Learning Machine End-to-End Delay Estimation in LLNs

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Solution Overview

Problem

Low Power and Lossy Networks (LLNs), such as IoT networks, face challenges with lossy links, low bandwidth, and limited resources, making it difficult for classic routing approaches to efficiently manage and predict network behavior, especially as the number of nodes increases.

Innovation Solution

The implementation of a Learning Machine-based approach using periodic round-trip probes and statistical analysis to estimate end-to-end delays in LLNs, employing algorithms like Variational Bayes Least Squares (VBLS) for regression and Expectation-Maximization to infer link-wise delays from sporadic round-trip delay data, allowing for proactive network management and monitoring.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If classic routing approaches are used in LLNs, then routing functionality is provided, but network management becomes inefficient and cannot handle large numbers of nodes effectively

Engineering Contradiction:
Improvenetwork management efficiencyVSAvoidnetwork scale
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent implements learning machines at network nodes that enable self-organized routing and delay estimation. Nodes automatically learn from observed traffic patterns and RTT measurements, eliminating the need for centralized control and manual configuration. This self-service capability allows the network to scale to large numbers of nodes while maintaining management efficiency.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent replaces classic mechanical routing algorithms with learning machine-based approaches. Instead of predetermined routing tables and static protocols, the system uses machine learning models that adaptively learn routing paths and delay characteristics from observed data, substituting rigid mechanical systems with flexible intelligent systems.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If extensive probing is performed to measure network delays, then accurate delay information is obtained, but computational costs and network overhead increase

Engineering Contradiction:
Improvedelay estimation accuracyVSAvoidcomputational cost
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent uses sporadic round-trip time measurements rather than continuous extensive probing. By performing delay measurements at selective intervals and using learning machines to interpolate and predict delays between measurements, the system achieves adequate measurement precision while significantly reducing computational overhead and energy consumption.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The patent creates virtual copies of delay measurements through learning machine predictions. Instead of performing actual measurements for every path and time point, the system learns from a subset of real measurements and generates predicted delay values for unmeasured scenarios, reducing the need for extensive actual probing while maintaining estimation accuracy.

Inventive Principle:
Principle #26Copying

3Reliability

If high-dimensional regression problems are solved using classic methods, then complete network analysis is achieved, but computational complexity becomes prohibitive

Engineering Contradiction:
Improvenetwork analysis completenessVSAvoidcomputational complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the high-dimensional regression problem into smaller, manageable components. The learning machines process local observations and features at each node, breaking down the global network analysis into distributed local computations. This segmentation reduces the dimensionality of individual regression problems while maintaining overall analysis completeness through aggregation of local results.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentUS9491076B2Learning end-to-end delays in computer networks from sporadic round-trip delay probing
Publication Date: 2016.11.08 CISCO TECHNOLOGY INC
  • US9491076B2 patent drawing
  • US9491076B2 patent drawing
  • US9491076B2 patent drawing

AI summary

In one embodiment, periodic round-trip probes are executed in a network, whereby a packet is transmitted along a particular communication path from a source to a destination and back to the source. Statistical information relating to the round-trip probes is gathered, and a transmission delay of the round-trip probes is calculated based on the gathered statistical information. Also, an end-to-end transmission delay along an arbitrary communication path in the network is estimated based on the calculated transmission delay of the round-trip probes.