Pub Date : 2012-10-22DOI: 10.1109/ISPCS.2012.6336610
M. Lipinski, T. Wlostowski, J. Serrano, P. Alvarez, J. D. Gonzalez Cobas, A. Rubini, P. Moreira
This paper describes the long-term performance of White Rabbit (WR) based time and frequency transfer in the systems deployed at CERN and Gran Sasso National Laboratory. WR is a new technology based on IEEE 1588-2008 and Synchronous Ethernet which allows for sub-nanosecond accuracy and picosecond precision of synchronization in an Ethernet-based network. The first installation of WR is used in the CERN Neutrino to Gran Sasso (CNGS) project to transfer the Coordinated Universal Time (UTC) from a Global Positioning System (GPS) receiver to the underground extraction/detection points. The data collected during the system operation is used to evaluate its performance. Additionally, the performance in varying temperature conditions is verified with tests in a climatic chamber. We evaluate time transfer by measuring the offset between the time reference and the time receiver (WR Node). The stability of the transfered frequency is evaluated by analyzing the Allan Deviation (ADEV) and the Maximum Time Interval Error (MTIE).
{"title":"Performance results of the first White Rabbit installation for CNGS time transfer","authors":"M. Lipinski, T. Wlostowski, J. Serrano, P. Alvarez, J. D. Gonzalez Cobas, A. Rubini, P. Moreira","doi":"10.1109/ISPCS.2012.6336610","DOIUrl":"https://doi.org/10.1109/ISPCS.2012.6336610","url":null,"abstract":"This paper describes the long-term performance of White Rabbit (WR) based time and frequency transfer in the systems deployed at CERN and Gran Sasso National Laboratory. WR is a new technology based on IEEE 1588-2008 and Synchronous Ethernet which allows for sub-nanosecond accuracy and picosecond precision of synchronization in an Ethernet-based network. The first installation of WR is used in the CERN Neutrino to Gran Sasso (CNGS) project to transfer the Coordinated Universal Time (UTC) from a Global Positioning System (GPS) receiver to the underground extraction/detection points. The data collected during the system operation is used to evaluate its performance. Additionally, the performance in varying temperature conditions is verified with tests in a climatic chamber. We evaluate time transfer by measuring the offset between the time reference and the time receiver (WR Node). The stability of the transfered frequency is evaluated by analyzing the Allan Deviation (ADEV) and the Maximum Time Interval Error (MTIE).","PeriodicalId":153925,"journal":{"name":"2012 IEEE International Symposium on Precision Clock Synchronization for Measurement, Control and Communication Proceedings","volume":"502 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116817172","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-10-22DOI: 10.1109/ISPCS.2012.6336630
D. Ingram, P. Schaub, D. Campbell, R. Taylor
Many substation applications require accurate time-stamping. The performance of systems such as Network Time Protocol (NTP), IRIG-B and one pulse per second (1-PPS) have been sufficient to date. However, new applications, including IEC 61850-9-2 process bus and phasor measurement, require accuracy of one microsecond or better. Furthermore, process bus applications are taking time synchronisation out into high voltage switchyards where cable lengths may have an impact on timing accuracy. IEEE Std 1588, Precision Time Protocol (PTP), is the means preferred by the smart grid standardisation roadmaps (from both the IEC and US National Institute of Standards and Technology) of achieving this higher level of performance, and integrates well into Ethernet based substation automation systems. Significant benefits of PTP include automatic path length compensation, support for redundant time sources and the cabling efficiency of a shared network. This paper benchmarks the performance of established IRIG-B and 1-PPS synchronisation methods over a range of path lengths representative of a transmission substation. The performance of PTP using the same distribution system is then evaluated and compared to the existing methods to determine if the performance justifies the additional complexity. Experimental results show that a PTP timing system maintains the synchronising performance of 1-PPS and IRIG-B timing systems, when using the same fibre optic cables, and further meets the needs of process buses in large substations.
