46 research outputs found

    Precise Network Time Monitoring: Picosecond-level packet timestamping for Fintech networks

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    Network visibility and monitoring are critical in modern networks due to the increased density, additional complexity, higher bandwidth, and lower latency requirements. Precise packet timestamping and synchronization are essential to temporally correlate captured information in different datacenter locations. This is key for visibility, event ordering and latency measurements in segments as telecom, power grids and electronic trading in finance, where order execution and reduced latency are critical for successful business outcomes. This contribution presents Precise Network Time Monitoring (PNTM), a novel mechanism for asynchronous Ethernet packet timestamping which adapts a Digital Dual Mixer Time Difference (DDMTD) implemented in an FPGA. Picosecond-precision packet timestamping is outlined for 1 Gigabit Ethernet. Furthermore, this approach is combined with the White Rabbit (WR) synchronization protocol, used as reference for the IEEE 1588-2019 High Accuracy Profile to provide unprecedented packet capturing correlation accuracy in distributed network scenarios thanks to its sub-nanosecond time transfer. The paper presents different application examples, describes the method of implementation, integration of WR with PNTM and subsequently describes experiments to demonstrate that PNTM is a suitable picosecond-level distributed packet timestamping solutionNational project AMIGA7 RTI2018-096228-B-C32Andalusian project SINPA B-TIC-445-UGR1

    Intelligent management and control for Wi-Fi small cells

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    In order to face the exponential growth of mobile data transmissions, it has been long since the concept of small cells is in the table, which provides high density deployments of small cells so as to provide a high capacity to a large number of users. The SENSEFUL project, being directed by a research team in the I2CAT foundation, studies the use of small cells with Wi-Fi technology, where both the access network and the backhaul share the same radio resource. The deployment of this new paradigm requires a deep study of improvements on the performance of access networks in terms of mobility while, at the same time, trying to improve the behaviour of the backhaul network by means of new techniques to access the shared medium. SENSEFUL has been granted the funding of the WiSHFUL open call, started up by a collective of entities and universities, of which we have mainly worked with the Technische Universität Berlin, due to the use we have made of their testbed, the TWIST. Using new techniques and technologies, such as the Software Defined Networking paradigm, an intelligent network is deployed, which can manage the network resources dynamically according to the requirements of the system. Regarding both of the fronts of SENSEFUL, the performance in the backhaul network and the mobility in the access network, the techniques that were applied are the following: For the backhaul network, an innovative proposal of a shared medium access mechanism has been studied. It is not yet standardized, because there are many research teams trying to achieve a functional system that can be applied to multiple scenarios. In this thesis, the Hybrid TDMA is studied, a Wi-Fi radio medium access protocol that uses a hybrid of carrier sense (CSMA) and time division (TDMA) in order to benefit from both systems. The main advantages that HTDMA brings are a better management of the quality of service in wireless networks, while solving some of the endemic problems of Wi-Fi, such as the hidden node or the exposed node. So as to work in this direction, first of all, a precise synchronization among the devices that will use this medium access mechanism is required; that is why the usual synchronisation mechanisms in Wi-Fi networks is one of the main topics that this thesis deals with. Regarding mobility in the access network, a new technique is used, which, despite being out of the scope of this thesis, it is indeed interesting and innovative. The BigAP unifies several access points under a shared BSSID, providing a seamless handover for the clients by making only a change on the transmission channel. Working in different environments and scenarios, this project studies the best synchronisation mechanisms for this field. Moreover, the HTDMA system is installed in a small test scenario so as to begin with the analysis of the operation of this hybrid mechanism and its performance under different conditions, as compared to the legacy CSMA

    Ultra Wideband-based wireless synchronization of IEEE 1588 clocks

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    Time-Sensitive Networking (TSN) requires clock synchronization superior to the well-known Network Time Protocol (NTP). The IEEE 802.1AS-2020 used for synchronization in TSN networks is based on the IEEE 1588-2019 standard (also known as Precision Time Protocol, PTP) defines methods and tools to perform sub-microsecond time synchronization over vari- ous communication channels. However, the IEEE 1588 implementation is commonly used with wired communication protocols, although there are use cases that could gain an advantage from a wireless solution. This paper investigates the possibility of PTP clock synchronization through wireless Ultra Wideband (UWB) communication. UWB excels where other wireless technologies are lacking: it provides high accuracy timestamping even if multipath propagation is present. The method is evaluated using commercial, well-accessible cheap hardware, resulting in the order of 10-nanosecond accuracy. The paper also highlights the main error components and requirements for improving wireless PTP synchronization

