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  • Dynamic Routing and Spectrum Allocation in Elastic Optical Networks  Open access

     Sayyad Khodashenas, Pouria
    Defense's date: 2014-06-05
    Department of Signal Theory and Communications, Universitat Politècnica de Catalunya
    Theses

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    Degut a l¿augment de serveis emergent com la distribució de vídeo d¿alta definició o les xarxes socials, el volum de tràfic IP ha crescut de manera exponencial durant els darrers temps. La conseqüència esperable és que els operadors de xarxes de telecomunicacions requeriran una nova generació de transport òptic en el futur proper, per donar servei a aquests grans i heterogenis volums de tràfic d¿una manera econòmicament eficient i escalable. Com a resposta a les creixents necessitats de capacitat i de diferents granularitats de tràfic de la Internet del Futur s¿ha proposat l¿arquitectura coneguda com ¿Elastic Optical Network¿ (EON) on s¿aconsegueix incrementar la flexibilitat en l¿aprovisionament de connexions. Per fer-ho, depenent del volum de tràfic s¿assigna la quantitat adient de l¿espectre òptic a cada connexió. D¿aquesta manera, les peticions de connexió que arriben poden ésser servides de manera eficient pel que fa a l¿espectre que utilitzen. Aquest avenç tecnològic implica però alguns reptes a nivell de xarxa, especialment pel que fa a l¿establiment eficient de les connexions. El problema de l¿encaminament i assignació de l¿espectre (RSA) ha merescut una gran atenció dels investigadors en els darrers anys, amb especial èmfasi a escenaris dinàmics, és a dir, en la fase d¿operació de la xarxa. En aquest cas, els processos d¿arribada i mort de les connexions són aleatoris i la xarxa ha d¿acomodar en temps real el tràfic ofert. Tot i els grans esforços dedicats a aquest tema, queden encara alguns punts a resoldre. Aquesta Tesi està dedicada a alguns d¿aquests temes oberts en l¿àmbit de les xarxes EON: 1) l¿agregació dinàmica de connexions de granularitat inferior a la longitud d¿ona, 2) la correlació entre la granularitat del tràfic i les polítiques de desfragmentació de l¿espectre, i, 3) utilitzar la fragmentació espectral per a una millor assignació de connexions d¿ample de banda canviant en el temps. El primer analitza la possibilitat d¿agregar connexions originades a la mateixa font però amb diferents destinacions dins d¿una EON, amb l¿objectiu d¿estalviar recursos tant pel que fa a nombre d¿equips transmissor utilitzats com a l¿espectre utilitzat. S¿ha proposat un nou algorisme que millora ambdós paràmetres, així com una arquitectura pels nodes de la xarxa que permet utilitzar l¿algorisme d¿agregació proposat de manera eficient des del punt de vista del cost. El problema de la fragmentació espectral en les EONs s¿ataca en la segona aportació d¿aquesta Tesi. S¿ha aconseguit demostrar la correlació entre l¿òptima (és a dir mínima) periodicitat de les accions de desfragmentació i la granularitat del tràfic suportat. S¿ha proposat un nou algorisme per a una desfragmentació eficient, l¿objectiu del qual és consolidar l¿espectre disponible en les fibres tan com sigui possible, al mateix temps que es redueix el nombre de connexions que has de ser reubicades en la xarxa. Finalment, en el tercer gran apartat de la Tesi, s¿estudia la possibilitat d¿utilitzar la fragmentació espectral en les EON per a una millor assignació dels recursos quan el tràfic és variant en el temps. En aquest context, s¿ha proposat i validat un algorisme d¿assignació de l¿espectre (SA) que incrementa de manera intencionada la fragmentació espectral de la xarxa. En aquesta proposta, l¿espectre assignat a cada nova connexió s¿ubica al bell mig del buit espectral més gran que es troba en tota la ruta, amb l¿objectiu de deixar tan espai com sigui possible entre les diferents connexions. Aquest espai és després utilitzat per a connexions que requereixen, al llarg de la seva existència, més espectre del que se¿ls ha assignat inicialment (incrementen el seu ample de banda).

