PTP Time Slave Feedback for Network-Wide Synchronization Status
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Solution Overview
Problem
In communication systems using Precision Time Protocol (PTP), the time master cannot determine the time synchronization status of time slaves not directly connected to it, leading to uncertainty in starting data transmission among multiple communication devices.
Innovation Solution
A communication system where each time slave notifies the time master of its time synchronization information, allowing the time master to determine the synchronization status of all time slaves, enabling timely and synchronized data transmission initiation and monitoring for potential time lags.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the time master uses PTP to perform time synchronization with time slaves, then time synchronization accuracy is improved, but the time master cannot determine the synchronization status of time slaves not directly connected to it
Solution Approach 1:
The patent introduces an intermediary mechanism where time synchronization information is transmitted through the network from time slaves to the time master, enabling the master to obtain synchronization status of all slaves even those not directly connected. This resolves the information loss problem while maintaining PTP synchronization accuracy.
Solution Approach 2:
The patent implements a feedback mechanism where time synchronization information is continuously monitored and reported back to the time master. This allows the master to determine synchronization completion status and make informed decisions about data transmission timing, resolving the inability to track remote slave synchronization status.
2Reliability
If the time master waits for all time slaves to complete synchronization before starting data transmission, then synchronization reliability is improved, but data transmission delay increases
Solution Approach 1:
The time master uses feedback from time synchronization information to determine when all slaves have completed synchronization. This enables the master to start data transmission at the optimal moment - immediately when synchronization is complete - rather than waiting for a predetermined period, thus reducing delay while maintaining reliability.
Solution Approach 2:
The system performs preliminary time synchronization actions before data transmission begins. By completing synchronization in advance and using feedback to confirm completion, the system ensures reliability is established beforehand while minimizing the waiting time before data transmission can start.
3Measurement precision
If the time master monitors time synchronization information from all time slaves, then synchronization completion detection accuracy is improved, but communication overhead increases
Solution Approach 1:
The patent makes the time synchronization information serve multiple functions: it is used both for actual time synchronization and for monitoring synchronization completion status. This multi-functionality allows the master to detect synchronization completion accurately without requiring separate monitoring messages, thus avoiding increased communication overhead.
Solution Approach 2:
The time synchronization information itself provides the monitoring function - the same data packets used for synchronization also contain the status information needed to detect completion. This self-service approach eliminates the need for additional dedicated monitoring communications, maintaining low overhead while achieving high detection accuracy.
Data Source
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AI summary
A communication system according to one aspect of the present disclosure is a communication system in which a plurality of communication devices are connected to a network. The plurality of communication devices include a time master including a master clock that manages time of the communication system and a plurality of time slaves each of which includes a slave clock time-synchronized with the master clock. Each of the plurality of time slaves includes a synchronization unit that performs time synchronization with another communication device connected adjacent to a master side on the network and a communication unit that notifies the time master of time synchronization information indicating time synchronization accuracy of the own device obtained by the synchronization unit.