Asymmetric Delay Measurement via Synchronous Ethernet Timestamps
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Solution Overview
Problem
Current methods for measuring asymmetric delay in optical fiber transmission links lack precision and require manual, complex processes, especially with the 1588 protocol, leading to low accuracy and increased project startup difficulties.
Innovation Solution
Implementing clock synchronization between master and slave terminals via synchronous Ethernet, recording timestamps during message transmission, and performing optical fiber switchover using internal switches to calculate asymmetric delay with nanosecond-level accuracy, eliminating the need for external instruments and manual fiber handling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If manual optical fiber switching and external instrument measurement are used, then the measurement process can be performed, but the measurement precision is low and the operation complexity increases
Solution Approach 1:
The terminal devices perform self-measurement of asymmetric delay using their own internal clocks and timestamping capabilities. The slave terminal calculates the asymmetric delay based on timestamps exchanged with the master terminal, eliminating the need for external measurement instruments and manual fiber switching operations.
Solution Approach 2:
The patent replaces manual mechanical fiber switching with automated electronic control. The system uses electronic timestamp recording and calculation to substitute for manual measurement procedures, achieving both higher precision and automated operation.
2Ease of manufacture
If manual optical fiber switching is performed, then the measurement can be conducted, but the device deployment complexity increases and convenience decreases
Solution Approach 1:
The terminal devices automatically perform the measurement function using their own resources (internal clocks, processors, and communication interfaces). This self-service capability eliminates the need for external instruments and manual intervention, simplifying device deployment while maintaining measurement functionality.
3Productivity
If external instruments are used for measurement, then the measurement can be performed, but the project startup process becomes inconvenient and complex
Solution Approach 1:
The terminal devices are equipped with built-in timestamp recording and calculation functions that enable them to perform asymmetric delay measurements independently. This eliminates the need for external measurement instruments and manual fiber switching, significantly improving project startup efficiency and operational convenience.
Solution Approach 2:
The terminal devices perform multiple functions including normal communication operations and asymmetric delay measurement using the same hardware resources (clocks, processors, communication interfaces). This multi-functionality eliminates the need for separate measurement instruments, streamlining project deployment.
Data Source
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AI summary
The disclosure discloses a method, terminal and system for measuring an asymmetric delay of a transmission link. The method includes: a slave terminal receives a first message including a first timestamp from a master terminal, and records a second timestamp of receiving the first message; the slave terminal performs switchover with the master terminal by exchanging messages with the master terminal; the slave terminal receives a second message including a third timestamp from the master terminal, and record a fourth timestamp of receiving the second message; and the slave terminal calculates an asymmetric delay of a transmission link according to the first timestamp, the second timestamp, the third timestamp, and the fourth timestamp. With the disclosure, clocks of a master terminal and a slave terminal are synchronized via a synchronous Ethernet, a timestamp of sending or receiving a message by the master terminal or the slave terminal is recorded, switchover between optical fibers on a link is performed by switching a switch, and after switchover, a message is sent again and timestamps of the message at the master terminal and the slave terminal are recorded. According to the four timestamps acquired two by two, the slave terminal can calculate an asymmetric delay of the transmission link quickly, with an accuracy up to a nanosecond level. Meanwhile, a measuring process is simplified.