    Triggered by emerging services such as high-definition video distribution or social networking, the IP traffic volume has been exponentially increasing to date. Furthermore, the traffic growth rate will not stop here due to the day by day technology advances. For example, new hardware advances such as multicore processing, virtualization and network storage will support new generation e-Science and grid applications, requesting data flows of 10 Gb/s up to terabit level. In response to these large capacity and diverse traffic granularity needs of the future Internet, the Elastic Optical Network (EON) architecture has been proposed. By breaking the fixed-grid spectrum allocation limit of conventional Wavelength Division Multiplexing (WDM) networks, EONs increase the flexibility in the connection provisioning. To do so, depending on the traffic volume, an appropriate-sized optical spectrum is allocated to a connection in EONs. Furthermore, unlike the rigid optical channels of conventional WDM networks, a lightpath can expand or contract elastically to meet different bandwidth demands in EONs. In this way, incoming connection requests can be served in a spectrum-efficient manner. This technological advance poses additional challenges on the networking level, specifically on the efficient connection establishment. The Routing and Spectrum Allocation (RSA) problem in elastic optical networks has grabbed a lot of attention lately, putting more emphasis on dynamic network scenarios. There, connection arrival and departure processes are random and the network has to accommodate incoming traffic in real time. Despite all efforts at studying the dynamic RSA problem from different perspectives, there are still some issues which need to be addressed. This thesis is devoted to the study of three still open issues in the EONs literature, 1) dynamic source aggregation of sub-wavelength connections, 2) correlation between traffic granularity and defragmentation periodicity and 3) using spectrum fragmentation to better allocate time-varying connections. The first issue deals with the possibility of aggregation of same source but different destination sub-wavelength connections in EONs, aiming to obtain both transmitter and spectrum usage savings. A novel algorithm for dynamic source aggregation of connections is proposed. Moreover, a novel node architecture enabling the realization of the proposed source aggregation scheme in a cost-effective way is introduced. A considerable improvement in the network spectrum utilization, as well as a significant reduction in the number of necessary transmitters per node is shown. The spectral fragmentation problem in elastic optical networks is addressed with the second issue. A correlation between the optimal (i.e., minimum) spectrum defragmentation periodicity in the network with the granularity of the supported traffic is investigated. A novel algorithm for efficient spectrum defragmentation is proposed, aiming to consolidate the available fiber spectrum as much as possible, while limiting the number of re-allocated active connections. It is shown that the spectral defragmentation periodicity can be effectively configured by having knowledge of the offered traffic granularity. The last issue is about lightpath adaptation under time variable traffic demands in EONs. Specifically, the possibility of utilizing the spectral fragmentation to increase the spectrum allocation capabilities of EONs is explored. In this context, a heuristic Spectrum Allocation (SA) algorithm, which intentionally increases the spectral fragmentation in the network is proposed and validated. In the proposal, the spectrum assigned to each new connection is in the middle of the largest free spectral void over the route, aiming to provide considerable spectral space between adjacent connections. These free spectral spaces are then used to allocate time-varying connections without requiring any lightpath re-allocation.