    Integration and characterisation of the performance of fifth-generation mobile technology (5g) connectivity over the University of Oulu 5g test network (5gtn) for cognitive edge node based on fractal edge platform

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    Abstract. In recent years, there has been a growing interest in cognitive edge nodes, which are intelligent devices that can collect and process data at the edge of the network. These nodes are becoming increasingly important for various applications such as smart cities, industrial automation, and healthcare. However, implementing cognitive edge nodes requires a reliable and efficient communication network. Therefore, this thesis assesses the performance of direct cellular (5G) and IEEE 802.11-based Wireless Local Area Network (WLAN) technology for three network architectures, which has the potential to offer low-latency, high-throughput and energy-efficient communication, for cognitive edge nodes. The study focused on evaluating the network performance metrics of throughput, latency, and power consumption for three different FRACTAL-based network architectures. These architectures include IEEE 802.11-based last mile, direct cellular (5G) backbone, and IEEE 802.11-based last mile over cellular (5G) backbone topologies. This research aims to provide insights into the performance of 5G technology for cognitive edge nodes. The findings suggest that the power consumption of IEEE 802.11-enabled nodes was only slightly higher than the reference case, indicating that it is more energy-efficient than 5G-enabled nodes. Additionally, in terms of latency, IEEE 802.11 technology may be more favourable. The throughput tests revealed that the cellular (5G) connection exhibited high throughput for communication between a test node and an upper-tier node situated either on the internet or at the network edge. In addition, it was found that the FRACTAL edge platform is flexible and scalable, and it supports different wireless technologies, making it a suitable platform for implementing cognitive edge nodes. Overall, this study provides insights into the potential of 5G technology and the FRACTAL edge platform for implementing cognitive edge nodes. The results of this research can be valuable for researchers and practitioners working in the field of wireless communication and edge computing, as it sheds light on the feasibility and performance of these technologies for implementing cognitive edge nodes in various applications

    Zeitsynchronisation in drahtgebundenen Rechnernetzen

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    Ausgehend von einer Analyse des Standes der Technik werden neuartige Verfahren für die Zeitsynchronisation in drahtgebundenen Netzwerken vorgestellt. Unter anderem wird, zum ersten Mal im Bereich der Zeitsynchronisation, eine Kombination aus Linearer Optimierung und Broadcast-Nachrichten vorgestellt, was eine Verbindung der jeweiligen Genauigkeits- und Skalierbarkeitsvorteile ermöglicht. Weiterhin wird, ebenfalls zum ersten Mal im Bereich der Zeitsynchronisation, eine Kombination aus Linearer Optimierung und Temperaturkompensation vorgestellt.Based on an analysis of the state of the art, several new time synchronization methods for wired networks are proposed. Among others, for the first time in the synchronization domain, a combination of linear programming and broadcast messages is proposed, which allows combining the respective accuracy and scalability advantages. Moreover, this thesis proposes combining linear programming and temperature compensation, also for the first time in the field of time synchronization

    Sistema de localização para hospitais com base em tempo de propagação

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    Mestrado em Engenharia de Computadores e TelemáticaO presente trabalho discute a localiza ção de pacientes em ambientes hospitalares e contêm as seguintes partes principais: em primeiro lugar, e introduzido o estado de arte sobre t écnicas de localiza ção de modo a fornecer ao leitor os conhecimentos básicos para os capítulos seguintes. Em segundo lugar, e efectuada uma avaliação do estado de arte tendo em conta os requisitos necessários para ambientes hospitalares. Em terceiro lugar, e especifi cado um sistema de localiza ção de pacientes com enfoque na sua arquitectura. A quarta e ultima parte cont em uma proposta de implementação de um sistema de localização, fazendo referencia a investiga ção actual, sendo tamb ém descrito o software do servidor de localiza ção que foi desenvolvido durante a tese.The present work discusses the localisation of patients in hospital environments and contains following main parts: Firstly, the state-of-the-art localisation techniques are introduced to provide the reader with the basic knowledge the following chapters are based on. Secondly, the state-of-the-art is evaluated regarding the requirements for a use in hospital environments. Thirdly, a blueprint design for a hospital patient localisation system, providing the key functionalities without looking at a speci c implementation, is developed. The fourth and last part contains the proposal of a speci c localisation system implementation by referencing to existing research and development as well as the introduction of a localisation server software that has been developed during the thesis

