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Computer Networks. 01/2012;
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ABSTRACT: The geographic layout of the physical Internet inherently determines important network properties and traffic characteristics. To give insight into the geography of the Internet, we examine the spatial properties of the topology and routing. To represent the network we conducted a geographically dispersed traceroute campaign, and embedded the extracted topology into the geographic space by applying a novel IP geolocalization service, called Spotter. In this paper we present the frequency analysis of link lengths, quantify path circuitousness and explore the symmetry of end-to-end Internet routes.
INFOCOM, 2011 Proceedings IEEE; 05/2011
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ABSTRACT: a b s t r a c t This study outlines two novel techniques which can be used in the area of IP geolocation. First we introduce a detailed path-latency model to be able to determine the overall prop-agation delays along the network paths more accurately. The knowledge of accurate prop-agation delay values then leads to more precise geographic distance estimation between hosts and measurement nodes. Besides these distance values the evaluation process also takes into account the discovered topology between the measurement points, and end-to-end latency measurements as well. In addition to the application of the detailed path-latency model, we describe a method which utilizes high-precision one-way delay measurements to further increase the accuracy of router geolocation techniques. The pre-cise one-way delay values are used as a ''path-constraint" to limit the overall geographic distance between the measurement nodes. This approach can be used to localize all the network routers along the network path between the measurement nodes, but cannot be applied to end-host localization. The techniques introduced in this paper are validated in wide range of experiments performed in the ETOMIC measurement infrastructure and in PlanetLab.
Computer Networks. 01/2010; 54.
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Hungarian Telecommunication. 01/2010;
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I. Csabai,
A. Fekete,
P. Hága,
B. Hullár,
G. Kurucz,
S. Laki,
P. Mátray,
J. Stéger,
G. Vattay,
F. Espina,
S. G. Jimenez,
M. Izal,
E. Magana,
D. Morato,
J. Aracil,
F. Gomez,
I. Gonzalez,
S. Lopez-Buedo,
V. Moreno,
J. Ramos
TRIDENTCOM, Berlin, Germany; 01/2010
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Proc. European Conf. Complex Systems, Warwick, UK. 01/2009;
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ABSTRACT: Efficient and reliable available bandwidth measurement remains an important goal for many applications. In this paper we introduce an empirical bandwidth estimation tool based on neural networks. Training the neural network on simulation data, it provides reliable estimation of physical and available bandwidth for simulated single and multi-hop networks, in laboratory environment and among the real world conditions of the ETOMIC testbed.
Testbeds and Research Infrastructure for the Development of Networks and Communities, 2007. TridentCom 2007. 3rd International Conference on; 06/2007
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ABSTRACT: 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.
INFOCOM 2006. 25th IEEE International Conference on Computer Communications. Proceedings; 05/2006
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Proc. IEEE INFOCOM. 01/2006;
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D. Morato,
E. Magana,
M. Izal,
J. Aracil,
F. Naranjo,
F. Astiz,
U. Alonso, I. Csabai,
P. Haga,
G. Simon,
J. Steger,
G. Vattay
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ABSTRACT: 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.
Testbeds and Research Infrastructures for the Development of Networks and Communities, 2005. Tridentcom 2005. First International Conference on; 03/2005
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I. K. Baldry,
K. Glazebrook,
T. Budavári,
D. J. Eisenstein,
J. Annis,
N. A. Bahcall,
M. R. Blanton,
J. Brinkmann, I. Csabai,
T. M. Heckman,
H. Lin,
J. Loveday,
R. C. Nichol,
D. P. Schneider
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ABSTRACT: We construct and analyse a u-band selected galaxy sample from the Sloan Digital Sky Survey (SDSS) Southern Survey, which covers 275 deg2. The sample includes 43 223 galaxies with spectroscopic redshifts in the range 0.005 < z < 0.3 and with 14.5 < u < 20.5. The signal-to-noise (S/N) ratio in the u-band Petrosian aperture is improved by co-adding multiple epochs of imaging data and by including sky-subtraction corrections. Luminosity functions for the near-UV 0.1u band (λ≈ 322 ± 26 nm) are determined in redshift slices of width 0.02, which show a highly significant evolution in M* of −0.8 ± 0.1 mag between z= 0 and 0.3; with M*−5 log h70=−18.84 ± 0.05 (AB mag), log φ*=−2.06 ± 0.03 (h370 Mpc−3) and log ρL= 19.11 ± 0.02 (h70 W Hz−1 Mpc−3) at z= 0.1. The faint-end slope determined for z < 0.06 is given by α=−1.05 ± 0.08. This is in agreement with recent determinations from the Galaxy Evolution Explorer at shorter wavelengths. Comparing our z < 0.3 luminosity density measurements with 0.2 < z < 1.2 from Classifying Objects by Medium Band Observations in 17 Filters (COMBO-17), we find that the 280-nm density evolves as ρL∝ (1 +z)β with β= 2.1 ± 0.2; and find no evidence for any change in slope over this redshift range. By comparing with other measurements of cosmic star formation history, we estimate that the effective dust attenuation at 280 nm has increased by 0.8 ± 0.3 mag between z= 0 and 1.
Monthly Notices of the Royal Astronomical Society 03/2005; 358(2):441 - 456. · 4.90 Impact Factor
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E. Magana,
D. Morato,
M. Izal,
J. Aracil,
F. Naranjo,
F. Astiz,
U. Alonso, I. Csabai,
P. Haga,
G. Simon,
J. Steger,
G. Vattay
[show abstract]
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ABSTRACT: 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.
IP Operations and Management, 2004. Proceedings IEEE Workshop on; 11/2004
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ABSTRACT: Self-similarity in the network traffic has been studied from several aspects:
both at the user side and at the network side there are many sources of the
long range dependence. Recently some dynamical origins are also identified: the
TCP adaptive congestion avoidance algorithm itself can produce chaotic and long
range dependent throughput behavior, if the loss rate is very high. In this
paper we show that there is a close connection between the static and dynamic
origins of self-similarity: parallel TCPs can generate the self-similarity
themselves, they can introduce heavily fluctuations into the background traffic
and produce high effective loss rate causing a long range dependent TCP flow,
however, the dropped packet ratio is low.
02/2004;