    Degut a l'augment de serveis emergent com la distribució de vídeo d'alta definició les xarxes socials, el volum de tràfic IP ha crescut de manera exponencial durant els darrers temps. S'espera que aquest creixement no s'aturi sinó que continui de manera imparable degut als constants avenços tecnològics. Alguns exemples d’això poden ser els processadors multi-nucli, la virtualització o el "cloud computing" que donaran suport a una nova generació de e-Science i d'aplicacions Grid per les quals caldran flux de dades des de 10 Gb/s fins al Terabit per segon. La conseqüència esperable és que els operadors de xarxes de telecomunicacions requeriran una nova generació de transport òptic en el futur proper, per donar servei a aquests grans i heterogenis volums de trafic d'una manera econòmicament eficient i escalable. Com a resposta a les creixents necessitats de capacitat i de diferents granularitats de tràfic de la Internet del Futur s'ha proposat l'arquitectura coneguda com "Elastic Optical Network" (EON). Trencant el rígid entramat de les xarxes WDM tradicionals, on s'ha de reservar tot un canal òptic per a cada comunicació, mitjançant les EON s'aconsegueix incrementar la flexibilitat en l'aprovisionament de connexions. per fer-ho, depenent del volum de tràfic s'assigna la quantitat adient de l'espectre òptic a cada connexió. I, anant encara un pas més enllà, per desfer la rigidesa dels canals convencionals de les xarxes amb multiplexació per divisió en longitud d'ona (WDM), les connexions òptiques en les EON poden expandir-se o contraure's de manera elàstica segons els requeriments d'ample de banda en cada moment. D'aquesta manera, les peticions de connexió que arriben poden ésser servides de manera eficient pel que fa a l'espectre que utilitzen. Aquest avenç tecnològic implica però alguns reptes a nivell de xarxa, especialment pel que fa a l'establiment eficient de les connexions. De manera similar a com succeeix en les xarxes WDM, una connexió ha d'ocupar la mateixa part de l'espectre en tots els links que la conformen, acomplint el principi de "continuïtat en l'espectre". A més a més, tot l'ample de banda de la connexió ha d'estar assignat de manera adjacent, acomplint el principi de "contigüitat en l'espectre". Per aconseguir aquests objectius, el problema de l'encaminament i assignació de l'espectre (RSA) ha merescut una gran atenció dels investigadors en els darrers anys, amb especial èmfasi a escenaris dinàmics, és a dir, en la fase d’operació de la xarxa. En aquest cas, els processos d'arribada i mort de les connexions són aleatoris i la xarxa ha d'acomodar en temps real el tràfic ofert. Tot i els grans esforços dedicats a aquest tema, queden encara alguns punts a resoldre. Aquesta Tesi està dedicada a alguns d'aquests temes oberts en l'àmbit de les xarxes EON: 1) l’agregació dinàmica de connexions de granularitat inferior a la longitud d'ona, 2) la correlació entre la granularitat del tràfic i les polítiques de desfragmentació de l'espectre, i, 3) utilitzar la fragmentació espectral per a una millor assignació de connexions d'ample de banda canviant en el temps. El primer tòpic analitza la possibilitat d'agregar connexions originades a la mateixa font però amb diferents destinacions dins d'una EON, amb l'objectiu d'estalviar recursos tant pel que fa a nombre d'equips transmissor utilitzats com a l'espectre utilitzat. S'ha proposat un nou algorisme que millora ambdós paràmetres, així com una arquitectura pels nodes de la xarxa que permet utilitzar l'algorisme d’agregació proposat de manera eficient des del punt de vista del cost. S'aconsegueix una considerable millora pel que fa a la utilització de l'espectre a més d'una significativa reducció en el nombre de transmissors per node que es requereixen. El problema de la fragmentació espectral en les EONs s'ataca en la segona aportació d'aquesta Tesi. S'ha aconseguit demostrar la correlació entre l’òptima (és a dir mínima) periodicitat de les accions de desfragmentació i la granularitat del tràfic suportat. S'ha proposat un nou algorisme per a una desfragmentació eficient, l'objectiu del qual és consolidar l'espectre disponible en les fibres tan com sigui possible, al mateix temps que es redueix el nombre de connexions que has de ser reubicades en la xarxa. Es demostra que, en una EON, es pot configurar de manera òptima la periodicitat de les desfragmentacions si es coneix la granularitat de les connexions a transportar. Finalment, en el tercer gran apartat de la Tesi, s'estudia la possibilitat d'utilitzar la fragmentació espectral en les EON per a una millor assignació dels recursos quan el tràfic és variant en el temps. En aquest context, s'ha proposat i validat un algorisme d’assignació de l'espectre (SA) que incrementa de manera intencionada la fragmentació espectral de la xarxa. En aquesta proposta, l'espectre assignat a cada nova connexi_o s'ubica al bell mig del buit espectral més gran que es troba en tota la ruta, amb l'objectiu de deixar tan espai com sigui possible entre les diferents connexions. Aquest espai és després utilitzat per a connexions que requereixen, al llarg de la seva existència, més espectre del que se'ls ha assignat inicialment (incrementen el seu ample de banda). Els resultats obtinguts mitjançant simulacions mostren significants millores en termes de Probabilitat de Bloqueig (BP) en la xarxa quan s'utilitza l'algorisme proposat. Després d'una introducció a la Tesi, el Capítol 2 ofereix una revisió de l’evolució de les xarxes òptiques de transport, tot introduint el concepte de xarxa òptica elàstica (EON). El Capítol 3 se centra en l'estudi dels mètodes d'encaminament i assignació de longitud d'ona en xarxes WDM convencionals, i la seva evolució cap al problema de l’assignació d'espectre (RSA) en EONs. El Capítol 4 detalla els estudis i les contribucions fetes en el tema d’agregació de connexions de granularitat inferior a la longitud d'ona en EONs. L'algorisme proposat, així com l'arquitectura de node que permet aplicar-lo es presenten en aquest Capítol. El problema de la fragmentació espectral en EONs i llurs solucions es revisen a fons en el Capítol 5. La correlació entre la periodicitat de les desfragmentacions espectrals i la granularitat del tràfic ofert s'estudien aquí. El Capítol 6 detalla el problema de servir connexions variants en el temps en EONs. Algunes polítiques proposades fins ara es revisen, i tot seguit se'n proposa una que, en certs aspectes, millora les prèvies. Finalment, cal destacar que aquest treball ha rebut el suport del Govern de la Generalitat de Catalunya, a través d'una beca FI-AGAUR, i que s'ha realitzat en el marc del projecte del Ministerio de Educación Ciencia y Deporte espanyol ELASTIC (TEC2011-27310).

