23 research outputs found

    The Dagstuhl Beginners Guide to Reproducibility for Experimental Networking Research

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    © Owner/Author | ACM 2019 This is the author's version of the work. It is posted here for your personal use. Not for redistribution. The definitive Version of Record was published in ACM SIGCOMM Computer Communication Review, http://dx.doi.org/10.1145/3314212.3314217.Reproducibility is one of the key characteristics of good science, but hard to achieve for experimental disciplines like Internet measurements and networked systems. This guide provides advice to researchers, particularly those new to the field, on designing experiments so that their work is more likely to be reproducible and to serve as a foundation for follow-on work by others.EC/H2020/679158/EU/Resolving the Tussle in the Internet: Mapping, Architecture, and Policy Making/ResolutioNe

    Bluetooth Mesh under the Microscope: How much ICN is Inside?

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    Bluetooth (BT) mesh is a new mode of BT operation for low-energy devices that offers group-based publish-subscribe as a network service with additional caching capabilities. These features resemble concepts of information-centric networking (ICN), and the analogy to ICN has been repeatedly drawn in the BT community. In this paper, we compare BT mesh with ICN both conceptually and in real-world experiments. We contrast both architectures and their design decisions in detail. Experiments are performed on an IoT testbed using NDN/CCNx and BT mesh on constrained RIOT nodes. Our findings indicate significant differences both in concepts and in real-world performance. Supported by new insights, we identify synergies and sketch a design of a BT-ICN that benefits from both worlds

    Best Practices for Notification Studies for Security and Privacy Issues on the Internet

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    Researchers help operators of vulnerable and non-compliant internet services by individually notifying them about security and privacy issues uncovered in their research. To improve efficiency and effectiveness of such efforts, dedicated notification studies are imperative. As of today, there is no comprehensive documentation of pitfalls and best practices for conducting such notification studies, which limits validity of results and impedes reproducibility. Drawing on our experience with such studies and guidance from related work, we present a set of guidelines and practical recommendations, including initial data collection, sending of notifications, interacting with the recipients, and publishing the results. We note that future studies can especially benefit from extensive planning and automation of crucial processes, i.e., activities that take place well before the first notifications are sent.Comment: Accepted to the 3rd International Workshop on Information Security Methodology and Replication Studies (IWSMR '21), colocated with ARES '2

