József Stéger
Eötvös Loránd University
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Publication
Featured researches published by József Stéger.
testbeds and research infrastructures for the development of networks and communities | 2005
Daniel Morató; Eduardo Magaña; Mikel Izal; Javier Aracil; Francisco Naranjo; F. Astiz; Ulisses Alonso; István Csabai; Péter Hága; G. Simon; József Stéger; Gábor Vattay
The European Traffic Observatory is a European Union VI Framework Program sponsored effort, within the Integrated Project EVERGROW, that aims at providing a paneuropean traffic measurement infrastructure with high-precision, GPS-synchronized monitoring nodes. This paper describes the system and node architectures, together with the management system. On the other hand, we also present the testing platform that is currently being used for testing ETOMIC nodes before actual deployment.
ip operations and management | 2004
Eduardo Magaña; Daniel Morató; Mikel Izal; Javier Aracil; F. Naranjo; F. Astiz; U. Alonso; István Csabai; P. Haga; G. Simon; József Stéger; Gábor Vattay
The European traffic observatory is a European Union VI framework program sponsored effort, within the integrated project EVERGROW, that aims at providing an panEuropean traffic measurement infrastructure with high-precision, GPS-synchronized monitoring nodes. This paper describes the system and node architectures, together with the management system.
Future Generation Computer Systems | 2015
Jeroen van der Ham; József Stéger; Sándor Laki; Yiannos Kryftis; Vasilis Maglaris; Cees de Laat
The NOVI Information Model (IM) and the corresponding data models are the glue between the software components in the NOVI Service Layer. The IM enables the communication among the various components of the NOVI Architecture and supports the various functionalities it offers. The NOVI IM consists of three main ontologies: resource, monitoring and policy ontology that have evolved over time to accommodate the emerging requirements of the NOVI architecture. This article presents the NOVI IM and its ontologies, together with an overview of how the NOVI software prototypes have benefited from using the IM.
ieee international conference computer and communications | 2006
István Csabai; Péter Hága; Péter Mátray; Gábor Simon; József Stéger; Gábor Vattay
This paper presents operational experience of large-scale unicast network tomography, that samples a part of the European Internet. In the paper we describe in detail the ETOMIC measurement platform that was used to conduct the experiments, and its potential in future scaled-up measurements. The main results of the paper are maps showing various spatial and temporal structure in the characteristics of queueing delay corresponding to the resolved part of the European Internet. These maps reveal that the average queueing delay on different network segments spans more than two orders of magnitude. At the most loaded time of day we find that the distribution of average queueing delays among the different segments follows closely a log-normal distribution.
2011 5th International DMTF Academic Alliance Workshop on Systems and Virtualization Management: Standards and the Cloud (SVM) | 2011
Jeroen van der Ham; Chrysa A. Papagianni; József Stéger; Péter Mátray; Yiannos Kryftis; Paola Grosso; Leonidas Lymberopoulos
Users of the Future Internet will expect seamless and secure access to virtual resources distributed across multiple domains. These federated platforms are the core of the Future Internet. It is clear that information models, and concrete implementation in data models, are necessary prerequisites for all federative operations, information exchanges, and service support. This position paper describes our approach to the development of an information model for federating virtual infrastructures. Our basic assumption is that semantic resource descriptions with context-awareness, in the form of Semantic Web descriptions, better support services in federated platforms. We use our experiences in the development of two ontologies for computer networks and for network monitoring, NDL and MOMENT, to support and guide our development. The requirements of our envisaged Information and Data models are driven from a concrete use-case, using PlanetLab and FEDERICA as examples of virtualized platforms in a Future Internet federated environment.
testbeds and research infrastructures for the development of networks and communities | 2010
István Csabai; Attila Fekete; Péter Hága; Béla Hullár; Gábor Kurucz; Sándor Laki; Péter Mátray; József Stéger; Gábor Vattay; Felix Espina; Santiago Garcia-Jimenez; Mikel Izal; Eduardo Magaña; Daniel Morató; Javier Aracil; Francisco Gómez; Ivan Gonzalez; Sergio López-Buedo; Victor Moreno; Javier Ramos
ETOMIC is a network traffic measurement platform with high precision GPS-synchronized monitoring nodes. The infrastructure is publicly available to the network research community, supporting advanced experimental techniques by providing high precision hardware equipments and a Central Management System. Researchers can deploy their own active measurement codes to perform experiments on the public Internet. Recently, the functionalities of the original system were significantly extended and new generation measurement nodes were deployed. The system now also includes well structured data repositories to archive and share raw and evaluated data. These features make ETOMIC as one of the experimental facilities that support the design, development and validation of novel experimental techniques for the future Internet. In this paper we focus on the improved capabilities of the management system, the recent extensions of the node architecture and the accompanying database solutions.
