1,011 research outputs found

    Segment Routing: a Comprehensive Survey of Research Activities, Standardization Efforts and Implementation Results

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    Fixed and mobile telecom operators, enterprise network operators and cloud providers strive to face the challenging demands coming from the evolution of IP networks (e.g. huge bandwidth requirements, integration of billions of devices and millions of services in the cloud). Proposed in the early 2010s, Segment Routing (SR) architecture helps face these challenging demands, and it is currently being adopted and deployed. SR architecture is based on the concept of source routing and has interesting scalability properties, as it dramatically reduces the amount of state information to be configured in the core nodes to support complex services. SR architecture was first implemented with the MPLS dataplane and then, quite recently, with the IPv6 dataplane (SRv6). IPv6 SR architecture (SRv6) has been extended from the simple steering of packets across nodes to a general network programming approach, making it very suitable for use cases such as Service Function Chaining and Network Function Virtualization. In this paper we present a tutorial and a comprehensive survey on SR technology, analyzing standardization efforts, patents, research activities and implementation results. We start with an introduction on the motivations for Segment Routing and an overview of its evolution and standardization. Then, we provide a tutorial on Segment Routing technology, with a focus on the novel SRv6 solution. We discuss the standardization efforts and the patents providing details on the most important documents and mentioning other ongoing activities. We then thoroughly analyze research activities according to a taxonomy. We have identified 8 main categories during our analysis of the current state of play: Monitoring, Traffic Engineering, Failure Recovery, Centrally Controlled Architectures, Path Encoding, Network Programming, Performance Evaluation and Miscellaneous...Comment: SUBMITTED TO IEEE COMMUNICATIONS SURVEYS & TUTORIAL

    NetGAP: A Graph-Grammar approach for concept design of networked platforms with extra-functional requirements

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    During the concept design of complex networked systems, concept developers have to assure that the choice of hardware modules and the topology of the target platform will provide adequate resources to support the needs of the application. For example, future-generation aerospace systems need to consider multiple requirements, with many trade-offs, foreseeing rapid technological change and a long time span for realization and service. For that purpose, we introduce NetGAP, an automated 3-phase approach to synthesize network topologies and support the exploration and concept design of networked systems with multiple requirements including dependability, security, and performance. NetGAP represents the possible interconnections between hardware modules using a graph grammar and uses a Monte Carlo Tree Search optimization to generate candidate topologies from the grammar while aiming to satisfy the requirements. We apply the proposed approach to the synthetic version of a realistic avionics application use case and show the merits of the solution to support the early-stage exploration of alternative candidate topologies. The method is shown to vividly characterize the topology-related trade-offs between requirements stemming from security, fault tolerance, timeliness, and the "cost" of adding new modules or links. Finally, we discuss the flexibility of using the approach when changes in the application and its requirements occur

    Adaptive Energy-aware Scheduling of Dynamic Event Analytics across Edge and Cloud Resources

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    The growing deployment of sensors as part of Internet of Things (IoT) is generating thousands of event streams. Complex Event Processing (CEP) queries offer a useful paradigm for rapid decision-making over such data sources. While often centralized in the Cloud, the deployment of capable edge devices on the field motivates the need for cooperative event analytics that span Edge and Cloud computing. Here, we identify a novel problem of query placement on edge and Cloud resources for dynamically arriving and departing analytic dataflows. We define this as an optimization problem to minimize the total makespan for all event analytics, while meeting energy and compute constraints of the resources. We propose 4 adaptive heuristics and 3 rebalancing strategies for such dynamic dataflows, and validate them using detailed simulations for 100 - 1000 edge devices and VMs. The results show that our heuristics offer O(seconds) planning time, give a valid and high quality solution in all cases, and reduce the number of query migrations. Furthermore, rebalance strategies when applied in these heuristics have significantly reduced the makespan by around 20 - 25%.Comment: 11 pages, 7 figure

    Industrial control protocols in the Internet core: Dismantling operational practices

