Posted Content•
Simulation of the IEEE 1588 Precision Time Protocol in OMNeT
TL;DR: The implementation of realistic clock noise and its synchronization via PTP in OMNeT++ is discussed and the components presented in this paper are intended to assist engineers with the configuration of PTP networks.
Abstract: Real-time systems rely on a distributed global time base. As any physical clock device suffers from noise, it is necessary to provide some kind of clock synchronization to establish such a global time base. Different clock synchronization methods have been invented for individual application domains. The Precision Time Protocol (PTP), which is specified in IEEE 1588, is another interesting option. It targets local networks, where it is acceptable to assume small amounts of hardware support, and promises sub-microsecond precision. PTP provides many different implementation and configuration options, and thus the Design Space Exploration (DSE) is challenging. In this paper we discuss the implementation of realistic clock noise and its synchronization via PTP in OMNeT++. The components presented in this paper are intended to assist engineers with the configuration of PTP networks.
Citations
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TL;DR: This article proposes to close the PTP loop through an extension that introduces new functionality and messages and demonstrates that the approach preserves PTP functionality, while successfully detecting cyber attacks against PTP components in a timely manner.
Abstract: The precision time protocol (PTP) is considered as one of the most favorable mechanisms for providing unified and precise time at the substation level in the smart grid. Nevertheless, PTP was shown to be vulnerable to cyber-attacks targeting its components and synchronization services. In this article, we capitalize on the theory and outcome of our previous work to contribute a more complete solution that addresses PTP cyber security. We propose to close the PTP loop through an extension that introduces new functionality and messages. This extension covers the PTP attack surface and enables the detection of attacks on PTP time synchronization. We formally model and verify the proposed extension using UPPAAL model checker. In addition, we validate the proposed extension using Omnet++ simulation. The evaluation demonstrates that our approach preserves PTP functionality, while successfully detecting cyber attacks against PTP components in a timely manner.
24 citations
Cites methods from "Simulation of the IEEE 1588 Precisi..."
...To validate the usefulness of our approach through Omnet++ simulation [24], we modify the PTP implementation provided by [25] to introduce our detection mechanism, and carry-on different cyber attacks....
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23 Oct 2018
TL;DR: A new simulation model of the gPTP protocol for time synchronization in OMNeT++ using the INET library is developed, compared it to results from the state-of-the-art, and would like to share it with the OM NeT++ community.
Abstract: The aim of this paper is to describe a developed simulation model of the gPTP protocol for time synchronization in OMNeT++ using the INET library. gPTP is part of the IEEE TSN standards. Unfortunately, there is currently no simulation model of gPTP available. Therefore, we developed a new simulation model, compared it to results from the state-ofthe-art, and would like to share it with the OMNeT++ community. The simulation model is based on the IEEE 802.1AS specification for full-duplex Ethernet according to a given network topology and use case scenario to analyze the results of the simulation as well as to provide a comparison with results from the state-of-the-art. Time synchronization and propagation delay measurements between time-aware systems are considered and results show that the simulation model works as expected.
7 citations
Cites background from "Simulation of the IEEE 1588 Precisi..."
...from [14], would be a reasonable extension for future work....
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12 Jun 2020
TL;DR: The basic architecture of the time synchronization system for the seafloor observatory network is introduced and deployment suggestions are proved to be rational and effective according to the performance of the asymmetric delay of the PTP clock port in simulation and evaluation.
Abstract: The special environment and tasks of the seafloor observatory network require sub-microsecond accuracy for time synchronization. It’s the mainstream technology to build a time synchronization system based on Precision Time Protocol (PTP) in the near future. However, for the multi-node, long-distance, ring topology seafloor observatory network, the deployment strategy of the time synchronization system has not been fully studied. In this work, the basic architecture of the time synchronization system for the seafloor observatory network is introduced. PTP clock models are constructed using the OMNeT++ simulation software, based on which the modeling of the time synchronization systems of linear and annular structures are realized. After simulation and analysis, deployment suggestions including synchronization interval setting and clock mode selection of the annular time synchronization system are proposed. The suggestions are proved to be rational and effective according to the performance of the asymmetric delay of the PTP clock port in simulation and evaluation.
3 citations
Cites methods from "Simulation of the IEEE 1588 Precisi..."
...The current researches of PTP clock models using OMNeT++ include the clock module developed by Liu Yingshu [12], ptp++ module by Martin Levesque [13], and LibPTP module by Wolfgang Wallner [14][15], which have been modified and improved to form the PTP_BasicNode module in this paper....
