Izal Azcárate, Mikel

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Izal Azcárate

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Mikel

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Ingeniería Eléctrica, Electrónica y de Comunicación

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ISC. Institute of Smart Cities

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Now showing 1 - 10 of 55
  • PublicationOpen Access
    Survey on quality of experience evaluation for cloud-based interactive applications
    (MDPI, 2024) Arellano Usón, Jesús; Magaña Lizarrondo, Eduardo; Morató Osés, Daniel; Izal Azcárate, Mikel; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute of Smart Cities - ISC
    A cloud-based interactive application (CIA) is an application running in the cloud with stringent interactivity requirements, such as remote desktop and cloud gaming. These services have experienced a surge in usage, primarily due to the adoption of new remote work practices during the pandemic and the emergence of entertainment schemes similar to cloud gaming platforms. Evaluating the quality of experience (QoE) in these applications requires specific metrics, including interactivity time, responsiveness, and the assessment of video- and audio-quality degradation. Despite existing studies that evaluate QoE and compare features of general cloud applications, systematic research into QoE for CIAs is lacking. Previous surveys often narrow their focus, overlooking a comprehensive assessment. They touch on QoE in broader contexts but fall short in detailed metric analysis. Some emphasise areas like mobile cloud computing, omitting CIA-specific nuances. This paper offers a comprehensive survey of QoE measurement techniques in CIAs, providing a taxonomy of input metrics, strategies, and evaluation architectures. State-of-the-art proposals are assessed, enabling a comparative analysis of their strengths and weaknesses and identifying future research directions.
  • PublicationOpen Access
    Resolución de alias para el cálculo de topologías
    (2007) García-Jiménez, Santiago; Magaña Lizarrondo, Eduardo; Izal Azcárate, Mikel; Morató Osés, Daniel; Automática y Computación; Automatika eta Konputazioa
    The network topology is a fundamental parameter for managers and researchers. The traditional methodology for discovering the topology of a network is based on the tool traceroute, used from several vantage points in different subnetworks. The result is a set of sink trees where the nodes are the discovered IP addresses from the routers. However, few tools have faced the problem of identifying the nodes in different sink trees as interfaces in the same router. This paper shows a new methodology for this problem of alias resolution. It has been used in the european research network using the ETOMIC platform. It shows that the traditional methodologies are not effective in today’s networking scenario but can be easily improved at least in a factor of 3 in the number of successes.
  • PublicationOpen Access
    The ETOMIC active probing infrastructure: demo proposal
    (2006) Csabai, István; Hága, Péter; Simon, Gábor; Stéger, József; Vattay, Gábor; Magaña Lizarrondo, Eduardo; Morató Osés, Daniel; Izal Azcárate, Mikel; Aracil Rico, Javier; Automática y Computación; Automatika eta Konputazioa
    ETOMIC (www.etomic.org) is a European Union sponsored effort, that aims at providing a Paneuropean traffic measurement infrastructure. This infrastructure contains 15 PC based active probing nodes equipped with high-precision, sending capable DAG cards and GPS receivers to achieve time synchronization. Such cards are specifically designed to transmit packet trains with strict timing, in the range of nanoseconds. Every kind of active probing techniques can be applied on the nodes, from the quite simple ping application to the complex network tomography methods which are based on the synchronized sending capability of the DAG cards. The measurement nodes are centrally managed via a web platform, where the new arbitrary measurement jobs can be uploaded to and handled. The management system schedules the jobs and does the maintenance tasks. Now, the infrastructure is opened to the networking community. This paper describes the node architectures, the management system, and the proposed conference demonstration.
  • PublicationOpen Access
    Midiendo retardos y pérdidas en las redes móviles de alta velocidad
    (2015) Prieto Suárez, Iria; Izal Azcárate, Mikel; Magaña Lizarrondo, Eduardo; Morató Osés, Daniel; Automática y Computación; Automatika eta Konputazioa
    Mobile networks are constantly evolving, but still, due to their nature, it is not trivial to analayse how they face up different kinds of traffic. On the Internet a wide range of services can be found. Usually the majority send large packets, i.e Web services, but others, like VoIP, send small packets. The question is how the mobile networks manage all this traffic. In this work experiments to measure losses and times of sending different packet size bursts are described. Also, preliminary results for experiments with a real network mobile client, are analaysed showing that the performance of the network is different depending on the size of packet.
  • PublicationOpen Access
    IP traffic prediction and equivalent bandwidth for DAMA TDMA protocols
    (IEEE, 2003) Aracil Rico, Javier; Izal Azcárate, Mikel; Morató Osés, Daniel; Magaña Lizarrondo, Eduardo; Automática y Computación; Automatika eta Konputazioa
    The use of IP traffic prediction techniques for DAMA TDMA protocols is investigated in this paper. The predicted traffic distribution is derived when the input traffic shows long-range dependence features. Furthermore, an equivalent bandwidth is calculated, which allows the wireless terminal to request a certain amount of bandwidth (slot duration) in terms of a target traffic loss probability. The numerical results indicate very good traffic prediction capabilities, together with moderate bandwidth loss.
  • PublicationOpen Access
