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  • A tutorial on the flexible optical networking paradigm: State of the art, trends, and research challenges

     Tomkos, Ioannis; Azodolmolky, Siamak; Sole Pareta, Josep; Careglio, Davide; Palkopoulou, Eleni
    Proceedings of the IEEE
    Vol. 102, num. 9, p. 1317-1337
    DOI: 10.1109/JPROC.2014.2324652
    Date of publication: 2014-09-01
    Journal article

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    Rigid fixed-grid wavelength division multiplexing (WDM) optical networks can no longer keep up with the emerging bandwidth-hungry and highly dynamic services in an efficient manner. As the available spectrum in optical fibers becomes occupied and is approaching fundamental limits, the research community has focused on seeking more advanced optical transmission and networking solutions that utilize the available bandwidth more effectively. To this end, the flexible/elastic optical networking paradigm has emerged as a way to offer efficient use of the available optical resources. In this work, we provide a comprehensive view of the different pieces composing the 'flexible networking puzzle' with special attention given to capturing the occurring interactions between different research fields. Only when these interrelations are clearly defined, an optimal network-wide solution can be offered. Physical layer technological aspects, network optimization for flexible networks, and control plane aspects are examined. Furthermore, future research directions and open issues are discussed.

  • Challenges and requirements of a control plane for elastic optical networks

     Sócrates Dantas, Joana; Careglio, Davide; Perello Muntan, Jordi; Melo Silveira, Regina; Ruggiero, Wilson Vicente; Sole Pareta, Josep
    Computer networks
    Vol. 72, p. 156-171
    DOI: 10.1016/j.comnet.2014.07.007
    Date of publication: 2014-10-29
    Journal article

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    Elastic optical networks have emerged as a promising technology for the efficient use of optical network resources. Its adaptable characteristics and adjustable data rate enable operators to meet the diverse granularity of their clients needs. In order to automate an elastic optical network operation, a control plane is required. Wavelength Switched Optical Networks (WSON) may already rely on a robust control plane which enables dynamic network management, provides prompt demand reply optimizing spectrum use, and implements important network features as survivability strategies, differentiated service, and grooming procedures. Due to its specific characteristics, elastic optical networks may not implement traditional WSON control plane solutions without further enhancement. Therefore, recent research efforts have been focusing on developing the control plane for this new technology, in most cases by proposing extensions to the currently available architectures. This paper describes a survey on the current ongoing research efforts to define elastic optical network control plane architecture. It identifies and classifies the most relevant proposals currently found in literature, and discusses how these propositions address the main requirements to design a control plane which enables automating the specific functions of an elastic optical network.

  • Network Traffic Classification: From Theory to Practice  Open access

     Carela Español, Valentin
    Universitat Politècnica de Catalunya
    Theses

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    Desde sus orígenes hasta la actualidad, Internet ha estado en constante evolución. El análisis y la monitorización de las redes tratan de arrojar luz sobre esta caja negra de ordenadores interconectados que es Internet. En particular, la clasificación de tráfico de red se ha vuelto crucial para la comprensión de Internet. Durante los últimos años, la comunidad investigadora ha propuesto muchas soluciones para clasificar con precisión el tráfico de red. Sin embargo, la continua evolución de las aplicaciones de Internet y sus técnicas para evitar ser detectadas hace su identificación un tarea muy complicada, que está lejos de estar completamente resuelta.Esta tesis aborda el problema de la clasificación de tráfico de red desde un punto de vista más práctico, tratando de hacer confluir las necesidades de los entornos reales y la investigación llevada a cabo. En este trabajo identificamos diferentes problemas que entorpecen la introducción de las nuevas propuestas para clasificar el tráfico en redes troncales. El primer bloque de esta tesis pretende facilitar el despliegue de las técnicas de clasificación en redes troncales. Para ello estudiamos la viabilidad de usar como entrada de nuestra técnica NetFlow, un protocolo de monitorización implementado en la mayoría de enrutadores. Además, dado que la aplicación de muestreo de paquetes es una práctica muy extendida en las redes troncales, estudiamos su impacto en la clasificación y proponemos un método para mejorar su precisión en este escenario. Los resultados muestran que es posible conseguir una alta precisión tanto con datos NetFlow muestreados como no muestreados, a pesar de la limitada información que nos proporciona NetFlow.Una vez desplegado el sistema de clasificación el siguiente objetivo es mantener su precisión a lo largo del tiempo. El segundo bloque se centra en este problema persiguiendo automatizar el proceso de mantenimiento y hacerlo sin intervención humana. Siguiendo la línea del primer bloque, proponemos un sistema de clasificación que combina varias técnicas que usan únicamente NetFlow como entrada para la clasificación. A partir de este sistema mostramos que los modelos de clasificación sufren de obsolescencia temporal y espacial y, para ello, diseñamos e implementamos un sistema de reentreno automático capaz de actualizar automáticamente los modelos y mantener la clasificación precisa a lo largo del tiempo. Yendo un paso más allá, introducimos el uso de técnicas de Aprendizaje Máquina (ML, por sus siglas en inglés) basadas en flujos de datos para la clasificación de tráfico de red. En particular, proponemos una solución basada en Hoeffding Adaptive Trees. Además de las características propias de las técnicas basadas en flujos de datos (i.e., inspección única de cada instancia, con una cantidad de memoria predefinida y en un tiempo limitado), nuestra técnica es capaz de adaptarse automáticamente a los cambios en el tráfico usando únicamente datos NetFlow como entrada para la clasificación. El tercer bloque pretende ser un primer paso hacia la validación imparcial de las propuestas de la literatura. El amplio rango de técnicas, conjuntos de datos y generadores de verdad terreno hacen la validación de los diferentes clasificadores una tarea muy complicada. Con ese fin evaluamos la fiabilidad de diferentes técnicas basadas en Inspección Profunda de Paquetes (DPI, por sus siglas en inglés) habitualmente usadas en la literatura para la generación de la verdad terreno. Los resultados muestran que algunas técnicas DPI presentan graves errores que desaconsejan su uso en su estado actual. Además, para abordar la falta de conjuntos de datos públicos, publicamos algunos de los usados en nuestras evaluaciones para facilitar la comparación de las técnicas existentes. En particular, el conjunto de datos publicado en el tercer bloque es el primer conjunto de datos etiquetado fiablemente y con el contenido completo que está disponible para la comunidad investigadora.

    Since its inception until today, the Internet has been in constant transformation. The analysis and monitoring of data networks try to shed some light on this huge black box of interconnected computers. In particular, the classification of the network traffic has become crucial for understanding the Internet. During the last years, the research community has proposed many solutions to accurately identify and classify the network traffic. However, the continuous evolution of Internet applications and their techniques to avoid detection make their identification a very challenging task, which is far from being completely solved. This thesis addresses the network traffic classification problem from a more practical point of view, filling the gap between the real-world requirements from the network industry, and the research carried out. The first block of this thesis aims to facilitate the deployment of existing techniques in production networks. To achieve this goal, we study the viability of using NetFlow as input in our classification technique, a monitoring protocol already implemented in most routers. Since the application of packet sampling has become almost mandatory in large networks, we also study its impact on the classification and propose a method to improve the accuracy in this scenario. Our results show that it is possible to achieve high accuracy with both sampled and unsampled NetFlow data, despite the limited information provided by NetFlow. Once the classification solution is deployed it is important to maintain its accuracy over time. Current network traffic classification techniques have to be regularly updated to adapt them to traffic changes. The second block of this thesis focuses on this issue with the goal of automatically maintaining the classification solution without human intervention. Using the knowledge of the first block, we propose a classification solution that combines several techniques only using Sampled NetFlow as input for the classification. Then, we show that classification models suffer from temporal and spatial obsolescence and, therefore, we design an autonomic retraining system that is able to automatically update the models and keep the classifier accurate along time. Going one step further, we introduce next the use of stream-based Machine Learning techniques for network traffic classification. In particular, we propose a classification solution based on Hoeffding Adaptive Trees. Apart from the features of stream-based techniques (i.e., process an instance at a time and inspect it only once, with a predefined amount of memory and a bounded amount of time), our technique is able to automatically adapt to the changes in the traffic by using only NetFlow data as input for the classification. The third block of this thesis aims to be a first step towards the impartial validation of state-of-the-art classification techniques. The wide range of techniques, datasets, and ground-truth generators make the comparison of different traffic classifiers a very difficult task. To achieve this goal we evaluate the reliability of different Deep Packet Inspection-based techniques (DPI) commonly used in the literature for ground-truth generation. The results we obtain show that some well-known DPI techniques present several limitations that make them not recommendable as a ground-truth generator in their current state. In addition, we publish some of the datasets used in our evaluations to address the lack of publicly available datasets and make the comparison and validation of existing techniques easier.