    Improving the accuracy of spoofed traffic inference in inter-domain traffic

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    Ascertaining that a network will forward spoofed traffic usually requires an active probing vantage point in that network, effectively preventing a comprehensive view of this global Internet vulnerability. We argue that broader visibility into the spoofing problem may lie in the capability to infer lack of Source Address Validation (SAV) compliance from large, heavily aggregated Internet traffic data, such as traffic observable at Internet Exchange Points (IXPs). The key idea is to use IXPs as observatories to detect spoofed packets, by leveraging Autonomous System (AS) topology knowledge extracted from Border Gateway Protocol (BGP) data to infer which source addresses should legitimately appear across parts of the IXP switch fabric. In this thesis, we demonstrate that the existing literature does not capture several fundamental challenges to this approach, including noise in BGP data sources, heuristic AS relationship inference, and idiosyncrasies in IXP interconnec- tivity fabrics. We propose Spoofer-IX, a novel methodology to navigate these challenges, leveraging Customer Cone semantics of AS relationships to guide precise classification of inter-domain traffic as In-cone, Out-of-cone ( spoofed ), Unverifiable, Bogon, and Unas- signed. We apply our methodology on extensive data analysis using real traffic data from two distinct IXPs in Brazil, a mid-size and a large-size infrastructure. In the mid-size IXP with more than 200 members, we find an upper bound volume of Out-of-cone traffic to be more than an order of magnitude less than the previous method inferred on the same data, revealing the practical importance of Customer Cone semantics in such analysis. We also found no significant improvement in deployment of SAV in networks using the mid-size IXP between 2017 and 2019. In hopes that our methods and tools generalize to use by other IXPs who want to avoid use of their infrastructure for launching spoofed-source DoS attacks, we explore the feasibility of scaling the system to larger and more diverse IXP infrastructures. To promote this goal, and broad replicability of our results, we make the source code of Spoofer-IX publicly available. This thesis illustrates the subtleties of scientific assessments of operational Internet infrastructure, and the need for a community focus on reproducing and repeating previous methods.A constatação de que uma rede encaminhará tráfego falsificado geralmente requer um ponto de vantagem ativo de medição nessa rede, impedindo efetivamente uma visão abrangente dessa vulnerabilidade global da Internet. Isto posto, argumentamos que uma visibilidade mais ampla do problema de spoofing pode estar na capacidade de inferir a falta de conformidade com as práticas de Source Address Validation (SAV) a partir de dados de tráfego da Internet altamente agregados, como o tráfego observável nos Internet Exchange Points (IXPs). A ideia chave é usar IXPs como observatórios para detectar pacotes falsificados, aproveitando o conhecimento da topologia de sistemas autônomos extraído dos dados do protocolo BGP para inferir quais endereços de origem devem aparecer legitimamente nas comunicações através da infra-estrutura de um IXP. Nesta tese, demonstramos que a literatura existente não captura diversos desafios fundamentais para essa abordagem, incluindo ruído em fontes de dados BGP, inferência heurística de relacionamento de sistemas autônomos e características específicas de interconectividade nas infraestruturas de IXPs. Propomos o Spoofer-IX, uma nova metodologia para superar esses desafios, utilizando a semântica do Customer Cone de relacionamento de sistemas autônomos para guiar com precisão a classificação de tráfego inter-domínio como In-cone, Out-of-cone ( spoofed ), Unverifiable, Bogon, e Unassigned. Aplicamos nossa metodologia em análises extensivas sobre dados reais de tráfego de dois IXPs distintos no Brasil, uma infraestrutura de médio porte e outra de grande porte. No IXP de tamanho médio, com mais de 200 membros, encontramos um limite superior do volume de tráfego Out-of-cone uma ordem de magnitude menor que o método anterior inferiu sob os mesmos dados, revelando a importância prática da semântica do Customer Cone em tal análise. Além disso, não encontramos melhorias significativas na implantação do Source Address Validation (SAV) em redes usando o IXP de tamanho médio entre 2017 e 2019. Na esperança de que nossos métodos e ferramentas sejam aplicáveis para uso por outros IXPs que desejam evitar o uso de sua infraestrutura para iniciar ataques de negação de serviço através de pacotes de origem falsificada, exploramos a viabilidade de escalar o sistema para infraestruturas IXP maiores e mais diversas. Para promover esse objetivo e a ampla replicabilidade de nossos resultados, disponibilizamos publicamente o código fonte do Spoofer-IX. Esta tese ilustra as sutilezas das avaliações científicas da infraestrutura operacional da Internet e a necessidade de um foco da comunidade na reprodução e repetição de métodos anteriores

    LIPIcs, Volume 277, GIScience 2023, Complete Volume

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    LIPIcs, Volume 277, GIScience 2023, Complete Volum

