Dynamic Route Entry Installation in LLN DAG Root
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Solution Overview
Problem
In Low-power and Lossy Networks (LLNs), the non-storing mode topology requires each data packet to be transmitted to the DAG root, leading to high network traffic and processing requirements, with low packet delivery rates due to the necessity of strict source routing headers.
Innovation Solution
A method where the DAG root identifies and installs temporary route entries in capable parent devices along the source-route path, allowing data packets to be routed directly to the destination without traversing the DAG root, reducing the need for strict source routing headers and optimizing paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If non-storing mode topology is used to reduce device complexity and memory usage, then device complexity and memory requirements are reduced, but network traffic increases and packet delivery rates decrease due to strict source routing requirements
Solution Approach 1:
The patent applies dynamics by enabling RPL nodes to dynamically switch between non-storing mode (for normal operation) and storing mode (for optimized paths). The DAG root dynamically installs temporary route entries in parent devices when beneficial, creating adaptive routing behavior that responds to network conditions and destination requirements, thus improving packet delivery rates without permanently increasing device complexity.
Solution Approach 2:
The patent applies local quality by allowing selective installation of route entries in specific parent devices along the source-route path to the DAG root. Instead of requiring all nodes to store routes or forcing all packets through the DAG root, the system locally optimizes specific paths by installing route entries only in capable parent devices, reducing network traffic for those specific destinations while maintaining non-storing mode for other nodes.
2Ease of operation
If all data packets are transmitted to the DAG root in non-storing mode, then routing simplicity is maintained, but network traffic increases and processing requirements at the DAG root increase
Solution Approach 1:
The patent applies taking out by extracting the route entry storage function from all RPL nodes and concentrating it selectively in specific parent devices along the source-route path. This allows optimized routing for specific destinations without requiring the DAG root to handle all packet forwarding, thereby reducing network traffic and processing requirements at the DAG root while maintaining routing simplicity through centralized route installation.
3Reliability
If strict source routing headers are required for all packets in non-storing mode, then routing control is maintained, but packet size increases and processing requirements increase
Solution Approach 1:
The patent applies segmentation by dividing the routing control mechanism into two segments: (1) DAG root-controlled route entry installation in parent devices, and (2) simplified local forwarding based on installed routes. This segmentation allows routing control to be maintained through centralized route installation while reducing processing requirements at individual nodes, as they only need to forward packets based on simple route entries rather than parsing complex source routing headers.
Data Source
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AI summary
In one embodiment, a method comprises identifying, by a network device operating in a network topology as a directed acyclic graph (DAG) root, a source-route path for reaching a destination device in the network topology; determining whether one or more parent devices along the source-route path between the network device and the destination device are capable of storing a route entry specifying routing information for reaching the destination device; and causing installation of a route entry for reaching the destination device in one or more of the parent devices determined as capable of storing the corresponding route entry.