  • ARQUITECTURA CON CONOCIMIENTO DEL ENTORNO DE LA FUTURA INTERNET

     Santos Boada, German; Barlet Ros, Pere; Hesselbach Serra, Xavier; Raspall Chaure, Federico; De Almeida Amazonas, Jose Roberto; Marzo Lázaro, José Luis; Fàbrega Soler, LLuís; Vilà Talleda, Pere; Calle Ortega, Eusebio; Sole Pareta, Josep
    Competitive project

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  • Sistemes de comunicacions i arquitectures de banda ampla (CBA)

     Sole Pareta, Josep; Careglio, Davide; Cruellas Ibarz, Juan Carlos; Barlet Ros, Pere; Santos Boada, German; Cabellos Aparicio, Alberto; Ricciardi, Sergio; Coras, Florin-tudorel; Llatser Marti, Ignacio; Carela Español, Valentin; Sócrates Dantas, Joana; Rodriguez Natal, Alberto; Abadal Cavalle, Sergi; Dimopoulos, Georgios; Gomez Cid-fuentes, Raul; Leon Gaixas, Sergio; Mestres Sugrañes, Albert; Perello Muntan, Jordi; Lopez Bresco, Albert; Domingo Pascual, Jordi
    Competitive project

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  • A study in current dynamic fragmentation-aware RSA algorithms

     Sócrates Dantas, Joana; Melo Silveira, Regina; Careglio, Davide; De Almeida Amazonas, Jose Roberto; Sole Pareta, Josep; Ruggiero, Wilson Vicente
    International Conference on Transparent Optical Networks
    p. 1-4
    DOI: 10.1109/ICTON.2014.6876510
    Presentation's date: 2014-07-06
    Presentation of work at congresses

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    Recently proposed Elastic Optical Networks (EON) provide optimized bandwidth utilization through a better fitting match between connection bandwidth requirements and spectrum occupation. In an EON, lightpaths are established using a Routing and Spectrum Assignment (RSA) algorithm. Nonetheless, a novel problem arises in EON, known as the fragmentation problem. Indeed, as connections are dynamically established and terminated, spectrum may become fragmented and jeopardize the establishment of future connections. In this situation, the contiguity and continuity constraints in the RSA problem are harder to be guaranteed and therefore connections' blocking probability increases. In this paper we present and analyse some fragmentation-aware RSA algorithms currently found in the literature and analyse their performance when implemented alone or in tandem.

  • A critical review of OpenFlow/SDN-based networks

     De Almeida Amazonas, Jose Roberto; Santos Boada, German; Sole Pareta, Josep
    International Conference on Transparent Optical Networks
    p. 1-5
    DOI: 10.1109/ICTON.2014.6876509
    Presentation's date: 2014-07-06
    Presentation of work at congresses

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    The separation of the data and control planes simplify the implementation of SDN applications. The centralised architecture of a controller based on the OpenFlow protocol is appealing to the network operators. We have reviewed the concept of SDNs and its extension to optical networks, and constrained and unconstrained wireless access networks. The current status of the proposed and implemented SDN architectures is such that the ful¿lment of a SLA is an open issue. This aspect is left to be tackled by the SDN applications and the proposed architectures do not provide means to describe the interplay between different technology domains. In this paper we make an in depth analysis of the current proposed architectures and identify important challenges to be addressed by a novel integrated SDN architecture.

  • Metaheuristic hybridizations for the regenerator placement and dimensioning problem in sub-wavelength switching optical networks

     Pedrola Escriba, Oscar; Careglio, Davide; Klinkowski, Miroslaw; Velasco Esteban, Luis; Bergman, K.; Sole Pareta, Josep
    European journal of operational research
    Vol. 224, num. 3, p. 614-624
    DOI: 10.1016/j.ejor.2012.08.011
    Date of publication: 2013-02-01
    Journal article

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    Physical layer impairments severely limit the reach and capacity of optical systems, thereby hampering the deployment of transparent optical networks (i.e., no electrical signal regenerators are required). Besides, the high cost and power-consumption of regeneration devices makes it unaffordable for network operators to consider the opaque architecture (i.e., regeneration is available at every network node). In this context, translucent architectures (i.e., regeneration is only available at selected nodes) have emerged as the most promising short term solution to decrease costs and energy consumption in optical backbone networks. Concurrently, the coarse granularity and inflexibility of legacy optical technologies have re-fostered great interest in sub-wavelength switching optical networks, which introduce optical switching in the time domain so as to further improve resources utilization. In these networks, the complex regenerator placement and dimensioning problem emerges. In short, this problem aims at minimizing the number of electrical regenerators deployed in the network. To tackle it, in this paper both a greedy randomized adaptive search procedure and a biased random-key genetic algorithm are developed. Further, we enhance their performance by introducing both path-relinking and variable neighborhood descent as effective intensification procedures. The resulting hybridizations are compared among each other as well as against results from optimal and heuristic mixed integer linear programming formulations. Illustrative results over a broad range of network scenarios show that the biased random-key genetic algorithm working in conjunction with these two intensification mechanisms represents a compelling network planning algorithm for the design of future sub-wavelength optical networks.

  • Low latency and high throughput dynamic network nfrastructures for high performance datacentre interconnects

     Ricciardi, Sergio; Sole Pareta, Josep; Pedrola Escriba, Oscar; Careglio, Davide
    Competitive project

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  • Scan detection under sampling: a new perspective

     Paredes Oliva, Ignasi; Barlet Ros, Pere; Sole Pareta, Josep
    Computer
    Vol. 46, num. 4, p. 38-44
    DOI: 10.1109/MC.2013.70
    Date of publication: 2013-04-01
    Journal article

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    In tests using the same fraction of packets for comparison, packet sampling outperformed flow sampling for scan detection, while both selective sampling and a proposed extension that uses significantly less resources were superior to either of these techniques. The Web extra at http://youtu.be/Mgf8_a0fRs0 is a slide show that considers how in tests using the same fraction of packets for comparison, packet sampling outperformed flow sampling for scan detection, while both selective sampling and a proposed extension that uses significantly less resources were superior to either technique.

