Dynamic Address Assignment for Address Aggregation in Low Power and Lossy Networks

• US 20120117208A1
• Filed: 11/09/2010
• Published: 05/10/2012
• Est. Priority Date: 11/09/2010
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Shaffer, Shmuel, Thubert, Pascal, Wetterwald, Patrick, Vasseur, Jean-Philippe
• Granted Patent: US 8,631,101 B2
• Time in Patent Office: Days
• US Class Current: 709/221
• CPC Class Codes: H04L 2101/668 Internet protocol [IP] address subnets
• CPC Class Codes: H04L 41/0816 the condition being an adaptation, e.g. in response to network events
• CPC Class Codes: H04L 41/085 Retrieval of network configuration; Tracking network configuration history
• CPC Class Codes: H04L 61/5038 for local use, e.g. in LAN or USB networks, or in a controller area network [CAN]
• CPC Class Codes: H04L 61/5053 Lease time; Renewal aspects
• CPC Class Codes: H04W 40/248 Connectivity information update
• CPC Class Codes: H04W 8/26 Network addressing or numbering for mobility support
• CPC Class Codes: Y02D 30/70 in wireless communication networks
• CPC Class Codes: Y04S 40/00 Systems for electrical power generation, transmission, distribution or end-user application management characterised by the use of communication or information technologies, or communication or information technology specific aspects supporting them

Abstract

A node in a Low power and Lossy Network (LLN) is managed by monitoring a routing configuration on a node in a LLN. A triggering parameter that is used to invoke an address change on a child node is tracked and a threshold against which to compare the triggering parameter is accessed. The triggering parameter is compared to the threshold. Based on results of comparing the triggering parameter to the threshold, it is determined that an address change at the child node is appropriate. An address change of a child node appearing in the routing configuration is invoked based on the determination that an address change is appropriate.

Claims

1. A method of managing a node in a Low power and Lossy Network (LLN), the method comprising:

monitoring a routing configuration on a node in a LLN;

tracking a triggering parameter that is used to invoke an address change on a child node;

accessing a threshold against which to compare the triggering parameter;

comparing the triggering parameter to the threshold;

determining, based on results of comparing the triggering parameter to the threshold, that an address change at the child node is appropriate; and

invoking an address change of a child node appearing in the routing configuration based on the determination that an address change is appropriate.

2. The method of claim 1 wherein tracking the triggering parameter includes tracking a memory size of a routing table on the node.

3. The method of claim 1 wherein tracking the triggering parameter includes tracking a number of child nodes associated with the node.

4. The method of claim 1 wherein tracking the triggering parameter includes tracking a number of child nodes that are associated with the node and that have a non-aggregated address.

5. The method of claim 1 wherein tracking the triggering parameter includes tracking a frequency at which nodes move in a directed acyclic graph (DAG) used to route packets.

6. The method of claim 1 wherein invoking the address change includes transmitting a unicast signaling message to the child node of the node, the unicast signaling message directing the child node to perform an address reconfiguration.

7. The method of claim 6 wherein transmitting the unicast signaling message to the child node includes transmitting a preferred prefix to be adopted by the child node as a result of performing address reconfiguration.

8. The method of claim 1 further comprising receiving an acknowledgement message indicating that the child node has performed address reconfiguration.

9. The method of claim 1 further comprising receiving an acknowledgement message indicating that the child node has not performed address reconfiguration.

10. The method of claim 1 further comprising updating the routing configuration by removing an address for the child node from a routing table.

11. The method of claim 1 further comprising updating the routing configuration to reflect an addition of a device including the child node that uses a preferred prefix.

12. The method of claim 1 further comprising:

receiving an acknowledgement message from the child node indicating that the child node has refused to perform the address reconfiguration command; and

transmitting a drop message to the child node indicating the node will no longer support the child node as a child.

13. The method of claim 1, further comprising triggering the address reconfiguration command in response to receiving an instruction from a network operator.

14. A method of managing a node in a LLN, the method comprising:

receiving, at the node and from a parent node, a unicast signaling message that includes an address reconfiguration command having a preferred prefix to be adopted by the node should be performed;

determining whether there is an active flow on the node;

reconfiguring, in response to determining that there is no active flow on the node, an address on the node using the preferred prefix; and

transmitting an acknowledgement message to the parent node indicating that address reconfiguration has been performed.

15. The method of claim 14 further comprising enabling the node to refuse the address reconfiguration command.

16. The method of claim 14 further comprising:

activating a delay timer for the node, the delay timer representing a period over which the node is configured delay respond pending a resolution of the active flow.

17. The method of claim 14 further comprising terminating the active flow upon expiration of the delay timer.

18. The method of claim 14 further comprising maintaining the active flow upon expiration of the delay timer and transmitting a response message to the parent node indicating that address reconfiguration command cannot be supported.

19. The method of claim 14 wherein determining whether there is the active flow includes determining whether the node is an endpoint in a communications session.

20. The method of claim 14 wherein determining whether there is the active flow includes determining that the node is locating along a path in a communications session between two other endpoints.

21. The method of claim 14 further comprising:

activating a delay timer for the node, the delay timer representing a period over which the node is configured delay respond pending a resolution of another event.

22. A system configured to manage a node in a LLN, the system comprising a processor and instructions that when executed on a processor cause the processor to perform operations that include:

monitoring a routing configuration on a node in a LLN;

tracking a triggering parameter that is used to invoke an address change on a child node;

accessing a threshold against which to compare the triggering parameter;

comparing the triggering parameter to the threshold;

determining, based on results of comparing the triggering parameter to the threshold, that an address change at the child node is appropriate; and

invoking an address change of a child node appearing in the routing configuration based on the determination that an address change is appropriate.

23. A system that manages a node in a LLN, the system comprising a processor and instructions that when executed on a processor cause the processor to perform instructions that include:

receiving, at the node and from a parent node, a unicast signaling message that includes an address reconfiguration command having a preferred prefix to be adopted by the node should be performed;

determining whether there is an active flow on the node;

reconfiguring, in response to determining that there is no active flow on the node, an address on the node using the preferred prefix; and

transmitting an acknowledgement message to the parent node indicating that address reconfiguration has been performed.

24. The system of claim 23 further comprising instructions that include:

activating a delay timer for the node, the delay timer representing a period over which the node is configured delay respond pending a resolution of another event.

25. A computer program stored on a computer readable medium that manages a node in a LLN, the computer program comprising instructions that when executed on a processor cause the processor to perform operations that include:

monitoring a routing configuration on a node in a LLN;

tracking a triggering parameter that is used to invoke an address change on a child node;

accessing a threshold against which to compare the triggering parameter;

comparing the triggering parameter to the threshold;

determining, based on results of comparing the triggering parameter to the threshold, that an address change at the child node is appropriate; and

invoking an address change of a child node appearing in the routing configuration based on the determination that an address change is appropriate.

26. A computer program stored on a computer readable medium that manages a node in a LLN, the computer program comprising instructions that when executed on a processor cause the processor to perform operations that include:

receiving, at the node and from a parent node, a unicast signaling message that includes an address reconfiguration command having a preferred prefix to be adopted by the node should be performed;

determining whether there is an active flow on the node;

reconfiguring, in response to determining that there is no active flow on the node, an address on the node using the preferred prefix; and

transmitting an acknowledgement message to the parent node indicating that address reconfiguration has been performed.