{"title":"Evaluation of Precision Time synchronisation methods for substation applications","authors":"D. Ingram, P. Schaub, D. Campbell, R. Taylor","doi":"10.1109/ISPCS.2012.6336630","DOIUrl":"https://doi.org/10.1109/ISPCS.2012.6336630","url":null,"abstract":"Many substation applications require accurate time-stamping. The performance of systems such as Network Time Protocol (NTP), IRIG-B and one pulse per second (1-PPS) have been sufficient to date. However, new applications, including IEC 61850-9-2 process bus and phasor measurement, require accuracy of one microsecond or better. Furthermore, process bus applications are taking time synchronisation out into high voltage switchyards where cable lengths may have an impact on timing accuracy. IEEE Std 1588, Precision Time Protocol (PTP), is the means preferred by the smart grid standardisation roadmaps (from both the IEC and US National Institute of Standards and Technology) of achieving this higher level of performance, and integrates well into Ethernet based substation automation systems. Significant benefits of PTP include automatic path length compensation, support for redundant time sources and the cabling efficiency of a shared network. This paper benchmarks the performance of established IRIG-B and 1-PPS synchronisation methods over a range of path lengths representative of a transmission substation. The performance of PTP using the same distribution system is then evaluated and compared to the existing methods to determine if the performance justifies the additional complexity. Experimental results show that a PTP timing system maintains the synchronising performance of 1-PPS and IRIG-B timing systems, when using the same fibre optic cables, and further meets the needs of process buses in large substations.","PeriodicalId":153925,"journal":{"name":"2012 IEEE International Symposium on Precision Clock Synchronization for Measurement, Control and Communication Proceedings","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129099514","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-10-22DOI: 10.1109/ISPCS.2012.6336634
P. Estrela, L. Bonebakker
This paper describes the challenges encountered when deploying PTPv2 on the worldwide network of a financial company, by upgrading nearly all servers in all data-centers over a period of two years, to achieve global microsecond level accuracy between any pair. Acknowledging that PTP was initially designed as a LAN protocol and that all current time-keeping industry efforts are focused on PTP, the issues can be broadly divided into a) issues on the PTPv2 standard itself, b) issues that have to be addressed when PTP is expanded to work over WANs, and c) issues that caused the biggest operational impact on the (tested) implementations. In all, this paper contributes concrete examples where PTP's byzantine robustness, scalability and efficiency characteristics range between absent to poor - and attempts to raise awareness on the steps needed to build PTP solutions with the characteristics that global users want.
{"title":"Challenges deploying PTPv2 in a global financial company","authors":"P. Estrela, L. Bonebakker","doi":"10.1109/ISPCS.2012.6336634","DOIUrl":"https://doi.org/10.1109/ISPCS.2012.6336634","url":null,"abstract":"This paper describes the challenges encountered when deploying PTPv2 on the worldwide network of a financial company, by upgrading nearly all servers in all data-centers over a period of two years, to achieve global microsecond level accuracy between any pair. Acknowledging that PTP was initially designed as a LAN protocol and that all current time-keeping industry efforts are focused on PTP, the issues can be broadly divided into a) issues on the PTPv2 standard itself, b) issues that have to be addressed when PTP is expanded to work over WANs, and c) issues that caused the biggest operational impact on the (tested) implementations. In all, this paper contributes concrete examples where PTP's byzantine robustness, scalability and efficiency characteristics range between absent to poor - and attempts to raise awareness on the steps needed to build PTP solutions with the characteristics that global users want.","PeriodicalId":153925,"journal":{"name":"2012 IEEE International Symposium on Precision Clock Synchronization for Measurement, Control and Communication Proceedings","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130031540","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-10-22DOI: 10.1109/ISPCS.2012.6336616
J. Mackay, R. Henry
A novel approach to bridging between an existing NTP time service and PTP has been devised. This bridge allows systems to add the PTP time service with sufficient accuracy and without degradation of the NTP service.
{"title":"A novel approach to the adaptation of PTP to an NTP network","authors":"J. Mackay, R. Henry","doi":"10.1109/ISPCS.2012.6336616","DOIUrl":"https://doi.org/10.1109/ISPCS.2012.6336616","url":null,"abstract":"A novel approach to bridging between an existing NTP time service and PTP has been devised. This bridge allows systems to add the PTP time service with sufficient accuracy and without degradation of the NTP service.","PeriodicalId":153925,"journal":{"name":"2012 IEEE International Symposium on Precision Clock Synchronization for Measurement, Control and Communication Proceedings","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127810228","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-10-22DOI: 10.1109/ISPCS.2012.6336621
Tal Mizrahi
Running clock synchronization protocols over packet based networks introduces a considerable challenge, since clock accuracy is highly sensitive to the network latency behavior. As packet based networks are becoming the common transport for most applications requiring clock synchronization, accuracy requirements are becoming increasingly stringent. In this paper we introduce a novel approach that uses multiple communication paths between the master and slave clocks to improve the clock accuracy without increasing the total rate of protocol messages. We show that the multi-path approach can also be used to reduce the time error caused by asymmetric communication paths. We present simulation results that demonstrate the effectiveness of our approach.