  • Cost feasibility analysis of translucent optical networks with shared wavelength converters

     Pedrola Escriba, Oscar; Careglio, Davide; Klinkowski, Miroslaw; Sole Pareta, Josep; Bergman, Keren
    Journal of optical communications and networking
    Vol. 5, num. 2, p. 104-115
    DOI: 10.1364/JOCN.5.000104
    Date of publication: 2013-01-07
    Journal article

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    Translucent optical networks have emerged as potential yet feasible candidates to bridge the gap between the opaque and transparent network architectures. By allowing electrical 3R signal regeneration only at selected points in the network, translucent architectures represent a cost-effective, power-ef¿cient solution. Concurrently, forecasts predicting highly dynamic traf¿c patterns make it crucial for next-generation transport networks to engage highly agile technologies that include sub-wavelength switching (SWS). In translucent SWS networks, contention resolution is achieved through the still technologically immature all-optical wavelength converters (WCs). Since WCs are expected to be expensive, power-consuming devices, there has been significant research effort on devising WC-sharing architectures, which aim at minimizing the number of these devices in the network. WC sharing, however, requires complex switching fabrics that involve a much higher number of optical gates and stronger degradation due to physical layer impairments (more electrical 3R regenerators). It is clear, then, that the technological interest in WC-sharing architectures mainly depends on the cost trade-offs existing between these three components.

  • Addressing Practical Challenges for Anomaly Detection in Backbone Networks  Open access

     Paredes Oliva, Ignasi
    Universitat Politècnica de Catalunya
    Theses

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    La monitorització de xarxa sempre ha estat sempre de gran importància per a operadors de xarxa i investigadors per múltiples raons que van des de la detecció d'anomalies fins a la classificació d'aplicacions. A mesura que les xarxes es tornen més i més complexes i les amenaces de seguretat segueixen creixent, aconseguir una comprensió més detallada del que passa a la xarxa s'ha convertit en una necessitat essencial. Concretament, degut al considerable increment del ciberactivisme, la investigació en el camp de la detecció d'anomalies ha crescut en els darrers anys i s¿han fet moltíssimes propostes. No obstant, aquestes solucions sovint no compleixen alguns requisits fonamentals quan es despleguen en entorns reals. En conseqüència, aquesta tesi se centra a omplir aquest forat entre la recerca i el món real. Abans d'iniciar aquest treball es van identificar diverses mancances. Primer, es va observar una clara manca d'informació detallada i actualitzada sobre les anomalies més comuns i les seves característiques. Segon, no tenir en compte el mostreig de dades (treballar amb només part de les dades) continua sent bastant estès tot i el sever efecte en el rendiment dels algorismes de detecció d'anomalies. Tercer i últim, els operadors de xarxa actualment han d'invertir moltes hores per a classificar i inspeccionar manualment les anomalies detectades per actuar en conseqüència i prendre les apropiades mesures de mitigació. Adicionalment, altres factors com per exemple, l'alt nombre de falsos positius i falsos negatius agreugen aquesta situació.Analitzar un tema és essencial per comprendre l'espai del problema i per poder-hi fer front de forma adequada. El primer bloc d'aquesta tesi pretén proporcionar informació detallada i actualitzada sobre les anomalies més freqüents en una xarxa troncal. Concretament, es comparen diverses solucions comercials per a la detecció d'anomalies i se n'estudien els seus punts forts i febles, així com els tipus d'anomalies de xarxa detectats i les seves característiques.En general, el mostreig de dades (és a dir, treballar només amb una part de la informació) en grans xarxes troncals s'ha convertit en gairebé obligatori i, per tant, tots els algorismes de detecció d'anomalies que no ho tenen en compte poden veure seriosament afectats el seu rendiment. El segon bloc d'aquesta tesi analitza i confirma el dramàtic impacte de mostreig en el rendiment de tècniques de detecció d'anomalies acceptades a l'estat de l'art. No obstant, es mostra que els resultats canvien significativament depenent de la mètrica usada per a fer la comparativa. Adicionalment, proposem una tècnica de mostreig que obté el mateix bon rendiment per a la detecció d'escanejos que una proposta recent, però treballa paquet per paquet enlloc de mantenir tots els fluxes a memòria. Així doncs, la nostra proposta és capaç de funcionar online i d¿usar molts menys recursos.Tot i la gran quantitat de tècniques proposades a la literatura per a la detecció d'esdeveniments anòmals, la investigació per a la seva posterior classificació i extracció (p.ex., per investigar més a fons el que va passar o per compartir l'evidència amb tercers involucrats) és més aviat marginal. Això fa que sigui més difícil per als operadors de xarxa analalitzar les anomalies reportades, ja que depenen únicament de la seva experiència. A més a més, aquesta tasca és un procés extremadament lent i propens a errors. El tercer bloc d'aquesta tesi presenta un sistema per a la detecció, extracció i classificació automàtica d'anomalies amb una alta precisió i molt pocs falsos positius. El quart i últim bloc d'aquesta tesi presenta una generalització del nostre sistema que se centra en l'anàlisi de tot el trànsit, no només en les anomalies. Aquest nou sistema pretén ajudar més als operadors ja que resumeix els patrons de trànsit més importants de la seva xarxa. En particular, es generalitza el sistema per fer front a l¿anomenat ¿big data¿ (una gran quantitat de dades).

    Network monitoring has always been a topic of foremost importance for both network operators and researchers for multiple reasons ranging from anomaly detection to tra c classi cation or capacity planning. Nowadays, as networks become more and more complex, tra c increases and security threats reproduce, achieving a deeper understanding of what is happening in the network has become an essential necessity. In particular, due to the considerable growth of cybercrime, research on the eld of anomaly detection has drawn signi cant attention in recent years and tons of proposals have been made. All the same, when it comes to deploying solutions in real environments, some of them fail to meet some crucial requirements. Taking this into account, this thesis focuses on lling this gap between the research and the non-research world. Prior to the start of this work, we identify several problems. First, there is a clear lack of detailed and updated information on the most common anomalies and their characteristics. Second, unawareness of sampled data is still common although the performance of anomaly detection algorithms is severely a ected. Third, operators currently need to invest many work-hours to manually inspect and also classify detected anomalies to act accordingly and take the appropriate mitigation measures. This is further exacerbated due to the high number of false positives and false negatives and because anomaly detection systems are often perceived as extremely complex black boxes. Analysing an issue is essential to fully comprehend the problem space and to be able to tackle it properly. Accordingly, the rst block of this thesis seeks to obtain detailed and updated real-world information on the most frequent anomalies occurring in backbone networks. It rst reports on the performance of di erent commercial systems for anomaly detection and analyses the types of network nomalies detected. Afterwards, it focuses on further investigating the characteristics of the anomalies found in a backbone network using one of the tools for more than half a year. Among other results, this block con rms the need of applying sampling in an operational environment as well as the unacceptably high number of false positives and false negatives still reported by current commercial tools. On the whole, the presence of ampling in large networks for monitoring purposes has become almost mandatory and, therefore, all anomaly detection algorithms that do not take that into account might report incorrect results. In the second block of this thesis, the dramatic impact of sampling on the performance of well-known anomaly detection techniques is analysed and con rmed. However, we show that the results change signi cantly depending on the sampling technique used and also on the common metric selected to perform the comparison. In particular, we show that, Packet Sampling outperforms Flow Sampling unlike previously reported. Furthermore, we observe that Selective Sampling (SES), a sampling technique that focuses on small ows, obtains much better results than traditional sampling techniques for scan detection. Consequently, we propose Online Selective Sampling, a sampling technique that obtains the same good performance for scan detection than SES but works on a per-packet basis instead of keeping all ows in memory. We validate and evaluate our proposal and show that it can operate online and uses much less resources than SES. Although the literature is plenty of techniques for detecting anomalous events, research on anomaly classi cation and extraction (e.g., to further investigate what happened or to share evidence with third parties involved) is rather marginal. This makes it harder for network operators to analise reported anomalies because they depend solely on their experience to do the job. Furthermore, this task is an extremely time-consuming and error-prone process. The third block of this thesis targets this issue and brings it together with the knowledge acquired in the previous blocks. In particular, it presents a system for automatic anomaly detection, extraction and classi cation with high accuracy and very low false positives. We deploy the system in an operational environment and show its usefulness in practice. The fourth and last block of this thesis presents a generalisation of our system that focuses on analysing all the tra c, not only network anomalies. This new system seeks to further help network operators by summarising the most signi cant tra c patterns in their network. In particular, we generalise our system to deal with big network tra c data. In particular, it deals with src/dst IPs, src/dst ports, protocol, src/dst Autonomous Systems, layer 7 application and src/dst geolocation. We rst deploy a prototype in the European backbone network of G EANT and show that it can process large amounts of data quickly and build highly informative and compact reports that are very useful to help comprehending what is happening in the network. Second, we deploy it in a completely di erent scenario and show how it can also be successfully used in a real-world use case where we analyse the behaviour of highly distributed devices related with a critical infrastructure sector.

