Clock Fault Detection in Synchronized Network Devices
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Solution Overview
Problem
In synchronized networks, such as synchronous Ethernet networks, poor quality clock signals can be inadvertently selected as reference clocks due to faulty clock quality indications, leading to degraded performance and reliability of communications.
Innovation Solution
A method where a first network device receives clock quality indications from other network devices, determines if the quality metric of the clock signal does not satisfy a threshold, and sends a clock fault notification to downgrade the clock quality indication, thereby selecting a new reference clock based on the downgraded indication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a network device selects a reference clock based on clock quality indications, then synchronization is established, but poor quality clock signals may be inadvertently selected leading to degraded performance and reliability
Solution Approach 1:
The patent implements a feedback mechanism where network devices monitor the actual performance of selected reference clocks and send notifications back to upstream devices. When a device detects that a reference clock does not meet quality thresholds, it sends a notification causing the upstream device to downgrade the clock quality indication, preventing poor quality clocks from being selected by other devices in the network.
Solution Approach 2:
The patent introduces an intermediary quality assessment mechanism where devices evaluate clock signals against defined thresholds before accepting them as reference clocks. This intermediary layer of quality verification acts as a filter between the clock source and the synchronization system, preventing poor quality clocks from compromising network reliability.
2Productivity
If clock quality indications are transmitted without verification, then network devices can quickly establish synchronization, but the quality metric may not reflect actual clock signal quality
Solution Approach 1:
The patent implements preliminary quality verification by establishing threshold criteria for clock signals before they are accepted as reference clocks. Devices perform initial quality assessments and only accept clocks that meet the predefined thresholds, ensuring quality verification happens before synchronization is fully established, thus maintaining both speed and accuracy.
3Device complexity
If all network devices use the same reference clock, then synchronization is simplified, but a single point of failure can degrade the entire network
Solution Approach 1:
The patent segments the reference clock selection process by allowing different network devices to independently evaluate and select reference clocks based on local quality measurements. Instead of forcing all devices to use a single centralized reference clock, each device can select from multiple available clocks, creating redundancy and preventing single points of failure while maintaining synchronization across the network.
Data Source
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AI summary
A first network device may receive, from a second network device, a clock quality indication that is associated with a clock of the second network device, wherein the clock of the second network device is a reference clock for a network that includes the first network device and the second network device. The first network device may determine, based on a clock signal of the second network device, that a quality metric of the clock does not satisfy a threshold. The first network device may provide, to the second network device, a clock fault notification to cause the second network device to downgrade the clock quality indication transmitted by the second network device. The first network device may select a new reference clock for the first network device based on receiving the downgraded clock quality indication from the second network device.