{"title":"Slave diversity: Using multiple paths to improve the accuracy of clock synchronization protocols","authors":"Tal Mizrahi","doi":"10.1109/ISPCS.2012.6336621","DOIUrl":"https://doi.org/10.1109/ISPCS.2012.6336621","url":null,"abstract":"Running clock synchronization protocols over packet based networks introduces a considerable challenge, since clock accuracy is highly sensitive to the network latency behavior. As packet based networks are becoming the common transport for most applications requiring clock synchronization, accuracy requirements are becoming increasingly stringent. In this paper we introduce a novel approach that uses multiple communication paths between the master and slave clocks to improve the clock accuracy without increasing the total rate of protocol messages. We show that the multi-path approach can also be used to reduce the time error caused by asymmetric communication paths. We present simulation results that demonstrate the effectiveness of our approach.","PeriodicalId":153925,"journal":{"name":"2012 IEEE International Symposium on Precision Clock Synchronization for Measurement, Control and Communication Proceedings","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115468025","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-10-22DOI: 10.1109/ISPCS.2012.6336617
A. Mahmood, F. Ring
The current goal for real-time communication infrastructure in factory automation is to merge and balance the best of both worlds, i. e. the reliability of wired networks, and the flexibility of wireless technologies. Hybrid wired-wireless networks are proposed for establishing real-time communication infrastructures in factory automation. However, the provisioning of synchronized clocks is often taken for granted, and issues regarding the integration of wired and wireless synchronization are neglected. In this study, the requirements for providing clock synchronization for such networks are investigated for an IEEE 802.11 WLAN-based hybrid network with IEEE 1588 as the desired synchronization protocol. The paper also presents simulation and implementation results to assess the synchronization performance of WLAN-based hybrid networks.
{"title":"Clock synchronization for IEEE 802.11 based wired-wireless hybrid networks using PTP","authors":"A. Mahmood, F. Ring","doi":"10.1109/ISPCS.2012.6336617","DOIUrl":"https://doi.org/10.1109/ISPCS.2012.6336617","url":null,"abstract":"The current goal for real-time communication infrastructure in factory automation is to merge and balance the best of both worlds, i. e. the reliability of wired networks, and the flexibility of wireless technologies. Hybrid wired-wireless networks are proposed for establishing real-time communication infrastructures in factory automation. However, the provisioning of synchronized clocks is often taken for granted, and issues regarding the integration of wired and wireless synchronization are neglected. In this study, the requirements for providing clock synchronization for such networks are investigated for an IEEE 802.11 WLAN-based hybrid network with IEEE 1588 as the desired synchronization protocol. The paper also presents simulation and implementation results to assess the synchronization performance of WLAN-based hybrid networks.","PeriodicalId":153925,"journal":{"name":"2012 IEEE International Symposium on Precision Clock Synchronization for Measurement, Control and Communication Proceedings","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130246850","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-10-22DOI: 10.1109/ISPCS.2012.6336614
D. Mendel, H. Schmit, D. Vijayaraghavan
1588 timestamping assumes a well-defined instant at which the beginning of a packet crosses the reference plane between the precision time protocol (PTP) node and the network. However, this definition is not clear in the case of a multi-lane serial bus such as 40GE/100GE. Furthermore, there is an implied time-ordering between the lanes of a serial bus that is not captured in the existing definition. This paper explores issues with multi-lane serial buses as it relates to time-stamping and proposes revised definitions for packet arrival time in the case of a serial bus.
{"title":"Packet arrival time in 1588 for 40GE/100GE","authors":"D. Mendel, H. Schmit, D. Vijayaraghavan","doi":"10.1109/ISPCS.2012.6336614","DOIUrl":"https://doi.org/10.1109/ISPCS.2012.6336614","url":null,"abstract":"1588 timestamping assumes a well-defined instant at which the beginning of a packet crosses the reference plane between the precision time protocol (PTP) node and the network. However, this definition is not clear in the case of a multi-lane serial bus such as 40GE/100GE. Furthermore, there is an implied time-ordering between the lanes of a serial bus that is not captured in the existing definition. This paper explores issues with multi-lane serial buses as it relates to time-stamping and proposes revised definitions for packet arrival time in the case of a serial bus.","PeriodicalId":153925,"journal":{"name":"2012 IEEE International Symposium on Precision Clock Synchronization for Measurement, Control and Communication Proceedings","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128696019","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-10-22DOI: 10.1109/ISPCS.2012.6336612
Tal Mizrahi
Time synchronization protocols have become very common in packet networks, and are consequently exposed to various security attacks. One of the most effective attacks against synchronization protocols is the delay attack, in which a man-in-the-middle attacker selectively delays the time protocol packets. This attack is exceptionally effective, as it cannot be prevented by conventional security measures such as authentication or encryption. In this paper we introduce a new approach to analyzing the delay attack, using a game theoretic model. We analyze the possible strategies of the attacker and attackee, and introduce a novel strategy for mitigating delay attacks using multiple paths between the master and slave clocks. We also discuss the Nash equilibria in our model and their connection to the possible outcomes of real-life attacks.