    La monitoritzaci o de xarxa sempre ha estat un tema de gran import ancia per operadors de xarxa i investigadors per m ultiples raons que van des de la detecci o d'anomalies fins a la classi caci o d'aplicacions. Avui en dia, a mesura que les xarxes es tornen m es i m es complexes, augmenta el tr ansit de dades i les amenaces de seguretat segueixen creixent, aconseguir una comprensi o m es profunda del que passa a la xarxa s'ha convertit en una necessitat essencial. Concretament, degut al considerable increment del ciberactivisme, la investigaci o en el camp de la detecci o d'anomalies ha crescut i en els darrers anys s'han fet moltes i diverses propostes. Tot i aix o, quan s'intenten desplegar aquestes solucions en entorns reals, algunes d'elles no compleixen alguns requisits fonamentals. Tenint aix o en compte, aquesta tesi se centra a omplir aquest buit entre la recerca i el m on real. Abans d'iniciar aquest treball es van identi car diversos problemes. En primer lloc, hi ha una clara manca d'informaci o detallada i actualitzada sobre les anomalies m es comuns i les seves caracter stiques. En segona inst ancia, no tenir en compte la possibilitat de treballar amb nom es part de les dades (mostreig de tr ansit) continua sent bastant est es tot i el sever efecte en el rendiment dels algorismes de detecci o d'anomalies. En tercer lloc, els operadors de xarxa actualment han d'invertir moltes hores de feina per classi car i inspeccionar manualment les anomalies detectades per actuar en conseqüencia i prendre les mesures apropiades de mitigaci o. Aquesta situaci o es veu agreujada per l'alt nombre de falsos positius i falsos negatius i perqu e els sistemes de detecci o d'anomalies s on sovint percebuts com caixes negres extremadament complexes. Analitzar un tema es essencial per comprendre plenament l'espai del problema i per poder-hi fer front de forma adequada. Per tant, el primer bloc d'aquesta tesi pret en proporcionar informaci o detallada i actualitzada del m on real sobre les anomalies m es freqüents en una xarxa troncal. Primer es comparen tres eines comercials per a la detecci o d'anomalies i se n'estudien els seus punts forts i febles, aix com els tipus d'anomalies de xarxa detectats. Posteriorment, s'investiguen les caracter stiques de les anomalies que es troben en la mateixa xarxa troncal utilitzant una de les eines durant m es de mig any. Entre d'altres resultats, aquest bloc con rma la necessitat de l'aplicaci o de mostreig de tr ansit en un entorn operacional, aix com el nombre inacceptablement elevat de falsos positius i falsos negatius en eines comercials actuals. En general, el mostreig de tr ansit de dades de xarxa ( es a dir, treballar nom es amb una part de les dades) en grans xarxes troncals s'ha convertit en gaireb e obligatori i, per tant, tots els algorismes de detecci o d'anomalies que no ho tenen en compte poden veure seriosament afectats els seus resultats. El segon bloc d'aquesta tesi analitza i confi rma el dram atic impacte de mostreig en el rendiment de t ecniques de detecci o d'anomalies plenament acceptades a l'estat de l'art. No obstant, es mostra que els resultats canvien signi cativament depenent de la t ecnica de mostreig utilitzada i tamb e en funci o de la m etrica usada per a fer la comparativa. Contr ariament als resultats reportats en estudis previs, es mostra que Packet Sampling supera Flow Sampling. A m es, a m es, s'observa que Selective Sampling (SES), una t ecnica de mostreig que se centra en mostrejar fluxes petits, obt e resultats molt millors per a la detecci o d'escanejos que no pas les t ecniques tradicionals de mostreig. En conseqü encia, proposem Online Selective Sampling, una t ecnica de mostreig que obt e el mateix bon rendiment per a la detecci o d'escanejos que SES, per o treballa paquet per paquet enlloc de mantenir tots els fluxes a mem oria. Despr es de validar i evaluar la nostra proposta, demostrem que es capa c de treballar online i utilitza molts menys recursos que SES. Tot i la gran quantitat de tècniques proposades a la literatura per a la detecci o d'esdeveniments an omals, la investigaci o per a la seva posterior classi caci o i extracci o (p.ex., per investigar m es a fons el que va passar o per compartir l'evid encia amb tercers involucrats) es m es aviat marginal. Aix o fa que sigui m es dif cil per als operadors de xarxa analalitzar les anomalies reportades, ja que depenen unicament de la seva experi encia per fer la feina. A m es a m es, aquesta tasca es un proc es extremadament lent i propens a errors. El tercer bloc d'aquesta tesi se centra en aquest tema tenint tamb e en compte els coneixements adquirits en els blocs anteriors. Concretament, presentem un sistema per a la detecci o extracci o i classi caci o autom atica d'anomalies amb una alta precisi o i molt pocs falsos positius. Adicionalment, despleguem el sistema en un entorn operatiu i demostrem la seva utilitat pr actica. El quart i ultim bloc d'aquesta tesi presenta una generalitzaci o del nostre sistema que se centra en l'an alisi de tot el tr ansit, no nom es en les anomalies. Aquest nou sistema pret en ajudar m es als operadors ja que resumeix els patrons de tr ansit m es importants de la seva xarxa. En particular, es generalitza el sistema per fer front al "big data" (una gran quantitat de dades). En particular, el sistema tracta IPs origen i dest i, ports origen i destí , protocol, Sistemes Aut onoms origen i dest , aplicaci o que ha generat el tr ansit i fi nalment, dades de geolocalitzaci o (tamb e per origen i dest ). Primer, despleguem un prototip a la xarxa europea per a la recerca i la investigaci o (G EANT) i demostrem que el sistema pot processar grans quantitats de dades r apidament aix com crear informes altament informatius i compactes que s on de gran utilitat per ajudar a comprendre el que est a succeint a la xarxa. En segon lloc, despleguem la nostra eina en un escenari completament diferent i mostrem com tamb e pot ser utilitzat amb exit en un cas d' us en el m on real en el qual s'analitza el comportament de dispositius altament distribuïts.

