Forming and maintaining access groups at the lan/wan interface

• US 5,365,523 A
• Filed: 11/16/1992
• Issued: 11/15/1994
• Est. Priority Date: 11/16/1992
• Status: Expired due to Term

• Current Assignee: Lenovo Singapore Pte Limited (Lenovo Group Ltd.)
• Original Assignee: International Business Machines Corporation
• Inventors: Li, Liang, Sandick, Haldon J., Peters, Marcia L., Derby, Jeffrey H., Drake, John E. Jr., Vu, Ken Van, Dykeman, Douglas H., Doeringer, Willibald A.
• Primary Examiner(s): Olms, Douglas W.
• Assistant Examiner(s): VU, HUY DUY
• Application Number:
  US07/976,826
• Time in Patent Office: 729 Days
• Field of Search: 370/85.2, 370/85.12, 370/85.13, 370/852, 370/85.1, 370/94.3, 370/94.1, 370/16, 370/13, 370/60
• US Class Current: 370/402
• CPC Class Codes: H04L 12/66 Arrangements for connecting between networks having differing types of switching systems, e.g. gateways

Abstract

Access agents in nodes at the LAN/WAN interface are formed into a group of access agents so that the access agents may be managed by the WAN as a group. The group must maintain group operation integrity in that if communications between agents in the group are broken, the access agents will coalesce into subgroups and continue performing communication jobs as a group activity. Each of the access agents contains a finite state machine to perform the tasks of group formation and maintenance. The formation of interconnected access agents into a group is accomplished by one access agent being identified as a group leader. All other access agents communicating with the group leader within the LAN may then join the group. The maintenance of group activity integrity is accomplished by detecting a break in group communication integrity and thereafter reforming the group into multiple smaller groups. The maintenance of group operation integrity also includes the merger of small groups into a large group when a bridge is added between LAN segments.

Claims

1. For use in a plural network communication system having multiple access agents at a network-to-network interface, a cooperative method for use by each of the access agents so that the access agents form and maintain the access agents common to the interface into a group for operative use as a group by the communication system, said method in each access agent comprising the steps of:

negotiating for leadership of the group with all other access agents common to the interface by testing whether or not a group leader message has been received from another access agent in a predetermined interval of time, and sending a negotiation message to the other access agents if a group leader message has not been received;

resolving conflicts in negotiation and assuming a role of group leader or a role of member of the group; and

maintaining group operation integrity after the group has been formed whereby the communication system may manage the access agents as a group.

2. The method of claim 1 wherein said step of resolving conflicts comprises the steps of:

testing whether the negotiation message from another access agent indicates the other access agent has a higher rank than the current access agent;

sending a group leader message to the other access agents if the current access agent has a higher rank;

or

sending a merge message to the other access agents if the current access agent has a lower rank.

3. For use in a plural network communication system having multiple access agents at a network-to-network interface, a cooperative method for use by each of the access agents so that the access agents form and maintain the access agents common to the interface into a group for operative use as a group by the communication system, said method in each access agent comprising the steps of:

negotiating for leadership of the group with all other access agents common to the interface;

resolving conflicts in negotiation and assuming a role of group leader or a role of member of the group;

maintaining group operation integrity after the group has been formed by testing whether or not a group leader message with a membership list message has been received from another access agent in a predetermined interval of time, sending a negotiation message to the other access agents if a group leader message has not been received, testing the membership list message to determine whether a group membership change has occurred if a group leader message is received, and updating the group membership list in the current access agent if group membership has changed.

4. The method of claim 3 wherein said step of resolving conflicts comprises the steps of:

testing whether the negotiation message from another access agent indicates the other access agent has a higher rank than the current access agent;

sending a group leader message to the other access agents if the current access agent has a higher rank;

or

sending a merge message to the other access agents if the current access agent has a lower rank.

5. For use in a plural network communication system having multiple access agents at a LAN/WAN interface, acooperative method for use by each of the access agents so that the access agents form and maintain the access agents common to the interface into a group for operative use as a group by the communication system, said method in each access agent comprising the steps of:

negotiating for leadership of the group with all other access agents common to the interface by testing whether or not a group leader message has been received from another access agent in a predetermined interval of time, said group leader message identifies the WAN attached to said another access agent, testing, if a group leader message is received, whether the group leader message comes from an access agent attached to the same WAN as the current access agent, and sending a negotiation message to the other access agents if a group leader message from an access agent attached to the same WAN has not been received;

resolving conflicts in negotiation and assuming a of group leader or a role of member of the group; and

maintaining group operation integrity after the group has been formed whereby the communication system may manage the access agents as group.