    Debido al aumento de servicios emergentes como la distribución de video de alta definición o las redes sociales, el volumen de tráfico IP ha crecido de manera exponencial durante los últimos tiempos. Se espera que este crecimiento no se pare sino que continúe de manera imparable debido a los constantes adelantos tecnológicos. Algunos ejemplos de esto pueden ser los procesadores multi-núcleo, la virtualización o el "cloud computing" que darán servicio a una nueva generación de aplicaciones de e-Science y de Grid para las cuáles serán necesarios flujos de datos desde 10 Gb/s hasta Terabits por segundo. La consecuencia esperable es que los operadores de redes de telecomunicaciones requerirán una nueva generación de transporte óptico en el futuro cercano, para dar servicio a estos grandes y heterogéneos volúmenes de tráfico de una manera económicamente eficiente y escalable. Como respuesta a las crecientes necesidades de capacidad y de diferentes granularidades de tráfico de la Internet del Futuro, se ha propuesto la arquitectura conocida como "Elastic Optical Network" (EON). Rompiendo el rígido entramado de las redes con multiplexación por división en longitud de onda (WDM) tradicionales, donde se tiene que reservar todo un canal óptico para cada comunicación, mediante las EON se consigue incrementar la flexibilidad en el aprovisionamiento de conexiones. Para hacerlo, dependiendo del volumen de tráfico se asigna la cantidad adecuada del espectro óptico a cada conexión. Y, yendo todavía un paso más allá, para deshacer la rigidez de los canales convencionales de las redes WDM, las conexiones ópticas en las EON pueden expandirse o contraerse de manera elástica según los requerimientos de ancho de banda en cada momento. De este modo, las peticiones de conexión que llegan pueden ser servidas de manera eficiente en cuanto al espectro que utilizan. Este adelanto tecnológico implica sin embargo algunos retos a nivel de red, especialmente en lo que se refiere al establecimiento eficiente de las conexiones. De manera similar a como sucede en las redes WDM, una conexión debe ocupar la misma parte del espectro en todos los links que la conforman, cumpliendo el principio de "continuidad espectral". Además, todo el ancho de banda de la conexión tiene que estar asignado de manera adyacente, cumpliendo el principio de "contigüidad espectral". Para conseguir estos objetivos, el problema del encaminamiento y asignación del espectro (RSA) ha merecido una gran atención de los investigadores en los últimos años, con especial énfasis en escenarios dinámicos, es decir, en la fase de operación de la red. En este caso, los procesos de llegada y finalización de las conexiones son aleatorios y la red tiene que acomodar en tiempo real el tráfico ofrecido. A pesar de los grandes esfuerzos dedicados a este tema, quedan todavía algunos puntos a resolver. Esta Tesis está dedicada a algunos de estos temas abiertos en el ámbito de las redes EON: 1) la agregación dinámica de conexiones de granularidad inferior a la longitud de onda, 2) la correlación entre la granularidad del tráfico y las políticas de desfragmentación del espectro, y, 3) utilizar la fragmentación espectral para una mejor asignación de conexiones de ancho de banda variante en el tiempo. El primer tópico analiza la posibilidad de agregar conexiones originadas en la misma fuente pero con diferentes destinos dentro de una EON, con el objetivo de ahorrar recursos tanto en cuanto a número de equipos transmisores utilizados como en el espectro utilizado. Se ha propuesto un nuevo algoritmo que mejora ambos parámetros, así como una arquitectura para los nodos de la red que permite utilizar el algoritmo de agregación propuesto de manera eficiente desde el punto de vista del coste. Se consigue una considerable mejora en cuanto a la utilización del espectro además de una significativa reducción en el número de trasmisores por nodo que se requieren. El problema de la fragmentación espectral en las EONs se ataca en la segunda aportación de esta Tesis. Se ha conseguido demostrar la correlación entre la óptima (es decir, mínima) periodicidad de las acciones de desfragmentación y la granularidad del tráfico soportado. Se ha propuesto un nuevo algoritmo para una desfragmentación eficiente, el objetivo del cual es consolidar el espectro disponible en las fibras tanto como sea posible, al mismo tiempo que se reduce el número de conexiones que deben ser reubicadas en la red. Se demuestra que, en una EON, se puede configurar de manera óptima la periodicidad de las desfragmentaciones si se conoce la granularidad de las conexiones a transportar. Finalmente, en el tercer gran apartado de la Tesis, se estudia la posibilidad de utilizar la fragmentación espectral en las EON para una mejor asignación de los recursos cuando el tráfico es variante en el tiempo. En este contexto, se ha propuesto y validado un algoritmo de asignación del espectro (SA) que incrementa de manera intencionada la fragmentación espectral de la red. En esta propuesta, el espectro asignado a cada nueva conexión se ubica en medio del vacío espectral más grande que se encuentra en toda la ruta, con el objetivo de dejar tanto espacio como sea posible entre las diferentes conexiones. Este espacio es después utilizado para conexiones que requieren, a lo largo de su existencia, más espectro del que se les ha asignado inicialmente (incrementan su ancho de banda). Los resultados obtenidos mediante simulaciones muestran significantes mejoras en términos de Probabilidad de Bloqueo (BP) de la red cuando se utiliza el algoritmo propuesto. Después de una introducción a la Tesis, el Capitulo 2 ofrece una revisión de la evolución delas redes ópticas de transporte, introduciendo el concepto de red óptica elástica (EON). El Capítulo 3 se centra en el estudio de los métodos de encaminamiento y asignación de longitud de onda en redes WDM convencionales, y su evolución hacia el problema de la asignación de espectro (RSA) en EONs. El Capítulo 4 detalla los estudios y las contribuciones hechas en el tema de agregación de conexiones de granularidad inferior a la longitud de onda en EONs. El algoritmo propuesto, así como la arquitectura de nodo que permite aplicarlo, se presentan en este Capitulo. El problema de la fragmentación espectral en las EONs y sus soluciones se revisan a fondo en el Capitulo 5. La correlación entre la periodicidad de las desfragmentaciones espectrales y la granularidad del tráfico ofrecido se estudian aquí. El Capitulo 6 detalla el problema de servir conexiones variantes en el tiempo en EONs. Algunas políticas propuestas hasta ahora se han revisado, y a continuación se propone una que, en algunos aspectos, mejora las previamente publicadas. Finalmente, hay que destacar que este trabajo ha recibido el apoyo del Gobierno de la Generalitat de Catalunya, a través de una beca FI-AGAUR, y que se ha realizado en el marco del proyecto ELASTIC (*TEC2011-27310), del Ministerio de Educación Ciencia y Deporte Español.