  • Area and laser power scalability analysis in photonic networks-on-chip

     Abadal Cavalle, Sergi; Cabellos Aparicio, Alberto; Lazaro Villa, Jose Antonio; Nemirovsky, Mario; Alarcon Cot, Eduardo Jose; Sole Pareta, Josep
    International Conference on Optical Network Design and Modeling
    p. 131-136
    Presentation's date: 2013-04-18
    Presentation of work at congresses

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    In the last decade, the field of microprocessor architecture has seen the rise of multicore processors, which consist of the interconnection of a set of independent processing units or cores in the same chip. As the number of cores per multiprocessor increases, the bandwidth and energy requirements for their interconnection networks grow exponentially and it is expected that conventional on-chip wires will not be able to meet such demands. Alternatively, nanophotonics has been regarded as a strong candidate for chip communication since it could provide high bandwidth with low area and energy footprints. However, issues such as the unavailability of efficient on-chip light sources or the difficulty of implementing all-optical buffering or header processing hinder the development of scalable photonic on-chip networks. In this paper, the area and laser power of several photonic on-chip network proposals is analytically modeled and its scalability is evaluated. Also, a graphene-based hybrid approach is presented

    In the last decade, the field of microprocessor architecture has seen the rise of multicore processors, which consist of the interconnection of a set of independent processing units or cores in the same chip. As the number of cores per multiprocessor increases, the bandwidth and energy requirements for their interconnection networks grow exponentially and it is expected that conventional on-chip wires will not be able to meet such demands. Alternatively, nanophotonics has been regarded as a strong candidate for chip communication since it could provide high bandwidth with low area and energy footprints. However, issues such as the unavailability of efficient on-chip light sources or the difficulty of implementing all-optical buffering or header processing hinder the development of scalable photonic on-chip networks. In this paper, the area and laser power of several photonic on-chip network proposals is analytically modeled and its scalability is evaluated. Also, a graphene-based hybrid wireless/optical-wired approach is presented, aiming at enabling end-to-end photonic on-chip networks to scale beyond thousands of cores

  • Survey on path computation element extensions for spectrum switched optical networks

     Sócrates Dantas, Joana; Careglio, Davide; Melo Silveira, Regina; Ruggiero, Wilson Vicente; Sole Pareta, Josep
    International Conference on Transparent Optical Networks
    p. Th.B4.1-1-Th.B4.1-4
    DOI: 10.1109/ICTON.2013.6603062
    Presentation's date: 2013-06
    Presentation of work at congresses

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    Recently, Spectrum Switched Optical Networks (SSON) have been receiving much interest from the research community due to their network performance benefits. Some of these benefits include the possibility of enabling either super channels or sub-wavelength channels, which meet better the granularity of Internet needs. Due to its specific routing and resource assignment characteristics, SSON's primordial procedures, as routing and spectrum assignment (RSA), cannot be suitably assisted by current related protocols from Wavelength Switched Optical Network (WSON). For this very reason, a SSON control plane architecture and protocols should be extended from WSON's control plane in order to be able to support specific information exchange. This paper presents the most recent Path Computation Element (PCE) architecture extension proposals in the literature, which intend to meet SSON specific requirements.

  • Cross-layer approaches for planning and operating impairment-aware optical networks

     Sole Pareta, Josep; Subramaniam, Suresh; Careglio, Davide; Spadaro, Salvatore
    Proceedings of the IEEE
    Vol. 100, num. 5, p. 1118-1129
    DOI: 10.1109/JPROC.2012.2185669
    Date of publication: 2012-05
    Journal article

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  • An energy-aware dynamic RWA framework for next-generation wavelength-routed networks

     Ricciardi, Sergio; Palmieri, Francesco; Fiore, Ugo; Careglio, Davide; Santos Boada, German; Sole Pareta, Josep
    Computer networks
    Vol. 56, num. 10, p. 2420-2442
    DOI: 10.1016/j.comnet.2012.03.016
    Date of publication: 2012-07-05
    Journal article

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  • Towards a statistical characterization of the interdomain traffic matrix

     Mikians, Jakub; Dhamdhere, A.; Dovrolis, C.; Barlet Ros, Pere; Sole Pareta, Josep
    Lecture notes in computer science
    Vol. 7290, p. 111-123
    DOI: 10.1007/978-3-642-30054-7_9
    Date of publication: 2012
    Journal article

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  • Graphene-enabled hybrid architectures for multiprocessors: bridging nanophotonics and nanoscale wireless communication

     Abadal Cavalle, Sergi; Cabellos Aparicio, Alberto; Lazaro Villa, Jose Antonio; Alarcon Cot, Eduardo Jose; Sole Pareta, Josep
    International Conference on Transparent Optical Networks
    p. 1-4
    Presentation's date: 2012-07-04
    Presentation of work at congresses

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  • A lightweight algorithm for traffic filtering over sliding windows

     Sanjuas Cuxart, Josep; Barlet Ros, Pere; Sole Pareta, Josep; Andriuzzi, Gabriella
    IEEE International Conference on Communications
    p. 1171-1176
    DOI: 10.1109/ICC.2012.6363985
    Presentation's date: 2012-06
    Presentation of work at congresses

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    The problem of testing whether a packet belongs to a set of filtered addresses has been traditionally addressed using Bloom filters. They have a small memory footprint and require few memory accesses per query and insertion, while presenting a small probability of false positive. The problem of automatic eviction of filtered addresses after a pre-configured time window is more challenging, since it requires tracking insertion times for later removal. This has been achieved in the literature by replacing the Bloom filter's vector of bits for a vector of timestamps. This approach precisely expires old items from the filter, but has a large memory footprint. We present a novel Bloom filter based data structure that features approximate information expiration. This small extra source of error allows for a more compact filter representation, thus becoming more suitable to fit in more expensive, faster memory.

    The problem of testing whether a packet belongs to a set of filtered addresses has been traditionally addressed using Bloom filters. They have a small memory footprint and require few memory accesses per query and insertion, while presenting a small probability of false positive. The problem of automatic eviction of filtered addresses after a pre-configured time window is more challenging, since it requires tracking insertion times for later removal. This has been achieved in the literature by replacing the Bloom filter's vector of bits for a vector of timestamps. This approach precisely expires old items from the filter, but has a large memory footprint. We present a novel Bloom filter based data structure that features approximate information expiration. This small extra source of error allows for a more compact filter representation, thus becoming more suitable to fit in more expensive, faster memory. Additionally, our data structure is more flexible in that it allows for balancing the trade-off between filtering and expiration accuracy. Our experiments show that this method can obtain up to orders of magnitude higher overall accuracy than the time-stamp approach using the same amount of memory.

  • Message from the iThings 2012 general chairs

     Sole Pareta, Josep
    IEEE International Conference on Green Computing and Communications
    p. XXIV
    DOI: 10.1109/GreenCom.2012.141
    Presentation's date: 2012-03-20
    Presentation of work at congresses

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  • PHLAME: a physical layer aware MAC protocol for electromagnetic nanonetworks in the terahertz band

     Jornet, Josep Miquel; Capdevila Pujol, Joan; Sole Pareta, Josep
    Nano communication networks
    Vol. 3, num. 1, p. 74-81
    DOI: 10.1016/j.nancom.2012.01.006
    Date of publication: 2012-03
    Journal article

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  • Green data center infrastructures in the cloud computing era

     Ricciardi, Sergio; Palmieri, Francesco; Torres Viñals, Jordi; Di Martino, Beniamino; Santos Boada, German; Sole Pareta, Josep
    Date of publication: 2012-11-29
    Book chapter

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  • Towards energy-oriented telecommunication networks

     Ricciardi, Sergio; Palmieri, Francesco; Fiore, Ugo; Careglio, Davide; Santos Boada, German; Sole Pareta, Josep
    Date of publication: 2012-11-29
    Book chapter

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  • Cross-Layer Modeling and Optimization of Next-Generation Internet Networks  Open access

     Pedrola Escriba, Oscar
    Department of Computer Architecture, Universitat Politècnica de Catalunya
    Theses

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    Scaling traditional telecommunication networks so that they are able to cope with the volume of future traffic demands and the stringent European Commission (EC) regulations on emissions would entail unaffordable investments. For this very reason, the design of an innovative ultra-high bandwidth power-efficient network architecture is nowadays a bold topic within the research community. So far, the independent evolution of network layers has resulted in isolated, and hence, far-from-optimal contributions, which have eventually led to the issues today's networks are facing such as inefficient energy strategy, limited network scalability and flexibility, reduced network manageability and increased overall network and customer services costs. Consequently, there is currently large consensus among network operators and the research community that cross-layer interaction and coordination is fundamental for the proper architectural design of next-generation Internet networks. This thesis actively contributes to the this goal by addressing the modeling, optimization and performance analysis of a set of potential technologies to be deployed in future cross-layer network architectures. By applying a transversal design approach (i.e., joint consideration of several network layers), we aim for achieving the maximization of the integration of the different network layers involved in each specific problem. To this end, Part I provides a comprehensive evaluation of optical transport networks (OTNs) based on layer 2 (L2) sub-wavelength switching (SWS) technologies, also taking into consideration the impact of physical layer impairments (PLIs) (L0 phenomena). Indeed, the recent and relevant advances in optical technologies have dramatically increased the impact that PLIs have on the optical signal quality, particularly in the context of SWS networks. Then, in Part II of the thesis, we present a set of case studies where it is shown that the application of operations research (OR) methodologies in the desing/planning stage of future cross-layer Internet network architectures leads to the successful joint optimization of key network performance indicators (KPIs) such as cost (i.e., CAPEX/OPEX), resources usage and energy consumption. OR can definitely play an important role by allowing network designers/architects to obtain good near-optimal solutions to real-sized problems within practical running times.