6. The method of claim 5 wherein said negotiation message identifies the WAN attached to the access agent sending the negotiation message and said step of resolving conflicts comprises the steps of:

testing whether the negotiation message from another access agent indicates the other access agent has a higher rank than the current access agent;

testing whether the negotiation message comes from another access agent attached to the same WAN as the current access agent;

sending a group leader message to the other access agents if the current access agent has a higher rank and is on the same WAN;

sending a merge message to the other access agents if the current access agent has a lower rank and is on the same WAN.

7. In a LAN/WAN communication system with network nodes at a LAN/WAN interface having access agents, each access agent for managing communications across the interface for its network node, said system having a group management system for managing communications through multiple access agents as a group, apparatus in each of said access agents for forming and maintaining as a multiple access group a plurality of access agents that share a common LAN/WAN interface and provide parallel access paths across the interface, said apparatus in each access agent comprising:

means for sending a negotiate message to other access agents in the access group to negotiate for leadership of the access group;

means for listening for negotiate message from other access agents in the access group;

means in response to no other negotiate messages within a predetermined time interval for sending a group leader message to other access agents in the access group; and

means responsive to a group leader message for joining the group;

whereby one access agent sending a group leader message becomes a monitor access agent and all other access agents in the access group become members of the access group.

8. The apparatus of claim 7 and in addition:

means in said monitor access agent responsive to a membership change message from said group management system for detecting a change in access group membership; and

means responsive to a change in access group membership for reforming the access agents into one or more new access groups.

9. The apparatus of claim 8 wherein said reforming means comprises:

means in said monitor access agent for sending a first group leader message and thereby said monitor access agent becomes a first monitor access agent, said sending means also sending a first group membership list message identifying the members of a first access group; and

means in a member access agent for receiving the first group leader message and the first group membership list message from said first monitor access agent and updating the membership list in the member access agent.

10. The apparatus of claim 9 wherein a second group of access agents includes all member access agents not receiving a group leader message from said first monitor access agent, and apparatus in each access agent in the second group comprises:

means in response to no group leader message for sending a negotiate message to access agents in the second access group to negotiate for leadership of access agents in the second group;

means for listening for a negotiate message from other access agents in the second access group;

means in response to no other negotiate messages from access agents in the second group for sending a second-group leader message; and

means responsive to the second group leader message for joining the second-group;

whereby one access agent sending a second group leader message becomes a second monitor access agent and all other access agents in the second access group become members of the second access group.

11. The apparatus of claim 10 and wherein each access agent in the second access group further comprises:

means in response to a negotiate message from other access agents in the second group for resolving leadership conflict between two or more access agents negotiating for second group leadership;

means in response to conflict resolution by said resolving means for sending a second group leader message.

12. In a LAN/WAN communication system with network nodes at a LAN/WAN interface having access agents, each access agent for managing communications across the interface for its network node, said system having a group management system for managing communications through multiple access agents as a group, apparatus in each of said access agents for forming and maintaining as a multiple access group a plurality of access agents that share a common LAN/WAN interface and provide parallel access paths across the interface, said apparatus in each access agent comprising;

means for sending a negotiate message to other access agents in the access group to negotiate for leadership of the access group;

means for listening for negotiate message from other access agents in the access group;

means in response to no other negotiate messages within a predetermined time interval for sending a group leader message to other access agents in the access group;

means in response to a negotiate message from other access agents for resolving leadership conflict between two or more access agents negotiating for group leadership;

means in response to conflict resolution by said resolving means for sending a group leader message; and

means responsive to a group leader message for joining the group;

whereby one access agent sending a group leader message becomes a monitor access agent and all other access agents in the access group become members of the access group.

13. The apparatus of claim 12 and in addition:

means in the monitor access agent responsive to a WAN identifier in messages from the other access agents for detecting a change in WAN identification for the WAN attached to the access agents in the access group; and

means responsive to a change in WAN identification for reforming the access agents into one or more new groups of access agents having a common WAN identifier.