  • Optimal route, spectrum, and modulation level assignment in split-spectrum-enabled dynamic elastic optical networks

     Pages Cruz, Albert; Perello Muntan, Jordi; Spadaro, Salvatore; Comellas Colome, Jaume
    Journal of optical communications and networking
    Date of publication: 2014-02-01
    Journal article

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    The spectrum fragmentation effect in elastic optical networks is one of their main limitations. Multiple techniques have been proposed to address this problem, with the split spectrum approach (SSA) being a very interesting candidate among them. This technique is based on splitting a demand into smaller sub-demands when a blocking situation arises. In split-spectrum-enabled networks, the route, spectrum, and modulation level assignment (RSMLA) problem that appears in elastic optical networks is further complicated due to the signal splitting operation. In this paper we present novel mechanisms to optimally attack this problem; various possible implementations of the SSA are also discussed. We highlight the benefits of the proposed mechanisms through illustrative results and compare the various implementation solutions in terms of average network cost.

  • Cost-efficient virtual optical network embedding for manageable inter-data-center connectivity

     Perello Muntan, Jordi; Spadaro, Salvatore; Pavón Mariño, Pablo
    ETRI journal
    Date of publication: 2013-02
    Journal article

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    Network virtualization opens the door to novel infrastructure services offering connectivity and node manageability. In this letter, we focus on the cost-efficient embedding of on-demand virtual optical network requests for interconnecting geographically distributed data centers. We present a mixed integer linear programming formulation that introduces flexibility in the virtual-physical node mapping to optimize the usage of the underlying physical resources. Illustrative results show that flexibility in the node mapping can reduce the number of add-drop ports required to serve the offered demands by 40%.

  • Protocol enhancements for "greening" optical networks

     Morea, Annalisa; Perello Muntan, Jordi; Spadaro, Salvatore; Verchere, Dominique; Vigoureux, Martin
    Bell labs technical journal
    Date of publication: 2013-12
    Journal article

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    The last decade has spurred a number of research efforts around energy efficiency in information and communication technologies (ICT). To reduce the energy consumed by optical transport networks, one option is to switch-off a certain number of optical systems according to the amount of transported traffic. Consequently, dynamic power management of optoelectronic devices and link sleep-mode approaches have been proposed; these capabilities quantitatively optimize the power requirements and the available bandwidth of the network as a whole. This paper presents enhancements embedded in Generalized Multiprotocol Label Switching (GMPLS)-based protocols enabling power control in optical devices, and then analyzes the impact of controlling the daily energy consumption of optical switching equipment in the network. We also present ongoing activities in specific standardization working groups for "greening the network" along with their proposals to improve the energy efficiency of future optical networks. © 2013 Alcatel-Lucent.

