RPL Parent Device Local Recovery Mechanism
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Solution Overview
Problem
Conventional RPL network devices face significant challenges in recovering from losing their parent node, leading to prolonged data loss and disruption in low power and lossy networks, especially in applications like industrial networking where timely recovery is critical.
Innovation Solution
The implementation of a method where an orphaned RPL network device executes fast local recovery by forwarding flagged data packets to neighboring nodes to detect loops and identify feasible successor parents, allowing for proactive re-parenting independent of the existing RPL routing protocol, thereby maintaining data plane traffic and accelerating the recovery process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional RPL network devices use standard re-parenting procedures after losing their parent node, then routing protocol compliance is maintained, but recovery time is prolonged and data loss occurs
Solution Approach 1:
The patent applies preliminary action by having orphaned nodes proactively search for and validate alternative parent nodes before actual data loss occurs. The node sends probe messages to potential parents and validates their feasibility in advance, so when the current parent fails, the node can immediately switch without waiting for the standard RPL re-parenting process, thereby preventing data loss and reducing recovery time
Solution Approach 2:
The patent implements feedback mechanisms where orphaned nodes continuously monitor parent node status and actively probe alternative parents. When a parent failure is detected, the node receives feedback from potential alternative parents about their availability and suitability, allowing rapid informed decision-making for re-parenting without prolonged data loss
2Reliability
If RPL network devices perform comprehensive parent validation and loop detection, then routing correctness is ensured, but processing overhead and complexity increase
Solution Approach 1:
The patent applies segmentation by dividing the complex parent validation and loop detection process into separate, modular functions: probe message generation, response validation, loop detection through flag checking, and feasibility determination. Each function handles a specific aspect of validation independently, reducing overall processing overhead while maintaining comprehensive routing correctness
Solution Approach 2:
The patent uses intermediary probe messages and validation flags as mediators between the orphaned node and potential parent nodes. These intermediaries carry validation information and loop detection flags, allowing comprehensive verification of routing correctness without requiring complex direct analysis between nodes, thereby reducing processing overhead
3Stability of the object's composition
If RPL network devices rely on control plane procedures for re-parenting, then protocol consistency is maintained, but data plane disruption increases
Solution Approach 1:
The patent applies preliminary action by completing all parent validation, loop detection, and feasibility verification in advance through control plane probe messages before data plane traffic needs to be redirected. This ensures protocol consistency is maintained while minimizing data plane disruption, as the re-parenting decision is already made and validated before actual data forwarding needs to change
Solution Approach 2:
The patent implements skipping by allowing orphaned nodes to bypass the lengthy standard RPL control plane re-parenting procedures and directly switch to pre-validated alternative parents. The node rushes through the re-parenting process by using previously gathered validation information, maintaining protocol consistency while dramatically reducing data plane disruption and improving continuity
Data Source
AI summary
In one embodiment, a network device (e.g., a RPL router) executes fast local RPL recovery in a low power and lossy network (LLN). The network device, in response to becoming an orphan in a directed acyclic graph (DAG) topology, can utilize the data plane to maintain at least some data traffic by randomly forwarding the data traffic to identified neighbor devices, while eliminating children from the list of forwarders and by finding successors that can be used for re-parenting. Hence, when a RPL network device having lost its last feasible parent can avoid data loss and accelerate a re-parenting process using local repair in the data plane instead of the control plane of the routing protocol used to establish the DAG topology.