  • Efficient Algorithms for Passive Network Measurement  Open access

     Sanjuas Cuxart, Josep
    Department of Computer Architecture, Universitat Politècnica de Catalunya
    Theses

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    Network monitoring has become a necessity to aid in the management and operation of large networks. Passive network monitoring consists of extracting metrics (or any information of interest) by analyzing the traffic that traverses one or more network links. Extracting information from a high-speed network link is challenging, given the great data volumes and short packet inter-arrival times. These difficulties can be alleviated by using extremely efficient algorithms or by sampling the incoming traffic. This work improves the state of the art in both these approaches. For one-way packet delay measurement, we propose a series of improvements over a recently appeared technique called Lossy Difference Aggregator. A main limitation of this technique is that it does not provide per-flow measurements. We propose a data structure called Lossy Difference Sketch that is capable of providing such per-flow delay measurements, and, unlike recent related works, does not rely on any model of packet delays. In the problem of collecting measurements under the sliding window model, we focus on the estimation of the number of active flows and in traffic filtering. Using a common approach, we propose one algorithm for each problem that obtains great accuracy with significant resource savings. In the traffic sampling area, the selection of the sampling rate is a crucial aspect. The most sensible approach involves dynamically adjusting sampling rates according to network traffic conditions, which is known as adaptive sampling. We propose an algorithm called Cuckoo Sampling that can operate with a fixed memory budget and perform adaptive flow-wise packet sampling. It is based on a very simple data structure and is computationally extremely lightweight. The techniques presented in this work are thoroughly evaluated through a combination of theoretical and experimental analysis.

  • Prospects of graphene-enabled wireless communications

     Llatser Marti, Ignacio; Abadal Cavalle, Sergi; Gómez Cid-Fuentes, Raül; Jornet, Josep Miquel; Cabellos Aparicio, Alberto; Alarcon Cot, Eduardo Jose; Sole Pareta, Josep; Akyildiz, Ian F.
    International Conference on GRAPHENE
    Presentation's date: 2012-04-10
    Presentation of work at congresses

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  • Access to the full text
    A comparative study of impairments aware optical networks planning tools  Open access

     Azodolmolky, Siamak; Angelou, Marianna; Tomkos, Ioannis; Morea, Annalisa; Pointurier, Yvan; Sole Pareta, Josep
    International ICST Conference on Broadband Communications, Networks, and Systems
    p. 483-490
    DOI: 10.1007/978-3-642-30376-0_35
    Presentation's date: 2012
    Presentation of work at congresses

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    Transparent and translucent optical networks are widely considered as the prime candidates for the core network technology of the future. These networks provide ultra high speed end-to-end connectivity with high quality of service (QoS) and resilience to failures. This will be achieved through appropriate network planning techniques. A downside of transparency, however, is the accumulation of physical layer impairments over long distances, which are difficult to mitigate using purely physical-layer techniques. Considering the impact of physical layer impairments on network planning and operation has received considerable attention from research community. A novel physical layer impairment aware network planning tool is presented in this paper. Its performance is quantitatively compared with results obtained by a state-of-the-art tool under a common network scenario. The differences between the two planning approaches are illustrated and discussed.

    Postprint (author’s final draft)

  • Practical anomaly detection based on classifying frequent traffic patterns

     Paredes Oliva, Ignasi; Castell Uroz, Ismael; Barlet Ros, Pere; Dimitropoulos, Xenofontas; Sole Pareta, Josep
    IEEE Global Internet Symposium
    p. 49-54
    DOI: 10.1109/INFCOMW.2012.6193518
    Presentation's date: 2012-03-30
    Presentation of work at congresses

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  • PCE QoS tools and related scalability in WDM networks

     Sócrates Dantas, Joana; Careglio, Davide; Melo Silveira, Regina; Vicente Ruggiero, Wilson; Sole Pareta, Josep
    International Conference on Transparent Optical Networks
    p. 1-7
    Presentation's date: 2012-07-02
    Presentation of work at congresses

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  • A novel impairment aware RWA algorithm with consideration of QoT estimation inaccuracy

     Azodolmolky, Siamak; Pointurier, Yvan; Angelou, Marianna; Careglio, Davide; Sole Pareta, Josep; Tomkos, Ioannis
    Journal of optical communications and networking
    Vol. 3, num. 4, p. 290-299
    DOI: 10.1364/JOCN.3.000290
    Date of publication: 2011-04
    Journal article

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    In all-optical networks the physical layer impairments accumulate along a lightpath and also vary dynamically, and a number of impairment aware routing and wavelength assignment (IA-RWA) techniques have been proposed in order to mitigate the physical layer impairments and find lightpaths that meet a required quality of transmission (QoT) constraint predefined by the network operator. However, in order to compute lightpaths, IA-RWAs typically rely on analytical models, which cannot be guaranteed to be fully accurate, and hence acceptance of lightpaths with poor QoT or rejection of lightpaths with acceptable QoT may ensue. We present a novel IA-RWA algorithm that not only considers the impact of physical impairments on RWA decisions, but also, for the first time, accounts for inaccuracy of the QoT estimators. The performance of our algorithm is compared with algorithms selected from the recent literature. All algorithms are evaluated through simulations in a realistic scenario. Our proposed novel algorithm outperforms the selected algorithms in terms of blocking rate and also the amount of required resources for achieving a very low (i.e., 5 £ 10¡6) blocking rate under similar assumptions. In addition we show that accounting for QoT estimation inaccuracy changes the performance of the proposed IA-RWA substantially, and hence that the QoT estimator inaccuracy is an important design parameter in transparent optical networking.