  • All-optical packet/circuit switching-based data center network for enhanced scalability, latency, and throughput

     Perello Muntan, Jordi; Spadaro, Salvatore; Ricciardi, Sergio; Careglio, Davide
    IEEE network
    Date of publication: 2013-12
    Journal article

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    Applications running inside data centers are enabled through the cooperation of thousands of servers arranged in racks and interconnected together through the data center network. Current DCN architectures based on electronic devices are neither scalable to face the massive growth of DCs, nor flexible enough to efficiently and cost-effectively support highly dynamic application traffic profiles. The FP7 European Project LIGHTNESS foresees extending the capabilities of today's electrical DCNs through the introduction of optical packet switching and optical circuit switching paradigms, realizing together an advanced and highly scalable DCN architecture for ultra-high-bandwidth and low-latency server-to-server interconnection. This article reviews the current DC and high-performance computing (HPC) outlooks, followed by an analysis of the main requirements for future DCs and HPC platforms. As the key contribution of the article, the LIGHTNESS DCN solution is presented, deeply elaborating on the envisioned DCN data plane technologies, as well as on the unified SDN-enabled control plane architectural solution that will empower OPS and OCS transmission technologies with superior flexibility, manageability, and customizability.

  • Traffic variation-aware networking for energy efficient optical communications

     Morea, Annalisa; Perello Muntan, Jordi; Spadaro, Salvatore
    International Conference on Optical Network Design and Modeling
    Presentation's date: 2013-04-17
    Presentation of work at congresses

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    'Traffic-aware' networking is a solution allowing the improvement of the energy efficiency of optical networks. The implementation of these networking schemes makes possible to adapt the number of fully powered systems to the amount of carried traffic. Various traffic-aware schemes are available in the literature; some acting on the optical amplifiers, others on the optoelectronic (OE) devices. In this paper we introduce the parameter p to measure the energy savings introduced by a 'traffic-aware' scheme; the savings are obtained by considering the maximum power required to transport the peak traffic and the average power required by the network to transport the traffic during a defined time-frame (e.g. day, week). The higher the p-parameter is, more energy-efficient the 'traffic-aware' solution is. The energy efficiency of three on-off strategies, acting separately and/or jointly to amplifiers and OE-devices, are compared and discussed in terms of management implementation and network resiliency.

    'Traffic-aware' networking is a solution allowing the improvement of the energy efficiency of optical networks. The implementation of these networking schemes makes possible to adapt the number of fully powered systems to the amount of carried traffic. Various traffic-aware schemes are available in the literature; some acting on the optical amplifiers, others on the optoelectronic (OE) devices. In this paper we introduce the parameter p to measure the energy savings introduced by a 'traffic-aware' scheme; the savings are obtained by considering the maximum power required to transport the peak traffic and the average power required by the network to transport the traffic during a defined time-frame (e.g. day, week). The higher the p-parameter is, more energy-efficient the 'traffic-aware' solution is. The energy efficiency of three on-off strategies, acting separately and/or jointly to amplifiers and OE-devices, are compared and discussed in terms of management implementation and network resiliency.

  • Access to the full text
    Link vs. opto-electronic device sleep mode approaches in survivable green optical networks  Open access

     Perello Muntan, Jordi; Morea, Annalisa; Spadaro, Salvatore; Tornatore, Massimo
    Optical Fiber Communication Conference and Exposition and National Fiber Optic Engineers Conference
    Presentation's date: 2013-03-20
    Presentation of work at congresses

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    Energy savings of link and OE device sleep mode approaches are compared in 1:1 protected optical networks, together with a hybrid solution combining both of them. The proposed hybrid solution can decrease network energy consumption by up to 82%.

    Energy savings of link and OE device sleep mode approaches are compared in 1:1 protected optical networks, together with a hybrid solution combining both of them. The proposed hybrid solution can decrease network energy consumption by up to 82%.

  • Experimental demonstration of a GMPLS-enabled impairment-aware lightpath restoration scheme

     Perello Muntan, Jordi; Spadaro, Salvatore; Agraz Bujan, Fernando; Angelou, Marianna; Azodolmolky, Siamak; Qin, Yixuan; Nejabati, Reza; Simeonidou, Dimitra; Kokkinos, Panagiotis; Varvarigos, Emmanouel A.; Tomkos, Ioannis
    Journal of optical communications and networking
    Date of publication: 2012-05
    Journal article

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  • Optimized burst LSP design for absolute QoS guarantees in GMPLS-controlled OBS networks

     Pedroso Mendonça, Pedro; Perello Muntan, Jordi; Careglio, Davide; Klinkowski, Miroslaw; Spadaro, Salvatore
    Journal of optical communications and networking
    Date of publication: 2012-02
    Journal article

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  • Strategies for virtual optical network allocation

     Pages Cruz, Albert; Perello Muntan, Jordi; Spadaro, Salvatore; Junyent Giralt, Gabriel
    IEEE communications letters
    Date of publication: 2012-02
    Journal article

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  • Benefits of implementing a dynamic impairment-aware optical network: results of EU Project DICONET