testbeds and research infrastructures for the development of networks and communities | 2011
Béla Hullár; Sándor Laki; József Stéger; István Csabai; Gábor Vattay
Distributed network measurements are essential to characterize the structure, dynamics and operational state of the Internet. Although in the last decades several such systems have been created, the easy access of these infrastructures and the orchestration of complex measurements are not solved. We propose a system architecture that combines the flexibility of mature network measurement facilities such as PlanetLab or ETOMIC with the general accessibility and popularity of public services like Web based bandwidth measurement or traceroute servers. To realize these requirements we developed a network measurement platform, called SONoMA, based on Web Services and the basic principles of SOA, which is a well established paradigm in distributed business application development. Our approach opens the door to perform atomic and complex network measurements in real time, handles heterogeneous measurement devices, automatically stores the results in a public database and protects against malicious users as well. Furthermore, SONoMA is not only a tool for network researchers but it opens the door to developing novel applications and services requiring real-time and large scale network measurements.
IEEE Communications Magazine | 2015
Vasilis Maglaris; Chrysa A. Papagianni; Georgios Androulidakis; Mary Grammatikou; Paola Grosso; J. van der Ham; C. de Laat; B. Pietrzak; Bartosz Belter; József Stéger; Sándor Laki; Mauro Campanella; Sebastià Sallent
This article presents the design and pilot implementation of a suite of intelligent methods, algorithms, and tools for federating heterogeneous experimental platforms (domains) toward a holistic Future Internet experimentation ecosystem. The proposed framework developed within the NOVI research and experimentation European collaborative effort, aims at providing a modular data, control, and management plane architecture that includes: an information model capturing the abstractions of virtualized resources residing in different yet interworking experimental platforms; resource mapping algorithms tackling the inter-domain virtual network embedding problem; mechanisms providing interoperability of monitoring tools; policy-based management services for role-based intra and inter-domain management policies; and dataplane stitching mechanisms to enable the composition of user-specific slices (baskets of virtual resources drawn from the federated substrate). The NOVI framework was deployed and validated in a combined testbed consisting of two dissimilar platforms: a private PlanetLab domain with resources interconnected over the public Internet; and FEDERICA, an infrastructure of virtual resources interconnected via dedicated networking facilities of European National Research and Education Networks and GÉANT. This pre-normative work is expected to contribute to bridging Future Internet experimental federations with interconnected cloud architectures and interworked public/private data-centers, adding value via its intelligent services, information models, and composite algorithms.
Complexus | 2006
Gábor Simon; József Stéger; Péter Hága; István Csabai; Gábor Vattay
In this paper we show how to go beyond the study of the topological properties of the Internet, by measuring its dynamical state using special active probing techniques and the methods of network tomography. We demonstrate this approach by measuring the key state parameters of Internet paths, the characteristics of queuing delay, in a part of the European Internet. In the paper we describe in detail the ETOMIC measurement platform that was used to conduct the experiments, and the applied method of queuing delay tomography. The main results of the paper are maps showing various spatial structure in the characteristics of queuing delay corresponding to the resolved part of the European Internet. These maps reveal that the average queuing delay of network segments spans more than two orders of magnitude, and that the distribution of this quantity is very well fitted by the log-normal distribution.
FP7 FIRE/EULER | 2013
József Stéger; Sándor Laki; Péter Mátray
Monitoring and measurement is a fundamental building block for developing and testing new protocols, routing algorithms and networked applications. In a federated virtualized testbed they allow other service components and testbed-users to follow the current state of the network, and on the other hand they enable intelligent automatic decision-making, e.g. during the embedding of a virtual topology. However, it is not a trivial task to enable federated monitoring functionalities due to the cross-domain nature of the system. The heterogeneity of the federated networks (including network elements and monitoring tools) pose a major challenge. In this chapter we present a framework that tackles some of the most important related problems. We also introduce a specific ontology to describe monitoring and network measurement tasks. This semantic approach enables the flexible integration of a wide range of monitoring tools, metrics and databases. Our Monitoring Framework was created within the NOVI FP7 STREP project which federates two major virtualized testbeds, PlanetLab and Federica.