14. The apparatus of claim 13 wherein said reforming means comprises:

said sending means in said monitor access agent for sending a first group leader message with a WAN identifier and thereby said monitor access agent becomes a first monitor access agent, said sending means also sending a first group membership list message identifying the members of a first access group; and

means in a member access agent for receiving the group leader message with the WAN identifier and the first group membership list message from said first monitor access agent and updating the membership list in the member access agent if the WAN identifier in the group leader message matches the WAN identifier of the member access agent.

15. The apparatus of claim 14 wherein a second group of member access agents has a common WAN identifier that is different from the WAN identifier in the group leader message, each access agent in the second group comprises:

means, in response to the lack of a group leader message with a WAN identifier that matches the WAN identifier of the access agent, for sending to access agents in the second group a negotiate message with a WAN identifier common to the second group access agents to negotiate for leadership of access agents in the second group;

means for listening for a negotiate message from other access agents in the second access group;

means in response to no other negotiate messages with a WAN identifier common to access agents in the second group for sending a second-group leader message with the WAN identifier common to the second group; and

means responsive to the second-group leader message for joining the second group;

whereby one access agent sending a second group leader message with a WAN identifier common to the second group becomes a second monitor access agent and all other access agents in the second group become members of the second access group.

16. The apparatus of claim 15 wherein each access agent in the second access group further comprises:

means in response to a negotiate message with a WAN identifier common to second group access agents for resolving leadership conflict between two or more access agents negotiating for group leadership of the second group;

means in response to conflict resolution by said resolving means for sending a second-group leader message with a WAN identifier common to the second access group.

17. In a plural network communication system having multiple access agents at a network-to-network interface, apparatus in each access agent cooperating with similar apparatus in the other access agents for forming and maintaining the access agents common to the interface into a group for operative use as a group by the communication system, said apparatus in each access agent comprises:

negotiation means for negotiating for leadership of the group by sending a negotiate message to all other access agents common to the interface;

means responsive to a negotiate message from another access agent for resolving conflicts in negotiation and sending a group leader message if the current access agent wins the conflict resolution or a merge message if the current access agent loses the conflict resolution; and

maintaining group operation integrity after the group has been formed whereby the communication system may manage the access agents as a group.

18. The apparatus of claim 17 wherein said negotiation means comprises:

means for testing whether or not a group leader message has been received from another access agent in a predetermined interval of time; and

means for sending a negotiate message to the other access agents if a group leader message has not been received.

19. The apparatus of claim 18 wherein said means for resolving conflicts comprises:

means for testing whether the negotiate message from another access agent indicates the other access agent has a higher rank than the current access agent;

means for sending a group leader message to the other access agents if the current access agent has a higher rank; and

means for sending a merge message to the other access agents if the current access agent has a lower rank.

20. The apparatus of claim 17 wherein said means for maintaining comprises:

means for testing whether or not a group leader message with a membership list message has been received from another access agent in a predetermined interval of time;

means responsive to no group leader message for sending a negotiate message to the other access agents;

means for testing the membership list message to determine whether a group membership change has occurred if a group leader message is received;

means responsive to a change in group membership for updating the group membership list in the current access agent.

21. The method of claim 20 wherein said means for resolving conflicts comprises:

means for testing whether the negotiate message from another access agent indicates the other access agent has a higher rank than the current access agent;

means for sending a group leader message to the other access agents if the current access agent has a higher rank; and

means for sending a merge message to the other access agents if the current access agent has a lower rank.

22. The apparatus of claim 17 wherein said network-to-network interface is a LAN/WAN interface and said means for negotiating comprises:

first means for testing whether or not a group leader message has been received from another access agent in a predetermined interval of time, said group leader message identifies the WAN attached to said another access agent;

second means responsive to a group leader message for testing whether the group leader message comes from an access agent attached to the same WAN as the current access agent; and

means responsive to said second testing means for sending a negotiate message to the other access agents if the group leader message does not come from an access agent attached to the same WAN as the current access agent.

23. The apparatus of claim 22 wherein said negotiate message identifies the WAN attached to the access agent sending the negotiate message and said means for resolving comprises:

third means for testing whether the negotiate message from another access agent indicates the other access agent has a higher rank than the current access agent;

fourth means for testing whether the negotiate message comes from another access agent attached to the same WAN as the current access agent;

means responsive to said third and fourth testing means for sending a group leader message to the other access agents if the current access agent has a higher rank and is on the same WAN; and

means responsive to said third and fourth testing means for sending a merge message to the other access agents if the current access agent has a lower rank and is on the same WAN.