Delay Measurement via Code Block in Industrial Ethernet
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Solution Overview
Problem
Time-slotting in virtual interleaving sublayer technology introduces one-way delay uncertainty due to the random relationship between service arrival moments and transmission timeslots, leading to asymmetric uplink and downlink delays, which disrupts time synchronization in industrial Ethernet networks.
Innovation Solution
A method and apparatus for determining and compensating for delay values by measuring the time difference between the insertion and detection of a measurement code block in a service flow, allowing for the calculation of uplink and downlink delays and their compensation to ensure symmetric time synchronization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If time-slotting is used in virtual interleaving sublayer technology, then the channel can transmit low-speed industrial Ethernet service, but one-way delay uncertainty is introduced due to random relationship between service arrival moments and transmission timeslot moments
Solution Approach 1:
A measurement code block is introduced as an intermediary element to track and measure delay. This code block is inserted into the service flow at a known moment and detected at the receiving end, providing a reference for calculating actual delay values despite the random time-slotting nature of the transmission medium.
Solution Approach 2:
The delay measurement mechanism provides feedback about actual transmission delays by detecting measurement code blocks and calculating time differences. This feedback enables the system to determine and compensate for asymmetric delays between uplink and downlink directions, improving synchronization accuracy.
2Adaptability or versatility
If service is mapped to timeslot at VIS, then time-division multiplexing is achieved, but delay uncertainty is introduced in both service mapping and egress buffering
Solution Approach 1:
The measurement code block serves as a mediator that traverses through the service mapping and egress buffering processes. By tracking this code block from insertion to detection, the system can measure the actual time loss introduced by these intermediate processes, enabling accurate delay compensation despite the nondeterministic nature of time-slotting.
3Length of stationary object
If cascaded devices are increased to extend network coverage, then network reachability is improved, but nondeterministic delays accumulate and communication efficiency is reduced
Solution Approach 1:
The measurement code block mechanism provides feedback on cumulative delays across cascaded devices. By detecting the measurement code block at each stage and calculating time differences, the system can identify and compensate for accumulated nondeterministic delays, maintaining communication efficiency even as network coverage extends through multiple cascaded devices.
Data Source
AI summary
This application provides an example delay measurement method and an example network device. The method includes receiving, by a first network device, a first service flow. The method also includes determining, by the first network device, a first delay value based on a first measurement code block in the first service flow. The first delay value is a time difference between a first moment at which the first measurement code block is detected in the first network device and a second moment at which the first measurement code block is detected in the first network device.