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An Improved Network Time Protocol for Industrial Internet of Things †
In the industrial Internet of Things, the network time protocol (NTP) can be used for time synchronization, allowing machines to run in sync so that machines can take critical actions within 1 ms. However, the commonly used NTP mechanism does not take into account that the network packet travel time...
Autores principales: | , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
MDPI
2022
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9269827/ https://www.ncbi.nlm.nih.gov/pubmed/35808516 http://dx.doi.org/10.3390/s22135021 |
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author | Hou, Ting-Chao Liu, Lin-Hung Lan, Yan-Kai Chen, Yi-Ting Chu, Yuan-Sun |
author_facet | Hou, Ting-Chao Liu, Lin-Hung Lan, Yan-Kai Chen, Yi-Ting Chu, Yuan-Sun |
author_sort | Hou, Ting-Chao |
collection | PubMed |
description | In the industrial Internet of Things, the network time protocol (NTP) can be used for time synchronization, allowing machines to run in sync so that machines can take critical actions within 1 ms. However, the commonly used NTP mechanism does not take into account that the network packet travel time over a link is time-varying, which causes the NTP to make incorrect synchronization decisions. Therefore, this paper proposed a low-cost modification to NTP with clock skew compensation and adaptive clock adjustment, so that the clock difference between the NTP client and NTP server can be controlled within 1 ms in the wired network environment. The adaptive clock adjustment skips the clock offset calculation when the NTP packet run trip time (RTT) exceeds a certain threshold. The clock skew compensation addresses the inherent issue that different clocks (or oscillators) naturally drift away from each other. Both adaptive clock adjustment and clock skew compensation are environment dependent and device dependent. The measurement result in our experimental environment shows that the when the RTT threshold is set at 1.7 ms, the best synchronization accuracy is achieved. |
format | Online Article Text |
id | pubmed-9269827 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2022 |
publisher | MDPI |
record_format | MEDLINE/PubMed |
spelling | pubmed-92698272022-07-09 An Improved Network Time Protocol for Industrial Internet of Things † Hou, Ting-Chao Liu, Lin-Hung Lan, Yan-Kai Chen, Yi-Ting Chu, Yuan-Sun Sensors (Basel) Article In the industrial Internet of Things, the network time protocol (NTP) can be used for time synchronization, allowing machines to run in sync so that machines can take critical actions within 1 ms. However, the commonly used NTP mechanism does not take into account that the network packet travel time over a link is time-varying, which causes the NTP to make incorrect synchronization decisions. Therefore, this paper proposed a low-cost modification to NTP with clock skew compensation and adaptive clock adjustment, so that the clock difference between the NTP client and NTP server can be controlled within 1 ms in the wired network environment. The adaptive clock adjustment skips the clock offset calculation when the NTP packet run trip time (RTT) exceeds a certain threshold. The clock skew compensation addresses the inherent issue that different clocks (or oscillators) naturally drift away from each other. Both adaptive clock adjustment and clock skew compensation are environment dependent and device dependent. The measurement result in our experimental environment shows that the when the RTT threshold is set at 1.7 ms, the best synchronization accuracy is achieved. MDPI 2022-07-03 /pmc/articles/PMC9269827/ /pubmed/35808516 http://dx.doi.org/10.3390/s22135021 Text en © 2022 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/). |
spellingShingle | Article Hou, Ting-Chao Liu, Lin-Hung Lan, Yan-Kai Chen, Yi-Ting Chu, Yuan-Sun An Improved Network Time Protocol for Industrial Internet of Things † |
title | An Improved Network Time Protocol for Industrial Internet of Things † |
title_full | An Improved Network Time Protocol for Industrial Internet of Things † |
title_fullStr | An Improved Network Time Protocol for Industrial Internet of Things † |
title_full_unstemmed | An Improved Network Time Protocol for Industrial Internet of Things † |
title_short | An Improved Network Time Protocol for Industrial Internet of Things † |
title_sort | improved network time protocol for industrial internet of things † |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9269827/ https://www.ncbi.nlm.nih.gov/pubmed/35808516 http://dx.doi.org/10.3390/s22135021 |
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