MinTree Routing in Constrained Networks
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Solution Overview
Problem
Low power and lossy networks (LLNs) face challenges in routing due to high complexity and scalability issues with existing proactive and reactive routing protocols, which are exacerbated by constraints such as low bandwidth, battery operation, and limited processing capabilities.
Innovation Solution
A capable node in the network hosts a path computation element (PCE) that computes a minimum spanning tree (MinTree) or Directed Acyclic Graph (DAG) based on neighborhood information, dividing nodes into routing (R) and host (H) nodes, where R nodes form interconnected paths and H nodes are within one hop of an R node, enabling efficient packet forwarding through local multicast.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If proactive or reactive routing protocols are used in LLNs, then routing functionality is provided, but code complexity and processing requirements increase significantly
Solution Approach 1:
The patent segments routing functionality by dividing network nodes into two distinct roles: border router nodes that execute full routing protocols and host nodes that use simplified forwarding rules. This segmentation allows routing functionality to be provided while reducing code complexity on the majority of host nodes, as they only need to implement basic packet forwarding based on received routing information from border routers.
2Reliability
If routing protocols compute and maintain routes in LLNs, then packet delivery is enabled, but processing capability and memory requirements increase
Solution Approach 1:
The patent extracts complex routing computation and maintenance functions from individual network nodes and consolidates them at border router nodes. Host nodes simply receive routing information and forwarding rules from border routers, eliminating the need for each node to independently compute and maintain routes. This extraction reduces processing capability and memory requirements at host nodes while maintaining packet delivery functionality.
3Loss of information
If routing information is propagated throughout the network, then route awareness is achieved, but network traffic increases
Solution Approach 1:
The patent applies local quality by providing different types of routing information to different nodes based on their roles. Border router nodes receive complete routing information for route computation, while host nodes receive only simplified forwarding rules and next-hop information needed for local packet forwarding. This localized information provision achieves necessary route awareness at each node while minimizing network traffic compared to propagating full routing information to all nodes.
Data Source
AI summary
In one embodiment, a capable node in a computer network may host a path computation element, receive one or more neighborhood discovery messages including neighborhood information from a plurality of nodes in the computer network, and compute a minimum spanning tree (MinTree) for the computer network based on the neighborhood information. The MinTree may divide the plurality of nodes in the computer network into a first subset of routing nodes and a second subset of host nodes. The first subset of routing nodes may form one or more interconnected paths of routing nodes within the MinTree, and each host node within the second subset of host nodes may be located within one hop of at least one routing node. The capable node may then communicate a MinTree message to the plurality of nodes in the computer network to build the MinTree by enabling routing on each routing node.