{"title":"A game theoretic analysis of delay attacks against time synchronization protocols","authors":"Tal Mizrahi","doi":"10.1109/ISPCS.2012.6336612","DOIUrl":"https://doi.org/10.1109/ISPCS.2012.6336612","url":null,"abstract":"Time synchronization protocols have become very common in packet networks, and are consequently exposed to various security attacks. One of the most effective attacks against synchronization protocols is the delay attack, in which a man-in-the-middle attacker selectively delays the time protocol packets. This attack is exceptionally effective, as it cannot be prevented by conventional security measures such as authentication or encryption. In this paper we introduce a new approach to analyzing the delay attack, using a game theoretic model. We analyze the possible strategies of the attacker and attackee, and introduce a novel strategy for mitigating delay attacks using multiple paths between the master and slave clocks. We also discuss the Nash equilibria in our model and their connection to the possible outcomes of real-life attacks.","PeriodicalId":153925,"journal":{"name":"2012 IEEE International Symposium on Precision Clock Synchronization for Measurement, Control and Communication Proceedings","volume":"4 75 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129841832","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-10-22DOI: 10.1109/ISPCS.2012.6336631
H. Kirrmann, C. Honegger, D. Ilie, I. Sotiropoulos
Seamless redundancy and precise clock synchronization are integrated fully in hardware (FPGA) with no processor support. The interaction between redundancy and clock synchronization is explained. Redundant synchronization messages are not be discarded, but used to improve clock accuracy. Measurement results confirm the validity of the concept. Performance of the full-hardware implementation is compared with that of a conventional software-hardware implementation.
{"title":"Performance of a full-hardware PTP implementation for an IEC 62439-3 redundant IEC 61850 substation automation network","authors":"H. Kirrmann, C. Honegger, D. Ilie, I. Sotiropoulos","doi":"10.1109/ISPCS.2012.6336631","DOIUrl":"https://doi.org/10.1109/ISPCS.2012.6336631","url":null,"abstract":"Seamless redundancy and precise clock synchronization are integrated fully in hardware (FPGA) with no processor support. The interaction between redundancy and clock synchronization is explained. Redundant synchronization messages are not be discarded, but used to improve clock accuracy. Measurement results confirm the validity of the concept. Performance of the full-hardware implementation is compared with that of a conventional software-hardware implementation.","PeriodicalId":153925,"journal":{"name":"2012 IEEE International Symposium on Precision Clock Synchronization for Measurement, Control and Communication Proceedings","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133450216","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2012-10-22DOI: 10.1109/ISPCS.2012.6336613
F. Núñez, Yongqiang Wang, Sachi Desai, George Cakiades, F. Doyle
Detection of events using a network of simple field sensors has gained interest due to its low cost and robustness. Sensor networks have been extensively analyzed recently in terms of stability, robustness, and efficiency. Time synchronization has proven to be critical in sensor fusion applications where time of arrival is a decision property, and thus an accurate common time reference is required. In this work, we analyze the dependence on time synchronization of an acoustic event detection system, and we present a bio-inspired synchronization algorithm for wireless sensor networks capable of providing the system with a common time reference to enable accurate detection.
{"title":"Bio-inspired synchronization of wireless sensor networks for acoustic event detection systems","authors":"F. Núñez, Yongqiang Wang, Sachi Desai, George Cakiades, F. Doyle","doi":"10.1109/ISPCS.2012.6336613","DOIUrl":"https://doi.org/10.1109/ISPCS.2012.6336613","url":null,"abstract":"Detection of events using a network of simple field sensors has gained interest due to its low cost and robustness. Sensor networks have been extensively analyzed recently in terms of stability, robustness, and efficiency. Time synchronization has proven to be critical in sensor fusion applications where time of arrival is a decision property, and thus an accurate common time reference is required. In this work, we analyze the dependence on time synchronization of an acoustic event detection system, and we present a bio-inspired synchronization algorithm for wireless sensor networks capable of providing the system with a common time reference to enable accurate detection.","PeriodicalId":153925,"journal":{"name":"2012 IEEE International Symposium on Precision Clock Synchronization for Measurement, Control and Communication Proceedings","volume":"53 4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2012-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128778153","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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