A packet filtering mechanism with a packet delay distribution estimation function for IEEE 1588 time synchronization in a congested network

2011 ◽  
Author(s):  
Takahide Murakami ◽  
Yukio Horiuchi ◽  
Kosuke Nishimura
Keyword(s):  
Time Synchronization ◽  
Packet Delay ◽  
Packet Filtering ◽  
Ieee 1588 ◽  
Delay Distribution ◽  
Distribution Estimation ◽  
Estimation Function

The Design of an IEEE 1588 End-to-End Transparent Ethernet Switch

2021 ◽  
Author(s):  
◽  
Caleb Gordon
Keyword(s):  
Packet Delay ◽  
Time Interval ◽  
Path Delay ◽  
Negative Effects ◽  
Ieee 1588 ◽  
Precision Time ◽  
End To End ◽  
And Control ◽  
Measurement And Control ◽  
Ethernet Switch

<p>In measurement and control systems there is often a need to synchronise distributed clocks. Traditionally, synchronisation has been achieved using a dedicated medium to convey time information, typically using the IRIG-B serial protocol. The precision time protocol (IEEE 1588) has been designed as an improvement to current methods of synchronisation within a distributed network of devices. IEEE 1588 is a message based protocol that can be implemented across packet based networks including, but not limited to, Ethernet. Standard Ethernet switches introduce a variable delay to packets that inhibits path delay measurements. Transparent switches have been introduced to measure and adjust for packet delay, thus removing the negative effects that these variations cause.  This thesis describes the hardware and firmware design of an IEEE 1588 transparent end-to-end Ethernet switch for Tekron International Ltd based in Lower Hutt, New Zealand. This switch has the ability to monitor all Ethernet traffic, identify IEEE 1588 timing packets, measure the delay that these packets experience while passing through the switch, and account for this delay by adjusting a time-interval field of the packet as it is leaving the switch. This process takes place at the operational speed of the port, and without introducing significant delay. Time-interval measurements can be made using a high-precision timestamp unit with a resolution of 1 ns. The total jitter introduced by this measurement process is just 4.5 ns through a single switch.</p>

IEEE 1588 based time synchronization system for a seafloor observatory network

2013 ◽  
Vol 14 (10) ◽  
pp. 766-776 ◽  
Author(s):  
De-jun Li ◽  
Gang Wang ◽  
Can-jun Yang ◽  
Bo Jin ◽  
Yan-hu Chen
Keyword(s):  
Time Synchronization ◽  
Synchronization System ◽  
Ieee 1588 ◽  
Seafloor Observatory ◽  
Seafloor Observatory Network

Design and Implementation of IEEE 1588 High Precision Clock Synchronization Based on GPS Time Service

2012 ◽  
Vol 532-533 ◽  
pp. 292-296 ◽  
Author(s):  
Kang Wang ◽  
Yong Hui Hu ◽  
Zai Min He ◽  
Hong Jiao Ma
Keyword(s):  
High Precision ◽  
Time Synchronization ◽  
Clock Synchronization ◽  
Time Service ◽  
Ieee 1588 ◽  
Design And Implementation ◽  
Nanosecond Range ◽  
Application Fields ◽  
Timing Requirement ◽  
Precision Clock

In view of PTP high precise timing requirement for many application fields, GPS time service is provided with the advantages of high precision and high stabilization. The principle and timescale of PTP based on GPS are analyzed and discussed. And then a PTP time synchronization platform with GPS-based UTC time is designed and implemented, the correlative key design flowchart is described as well. Finally, the paper gives the experiment results, which show the time synchronization accuracies can reach nanosecond range.

On the Packet Delay Distribution in Power-Law Networks

2009 ◽  
Author(s):  
Takahiro Hirayama ◽  
Shin'ichi Arakawa ◽  
Ken-ichi Arai ◽  
Masayuki Murata
Keyword(s):  
Power Law ◽  
Packet Delay ◽  
Delay Distribution

scholarly journals CoSiWiNeT: A Clock Synchronization Algorithm for Wide Area IIoT Network

2021 ◽  
Vol 11 (24) ◽  
pp. 11985
Author(s):  
Rahul Nandkumar Gore ◽  
Elena Lisova ◽  
Johan Åkerberg ◽  
Mats Björkman
Keyword(s):  
Failure Modes ◽  
Time Synchronization ◽  
Clock Synchronization ◽  
Packet Delay ◽  
Wide Area ◽  
Monitoring And Control ◽  
Performance Measurements ◽  
Public And Private ◽  
Hardware Failure ◽  
Delay Variations

Recent advances in the industrial internet of things (IIoT) and cyber–physical systems drive Industry 4.0 and have led to remote monitoring and control applications that require factories to be connected to remote sites over wide area networks (WAN). The adequate performance of remote applications depends on the use of a clock synchronization scheme. Packet delay variations adversely impact the clock synchronization performance. This impact is significant in WAN as it comprises wired and wireless segments belonging to public and private networks, and such heterogeneity results in inconsistent delays. Highly accurate, hardware–based time synchronization solutions, global positioning system (GPS), and precision time protocol (PTP) are not preferred in WAN due to cost, environmental effects, hardware failure modes, and reliability issues. As a software–based network time protocol (NTP) overcomes these challenges but lacks accuracy, the authors propose a software–based clock synchronization method, called CoSiWiNeT, based on the random sample consensus (RANSAC) algorithm that uses an iterative technique to estimate a correct offset from observed noisy data. To evaluate the algorithm’s performance, measurements captured in a WAN deployed within two cities were used in the simulation. The results show that the performance of the new algorithm matches well with NTP and state–of–the–art methods in good network conditions; however, it outperforms them in degrading network scenarios.

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