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    Industrial control systems (ICS) are managed remotely with the help of dedicated protocols that were originally designed to work in walled gardens. Many of these protocols have been adapted to Internet transport and support wide-area communication. ICS now exchange insecure traffic on an inter-domain level, putting at risk not only common critical infrastructure but also the Internet ecosystem (e.g., by DRDoS attacks). In this paper, we measure and analyze inter-domain ICS traffic at two central Internet vantage points, an IXP and an ISP. These traffic observations are correlated with data from honeypots and Internet-wide scans to separate industrial from non-industrial ICS traffic. We uncover mainly unprotected inter-domain ICS traffic and provide an in-depth view on Internet-wide ICS communication. Our results can be used (i) to create precise filters for potentially harmful non-industrial ICS traffic and (ii) to detect ICS sending unprotected inter-domain ICS traffic, being vulnerable to eavesdropping and traffic manipulation attacks. Additionally, we survey recent security extensions of ICS protocols, of which we find very little deployment. We estimate an upper bound of the deployment status for ICS security protocols in the Internet core

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    SRAD: Smart Routing Algorithm Design for Supporting IoT Network Architecture

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    The smart things require applications and services such as high-speed wireless, high-definition IP video cameras, and high-bandwidth connectivity. Therefore, Fog computing is responsible reducing the amount of data sent to the cloud with smart router over the core network. The IP/MPLS network design to support unicast traffic under delay constraints is a severe problem. To realize such design, especially for communication networks that can be represented by M/M/1 model, this paper develops an algorithm based on Mesh Network Topological Optimization and Routing (MENTOR)-II was called “Smart MENTOR-II”. The simulation results show that, in almost all test cases, the proposed algorithm yields lower installation cost and delay constraints than the ordinary MENTOR-II

    An application of an ethernet based protocol for communication and control in automated manufacturing

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    The exchange of information in the industrial environment is essential in order to achieve complete integration and control of manufacturing processes. At present the majority of devices present in the shop floor environment are still used as stand alone machines. They do not take advantage of the possibilities offered by a communication link to improve the manufacturing process. The subject of this research has been centered on the development of a simple, flexible and inexpensive support system for communication and control of manufacturing processes. As a result, a system with these features has been proposed and implemented on a simulated workcell. The area footwear manufacturing was chosen for modelling the workcell. The components of the manufacturing support system were developed using an object oriented approach which allowed modularity and software reuse. In order to achieve communication between the components, a communication protocol was developed following the process defined in the rapid protocol implementation framework. Ethernet was selected for implementing the lower levels of the protocol. Java, a new object oriented programming language used for the implementation of the system, showed that it could became a promising language for the implementation of manufacturing applications. In particular the platform independence feature of the language allows the immediate porting of applications to systems with different features. The manufacturing cell simulation had shown that the times associated with the manufacturing support system operations are compatible for its use in applications where the response times are in the order of one second

    Protection of AC and DC Microgrids: Challenges, Solutions and Future Trends

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    The Murchison Widefield Array: Design Overview

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    The Murchison Widefield Array (MWA) is a dipole-based aperture array synthesis telescope designed to operate in the 80-300 MHz frequency range. It is capable of a wide range of science investigations, but is initially focused on three key science projects. These are detection and characterization of 3-dimensional brightness temperature fluctuations in the 21cm line of neutral hydrogen during the Epoch of Reionization (EoR) at redshifts from 6 to 10, solar imaging and remote sensing of the inner heliosphere via propagation effects on signals from distant background sources,and high-sensitivity exploration of the variable radio sky. The array design features 8192 dual-polarization broad-band active dipoles, arranged into 512 tiles comprising 16 dipoles each. The tiles are quasi-randomly distributed over an aperture 1.5km in diameter, with a small number of outliers extending to 3km. All tile-tile baselines are correlated in custom FPGA-based hardware, yielding a Nyquist-sampled instantaneous monochromatic uv coverage and unprecedented point spread function (PSF) quality. The correlated data are calibrated in real time using novel position-dependent self-calibration algorithms. The array is located in the Murchison region of outback Western Australia. This region is characterized by extremely low population density and a superbly radio-quiet environment,allowing full exploitation of the instrumental capabilities.Comment: 9 pages, 5 figures, 1 table. Accepted for publication in Proceedings of the IEE
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