    Evaluation of IEEE 802.1 Time Sensitive Networking Performance for Microgrid and Smart Grid Power System Applications

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    Proliferation of distributed energy resources and the importance of smart energy management has led to increased interest in microgrids. A microgrid is an area of the grid that can be disconnected and operated independently from the main grid when required and can generate some or all of its own energy needs with distributed energy resources and battery storage. This allows for the microgrid area to continue operating even when the main grid is unavailable. In addition, often a microgrid can utilize waste heat from energy generation to drive thermal loads, further improving energy utilization. This leads to increased reliability and overall efficiency in the microgrid area.As microgrids (and by extension the smart grid) become more widespread, new methods of communication and control are required to aid in management of many different distributed entities. One such communication architecture that may prove useful is the set of IEEE 802.1 Time Sensitive Networking (TSN) standards. These standards specify improvements and new capabilities for LAN based communication networks that previously made them unsuitable for widespread deployment in a power system setting. These standards include specifications for low latency guarantees, clock synchronization, data frame redundancy, and centralized system administration. These capabilities were previously available on proprietary or application specific solutions. However, they will now be available as part of the Ethernet standard, enabling backwards compatibility with existing network architecture and support with future advances.Two of the featured standards, IEEE 802.1AS (governing time-synchronization) and IEEE 802.1Qbv (governing time aware traffic shaping), will be tested and evaluated for their potential utility in power systems and microgrid applications. These tests will measure the latency achievable using TSN over a network at various levels of congestion and compare these results with UDP and TCP protocols. In addition, the ability to use synchronized clocks to generate waveforms for microgrid inverter synchronization will be explored

    QoS-aware architectures, technologies, and middleware for the cloud continuum

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    The recent trend of moving Cloud Computing capabilities to the Edge of the network is reshaping how applications and their middleware supports are designed, deployed, and operated. This new model envisions a continuum of virtual resources between the traditional cloud and the network edge, which is potentially more suitable to meet the heterogeneous Quality of Service (QoS) requirements of diverse application domains and next-generation applications. Several classes of advanced Internet of Things (IoT) applications, e.g., in the industrial manufacturing domain, are expected to serve a wide range of applications with heterogeneous QoS requirements and call for QoS management systems to guarantee/control performance indicators, even in the presence of real-world factors such as limited bandwidth and concurrent virtual resource utilization. The present dissertation proposes a comprehensive QoS-aware architecture that addresses the challenges of integrating cloud infrastructure with edge nodes in IoT applications. The architecture provides end-to-end QoS support by incorporating several components for managing physical and virtual resources. The proposed architecture features: i) a multilevel middleware for resolving the convergence between Operational Technology (OT) and Information Technology (IT), ii) an end-to-end QoS management approach compliant with the Time-Sensitive Networking (TSN) standard, iii) new approaches for virtualized network environments, such as running TSN-based applications under Ultra-low Latency (ULL) constraints in virtual and 5G environments, and iv) an accelerated and deterministic container overlay network architecture. Additionally, the QoS-aware architecture includes two novel middlewares: i) a middleware that transparently integrates multiple acceleration technologies in heterogeneous Edge contexts and ii) a QoS-aware middleware for Serverless platforms that leverages coordination of various QoS mechanisms and virtualized Function-as-a-Service (FaaS) invocation stack to manage end-to-end QoS metrics. Finally, all architecture components were tested and evaluated by leveraging realistic testbeds, demonstrating the efficacy of the proposed solutions
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