  • Performance overview of the quasi-synchronous operation mode in optical burst switching (OBS) networks

     Pedrola Escriba, Oscar; Rumley, Sébastien; Careglio, Davide; Klinkowski, Miroslaw; Gaumier, Christian; Sole Pareta, Josep
    Optical switching and networking
    Vol. 8, num. 1, p. 32-45
    DOI: 10.1016/j.osn.2010.06.001
    Date of publication: 2011-01
    Journal article

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  • Offline routing and regenerator placement and dimensioning for translucent OBS networks

     Pedrola Escriba, Oscar; Careglio, Davide; Klinkowski, Miroslaw; Sole Pareta, Josep
    Journal of optical communications and networking
    Vol. 3, num. 9, p. 651-666
    DOI: 10.1364/JOCN.3.000651
    Date of publication: 2011-09
    Journal article

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    The deployment of translucent optical networks is considered the most promising short term solution to decrease costs and energy consumption in optical backbone networks. In fact, translucent wavelength switched optical networks (WSONs) have recently received great attention from the research community due to their technological maturity. However, the inflexibility and coarse granularity of WSONs is(re)-fostering research interest in sub-wavelength switching technologies such as optical burst switching (OBS). In OBS, however, the majority of research works neglect the impact of physical layer impairments by considering either fully transparent (i.e., with optical 3R regeneration)or opaque (i.e., with electrical 3R regeneration) networks. For this very reason, in this paper we present a translucent OBS (T-OBS) network architecture which aims at bridging the gap between the transparent and opaque solutions. In the T-OBS network the problem of routing and regenerator placement and dimensioning (RRPD) emerges. Joint RRPD is a complex problem and, in order to approach it, we propose to decompose it into the routing and RPD subproblems. As a consequence, we provide a mixed integer linear programming formulation of the routing problem and several heuristic strategies for the RPD problem. Illustrative numerical results prove the effectiveness of these methods at minimizing the number of electrical 3R regenerators deployed in the network. Considering a broad range of network topologies, we show that the proposed RPD heuristics ensure a proper quality of transmission performance whilst at the same time providing a cost-effective T-OBS network architecture.

  • Predictive Resource Management of Multiple Monitoring Applications

     Barlet Ros, Pere; Iannaccone, Gianluca; Sanjuas Cuxart, Josep; Sole Pareta, Josep
    IEEE-ACM transactions on networking
    Vol. 19, num. 3, p. 788-801
    DOI: 10.1109/TNET.2010.2089469
    Date of publication: 2011-06
    Journal article

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  • Joint routing and wavelength allocation subject to absolute QoS constraints in OBS networks

     Klinkowski, Miroslaw; Pedroso, Pedro; Careglio, Davide; Pioro, Michael; Sole Pareta, Josep
    Journal of lightwave technology
    Vol. 29, num. 22, p. 3433-3444
    DOI: 10.1109/JLT.2011.2169392
    Date of publication: 2011-09
    Journal article

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  • Analysis of the impact of sampling on NetFlow traffic classification

     Carela Español, Valentin; Barlet Ros, Pere; Cabellos Aparicio, Alberto; Sole Pareta, Josep
    Computer networks
    Vol. 55, num. 5, p. 1083-1099
    DOI: 10.1016/j.comnet.2010.11.002
    Date of publication: 2011-04-01
    Journal article

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  • Organización del NaNoNetworking Summit 2011

     Sole Pareta, Josep
    Competitive project

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  • Organización de IEEE Monacom 2011

     Sole Pareta, Josep; Cabellos Aparicio, Alberto
    Competitive project

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  • DISEÑO Y OPTIMIZACIÓN DE REDES ÓPTICAS MULTI-CAPA CONSCIENTES DEL GASTO ENERGÉTICO

     Santos Boada, German; Sole Pareta, Josep; Pedroso Mendonça, Pedro; Sócrates Dantas, Joana; Ricciardi, Sergio; Pedrola Escriba, Oscar; Careglio, Davide
    Competitive project

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  • MEDICIÓN EFICIENTE DEL TRÁFICO EN REDES AVANZADAS (METRA)

     Sanjuas Cuxart, Josep; Sole Pareta, Josep; Barlet Ros, Pere
    Competitive project

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  • GMPLS-OBS Interoperability And Routing Scalability in Internet  Open access

     Mendonça Pedroso, Pedro Miguel
    Department of Computer Architecture, Universitat Politècnica de Catalunya
    Theses

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    The popularization of Internet has turned the telecom world upside down over the last two decades. Network operators, vendors and service providers are being challenged to adapt themselves to Internet requirements in a way to properly serve the huge number of demanding users (residential and business). The Internet (data-oriented network) is supported by an IP packet-switched architecture on top of a circuit-switched, optical-based architecture (voice-oriented network), which results in a complex and rather costly infrastructure to the transport of IP traffic (the dominant traffic nowadays). In such a way, a simple and IP-adapted network architecture is desired. From the transport network perspective, both Generalized Multi-Protocol Label Switching (GMPLS) and Optical Burst Switching (OBS) technologies are part of the set of solutions to progress towards an IP-over-WDM architecture, providing intelligence in the control and management of resources (i.e. GMPLS) as well as a good network resource access and usage (i.e. OBS). The GMPLS framework is the key enabler to orchestrate a unified optical network control and thus reduce network operational expenses (OPEX), while increasing operator's revenues. Simultaneously, the OBS technology is one of the well positioned switching technologies to realize the envisioned IP-over-WDM network architecture, leveraging on the statistical multiplexing of data plane resources to enable sub-wavelength in optical networks. Despite of the GMPLS principle of unified control, little effort has been put on extending it to incorporate the OBS technology and many open questions still remain. From the IP network perspective, the Internet is facing scalability issues as enormous quantities of service instances and devices must be managed. Nowadays, it is believed that the current Internet features and mechanisms cannot cope with the size and dynamics of the Future Internet. Compact Routing is one of the main breakthrough paradigms on the design of a routing system scalable with the Future Internet requirements. It intends to address the fundamental limits of current stretch-1 shortest-path routing in terms of RT scalability (aiming at sub-linear growth). Although "static" compact routing works fine, scaling logarithmically on the number of nodes even in scale-free graphs such as Internet, it does not handle dynamic graphs. Moreover, as multimedia content/services proliferate, the multicast is again under the spotlight as bandwidth efficiency and low RT sizes are desired. However, it makes the problem even worse as more routing entries should be maintained. In a nutshell, the main objective of this thesis in to contribute with fully detailed solutions dealing both with i) GMPLS-OBS control interoperability (Part I), fostering unified control over multiple switching domains and reduce redundancy in IP transport. The proposed solution overcomes every interoperability technology-specific issue as well as it offers (absolute) QoS guarantees overcoming OBS performance issues by making use of the GMPLS traffic-engineering (TE) features. Keys extensions to the GMPLS protocol standards are equally approached; and ii) new compact routing scheme for multicast scenarios, in order to overcome the Future Internet inter-domain routing system scalability problem (Part II). In such a way, the first known name-independent (i.e. topology unaware) compact multicast routing algorithm is proposed. On the other hand, the AnyTraffic Labeled concept is also introduced saving on forwarding entries by sharing a single forwarding entry to unicast and multicast traffic type. Exhaustive simulation campaigns are run in both cases in order to assess the reliability and feasible of the proposals.

  • Physical Impairments Aware Planning and Operation of Transparent Optical Networks

     Azodolmolky, Siamak
    Department of Computer Architecture, Universitat Politècnica de Catalunya
    Theses

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  • Regenerator Placement Strategies for Translucent OBS Networks

     Pedrola Escriba, Oscar; Careglio, Davide; Klinkowski, Miroslaw; Sole Pareta, Josep
    Journal of lightwave technology
    Vol. 29, num. 22, p. 3408-3420
    DOI: 10.1109/JLT.2011.2168806
    Date of publication: 2011-11-15
    Journal article

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  • Towards an energy-aware internet: modeling a crosslayer optimization approach

     Ricciardi, Sergio; Careglio, Davide; Santos Boada, German; Sole Pareta, Josep; Fiore, Ugo; Palmieri, Francesco
    Telecommunication systems
    Vol. 52, num. 2, p. 1247-1268
    DOI: 10.1007/s11235-011-9645-7
    Date of publication: 2011-12-31
    Journal article

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    The containment of power consumption and the use of alternative green sources of energy are the new main goals of telecommunication operators, to cope with the rising energy costs, the increasingly rigid environmental standards, and the growing power requirements of modern high-performance networking devices. To address these challenges, we envision the necessity of introducing energy-efficiency and energy-awareness in the design, configuration and management of networks, and specifically in the design and implementation of enhanced control-plane protocols to be used in next generation networks. Accordingly, we focus on research and industrial challenges that foster new developments to decrease the carbon footprint while leveraging the capacities of highly dynamic, ultra-high-speed, networking. We critically discuss current approaches, research trends and technological innovations for the coming green era and we outline future perspectives towards new energy-oriented network planning, protocols and algorithms. We also combine all the above elements into a comprehensive energy-oriented network model within the context of a general constrained routing and wavelength assignment problem framework, and analyze and quantify through ILP formulations the savings that can be attained on the next generation networks.

