Precision Time Protocol

About: Precision Time Protocol is a research topic. Over the lifetime, 604 publications have been published within this topic receiving 6006 citations. The topic is also known as: PTP & IEEE 1588.

Experimental Assessment of a PTP-based System for Large Scale Time Synchronization of Smart Grids

Abstract: Accurate and stable time synchronization is crucial for the reliable operation of monitoring, protection and control systems in smart grids. As an alternative to GPS-based time synchronization of Phasor Measurement Units over a wide area network, this paper investigates the performance of Precision Time Protocol (PTP). After introducing time synchronization requirements in power systems and exploring the main vulnerabilities, experimental results related to a test PTP architecture are presented, in order to assess its feasibility.

Research on Multi-axis Synchronous Control in Network CNC System

Abstract: This paper investigated the multi-axis synchronous control in a typical CNC system. The necessity of utilizing field bus is identified. In addition, the effect of jitter and skew on CNC system is analysed. A novel set-up scheme for network CNC system and corresponding EtherCNC protocol are proposed. The network topology and frame structure and the principle are introduced in detail. The hardware precision time protocol realization method is proposed. The effect of jitter on position precision controlling was validated with the experimental characterization of the proposed scheme.

Experimental verification of the egress and ingress latency correction in PTP clocks

Abstract: Precise time synchronization using the Precision Time Protocol (PTP, IEEE 1588-2008) is based on time-stamping of data packets on egress and ingress. The accuracy of the time-stamps is highly affected by the ingress and egress latencies of the PTP node. For an accurate synchronization it is therefore crucial to know the characteristics of these latencies. In our paper we present a measurement setup that enables the direct measurement of both the ingress and egress latencies of a PTP clock. In contrast to our earlier work, the principle utilizes standard PTP peer delay mechanism messages. It can therefore be applied to any PTP clock that supports the peer delay mechanism. It can thus verify whether the egress and ingress latencies of commercially available devices are correctly compensated. In our contribution we give a detailed description of the measurement setup. We demonstrate the feasibility of the system by presenting results for several devices with different time-stamping hardware.

NetFPGA based IEEE 1588 module for time-synchronized software-defined networking

Abstract: Software Defined Networking (SDN) is an emerging technology to enhance flexible control on networks through abstraction of lower-level switch functionality. Recently using SDN to construct mobile backhaul networks has attracted a lot of attention. Although IEEE has defined IEEE 1588 Precision Time Protocol (PTP) for providing accurate time synchronization in Ethernet networks, how to distribute accurate time in SDN to facilitate synchronization among wireless base stations is still not clear. In this paper, we present an implementation of a NetFPGA based PTP module to support time-synchronized SDN. The PTP module can be embedded inside an SDN switch or can be placed as an external add-on module to an SDN switch. Both solutions can turn a PTP unaware switch into PTP aware. In our system, an SDN controller can configure the PTP module to determine the routing paths for clock distribution. We have developed a frequency compensation circuit to increase the accuracy. In addition, a moving average technique is applied to stabilize the clock output. Experimental results show that our NetFPGA based SDN switch can provide accurate clock distribution with maximum 50 nsec deviation along a three-hop path over 1 hour measurement. The performance of the proposed PTP switch can meet the microsecond-level requirement for time synchronization in cellular wireless networks.

Measurement Tools for Substation Equipment: Testing the Interoperability of Protocols for Time Transfer and Communication

Abstract: A test harness was designed and developed at the National Institute of Standards and Technology (NIST) to study the interoperability of the Precision Time Protocol (PTP) Power Profile and other communication standards for substation automation. Particular focus of the harness is on protocols that purport to comply to standards established by the Institute of Electronics and Electrical Engineering (IEEE) and the International Electrotechnical Commission (IEC). The test harness is intended for field evaluation of substation equipment and includes 3-phase electrical waveform generation capabilities, timing reference signal sources, measurement hardware for network clocks and software for monitoring and analyzing communication and time transfer protocols.The test harness was demonstrated at a Universal Communications Architecture International Users Group (UCAIug) Interoperability Plugfest (IOP) in 2017 where over 200 participants gathered to evaluate the interoperability between their products and tools.