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.

Emerging solutions for time protocol security

Abstract: Security has historically not been a top consideration for the developers of time synchronization protocols. However, in recent years rising awareness of the overall importance of security in general along with increasing examples of targeted vulnerability analysis and incidents exploiting the underlying weaknesses of existing solutions has increased the demand for standards based security mechanisms for network time synchronization protocols. This paper provides an overview of the general approach and discusses some key components being standardized as part of both the IEEE 1588 Precision Time Protocol (PTP) and the IETF Network Time Security (NTS) efforts. It also discusses the underlying motivation and requirements driving these efforts and identifies some next steps and possible avenues of further investigation.

Time-complemented event-driven control framework for distributed motion control systems based on IEC 61499 and IEEE 1588

Abstract: This paper presents a preliminary study towards the applications of IEC 61499 Function Block standard in distributed motion control systems, where synchronization is of crucial importance. In particular, an investigation on the possibilities of applying event-driven function blocks in the time-based motion control system has been performed on the SIDEL SL90 packaging machine's control system. To achieve the required high-precision time synchronization and to provide the reference time, the IEEE 1588 Precision Time Protocol has been implemented in this work as the essential part of the packaging control system. A time-complemented event-based control framework has also been proposed.

Method and system for improving PTP time synchronization precision

Abstract: The invention provides a method and a system for improving PTP (Precision Time Protocol) time synchronization precision. The method comprises the following steps: sealing a timestamp on each transmitted or received PTP message on the connection part of the connection medium access control layer and the physical layer; obtaining the adjusted PTP count time through adjusting the time shift and the time deviation; judging whether the PTP count time is between -1/2f and +1/2f of whole second while the PTP message is triggered at second pulse, and transmitting the second pulse while the PTP count time is between -1/2f and +1/2f of the whole second. The invention judges whether transmitting the PTP clock output signal through turning a PTP counter in seconds when nanosecond is between the allowed precision range, so the synchronization precision is improved for double than the PTP count resolution ratio, and the nanosecond synchronization precision is realized from the connection between the main node and secondary node enabled by PTP.

A synchronous Gigabit Ethernet protocol stack for high-throughput UDP/IP applications

Abstract: State of the art detector readout electronics require high-throughput data acquisition (DAQ) systems. In many applications, e. g. for medical imaging, the front-end electronics are set up as separate modules in a distributed DAQ. A standardized interface between the modules and a central data unit is essential. The requirements on such an interface are varied, but demand almost always a high throughput of data. Beyond this challenge, a Gigabit Ethernet interface is predestined for the broad requirements of Systems-on-a-Chip (SoC) up to large-scale DAQ systems. We have implemented an embedded protocol stack for a Field Programmable Gate Array (FPGA) capable of high-throughput data transmission and clock synchronization. A versatile stack architecture for the User Datagram Protocol (UDP) and Internet Control Message Protocol (ICMP) over Internet Protocol (IP) such as Address Resolution Protocol (ARP) as well as Precision Time Protocol (PTP) is presented. With a point-to-point connection to a host in a MicroTCA system we achieved the theoretical maximum data throughput limited by UDP both for 1000BASE-T and 1000BASE-KX links. Furthermore, we show that the random jitter of a synchronous clock over a 1000BASE-T link for a PTP application is below 60 ps.

Application of IEEE1588 time synchronization protocol in digital substation

Abstract: According to the time synchronization requirements of IEC61850 at different levels of digital substation,three synchronization modes are compared:hard-wired,SNTP(Simple Network Time Protocol) and IEEE1588 PTP(Precision Time Protocol).The clock types of IEEE1588 and their relationships are introduced and the principle of IEEE1588 PTP synchronization is analyzed in detail.The feasibility of IEEE1588 PTP synchronization with current hardware supporting conditions of digital substation is described.Two schemes of IEEE1588 PTP application in IEC61850-based substation for future substation automation systems are proposed:one for single substation and the other for multiple substations.In the proposed schemes,the redundant configuration of grandmaster clock using Beidou navigation satellite system,GPS(Global Positioning System) and atomic clock is discussed.