Inter-PAN Path Stitching for LLN Border Devices
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Solution Overview
Problem
Existing Low Power and Lossy Networks (LLNs) face scalability issues due to the need for inter-PAN traffic to route through root network devices, which act as bottlenecks, limiting the ability to implement peer-to-peer routing across different Directed Acyclic Graph (DODAG) topologies within Personal Area Networks (PANs).
Innovation Solution
A method and apparatus that enable a controller device in an LLN to determine neighboring LLN border devices across different PANs, generating an inter-PAN path that stitches between DODAG topologies, allowing network traffic to bypass root devices by utilizing neighboring link layer connections between border devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If inter-PAN traffic is routed through root network devices, then routing paths can be established within a single PAN, but root devices become bottlenecks limiting network scalability
Solution Approach 1:
The patent segments the routing function by introducing intermediate border devices that can establish routing paths between different PANs independently of root devices. This divides the monolithic root-device-dependent routing into distributed routing segments, allowing parallel path establishment and eliminating the bottleneck at root devices, thereby improving network scalability while maintaining routing flexibility
Solution Approach 2:
The patent introduces border devices as intermediary elements between different PANs. These border devices act as mediators that can directly establish routing paths with border devices in other PANs, bypassing the need for traffic to traverse through root devices. This intermediary mechanism enables scalable inter-PAN communication while preserving routing path flexibility
2Ease of operation
If a centralized root device establishes all routing paths, then routing management is simplified, but the root device becomes a single point of failure and performance bottleneck
Solution Approach 1:
The patent segments the centralized routing management function into distributed routing capabilities at border devices. Each border device can independently establish and manage routing paths to neighboring PANs, distributing the routing management load and eliminating the single point of failure at the root device, thereby improving network robustness while maintaining operational simplicity through standardized border device interfaces
Solution Approach 2:
The patent enables border devices to pre-establish routing paths and maintain routing state information in advance. This preliminary action allows border devices to quickly respond to traffic demands without requiring real-time coordination with root devices, improving network robustness by reducing dependency on centralized control while keeping routing management simple through pre-configured path information
Data Source
AI summary
In one embodiment, a method comprises determining, by a controller device in a low power and lossy network (LLN), that a first LLN border device is in a first personal area network (PAN) having a first directed acyclic graph (DAG) topology, and that the first LLN border device is a neighbor of a second LLN border device in a second PAN of the LLN having a second DAG topology; receiving a path request for a third LLN device in the first PAN to reach a fourth LLN device in the second PAN; and generating an inter-PAN path between the third LLN device and the fourth LLN device via the first and second LLN border devices, the inter-PAN path providing a stitching between the first DAG topology and the second DAG topology.