585 research outputs found

    Diamond Detectors for the TOTEM Timing Upgrade

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    This paper describes the design and the performance of the timing detector developed by the TOTEM Collaboration for the Roman Pots (RPs) to measure the Time-Of-Flight (TOF) of the protons produced in central diffractive interactions at the LHC. The measurement of the TOF of the protons allows the determination of the longitudinal position of the proton interaction vertex and its association with one of the vertices reconstructed by the CMS detectors. The TOF detector is based on single crystal Chemical Vapor Deposition (scCVD) diamond plates and is designed to measure the protons TOF with about 50 ps time precision. This upgrade to the TOTEM apparatus will be used in the LHC run 2 and will tag the central diffractive events up to an interaction pileup of about 1. A dedicated fast and low noise electronics for the signal amplification has been developed. The digitization of the diamond signal is performed by sampling the waveform. After introducing the physics studies that will most profit from the addition of these new detectors, we discuss in detail the optimization and the performance of the first TOF detector installed in the LHC in November 2015.Comment: 26 pages, 18 figures, 2 tables, submitted for publication to JINS

    Challenges and solutions for secure information centric networks: a case study of the NetInf architecture

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    A large number of emerging Internet applications require information dissemination across different organizational boundaries, heterogeneous platforms, and a large, dynamic population of publishers and subscribers. A new information-centric network architecture called Network of Information (NetInf) has been developed in the context of the FP7 EU-funded 4WARD project. This architecture can significantly improve large scale information distribution. Furthermore, it supports future mobile networks in situations with intermittent and heterogeneous connectivity and connects the digital with the physical world to enable better user experience. However, NetInf is still in an early stage of implementation and its security is yet to be evaluated. The security concern of NetInf is a major factor for its wide-scale adoption. Therefore, this paper uses the X.805 security standard to analyse the security of the NetInf architecture. The analysis highlights the main source of threats and potential security services to tackle them. The paper also defines a threat model in the form of possible attacks against the NetInf architecture

    Challenges and solutions for secure information centric networks: a case study of the NetInf architecture

    Get PDF
    A large number of emerging Internet applications require information dissemination across different organizational boundaries, heterogeneous platforms, and a large, dynamic population of publishers and subscribers. A new information-centric network architecture called Network of Information (NetInf) has been developed in the context of the FP7 EU-funded 4WARD project. This architecture can significantly improve large scale information distribution. Furthermore, it supports future mobile networks in situations with intermittent and heterogeneous connectivity and connects the digital with the physical world to enable better user experience. However, NetInf is still in an early stage of implementation and its security is yet to be evaluated. The security concern of NetInf is a major factor for its wide-scale adoption. Therefore, this paper uses the X.805 security standard to analyse the security of the NetInf architecture. The analysis highlights the main source of threats and potential security services to tackle them. The paper also defines a threat model in the form of possible attacks against the NetInf architecture

    QoS support in satellite and wireless networks : study under the network simulator (NS-2)

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    Aquest projecte es basa en l'estudi de l'oferiment de qualitat de servei en xarxes wireless i satel·litals. Per això l'estudi de les tècniques de cross-layer i del IEEE 802.11e ha sigut el punt clau per al desenvolupament teòric d'aquest estudi. Usant el simulador de xarxes network simulator, a la part de simulacions es plantegen tres situacions: l'estudi de la xarxa satel·lital, l'estudi del mètode d'accés HCCA i la interconnexió de la xarxa satel·lital amb la wireless. Encara que aquest últim punt, incomplet en aquest projecte, ha de ser la continuació per a futures investigacions.Este proyecto se basa en el estudio del ofrecimiento de calidad de servicio en redes wireless y satelitales. Por eso el estudio de las técnicas de cross-layer y del IEEE 802.11eha sido el punto clave para el desarrollo teórico de este estudio. Usando el simulador de redes network simulator, en la parte de simulaciones se plantean tres situaciones: el estudio de la red satelital, el estudio del método de acceso HCCA y la interconexión de la red satelital con la wireless. Aunque este último punto, incompleto en este proyecto, tiene que ser la continuación para futuras investigaciones.This project is based on the study of offering quality of service in satellite and wireless networks. For that reason the study of the techniques of cross-layer and the IEEE 802.11e has been the key point for the theoretical development of this study. Using the software network simulator, in the part of simulations three situations consider: the study of the satellite network, the study of the access method HCCA and the interconnection of the satellite network with the wireless. Although this last point, incomplete in this work, must be the continuation for future investigations

