Network Switch Mode Switching for Cut-Through Latency and Fault Isolation

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Solution Overview

Problem

Existing network switches struggle to balance low latency and fault isolation, with cut-through switching offering low latency but poor fault isolation, and store-and-forward switching providing fault tolerance at the cost of significant latency.

Innovation Solution

A network switch that dynamically switches between cut-through and store-and-forward modes based on port health metrics, automatically changing to store-and-forward mode when health metrics fall below a threshold and alerting a remote system if the degradation persists.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If cut-through switching is used, then latency is reduced, but fault isolation capability deteriorates

Engineering Contradiction:
ImprovelatencyVSAvoidfault isolation capability
Core Design Contradiction:
Loss of timeVSReliability

Solution Approach 1:

The switch dynamically changes its operating mode between cut-through and store-and-forward based on real-time health metrics of network ports. When a port's health metric falls below a threshold, the switch transitions to store-and-forward mode for that port to improve fault isolation, and switches back to cut-through mode when the port recovers, thus adaptively balancing latency and reliability.

Inventive Principle:
Principle #15Dynamics

2Reliability

If store-and-forward switching is used, then fault isolation capability is improved, but latency increases

Engineering Contradiction:
Improvefault isolation capabilityVSAvoidlatency
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The switch applies different switching modes to different ports based on their individual health metrics. Only ports with degraded health metrics are switched to store-and-forward mode, while healthy ports continue to operate in cut-through mode. This localized approach ensures fault isolation is improved only where necessary, minimizing the overall latency impact on the network.

Inventive Principle:
Principle #3Local quality

3Reliability

If the switch operates in store-and-forward mode to isolate faults, then error propagation is reduced, but network performance deteriorates

Engineering Contradiction:
Improveerror propagation controlVSAvoidnetwork performance
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The switch dynamically adjusts its operating mode based on real-time monitoring of port health metrics. When error rates or other health indicators exceed thresholds, the switch transitions to store-and-forward mode to prevent error propagation. When the port health improves, the switch returns to cut-through mode to restore optimal performance, thus temporarily sacrificing performance only when necessary for error control.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP4250678B1Cut-through latency and network fault diagnosis with limited error propagation
Publication Date: 2025.10.22 AVAGO TECHNOLOGIES INTERNATIONAL SALES PTE LTD
  • EP4250678B1 patent drawingFigure 1A
  • EP4250678B1 patent drawingFigure 1B
  • EP4250678B1 patent drawingFigure 2A

AI summary

A switch may operate in a cut-through mode and a store-and-forward mode. While in a default cut-through mode, the switch continuously monitors ports for certain health metrics. If those health metrics fall below a threshold, the switch changes to operate in a store-and-forward mode, either for a predetermined period of time or until the health metrics rise above a threshold, at which point the switch can resume cut-through mode operations. If health metrics fall below an even lower threshold, or remain below threshold for a predefined period of time, the switch can automatically alert a remote system or software process.