  • Saving energy in data center infrastructures

     Ricciardi, Sergio; Careglio, Davide; Santos Boada, German; Sole Pareta, Josep; Fiore, Ugo; Palmieri, Francesco
    International Conference on Data Compression, Communication and Processing
    p. 265-270
    Presentation's date: 2011-06-21
    Presentation of work at congresses

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    At present, data centers consume a considerable percentage of the worldwide produced electrical energy, equivalent to the electrical production of 26 nuclear power plants, and such energy demand is growing at fast pace due to the ever increasing data volumes to be processed, stored and accessed every day in the modern grid and cloud infrastructures. Such energy consumption growth scenario is clearly not sustainable and it is necessary to limit the data center power budget by controlling the absorbed energy while keeping the desired level of service. In this paper, we describe Energy Farm, a data center energy manager that exploits load fluctuations to save as much energy as possible while satisfying quality of service requirements. Energy Farm achieves energy savings by aggregating traffic during low load periods and temporary turning off a subset of computing resources. Energy Farm respects the logical and physical dependencies of the interconnected devices in the data center and performs automatic shut down even in emergency cases such as temperature peaks and power leakages. Results show that high resource utilization efficiency is possible in data center infrastructures and that huge savings in terms of energy (MWh), emissions (tons of CO2) and costs (kε) are achievable.

  • PCE algorithm for traffic grooming and QoS in multi-layer/multi-domain IP over WDM networks

     Sócrates Dantas, Joana; Careglio, Davide; Melo Silveira, Regina; Vicente Ruggiero, Wilson; Sole Pareta, Josep
    International Conference on Transparent Optical Networks
    p. 1-5
    DOI: 10.1109/ICTON.2011.5970777
    Presentation's date: 2011-06-21
    Presentation of work at congresses

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    Differentiated services provision according to clients or applications is an added feature that network operators ambition to fully provide. One of the possible approaches is to map DiffServ into MPLS based network. However in an IP over WDM (Wavelength Division Multiplexing) network data flow traverse multiple layers and, therefore, Class-Type information from the MPLS DiffServ layer is eventually lost. Besides, with the implement of a Path Computation Element (PCE) on multi-layer and multi-domain networks, the bandwidth constraints used to differentiate services are no longer applied. This paper presents a proposal for a QoS DiffServ approach applied on PCE as a traffic grooming technique for WDM core networks and the problematic involved on the application of this technology on multilayer and multi-domain networks.

  • Translucent OBS network architectures with Dedicated and Shared wavelength resources

     Pedrola Escriba, Oscar; Careglio, Davide; Klinkowski, Miroslaw; Sole Pareta, Josep
    European Conference on Networks and Optical Communications
    p. 92-95
    Presentation's date: 2011-07-21
    Presentation of work at congresses

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    The deployment of translucent optical networks is considered the most promising short term solution to decrease costs and energy consumption in optical backbone networks. Indeed, due to the technological maturity of translucent wavelength switched optical network (WSON) architectures, they have already caught close attention from the research community. Moreover, recent advances and enhancements in optical devices are now (re-)fostering research interest in sub-wavelength technologies like, among others, optical burst switching (OBS) and optical packet switching (OPS). Hence, in this paper, we evaluate and compare two novel node architectures for a translucent OBS(T-OBS) network. To be precise, we study nodes with both dedicated and shared wavelength converter resources (i.e. DWC and SWC). To this end, we consider the impact of the main physical layer impairments (PLIs) and make use of a routing and regenerator placement and dimensioning (RRPD)algorithm to minimize the number of optical-electrical-optical (O/E/O) regenerators deployed in the network whilst, at the same time, guaranteeing a target quality of transmission (QoT)network performance. The results presented prove the feasibility and the significant savings, in terms of the number of wavelength converters (WCs), that can be achieved by considering a network with shared wavelength converter resources.

  • Access to the full text
    Exploring the physical channel of diffusion-based molecular communication by simulation  Open access

     Llatser Marti, Ignacio; Pascual, Iñaki; Garralda, N.; Cabellos Aparicio, Alberto; Pierobon, Massimiliano; Alarcon Cot, Eduardo Jose; Sole Pareta, Josep
    IEEE Global Communications Conference
    p. 1-5
    DOI: 10.1109/GLOCOM.2011.6134028
    Presentation's date: 2011-12
    Presentation of work at congresses

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    Diffusion-based molecular communication is a promising bio-inspired paradigm to implement nanonetworks, i.e., the interconnection of nanomachines. The peculiarities of the physical channel in diffusion-based molecular communication require the development of novel models, architectures and protocols for this new scenario, which need to be validated by simulation. With this purpose, we present N3Sim, a simulation framework for diffusion-based molecular communication. N3Sim allows to simulate scenarios where transmitters encode the information by releasing molecules into the medium, thus varying their local concentration. N3Sim models the movement of these molecules according to Brownian dynamics, and it also takes into account their inertia and the interactions among them. Receivers decode the information by sensing the particle concentration in their neighborhood. The benefits of N3Sim are multiple: the validation of channel models for molecular communication and the evaluation of novel modulation schemes are just a few examples.

    Postprint (author’s final draft)

  • RRPD strategies for a T-OBS network architecture

     Pedrola Escriba, Oscar; Careglio, Davide; Klinkowski, Miroslaw; Sole Pareta, Josep
    International Conference on High Performance Switching and Routing
    p. 95-100
    DOI: 10.1109/HPSR.2011.5986009
    Presentation's date: 2011-07-05
    Presentation of work at congresses

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    In this paper, we deal with the physical layer impairments (PLIs) in optical burst switching (OBS). In particular we present a formulation of the routing and regenerator placement and dimensioning (RRPD) problem for a feasible translucent OBS (T-OBS) network architecture. Since addressing the joint RRPD problem results in an extremely complex undertaking, we decouple the problem, and hence, we eventually provide formal models to solve routing and RPD separately in the socalled R+RPD problem. Thus, making use of mixed integer linear programming (MILP) formulations, we first address the routing problem with the aim of minimizing congestion in bottleneck network links, and second, we tackle the issue of performing a sparse placement of electrical regenerators in the network. Since the RPD formulation requires high computational effort for large problem instances, we also propose two alternative heuristic strategies that provide good near-optimal solutions within reasonable time limits. To be precise, we evaluate the trade-off between optimality and complexity provided by these methods. Finally, we conduct a series of simulation experiments on the T-OBS network that prove that the R+RPD strategies effectively deal with burst losses caused by the impact of PLIs, and therefore, ensure that the overall T-OBS network performance remains unaffected.

  • Analyzing local strategies for energy efficient networking

     Ricciardi, Sergio; Careglio, Davide; Fiore, Ugo; Palmieri, Francesco; Santos Boada, German; Sole Pareta, Josep
    International Conferences on Networking
    p. 291-300
    Presentation's date: 2011-05-13
    Presentation of work at congresses

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  • Energy-aware RWA for WDM networks with dual power sources

     Ricciardi, Sergio; Careglio, Davide; Palmieri, Francesco; Fiore, Ugo; Santos Boada, German; Sole Pareta, Josep
    IEEE International Conference on Communications
    p. 1-6
    Presentation's date: 2011-06
    Presentation of work at congresses

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