Link State Flooding Rate Control Using LSP Acknowledgments

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Solution Overview

Problem

Link state flooding in large networks requires significant time and resources, and traditional flow control techniques are difficult to implement when data streams consist of individual Protocol Data Units (PDUs, leading to inefficient network and computing resource usage.

Innovation Solution

An adaptive algorithm at the transmitter determines the highest LSP transmission rate based on the receiver's capability, optimizing flooding without direct rate signaling from the receiver.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If link state flooding is performed in large networks, then complete topology information is distributed to all nodes, but the time and resources required increase significantly

Engineering Contradiction:
Improvetopology information completenessVSAvoidflooding completion time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent implements dynamic flow control by continuously adjusting the LSP transmission rate based on receiver buffer status. The transmitter monitors buffer occupancy and adapts the flooding rate in real-time, transitioning between different transmission phases (normal, slowdown, pause) to optimize both completeness and timing of topology distribution

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent employs feedback mechanisms where the receiver sends buffer status information back to the transmitter. This feedback loop enables the transmitter to adjust its flooding rate based on actual receiver capacity, preventing overflow while ensuring complete topology information delivery

Inventive Principle:
Principle #23Feedback

2Ease of operation

If traditional flow control techniques are used with individual PDUs, then data transmission can be controlled, but implementation becomes difficult and resource usage becomes inefficient

Engineering Contradiction:
Improveflow control implementabilityVSAvoidnetwork resource efficiency
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

The patent segments the flooding process into distinct phases (normal phase, slowdown phase, pause phase) based on buffer occupancy thresholds. This segmentation simplifies flow control implementation by providing clear decision boundaries while maintaining efficient resource usage through phase-specific transmission rates

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the transmission rate parameter dynamically based on receiver buffer status. By adjusting the LSP transmission rate according to buffer occupancy levels, the system achieves efficient resource utilization without complex flow control mechanisms

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4413711B1Link state flooding transmitter-based flow control
Publication Date: 2026.01.21 CISCO TECHNOLOGY INC
  • EP4413711B1 patent drawingFigure 1
  • EP4413711B1 patent drawingFigure 2~3
  • EP4413711B1 patent drawingFigure 4~5

AI summary

In one embodiment, a method for link state flooding between a network node and a receiving node includes determining a current transmit rate that Link State Protocol Data Units (LSPs) are being transmitted from the network node to the receiving node. The method further includes determining an LSP acknowledgment rate that indicates a rate at which a plurality of LSP acknowledgments are received at the network node from the receiving node. The method further includes determining a new transmit rate based on the current transmit rate and the LSP acknowledgment rate. The method further includes transmitting a plurality of LSPs from the network node to the receiving node using the new transmit rate.