one version number supported at all the nodes in the quorum, wherein the offline node does not need to arbitrate to obtain exclusive access to return to the online state.

16. The system of claim 13, wherein the message manager performs operations as an updating node in the quorum comprising:

transitioning to exit the quorum in response to initiating an operation to update to support an update message version number;

applying the update message version number to the updating node in response to the updating node transitioning to exit the quorum; and

performing the operations of the joining node to rejoin the quorum in response to updating to the update message version number.

17. The system of claim 11, further comprising:

wherein the nodes maintain at least one message table, wherein each message table is associated with one of the message version numbers, wherein each message table indicates a message specific version number for each supported message indicated in the message table; and

wherein the message manager performs operations as a sending node to send a selected message to a receiving node, comprising;

determining from the version information a common message version number supported by both the sending and receiving nodes;

determining from the message table associated with the determined highest message version number the message specific version number for the selected message; and

transmitting the determined message specific version of the message to the receiving node.

18. A method, comprising:

maintaining, by nodes in a network, version information of nodes in the network, wherein the version information for the nodes indicates a message version number of messages supported at the node, wherein the nodes supporting one message version number can receive messages having that message version number;

using, by the nodes, the version information to determine whether there is at least one common message version number among the nodes; and

negotiating, by the nodes supporting the at least one common message version number, to join a quorum of the nodes having the at least one common message version number.

19. The method of claim 18, wherein the nodes include node information indicating whether the nodes are in the quorum and in an offline or online state, wherein nodes in the offline state receive a subset of messages received by nodes in the online state, and wherein nodes in the online and offline states receive messages from other nodes negotiating to join the quorum, further comprising:

transitioning, by a transitioning node comprising one of the nodes in the quorum, to the offline state;

determining, by the transitioning node in the offline state, whether the transitioning node has at least one message version number supported by the nodes in the quorum in the online and offline states in response to the transitioning node initiating an operation to return to the online state;

transitioning, by the transitioning node, to the online state in the quorum in response to determining that the transitioning node supports one message version number that is common with respect to the other nodes in the quorum.

20. The method of claim 18, wherein the nodes include node information indicating whether the nodes are in the quorum and in an offline or online state, further comprising:

determining, by a joining node that is not in the quorum, whether the joining node supports at least one version number supported at all the nodes in the quorum in the offline and online states; and

joining, by the joining node, the quorum in the online state in response to determining that the joining node supports the at least one version number supported at all the nodes in the quorum.

21. The method of claim 20, further comprising:

arbitrating, by the joining node not in the quorum, to obtain permission to negotiate to join the quorum to serialize the joining nodes negotiations to join the quorum, wherein the operation of determining whether the joining node supports the at least one version number supported at all the nodes in the quorum is performed in response to obtaining permission to negotiate to join the quorum.

22. The method of claim 21, further comprising:

determining, by an offline node that is in the offline state in the quorum, whether the offline node supports at least one version number supported at all the nodes in the quorum in the offline and online states; and

returning, by the offline node, to the online state in response to determining that the offline node supports the at least one version number supported at all the nodes in the quorum, wherein the offline node does not need to arbitrate to obtain exclusive access to return to the online state.

23. The method of claim 20, further comprising:

transitioning, by an updating node in the quorum to exit the quorum in response to initiating an operation to update to support an update message version number;

applying the update message version number to the updating node in response to the updating node transitioning to exit the quorum; and

performing, by the updating node, the operations of the joining node to rejoin the quorum in response to updating to the update message version number.

24. The method of claim 18, further comprising:

maintaining, by the nodes, at least one message table, wherein each message table is associated with one of the message version numbers, wherein each message table indicates a message specific version number for each supported message indicated in the message table; and

initiating, by a sending node, an operation to send a selected message to a receiving node;

determining by the sending node, from the version information, a common message version number supported by both the sending and receiving nodes;

determining, by the sending node, from the message table associated with the determined highest message version number the message specific version number for the selected message; and

transmitting, by the sending node, the determined message specific version of the message to the receiving node.