    Cross-layer latency-aware and -predictable data communication

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    Cyber-physical systems are making their way into more aspects of everyday life. These systems are increasingly distributed and hence require networked communication to coordinatively fulfil control tasks. Providing this in a robust and resilient manner demands for latency-awareness and -predictability at all layers of the communication and computation stack. This thesis addresses how these two latency-related properties can be implemented at the transport layer to serve control applications in ways that traditional approaches such as TCP or RTP cannot. Thereto, the Predictably Reliable Real-time Transport (PRRT) protocol is presented, including its unique features (e.g. partially reliable, ordered, in-time delivery, and latency-avoiding congestion control) and unconventional APIs. This protocol has been intensively evaluated using the X-Lap toolkit that has been specifically developed to support protocol designers in improving latency, timing, and energy characteristics of protocols in a cross-layer, intra-host fashion. PRRT effectively circumvents latency-inducing bufferbloat using X-Pace, an implementation of the cross-layer pacing approach presented in this thesis. This is shown using experimental evaluations on real Internet paths. Apart from PRRT, this thesis presents means to make TCP-based transport aware of individual link latencies and increases the predictability of the end-to-end delays using Transparent Transmission Segmentation.Cyber-physikalische Systeme werden immer relevanter für viele Aspekte des Alltages. Sie sind zunehmend verteilt und benötigen daher Netzwerktechnik zur koordinierten Erfüllung von Regelungsaufgaben. Um dies auf eine robuste und zuverlässige Art zu tun, ist Latenz-Bewusstsein und -Prädizierbarkeit auf allen Ebenen der Informations- und Kommunikationstechnik nötig. Diese Dissertation beschäftigt sich mit der Implementierung dieser zwei Latenz-Eigenschaften auf der Transport-Schicht, sodass Regelungsanwendungen deutlich besser unterstützt werden als es traditionelle Ansätze, wie TCP oder RTP, können. Hierzu wird das PRRT-Protokoll vorgestellt, inklusive seiner besonderen Eigenschaften (z.B. partiell zuverlässige, geordnete, rechtzeitige Auslieferung sowie Latenz-vermeidende Staukontrolle) und unkonventioneller API. Das Protokoll wird mit Hilfe von X-Lap evaluiert, welches speziell dafür entwickelt wurde Protokoll-Designer dabei zu unterstützen die Latenz-, Timing- und Energie-Eigenschaften von Protokollen zu verbessern. PRRT vermeidet Latenz-verursachenden Bufferbloat mit Hilfe von X-Pace, einer Cross-Layer Pacing Implementierung, die in dieser Arbeit präsentiert und mit Experimenten auf realen Internet-Pfaden evaluiert wird. Neben PRRT behandelt diese Arbeit transparente Übertragungssegmentierung, welche dazu dient dem TCP-basierten Transport individuelle Link-Latenzen bewusst zu machen und so die Vorhersagbarkeit der Ende-zu-Ende Latenz zu erhöhen

    12th International Conference on Geographic Information Science: GIScience 2023, September 12–15, 2023, Leeds, UK

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    Cloud and mobile infrastructure monitoring for latency and bandwidth sensitive applications