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01 Dec 2018
TL;DR: An extension of Precision Time Protocol to enable energy-efficient clock synchronization between the nodes within Wireless Sensor Network (WSN) to reduce clock convergence time and energy needed by considering out-degree of clocks without sacrificing synchronization accuracy is proposed.
Abstract: In this paper, an extension of Precision Time Protocol (PTP) to enable energy-efficient clock synchronization between the nodes within Wireless Sensor Network (WSN) is proposed. PTP is nanosecond accuracy clock synchronization protocol in which nodes are organized in master-slave hierarchy on the basis of clock accuracy by means of Best Master Clock (BMC) algorithm. The algorithm considers clock accuracy to select best clock in the system. A novel modification of IEEE 1588 BMC algorithm for energy-constraint multi-hop WSN has been proposed to reduce clock convergence time and energy needed by considering out-degree of clocks without sacrificing synchronization accuracy. The new algorithm results in energy efficient clock synchronization that makes it most appropriate for low-power multi-hop wireless sensor networks. We present NS-3 simulation data that confirms the effectiveness of work.
2 citations
Cites methods from "Simulation of the IEEE 1588 Precisi..."
...Based on the results of the DSC algorithm, the SD algorithm computes the recommended state for ports of clocks [4]....
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Dissertation•
11 Sep 2018
TL;DR: This thesis focuses on the substation, a basic block of the smart grid system, along with its recommended time synchronization mechanism - the Precision Time Protocol (PTP) - in order to address threats associated with PTP, and proposes practical and efficient detection, prevention, mitigation techniques and methodologies that will harden and enhance the security and usability of PTP in a substation.
Abstract: The current electric grid is considered as one of the greatest engineering achievements of the twentieth century. It has been successful in delivering power to consumers for decades. Nevertheless, the electric grid has recently experienced several blackouts that raised several concerns related to its availability and reliability. The aspiration to provide reliable and efficient energy, and contribute to environment protection through the increasing utilization of renewable energies are driving the need to deploy the grid of the future, the smart grid. It is expected that this grid will be self-healing from power disturbance events, operating resiliently against physical and cyber attack, operating efficiently, and enabling new products and services. All these call for a grid with more Information and Communication Technologies (ICT). As such, power grids are increasingly absorbing ICT technologies to provide efficient, secure and reliable two-way communication to better manage, operate, maintain and control electric grid components.
On the other hand, the successful deployment of the smart grid is predicated on the ability to secure its operations. Such a requirement is of paramount importance especially in the presence of recent cyber security incidents. Furthermore, those incidents are subject to an augment with the increasing integration of ICT technologies and the vulnerabilities they introduce to the grid. The exploitation of these vulnerabilities might lead to attacks that can, for instance, mask the system observability and initiate cascading failures resulting in undesirable and severe consequences.
In this thesis, we explore the security aspects of a key enabling technology in the smart grid, accurate time synchronization. Time synchronization is an immense requirement across the domains of the grid, from generation to transmission, distribution, and consumer premises. We focus on the substation, a basic block of the smart grid system, along with its recommended time synchronization mechanism - the Precision Time Protocol (PTP) - in order to address threats associated with PTP, and propose practical and efficient detection, prevention, mitigation techniques and methodologies that will harden and enhance the security and usability of PTP in a substation. In this respect, we start this thesis with a security assessment of PTP that identifies PTP security concerns, and then address those concerns in the subsequent chapters. We tackle the following main threats associated with PTP: 1) PTP vulnerability to fake timestamp injection through a compromised component 2) PTP vulnerability to the delay attack and 3) The lack of a mechanism that secures the PTP network. Next, and as a direct consequence of the importance of time synchronization in the smart grid, we consider the wide area system to demonstrate the vulnerability of relative data alignment in Phasor Data Concentrators to time synchronization attacks. These problems will be extensively studied throughout this thesis, followed by discussions that highlight open research directions worth further investigations.
1 citations
Cites methods from "Simulation of the IEEE 1588 Precisi..."
...To validate the usefulness of our approach through Omnet++ simulation [121], we modify the PTP implementation provided by [122] to introduce our detection mechanism, and carry-on different cyber attacks....
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References
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27 Sep 2004
TL;DR: A protocol is provided in this standard that enables precise synchronization of clocks in measurement and control systems implemented with technologies such as network communication, local computing, and distributed objects.
