IRB Device Duplicate Address Detection Filter

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Solution Overview

Problem

Integrated routing and bridging (IRB) devices face address conflicts due to incomplete duplicate address detection when multiple layer 2 interfaces are activated, leading to potential network traffic errors and communication issues.

Innovation Solution

The IRB device performs duplicate address detection for all activated layer 2 interfaces by activating a filter to prevent traffic transmission errors and using neighbor solicitation messages to identify duplicate IP addresses, ensuring thorough detection and conflict resolution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the layer 3 interface is activated based on the first layer 2 interface without re-detection for subsequent layer 2 interfaces, then the device complexity and processing overhead are reduced, but address conflicts occur due to incomplete duplicate address detection

Engineering Contradiction:
Improveaddress conflict preventionVSAvoiddetection process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The system performs duplicate address detection in advance for each layer 2 interface before activating the layer 3 interface. When a second layer 2 interface is activated, the system re-performs duplicate address detection proactively rather than waiting for conflicts to occur, preventing address conflicts before they can affect network communication.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If duplicate address detection is performed only once during initial activation, then the processing time and energy consumption are reduced, but network communication reliability deteriorates due to undetected address conflicts

Engineering Contradiction:
Improvenetwork communication reliabilityVSAvoiddetection time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The system performs duplicate address detection periodically whenever a layer 2 interface is activated. Instead of a single initial detection, the system implements periodic re-detection triggered by interface activation events, ensuring that address conflicts are detected whenever network topology changes occur, thereby maintaining high communication reliability.

Inventive Principle:
Principle #19Periodic action

3Reliability

If the filter is maintained permanently after initial detection, then address conflicts are prevented, but network traffic transmission efficiency is reduced due to unnecessary filtering

Engineering Contradiction:
Improveaddress conflict preventionVSAvoidnetwork traffic transmission efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The filter state is made dynamic rather than static. The filter is activated temporarily when a duplicate address is detected and deactivated when no duplicate address is detected. This dynamic adjustment of filter state based on real-time detection results prevents address conflicts while avoiding unnecessary filtering of legitimate network traffic, thereby maintaining transmission efficiency.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3226520B1Performing duplicate address detection for an integrated routing and bridging device
Publication Date: 2021.10.13 JUNIPER NETWORKS INC
  • EP3226520B1 patent drawingFigure 1A
  • EP3226520B1 patent drawingFigure 1B
  • EP3226520B1 patent drawingFigure 1C

AI summary

A device may activate a layer 3 interface of the device based on activation of a first layer 2 interface associated with the layer 3 interface. The device may detect activation of a second layer 2 interface, associated with the layer 3 interface, after activating the layer 3 interface. The device may activate a filter to prevent transfer of network traffic via the second layer 2 interface based on detecting activation of the second layer 2 interface. The device may perform duplicate address detection, in association with the second layer 2 interface, for a layer 3 network address assigned to the device. The device may determine whether the layer 3 network address is a duplicate network address based on performing the duplicate address detection. The device may selectively maintain or deactivate the filter based on determining whether the layer 3 network address is a duplicate network address.