Boundary Clock Time Synchronization Without Local Calibration
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Solution Overview
Problem
Existing clock synchronization networks, such as those based on IEEE1588, require network apparatuses to calibrate their time and frequency according to a clock source, limiting their flexibility and application scenarios.
Innovation Solution
A method where network apparatuses exchange time synchronization packets without calibrating their local clocks, determining frequency and time deviations to generate corrected timestamps, allowing them to function as master clocks without calibrating their clocks, thereby extending their application scenarios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the network apparatus calibrates time and frequency according to a clock source before functioning as a master clock, then timing accuracy is improved, but flexibility and application scenario versatility deteriorate
Solution Approach 1:
The network apparatus performs preliminary calibration by exchanging time synchronization packets with a clock source to obtain time deviation and frequency deviation information before functioning as a master clock. This preliminary action enables the apparatus to maintain accurate timing without requiring continuous calibration, thereby achieving both timing accuracy and operational flexibility.
Solution Approach 2:
The patent introduces time synchronization packets as an intermediary carrier to transfer timing information between the clock source and the network apparatus. These packets enable the apparatus to obtain calibration data without direct continuous connection to the clock source, allowing the apparatus to function independently as a master clock while maintaining timing accuracy.
2Adaptability or versatility
If the network apparatus functions as a master clock without calibrating its local clock, then flexibility and application scenario versatility are improved, but timing accuracy deteriorates
Solution Approach 1:
The network apparatus obtains feedback information in the form of time deviation and frequency deviation from exchanged time synchronization packets. This feedback enables the apparatus to correct its local clock measurements and generate accurate timestamps even when functioning as a master clock without continuous calibration, thus maintaining timing accuracy while enjoying operational flexibility.
Solution Approach 2:
The patent changes the operational parameters of the network apparatus by allowing it to use uncalibrated local clock readings combined with deviation corrections from synchronization packets. This parameter change enables the apparatus to switch between calibrated and uncalibrated modes, achieving both flexibility and timing accuracy through dynamic parameter adjustment.
3Measurement precision
If the network apparatus exchanges time synchronization packets to obtain deviation information, then timing accuracy is maintained without calibration, but device complexity increases
Solution Approach 1:
The network apparatus is designed with multi-functionality to perform both time synchronization packet exchange and master clock operations using the same hardware resources. By making the apparatus universal in its capabilities, the patent avoids adding dedicated calibration hardware, thus maintaining timing accuracy through software-based deviation correction without significantly increasing device complexity.
Data Source
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AI summary
A method for exchanging a time synchronization packet is provided, including: exchanging, by a network apparatus, a clock synchronization packet with a first clock source, where the network apparatus includes a boundary clock; determining, by the network apparatus, a first time deviation of the boundary clock relative to the first clock source according to the clock synchronization packet exchanged with the first clock source, where the boundary clock avoids performing an operation of calibrating a time of a local clock of the boundary clock according to the first time deviation; and sending, by the network apparatus, a clock synchronization packet to a first slave clock of the boundary clock, where the clock synchronization packet sent by the network apparatus to the first slave clock includes a first timestamp generated by the boundary clock, a value of the first timestamp is equal to a first corrected value, and the first corrected value is a value obtained by the boundary clock by correcting the time of the local clock by using the first time deviation. In addition, another method and a network apparatus are further provided. The foregoing solutions help extend an application scenario of the network apparatus.