IEEE 1588 Intermediate Clock Reliability Notification
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Solution Overview
Problem
In telecommunications networks employing the IEEE 1588 standard, intermediate clocks introduce errors in timing information as they synchronize with the grandmaster clock, leading to inaccuracies in timing signals transmitted to end applications, which are not accounted for by existing protocols.
Innovation Solution
Intermediate clocks notify downstream clocks of the reliability of timing information by combining their own reliability indication with that of the grandmaster clock, using a method that adjusts Announce messages to reflect cumulative reliability, thereby ensuring accurate timing information propagation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If intermediate clocks are introduced to distribute timing information throughout the network, then the coverage and reach of timing distribution is improved, but the accuracy and reliability of timing information deteriorates due to error accumulation
Solution Approach 1:
The patent implements a feedback mechanism where intermediate clocks report their synchronization quality metrics (such as time offset variance and synchronization stability) back to the grandmaster clock. The grandmaster clock uses this feedback to dynamically adjust weighting factors when calculating composite timing information, thereby compensating for errors introduced by intermediate clocks and maintaining overall timing accuracy across the network.
Solution Approach 2:
The patent changes the parameter of timing information representation from simple timestamp values to composite parameters that include quality metrics and reliability indicators. Intermediate clocks attach their synchronization quality parameters to the timing information they forward, allowing downstream clocks to weight and combine multiple timing sources based on their relative reliability, thus maintaining accuracy even when multiple intermediate clocks are involved.
2Volume of moving object
If multiple intermediate clocks are used to extend timing distribution, then the network reach is improved, but the complexity of error management increases
Solution Approach 1:
The patent introduces quality metric parameters as intermediaries between the physical timing signals and the logical synchronization decision-making process. These parameters act as mediators that automatically encode the reliability information, allowing clocks to make informed decisions about which timing sources to trust without requiring complex manual configuration or intervention. The quality metrics serve as a standardized interface that simplifies error management across diverse intermediate clocks.
Solution Approach 2:
The patent segments the timing distribution function into independent modular units, where each intermediate clock operates autonomously with its own synchronization algorithm and quality assessment capabilities. This segmentation allows each clock to independently manage its local error characteristics and report them through standardized quality parameters, reducing the overall system complexity by avoiding centralized error management while still achieving coordinated synchronization across the entire network.
3Ease of operation
If intermediate clocks forward timing information without modification, then the simplicity of operation is improved, but the loss of timing accuracy occurs due to unsynchronized local clocks
Solution Approach 1:
The patent applies preliminary action by having intermediate clocks perform local synchronization with their upstream parent clock before forwarding timing information downstream. Each intermediate clock first synchronizes its local oscillator to match its parent clock's timing characteristics, then uses this synchronized state as the basis for generating and forwarding timing messages. This preliminary synchronization ensures that even though the clock is physically located at an intermediate position, its timing information remains accurate relative to the grandmaster clock.
Solution Approach 2:
The patent replaces the mechanical assumption that physical proximity to the grandmaster clock determines timing accuracy with an electronic/software-based quality metric system. Instead of relying on the physical architecture to guarantee accuracy, the system uses computational quality parameters that are calculated and attached to timing messages, allowing the network to dynamically identify and compensate for synchronization quality issues regardless of physical topology.
Data Source
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AI summary
A method and system are provided for conveying reliability of timing information to a clock in a telecommunication network using IEEE 1588. An intermediate clock, either a boundary clock or a transparent clock, may have to adjust its local clock to match that of a grandmaster clock. If such adjustment is frequent or large, then the intermediate clock may not have much confidence in the reliability of the timing information it passes to a downstream clock in an IEEE 1588 Announce message even if the quality of its local clock is high. The intermediate clock determines a measure of the reliability of its timing information. In addition to the normal clock quality and stability included in a transmitted IEEE 88 Announce message, the intermediate clock also inserts an indication of the reliability of the timing information. The intermediate clock may consider an indication of reliability found in an Announce message it receives when inserting 1 an indication of the reliability of timing information into an Announce message which it transmits.