Open Access
Techniques for better alias resolution in Internet topology discovery
(IEEE, 2009) García-Jiménez, Santiago; Magaña Lizarrondo, Eduardo; Morató Osés, Daniel; Izal Azcárate, Mikel; Automática y Computación; Automatika eta Konputazioa
One of the challenging problems related with network topology discovery in Internet is the process of IP address alias identification. Topology information is usually obtained from a set of traceroutes that provide IP addresses of routers in the path from a source to a destination. If these traceroutes are repeated between several source/destination pairs we can get a sampling of all IP addresses for crossed routers. In order to generate the topology graph in which each router is a node, it is needed to identify all IP addresses that belong to the same router. In this work we propose improvements over existing methods to obtain alias identification related mainly with the types and options in probing packets.
Open Access
Detección de congestión en la Internet europea
(IEEE, 2007) Hernández, Ana; Magaña Lizarrondo, Eduardo; Izal Azcárate, Mikel; Morató Osés, Daniel; Automática y Computación; Automatika eta Konputazioa
In this paper we present a study about the utilization of one-way delay measurements to detect and characterize network congestion in the european Internet. The experiments have been made using the ETOMIC platfom that allows one-way delay measurement with high precision timestamps. We have found a peculiar router behaviour in which the bottleneck is not the available bandwidth but it is the packet processing power of the router (backplane and CPU constraints). This router has been characterized with several network parameters. Some of them are the dependency of this limitation with the input data rate in packets per second, the size of burst packet losses measured in packets or time and the absence of specific scheduling algorithms in the router that could affect to larger flows.
Open Access
Predicción de tráfico de Internet and aplicaciones
(2001) Bernal, I.; Aracil Rico, Javier; Morató Osés, Daniel; Izal Azcárate, Mikel; Magaña Lizarrondo, Eduardo; Díez Marca, L. A.; Automática y Computación; Automatika eta Konputazioa
In this paper we focus on traffic prediction as a means to achieve dynamic bandwidth allocation in a generic Internet link. Our findings show that coarse prediction (bytes per interval) proves advantageous to perform dynamic link dimensioning, even if we consider a part of the top traffic producers in the traffic predictor.
Open Access
Mejoras en la identificación de tráfico de aplicación basado en firmas
(2008) Santolaya Bea, Néstor; Magaña Lizarrondo, Eduardo; Izal Azcárate, Mikel; Morató Osés, Daniel; Automática y Computación; Automatika eta Konputazioa
Traffic identification has been based traditionally on transport protocol ports, associating always the same ports with the same applications. Nowadays that assumption is not true and new methods like signature identification or statistical techniques are applied. This work presents a method based on signature identification with some improvements. The use of regular expressions for typical applications has been studied deeply and its use has been improved in the aspects of percentage identification and resources consumption. On the other hand, a flows-record structure has been applied in order to classify those packets that do not verify any regular expression. Results are compared with the opensource related project L7-filter, and the improvements are presented. Finally, detailed regular expressions for analyzed applications are included in the paper, especially P2P applications.
Open Access
Video over OBS Networks
(2008) Espina Antolín, Félix; Morató Osés, Daniel; Izal Azcárate, Mikel; Magaña Lizarrondo, Eduardo; Automática y Computación; Automatika eta Konputazioa
Open Access
Approximations for end-to-end delay analysis in OBS networks with light load
(IEEE, 2004) Morató Osés, Daniel; Magaña Lizarrondo, Eduardo; Izal Azcárate, Mikel; Automática y Computación; Automatika eta Konputazioa
In this paper we provide an analysis of end-to-end delay in OBS networks and a large deviations approximation. The analysis is based on an exponential approximation of the OBS router blocking time and on the assumption of Poisson arrivals in routers along the path from source to destination. On the other hand, a lightload assumption is performed, namely, waiting time is mainly due to residual life of the output wavelengths and not to buffering.
Open Access
Delay-throughput curves for timer-based OBS burstifiers with light load
(IEEE, 2006) Izal Azcárate, Mikel; Aracil Rico, Javier; Morató Osés, Daniel; Magaña Lizarrondo, Eduardo; Automática y Computación; Automatika eta Konputazioa
The OBS burstifier delay-throughput curves are analyzed in this paper. The burstifier incorporates a timer-based scheme with minimum burst size, i. e., bursts are subject to padding in light-load scenarios. Precisely, due to this padding effect, the burstifier normalized throughput may not be equal to unity. Conversely, in a high-load scenario, padding will seldom occur. For the interesting light-load scenario, the throughput delay curves are derived and the obtained results are assessed against those obtained by trace-driven simulation. The influence of long-range dependence and instantaneous variability is analyzed to conclude that there is a threshold timeout value that makes the throughput curves flatten out to unity. This result motivates the introduction of adaptive burstification algorithms, that provide a timeout value that minimizes delay, yet keeping the throughput very close to unity. The dependence of such optimum timeout value with traffic long-range dependence and instantaneous burstiness is discussed. Finally, three different adaptive timeout algorithms are proposed, that tradeoff complexity versus accuracy.
Open Access
The European Traffic Observatory Measurement Infraestructure (ETOMIC): a testbed for universal active and passive measurements
(IEEE, 2005) Morató Osés, Daniel; Magaña Lizarrondo, Eduardo; Izal Azcárate, Mikel; Aracil Rico, Javier; Naranjo Abad, Francisco José; Alonso Camaró, Ulisses; Astiz Saldaña, Francisco Javier; Vattay, Gábor; Csabai, István; Hága, Péter; Simon, Gábor; Stéger, József; Automática y Computación; Automatika eta Konputazioa
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 highprecision, 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.
Open Access
Multiresolution analysis of optical burst switching traffic
(IEEE, 2003) Aracil Rico, Javier; Morató Osés, Daniel; Magaña Lizarrondo, Eduardo; Izal Azcárate, Mikel; Automática y Computación; Automatika eta Konputazioa
In this paper, a Multiresolution Analysis is conducted in order to study the self-similar features of Optical Burst Switching (OBS) traffi c. The scenario consists of an OBS backbone with input traffic from a large number of Internet users, that generate Poisson-arriving heavytailed bursts. The results show that long-range dependence is preserved at timescales longer than the burst assembly timeout value while the traffic variability at short timescales is increased.
Open Access
On linear prediction of Internet traffic for packet and burst switching networks
(IEEE, 2001) Morató Osés, Daniel; Aracil Rico, Javier; Díez Marca, L. A.; Izal Azcárate, Mikel; Magaña Lizarrondo, Eduardo; Automática y Computación; Automatika eta Konputazioa
In this paper, we show that prediction algorithms in the least mean square error sense prove better in a burst rather than in a packet switching network. For the latter, further information about the packet arrival distribution within the prediction interval is required. Regarding burst switching, we compare Optical Burst Switching networks with and without linear prediction to conclude that linear prediction provides a significant improvement in end-to-end latency with low bandwidth waste.