Abstract: A protocol is provided in this standard that enables precise synchronization of clocks in measurement and control systems implemented with technologies such as network communication, local computing, and distributed objects. The protocol is applicable to systems communicating via packet networks. Heterogeneous systems are enabled that include clocks of various inherent precision, resolution, and stability to synchronize. System-wide synchronization accuracy and precision in the sub-microsecond range are supported with minimal network and local clock computing resources. Simple systems are installed and operated without requiring the management attention of users because the default behavior of the protocol allows for it.
1,428 citations
05 Dec 2002
TL;DR: This paper discusses the major features and design objectives of the IEEE-1588 standard, designed to serve the clock synchronization needs of industrial systems, and recent performance results of prototype implementations of this standard in an Ethernet environment are presented.
Abstract: This paper discusses the major features and design objectives of the IEEE-1588 standard. Recent performance results of prototype implementations of this standard in an Ethernet environment are presented. Potential areas of application of this standard are outlined.
1,112 citations
Book•
09 Mar 2006
TL;DR: The IEEE 1588-2002 standard as mentioned in this paper is used to synchronize real-time clocks integral to each component of a distributed measurement and control system, allowing the use of new techniques in solving problems with complex synchronization requirements or arising from the interaction of many sensors and actuators.
Abstract: A common sense of time among the elements of a distributed measurement and control system allows the use of new techniques in solving problems with complex synchronization requirements or arising from the interaction of many sensors and actuators. Such a common sense of time may be accomplished using the standard IEEE 1588-2002 to synchronize real-time clocks integral to each component of the system. IEEE 1588, expands the performance capabilities of Ethernet networks so that they become relevant for measurement and control; this monograph embodies the first unified treatment of the associated technology, standards and applications. Readers will gain understanding of the technological context of IEEE 1588 and its role in a variety of application settings. To engineers this monograph provides detailed discussion of the complex features of the standard. Together with the essential material on best practice and implementation issues, these provide invaluable assistance in the design of new applications.
206 citations
"Simulation of the IEEE 1588 Precisi..." refers background in this paper
...For a detailed discussion the interested reader is referred to the literature, e.g. [5]....
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Proceedings Article•
01 Dec 1992TL;DR: A new algorithm and computer code is presented for simulating power law noises with arbitrary a and it is shown to provide improvements, particularly because it results in non-stationary noise sequences that are also scale- invariant and causal and have the proper autospectral densities and Allan variances.
Abstract: Power law noise plays an important role in the description of high performance oscillators. Commonly, five types of noise are considered to affect clocks and clock measurements: white phase, flicker phase, white frequency, flicker frequency and random walk frequency. These noise types are distinguished by the slopes of their spectral densities, S,@ =y (on a log-log scale). The noise is inherent both to the oscillators and to the measurement systems and defines the limits of stability of the clocks. Accurate simulation of the noise can be important for testing the measurement system and the characterization software. This paper presents a new algorithm and computer code for simulating power law noises with arbitrary a (it is not restricted to the integer values mentioned above). The general theory of noise simulation is investigated to determine the criteria for evaluating and deriving simulation methods. Past techniques are evaluted and the new method is shown to provide improvements, particularly because it results in non-stationary noise sequences that are also scale- invariant and causal and have the proper autospectral densities and Allan variances.
49 citations
"Simulation of the IEEE 1588 Precisi..." refers methods in this paper
...An algorithm on how to simulate a particular important noise type (Powerlaw Noise (PLN)) is given in [4]....
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TL;DR: The results show that the behaviour of distributed sensor systems, resulting from imperfect timebases, can be accurately simulated, and a model that was optimised for use in DES is presented.
Abstract: Distributed sensor systems require clock synchronization between all sensor nodes to provide consistent view of the overall system. Owing the growing size of networks, the evaluation of the synchronization performance becomes difficult, if done by means of experiments. Simulation is another method to tackle this issue. Realistic simulation of synchronization schemes requires accurate modelling of oscillators which are the driving timers generating various events. One way to characterise oscillators is to utilize the Allan variance, which can be used to generate a phenomenological model based on power spectral density. Since discrete event simulation (DES) tools are widely used to model network protocols, models which combine accuracy and performance are needed. This paper presents a model that was optimised for use in DES. To verify that the simulation results sufficiently match measurements, an implementation in OMNeT
15 citations
"Simulation of the IEEE 1588 Precisi..." refers methods in this paper
...In [3] an efficient implementation of the above mentioned noise simulation and its implementation in OMNeT++ are described, however to the best knowledge of the author this implementation is not freely available and the description contains not enough details to reproduce their results....
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