    Validation of HTTP response time from network traffic as an alternative to web browser instrumentation
    (IEEE, 2021) López Romera, Carlos; Morató Osés, Daniel; Magaña Lizarrondo, Eduardo; Izal Azcárate, Mikel; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación
    The measurement of response time in hypertext transfer protocol (HTTP) requests is the most basic proxy measurement method for evaluating web browsing quality. It is used in the research literature and in application performance measurement instruments. During the development of a website, response time is obtained from in-browser measurements. After the website has been deployed, network traffic is used to continuously monitor activity, and the measurement data are used for service management and planning. In this study, we evaluate the accuracy of the measurements obtained from network traffic by comparing them with the in-browser measurement of resource load time. We evaluate the response times for encrypted and clear-text requests in an emulated network environment, in a laboratory deployment equivalent to a data centre network, and accessing popular web sites on the public Internet. The accuracy for response time measurements obtained from network traffic is noticeable higher for Internet long distance paths than for lowdelay paths (below 20 ms round-trip). The overhead of traffic encryption in secure HTTP requests has a negative effect on measurement accuracy, and we find relative measurement errors higher than 70% when using network traffic to infer HTTP response times compared
  • PublicationOpen 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.
  • PublicationOpen Access
    Online classification of user activities using machine learning on network traffic
    (Elsevier, 2020) Labayen Guembe, Víctor; Magaña Lizarrondo, Eduardo; Morató Osés, Daniel; Izal Azcárate, Mikel; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren
    The daily deployment of new applications, along with the exponential increase in network traffic, entails a growth in the complexity of network analysis and monitoring. Conversely, the increasing availability and decreasing cost of computational capacity have increased the popularity and usability of machine learning algorithms. In this paper, a system for classifying user activities from network traffic using both supervised and unsupervised learning is proposed. The system uses the behaviour exhibited over the network and classifies the underlying user activity, taking into consideration all of the traffic generated by the user within a given time window. Those windows are characterised with features extracted from the network and transport layer headers in the traffic flows. A three-layer model is proposed to perform the classification task. The first two layers of the model are implemented using K-Means, while the last one uses a Random Forest to obtain the activity labels. An average accuracy of 97.37% is obtained, with values of precision and recall that allow online classification of network traffic for Quality of Service (QoS) and user profiling, outperforming previous proposals.
  • PublicationOpen Access
    Protocol-agnostic method for monitoring interactivity time in remote desktop services
    (Springer Nature, 2021-02-24) Arellano Usón, Jesús; Magaña Lizarrondo, Eduardo; Morató Osés, Daniel; Izal Azcárate, Mikel; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute of Smart Cities - ISC
    The growing trend of desktop virtualisation has facilitated the reduction of management costs associated with traditional systems and access to services from devices with different capabilities. However, desktop virtualisation requires controlling the interactivity provided by an infrastructure and the quality of experience perceived by users. This paper proposes a methodology for the quantification of interactivity based on the measurement of the time elapsed between user interactions and the associated responses. Measurement error is controlled using a novel mechanism for the detection of screen changes, which can lead to erroneous measurements. Finally, a campus virtual desktop infrastructure and the Amazon WorkSpaces solution are analysed using this proposed methodology. The results demonstrate the importance of the location of virtualisation infrastructure and the types of protocols used by remote desktop services.
  • PublicationOpen Access
    Analysis of Internet services in IP over ATM networks
    (IEEE, 1999) Aracil Rico, Javier; Morató Osés, Daniel; Izal Azcárate, Mikel; Automática y Computación; Automatika eta Konputazioa
    This paper presents a trace-driven analysis of IP over ATM services from a user-perceived quality of service standpoint. QoS parameters such as the sustained throughput for transactional services and other ATM layer parameters such as the burstiness (MBS) per connection are derived. On the other hand, a macroscopic analysis that comprises percentage of flows and bytes per service, TCP transaction duration and mean bytes transferred in both ways is also presented. The traffic trace is obtained with a novel measurement equipment that combines a header extraction hardware and a high end UNIX workstation capable of providing a timestamp accuracy in the order of microseconds. The ATM link under analysis concentrates traffic from a large population of 1,500 hosts from Public University of Navarra campus network, that produce 1,700,000 TCP connections approximately in the measurement period of one week. The results obtained from such a wealth of data suggest that QoS is primarily determined by transport protocols and not by ATM bandwidth. The sustained throughput of TCP connections never grows beyond 80 Kbps with 70% probability in the data transfer phase (i. e., in the ESTABLISHED state) and we observe a strong influence of the connection establishment phase in the user-perceived throughput. On the other hand, the burstiness of individual TCP connections is rather small, namely TCP connections do not produce bursts according to the geometric law given by slow start and commonly assumed in previously published studies.