    Evaluation and analysis of realizing broker-based content routing protocols in SDN

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    Publish/subscribe provides a valuable communication model to the future Internet due to the decoupling of end-users from each other. One of the stubborn challenges that face recent content-based publish/subscribe systems is the trade-off between the usage of the network bandwidth and the end-to-end delay of published events. This trade-off is imposed by the fact that most implementations depend on software brokers to filter incoming messages towards received requests from subscribers. Although this approach for filtering may present the most bandwidth efficient solutions, the use of brokers adds to the network end-to-end delay. The installed brokers are implemented at the application layer and hence the original path between publishers and subscribers is extended which adds to the delay in which messages are forwarded from publishers to subscribers. Along with the delay imposed by the extended path, another processing delay is added to the system based on the time needed for filtering incoming messages at the brokers. As the time factor is crucial to the real-world applications that depend on the content-based publish/subscribe paradigm, recent implementations try to tackle this problem by exploiting the deployed hardware in the underlying infrastructure for filtering operations. In-network filtering is enabled with the help of Software Defined Networking (SDN) technology as it allows the installment of content filters directly to the network switches/routers. Even though this approach significantly reduces the end-to-end delay, it suffers when the bandwidth efficiency is evaluated. Caused by the inherited hardware limitations, installing content filters on hardware network elements limits their expressiveness. This increases the number of published messages from publishers to subscribers on different network links which requires more bandwidth. As an intermediate solution between the two filtering approaches, the work of this thesis is the realization of a hybrid content-based publish/subscribe middleware that allows filtering operations in both network and application layers

    Mesh-based content routing using XML

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    Diamond detectors for the TOTEM timing upgrade

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    This paper describes the design and the performance of the timing detector developed by the TOTEM Collaboration for the Roman Pots (RPs) to measure the Time-Of-Flight (TOF) of the protons produced in central diffractive interactions at the LHC. The measurement of the TOF of the protons allows the determination of the longitudinal position of the proton interaction vertex and its association with one of the vertices reconstructed by the CMS detectors. The TOF detector is based on single crystal Chemical Vapor Deposition (scCVD) diamond plates and is designed to measure the protons TOF with about 50 ps time precision. This upgrade to the TOTEM apparatus will be used in the LHC run 2 and will tag the central diffractive events up to an interaction pileup of about 1. A dedicated fast and low noise electronics for the signal amplification has been developed. The digitization of the diamond signal is performed by sampling the waveform. After introducing the physics studies that will most profit from the addition of these new detectors, we discuss in detail the optimization and the performance of the first TOF detector installed in the LHC in November 2015.Peer reviewe

    Hybrid application layer and in-network content-based filtering in SDN

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    Content-routing as provided by publish/subscribe systems has evolved as a key paradigm for interactions between loosely coupled application components (content publishers and subscribers). Using content-based forwarding rules (also called content filters) installed on content-based routers (also termed brokers), bandwidth-efficiency is increased by only forwarding content to the subset of subscribers who are actually interested in the published content. Software Defined Networking (SDN) is a method that enables installation of filters directly on the TCAM memory of network routers. Compared to traditional broker networks, SDN can significantly reduce the latency until events can be received by subscribers: i) the matching time is significantly reduced, and ii) the communication path can be adapted to directly reflect the underlying network topology and therefore reduce the number of forwarding hops for packets. Initial studies have shown that content-routing protocols based on spatial indexing are very well suited to realize a mapping of filtering operations to header-based packet matching performed in TCAM memory. Filters are represented by identifiers constituting the matching field of flows on switches. However, the limited number of available bits for content representation and the limited number of flows available on the TCAM memory for pub/sub traffic limits the expressiveness of these filters, resulting in false positives or unnecessary traffic in the system. The objective of this thesis, is to design and implement a hybrid pub/sub middleware that allows for filtering of events both on the application layer as well as on the network layer. However, this leads to a trade-off between expressiveness and line-rate performance. In particular, this thesis investigates mechanisms to reduce false positives in the system while maintaining end-to-end latency guarantees at subscribers
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