Topic
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.
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TL;DR: From the results, it is found that the system clock of an embedded system and desktop computers all accord with the demand of the PTPd, and the P TPd can be used as a software time measurement tool in the submicrosecond range.
Abstract: The precision time synchronization protocol daemon (PTPd) is a software package that realizes a PTP. In this paper, a traceable PTPd measurement system is examined. The key component of the proposed time measurement system is the PTPd. It runs in a Linux kernel-based network. The PTPd operation mode is free running. A stable clock (i.e., an embedded system oscillator in our experiments) plays the role of a master clock. Measured clocks (i.e., desktop system time in our experiments) play the roles of slave clocks. From our results, we find that the system clock of an embedded system and desktop computers all accord with the demand of the PTPd, and the PTPd can be used as a software time measurement tool in the submicrosecond range.
5 citations
Patent•
06 Nov 2014
TL;DR: In this paper, the first packet includes a first message generated according to a precision-time protocol and a first encapsulation that encapsulates one or more fields of the first message.
Abstract: Aspects of the disclosure provide a method that includes receiving a first packet through a network at a first device. The first packet includes a first message generated according to a precision time protocol and a first encapsulation that encapsulates one or more fields of the first message. Further, the method includes security-verifying the first packet based on the first message and the first encapsulation, and processing the first message according to the precision time protocol after the first packet is security-verified.
5 citations
Patent•
27 Mar 2013
TL;DR: In this paper, an accurate clock synchronization protocol related with network communication, local calculation and distributed objects in a measurement and control network is defined, has the advantages that high-accuracy synchronization at the submicrosecond level can be achieved, and the protocol is incomparable for the network time protocol (NTP) with the synchronization accuracy only up to the millisecond level.
Abstract: The invention relates to the network technology, particularly to the communication network time synchronization technology. An application of a precision time protocol to a smart substation comprises the precision time protocol operating in the smart substation, an ordinary clock, a boundary clock and a management node, wherein the ordinary clock is only provided with a communication port of the precision time protocol, while the boundary clock is provided with more than two communication ports of the precision time protocol, and each communication port of the precision time protocol provides independent precision time protocol communication. An accurate clock synchronization protocol related with network communication, local calculation and distributed objects in a measurement and control network is defined, has the advantages that high-accuracy synchronization at the submicrosecond level can be achieved, and the protocol is incomparable for the network time protocol (NTP) with the synchronization accuracy only up to the millisecond level.
5 citations
Journal Article•
TL;DR: Improved protocol SN-NTP, based on the priority scheduling foundation of switch protocol IEEE802.1p, is proposed, which enhances the synchronization accuracy of NTP to 17 times the original theoretically and performance test of ship power monitoring network shows that the synchronized accuracy is improved.
Abstract: In order to improve the synchronization accuracy of NTP(Network Time Protocol) for switch-oriented power monitoring networks,an improved protocol,SN-NTP(Switch Networks-NTP),is proposed,which enhances the synchronization accuracy to 17 times the original theoretically.SN-NTP is based on the priority scheduling foundation of switch protocol IEEE802.1p.First,NTP client continuously sends the short packets with higher priority to NTP server to block the switch path and make other data packets in waiting state.Then,NTP client sends NTP request packet with highest priority to NTP server to seize the switch path of short packets.By the above two steps,the maximum waiting time of request packet under SN-NTP becomes one seventeenth of that under NTP and the synchronization accuracy is improved.SN-NTP performance test of ship power monitoring network shows that the synchronization accuracy is improved to 15 to 24 times the original,coinciding with theoretical analysis.
5 citations
28 Jun 2009
TL;DR: A multimedia streaming system based on the synchronization of multiple playback clients as a ‘swarm' based on precise clock synchronization with the PTP protocol and adjusting the client-specific sampling rates according to the true playback rates of other clients is introduced.
Abstract: IP networks allow constructing versatile device configurations for multimedia streaming. However, the stochastic nature of the packet-switched data transmission may complicate IP-based implementations of some conventional applications such as analog wired transmission of synchronized multi-channel audio. This paper introduces a multimedia streaming system based on the synchronization of multiple playback clients as a ‘swarm’. The proposed ‘swarm synchronization’ mechanism is based on precise clock synchronization with the PTP protocol and adjusting the client-specific sampling rates according to the true playback rates of other clients. A streamlined version of the RTP protocol is employed to minimize playout delay. The proposed system is empirically evaluated in wired Ethernet LAN and in wireless IEEE 802.11g LAN. The experimental results show that in the Ethernet network the proposed streaming system is able to achieve very precise synchronization.
5 citations