Diagnostic Transmissions for Hidden Intermediary Node Detection

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Solution Overview

Problem

Network controllers are unable to detect and manage unknown or malicious network nodes that do not transmit advertisements, leading to disruptions and security vulnerabilities.

Innovation Solution

Diagnostic techniques involving diagnostic transmissions between network nodes to identify the presence and functionality of intermediary nodes by analyzing discrepancies in addresses, data types, processing times, and other network parameters.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If the network controller relies on advertisements from network nodes to maintain topology, then the topology can be automatically updated, but the network controller becomes unaware of nodes that do not transmit advertisements

Engineering Contradiction:
Improveautomatic topology updateVSAvoidvisibility of network nodes
Core Design Contradiction:
Extent of automationVSLoss of information

Solution Approach 1:

The network controller proactively sends diagnostic transmissions to suspected locations where intermediary nodes may exist, before these nodes can cause network disruptions. This preliminary action allows the controller to detect and identify hidden nodes before they interfere with normal network operations.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces diagnostic transmissions as an intermediary mechanism between the network controller and potential hidden nodes. These diagnostic packets act as mediators that reveal the presence of intermediary nodes by observing how they handle or modify the transmissions.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If transparent firewall nodes are added to the network without updating topology, then network security is enhanced, but the network controller remains unaware of these nodes

Engineering Contradiction:
Improvenetwork securityVSAvoidtopology awareness
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The system implements feedback mechanisms where the network controller sends diagnostic transmissions and analyzes the responses to detect transparent firewall nodes. The feedback from how these nodes handle diagnostic packets (modifying headers, dropping packets, or forwarding unchanged) reveals their presence and allows the controller to update the topology accordingly.

Inventive Principle:
Principle #23Feedback

3Reliability

If diagnostic transmissions are sent to detect intermediary nodes, then network security is improved, but network traffic increases

Engineering Contradiction:
Improvenetwork securityVSAvoidnetwork traffic
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

Instead of continuously monitoring all network traffic, the system performs partial diagnostics by sending diagnostic transmissions only to specific suspected locations or under certain conditions. This approach provides sufficient security detection while minimizing the overall increase in network traffic.

Inventive Principle:
Principle #16Partial or excessive action

Solution Approach 2:

The network controller performs diagnostic transmissions periodically or on-demand rather than continuously, reducing the overall traffic load while maintaining effective detection of intermediary nodes. The periodic nature allows the system to balance security monitoring with normal network operations.

Inventive Principle:
Principle #19Periodic action

Data Source

PatentEP4162654B1Diagnosing intermediary network nodes
Publication Date: 2025.07.16 CISCO TECHNOLOGY INC
  • EP4162654B1 patent drawingFigure 1
  • EP4162654B1 patent drawingFigure 2A
  • EP4162654B1 patent drawingFigure 2B

AI summary

This disclosure describes techniques for diagnosing a presence or malfunction of a network node. In an example method, a first network node receives an indication of a diagnostic transmission originating from a second network node. The second network node further receives a forwarded transmission corresponding to the diagnostic transmission. The first network node diagnoses at least one of a presence or a malfunction of an intermediary node between the first network node and the second network node based on at least one of the indications of the diagnostic transmission or the forwarded transmission.