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    This PhD thesis involves the study of cloud computing infrastructures (from the networking perspective) to assess the feasibility of applications gaining increasing popularity over recent years, including multimedia and telemedicine applications, demanding low, bounded latency and sufficient bandwidth. I also focus on the case of telemedicine, where remote imaging applications (for example, telepathology or telesurgery) need to achieve a low and stable latency for the remote transmission of images, and also for the remote control of such equipment. Another important use case for telemedicine is denoted as remote computation, which involves the offloading of image processing to help diagnosis; also in this case, bandwidth and latency requirements should be enforced to ensure timely results, although they are less strict compared to the previous scenario. Nowadays, the capability of gaining access to IT resources in a rapid and on-demand fashion, according to a pay-as-you-go model, has made the cloud computing a key-enabler for innovative multimedia and telemedicine services. However, the partial obscurity of cloud performance, and also security concerns are still hindering the adoption of cloud infrastructure. To ensure that the requirements of applications running on the cloud are satisfied, there is the need to design and evaluate proper methodologies, according to the metric of interest. Moreover, some kinds of applications have specific requirements that cannot be satisfied by the current cloud infrastructure. In particular, since the cloud computing involves communication to remote servers, two problems arise: firstly, the core network infrastructure can be overloaded, considering the massive amount of data that has to flow through it to allow clients to reach the datacenters; secondly, the latency resulting from this remote interaction between clients and servers is increased. For these, and many other cases also beyond the field of telemedicine, the Edge and Fog computing paradigms were introduced. In these new paradigms, the IT resources are deployed not only in the core cloud datacenters, but also at the edge of the network, either in the telecom operator access network or even leveraging other users' devices. The proximity of resources to end-users allows to alleviate the burden on the core network and at the same time to reduce latency towards users. Indeed, the latency from users to remote cloud datacenters encompasses delays from the access and core networks, as well as the intra-datacenter delay. Therefore, this latency is expected to be higher than that required to interconnect users to edge servers, which in the envisioned paradigm are deployed in the access network, that is, nearby final users. Therefore, the edge latency is expected to be reduced to only a portion of the overall cloud delay. Moreover, the edge and central resources can be used in conjunction, and therefore attention to core cloud monitoring is of capital importance even when edge architectures will have a widespread adoption, which is not the case yet. While a lot of research work has been presented for monitoring several network-related metrics, such as bandwidth, latency, jitter and packet loss, less attention was given to the monitoring of latency in cloud and edge cloud infrastructures. In detail, while some works target cloud-latency monitoring, the evaluation is lacking a fine-grained analysis of latency considering spatial and temporal trends. Furthermore, the widespread adoption of mobile devices, and the Internet of Things paradigm further accelerate the shift towards the cloud paradigm for the additional benefits it can provide in this context, allowing energy savings and augmenting the computation capabilities of these devices, creating a new scenario denoted as mobile cloud. This scenario poses additional challenges for its bandwidth constraints, accentuating the need for tailored methodologies that can ensure that the crucial requirements of the aforementioned applications can be met by the current infrastructure. In this sense, there is still a gap of works monitoring bandwidth-related metrics in mobile networks, especially when performing in-the-wild assessment targeting actual mobile networks and operators. Moreover, even the few works testing real scenarios typically consider only one provider in one country for a limited period of time, lacking an in-depth assessment of bandwidth variability over space and time. In this thesis, I therefore consider monitoring methodologies for challenging scenarios, focusing on latency perceived by customers of public cloud providers, and bandwidth in mobile broadband networks. Indeed, as described, achieving low latency is a critical requirement for core cloud infrastructures, while providing enough bandwidth is still challenging in mobile networks compared to wired settings, even with the adoption of 4G mobile broadband networks, expecting to overcome this issue only with the widespread availability of 5G connections (with half of total traffic expected to come from 5G networks by 2026). Therefore, in the research activities carried on during my PhD, I focused on monitoring latency and bandwidth on cloud and mobile infrastructures, assessing to which extent the current public cloud infrastructure and mobile network make multimedia and telemedicine applications (as well as others having similar requirements) feasible

    Contextualization in Video Education in Africa: A Participatory, Applied Cognitive Science Approach

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    This research was conducted to better understand video as a learning medium for adult skill learning in developing nations. It included a Participatory Video project, guiding media creation with Cognitive Science and an experimental study about the effect of the inclusion of contextual information in learning from video. The research was conducted in The Gambia, West Africa, with Gambian collaborators for the Participatory Video creation and Gambian rural women as the experimental participants. In this work, the Participatory Video creation process was shared, including how Cognitive Science research was used to guide it. The second research component used experimental methodology in a rural village to examine how extra auditory contextual information affected learning from video. Ninety-two rural Gambian women saw either a direct version of a video about composting or a version with extra contextual information. Learning was measured through the average number of key elements mentioned during reteaching. The learning was high in both groups, and not significantly different. There was a significant interaction between prior knowledge about composting and video version viewed. Additionally, in the experimental research, qualitative, open-ended interviews were used to examine Gambian attitudes regarding video learning. Villagers valued the access to information, the benefits that access provided, the power it gave them in their worlds, and the visual nature of the presentation. This information can be used to guide a continued video refinement process. All of these components contribute to different fields to improve the overall understanding of video education for adults in rural, developing areas
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