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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.


Papers
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Proceedings ArticleDOI
07 Jul 2014
TL;DR: This work establishes quantitatively the link between network load and user experience using a state-of-the-art web QoE monitoring framework, and shows how the PTPv2-based load estimation scheme can be integrated in an OTT service architecture and be utilized for load-aware, QOE-optimized content delivery decisions.
Abstract: The recently-standardized Precision Time Protocol v2 (PTPv2) aims at achieving sub-microsecond-level synchronization between network clocks. In this work, we make the case for an alternative use of it: Adopting a learning approach, we observe its delay behavior during the protocol message exchange, derive models of its dependence on network load and build a realtime load estimation service. Then, as an application scenario of this service, we turn our attention to the provision of Over-the- Top (OTT) services. In such an environment, and assuming a level of cooperation between the ISP and the OTT provider, we demonstrate how our service can be used for estimating user experience for web applications. To this end, we establish quantitatively the link between network load and user experience using a state-of-the-art web QoE monitoring framework, and show how our PTPv2-based load estimation scheme can be integrated in an OTT service architecture and be utilized for load-aware, QoE-optimized content delivery decisions

23 citations

Patent
James Aweya1
09 Dec 2013
TL;DR: In this paper, a two-dimensional linear programming technique for estimating clock offset and skew, particularly from two-way exchange of timing messages between a master and a slave device, is presented.
Abstract: This invention relates to methods and devices for synchronization using linear programming, especially over packet networks using, for example, the IEEE 1588 Precision Time Protocol (PTP). Timing protocol messages are exposed to artifacts in the network such as packet delay variations (PDV) or packet losses. Embodiments of the invention provide a two-dimensional linear programming technique for estimating clock offset and skew, particularly from two-way exchange of timing messages between a master and a slave device. Some embodiments include a skew and offset adjustable free-running counter for regenerating the master time and frequency at the slave device.

22 citations

Proceedings Article
15 Feb 2009
TL;DR: This paper implements IEEE 1588 Precision Time Protocol in wireless LAN devices to characterize delay jitter and clock synchronization accuracy, and indicates a strong potential to provide a high fidelity real-time multi-channel multimedia networking service within 430-microsecond synchronization accuracy at an approximately 80 Mbps streaming rate.
Abstract: When a single source of multimedia contents is distributed to multiple reproduction devices, the audio and video contents require synchronous play for multi-channel stereo sound and lip-synchronization. This paper investigates capability of IEEE 802.11n wireless LANs for providing synchronized services of real-time multimedia traffic. We implement IEEE 1588 Precision Time Protocol in wireless LAN devices to characterize delay jitter and clock synchronization accuracy. The results indicate a strong potential to provide a high fidelity real-time multi-channel multimedia networking service within 430-microsecond synchronization accuracy at an approximately 80 Mbps streaming rate.

22 citations

Journal ArticleDOI
TL;DR: A detailed threat analysis of the Precision Time Protocol standard is presented, in which the security properties that should be addressed by any security extension are highlighted and an efficient elliptic-curve Public-Key signatures are suggested.
Abstract: The Precision Time Protocol (PTP) aims to provide highly accurate and synchronized clocks. Its defining standard, IEEE 1588, has a security section (“Annex K”) which relies on symmetric-key cryptography. In this paper we present a detailed threat analysis of the PTP standard, in which we highlight the security properties that should be addressed by any security extension. During this analysis we identify a sequence of new attacks and suggest non-cryptographic network-based defenses that mitigate them. We then suggest to replace Annex K's symmetric cryptography by an efficient elliptic-curve Public-Key signatures. We implemented all our attacks to demonstrate their effectiveness, and also implemented and evaluated both the network and cryptographic defenses. Our results show that the proposed schemes are extremely practical, and much more secure than previous suggestions.

22 citations

Journal ArticleDOI
TL;DR: An algorithm built on top of a precision time protocol (PTP) implementation that allows for synchronization, syntonization and absolute time referencing to coordinated universal time (UTC), including the estimation of timestamp uncertainty is described.
Abstract: In this paper, we describe an algorithm built on top of a precision time protocol (PTP) implementation that allows for synchronization, syntonization and absolute time referencing to coordinated universal time (UTC), including the estimation of timestamp uncertainty. We call this the software grandmaster (SWGM) algorithm, since it provides similar services to a PTP grandmaster clock. We show that SWGM allows timestamps to be coordinated between multiple participants in a distributed measurement system with typical performance of plusmn 86 ns [root mean square (rms)] over commodity switched Ethernet connections using hardware PTP and hardware-derived timestamps. We further show that when software-derived timestamps are used the uncertainty in the timestamps is primarily driven by the latency of the system calls to read the PTP hardware, and may be on the order of 15-25 s (rms) depending on process priority, hardware bus speed, and host processor clock rate. We also show that SWGM is robust against dropped network packets up to approximately 60% loss of packets.

22 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202126
202045
201936
201839
201732
201654