     Angelou, Marianna; Azodolmolky, Siamak; Tomkos, Ioannis; Perello Muntan, Jordi; Spadaro, Salvatore; Careglio, Davide; Manousakis, Kostas; Kokkinos, Panagiotis; Varvarigos, Emmanouel A.; Staessens, Dimitri; Colle, Didier; Saradhi, Chava Vijaya; Gagnaire, Maurice; Ye, Yabin
    IEEE communications magazine
    Date of publication: 2012
    Journal article

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  • Advanced Routing Mechanisms in ASON/GMPLS Networks  Open access

     Agraz Bujan, Fernando
    Defense's date: 2012-10-01
    Department of Signal Theory and Communications, Universitat Politècnica de Catalunya
    Theses

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    Current network infrastructures are supported on a layered model whereby heterogeneous data traffic can be seamlessly transported. In this architecture, where client/server relationships are established between adjacent layers, there exists an IP layer on top, two intermediate Asynchronous Transfer Mode (ATM) and Synchronous Digital Hierarchy (SDH) layers, and a Wavelength Division Multiplexing (WDM) layer at the bottom. Despite the benefits provided by the intermediate ATM and SDH layers (i.e., QoS and resilience), the complex interaction between them and the introduced overhead motivate an evolution towards a lighter model, where IP flows are directly sent through the WDM layer. In this new IP/WDM model the functionalities formerly provided by the ATM and SDH layers are moved to the optical domain. From an operational perspective, the static nature of current transport networks, which leads to long service provisioning times (i.e., hours or days), becomes incompatible with the dynamic patterns associated to the prevalent IP traffic. To overcome these limitations, the ITU-T proposed the Automatically Switched Optical Network (ASON) architecture, which utilizes a control plane to provide fast and reliable lightpaths within the optical transport network. In addition, the Generalized Multi-Protocol Label Switching (GMPLS) model defined by the IETF appears as the most promising technology to implement the functionalities of the ASON control plane. Although being a significant advance towards flexible and easy-to-maintain transport network architectures, the ASON/GMPLS paradigm still presents three major open issues that are addressed in this thesis. First, due to the coarse granularity offered by the WDM transport technology, established connections remain underused when sub-wavelength client flows must be transmitted. In light of this, a multi-layer approach, where different higher level data flows are aggregated in the IP layer and transmitted over the same optical path, appears as the most valid solution. Besides, the GMPLS technology is more than indicated to implement the control plane in this multi-layer architecture, since it allows the management of different switching technologies in an integrated way. In this regard, this thesis reports the experimental design and validation of a GMPLS-controlled multi-layer optical transport network. Second, even though pure optical transmission enabled by WDM provides high bandwidth in a cost-effective way, it is also very sensitive to the physical layer impairments that affect to the transmitted optical signal and, thus, to the transported data. Hence, a control plane capable of managing physical layer information to provide feasible lightpaths becomes a must. This thesis introduces and experimentally evaluates different architectural solutions to implement an impairment-aware GMPLS-based control plane. Finally, as transport network infrastructures grow, they are typically segmented into domains due to administrative, technological, or scalability reasons. Furthermore, the interconnection of network infrastructures managed by different operators is mandated by the need to provide long distance connectivity. Here, confidentiality and reliability concerns become of paramount importance. All this justifies the need for multi-domain networks. In GMPLS-controlled multi-domain optical transport networks, this partitioning affects to end-to-end service provisioning, which is hindered by the reduced information exchange between domains resulting from the fulfillment of segmentation criteria. As the third goal of this thesis, different mechanisms for scalable and effective end-to-end service provisioning are proposed in this multi-domain scenario.

    Les xarxes de comunicacions actuals segueixen un model distribuït de quatre capes que permet la transmissió de tràfic de dades heterogeni de forma eficaç sobre la mateixa infraestructura de transport. En aquesta arquitectura, la capa superior correspon a la capa IP, seguida per dues capes intermèdies que són la capa ATM (Asynchronous Transfer Mode) i la capa SDH (Synchronous Digital Hierarchy) i, finalment, la capa WDM (Wavelength Division Multiplexing). Encara que les capes ATM i SDH proporcionen beneficis com qualitat de servei i protecció i restauració, també comporten una sèrie de problemes com interaccions complexes entre elles i un excés d'informació de control. Això fa necessari evolucionar cap a una arquitectura més lleugera on els fluxos IP es puguin enviar directament a través de la capa WDM. En aquest nou model IP/WDM les funcionalitats proporcionades inicialment per les capes ATM i SDH es traspassen al domini òptic.Des d'un punt de vista operacional, la naturalesa estàtica del model en quatre capes fa que els temps de provisió de serveis siguin molt llargs (d'hores o dies) i, per tant, incompatibles amb els patrons de tràfic IP que són altament dinàmics. Per superar aquestes limitacions, la ITU-T va proposar l'arquitectura ASON (Automatically Switched Optical Network) que utilitza un pla de control per proporcionar connexions en la xarxa òptica de forma ràpida i fiable. A més, la tecnologia GMPLS (Generalized Multi-Protocol Label Switching), definida per la IETF, apareix com el model més prometedor per implementar les funcionalitats del pla de control d'ASON.Tot i que el paradigma ASON/GMPLS suposa un avenç significatiu per aconseguir un model flexible i fàcil de mantenir, encara presenta una sèrie de limitacions que es tracten en aquesta tesi.Primer, degut a la granularitat de longitud d'ona oferida per la tecnologia de transport WDM, els circuits òptics establerts queden infrautilitzats quan transmeten fluxos de dades de client de granularitat inferior. Per aquest motiu una solució multi-capa, en la que aquests fluxos de client puguin ser agregats a la capa IP i després transportats pel mateix circuit en la capa òptica, sembla la més apropiada. A més, la tecnologia GMPLS resulta molt adient per implementar el pla de control en aquesta arquitectura multi-capa, ja que permet la gestió de diferents tecnologies de commutació de forma integrada. En aquest context, aquesta tesi descriu el desenvolupament i validació experimental d'una xarxa de transport òptic multi-capa controlada per un pla de control GMPLS.En segon lloc, encara que la transmissió purament òptica basada en WDM proporciona un gran ample de banda amb un cost reduït, també és molt sensible als efectes negatius que afecten al senyal òptic transmès i, per tant, a la informació transportada. En aquest context esdevé necessari un pla de control que sigui capaç de manegar la informació associada a la capa òptica. Aquesta tesi presenta i avalua de forma experimental diferents solucions per implementar un pla de control GMPLS amb gestió dels impediments físics associats a la capa òptica.Finalment, degut al creixement de les infraestructures de xarxa, aquestes s'acostumen a particionar ja sigui per raons tecnològiques, administratives o d'escalabilitat. A més, la interconnexió entre dominis de diferents operadors, necessària per proporcionar connectivitat a llarga distància, implica problemes de confidencialitat entre operadors. Tot això dóna lloc a les xarxes multi-domini. En xarxes òptiques multi-domini controlades amb GMPLS, aquest particionat afecta a la provisió de serveis extrem a extrem, que es veu afectada pel limitat intercanvi d'informació causat per la necessitat de satisfer els requeriments esmentats. El tercer objectiu d'aquesta tesi consisteix en proporcionar mecanismes de provisió de connexions extrem a extrem, escalables i efectius, en aquest escenari multi-domini.

  • Enhanced optical networks featuring adaptable and highly scalable multi-granular transport services

     Ruiz Ramírez, Marc; Junyent Giralt, Gabriel; Comellas Colome, Jaume; Gené Bernaus, Joan M.; Conesa Fernandez, Josep; Velasco Esteban, Luis; Perello Muntan, Jordi; Agraz Bujan, Fernando; Hernandez Sola, Guillem; Pages Cruz, Albert; Khodashenas, Pooria Saiyad; Spadaro, Salvatore
    Participation in a competitive project

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  • Enhanced Optical Networks Featuring Adaptable and Highly Scalable Multi-granular Transport Services (ELASTIC) - TEC2011-27310

     Junyent Giralt, Gabriel; Spadaro, Salvatore; Comellas Colome, Jaume; Gené Bernaus, Joan M.; Velasco Esteban, Luis; Perello Muntan, Jordi; Conesa Fernandez, Josep; Agraz Bujan, Fernando; Ruiz Ramírez, Marc; Hernandez Sola, Guillem; Pages Cruz, Albert; Khodashenas, Pooria Saiyad
    Participation in a competitive project

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  • Lightpath fragmentation for efficient spectrum utilization in dynamic elastic optical networks

     Pages Cruz, Albert; Perello Muntan, Jordi; Spadaro, Salvatore
    International Conference on Optical Networking Design and Modeling
    Presentation's date: 2012-04-18
    Presentation of work at congresses

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  • ONDM 2012

     Pages Cruz, Albert; Perello Muntan, Jordi; Spadaro, Salvatore
    Award or recognition

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  • Planning of optical and IT resources for efficient virtual infrastructure embedding

     Pages Cruz, Albert; Perello Muntan, Jordi; Spadaro, Salvatore
    International Conference on Photonics in Switching
    Presentation's date: 2012-09-14
    Presentation of work at congresses

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    This work addresses the offline problem of efficiently planning network substrates joining geographically distributed IT resource locations over high-capacity optical resources. Given an already known set of virtual infrastructure demands to be embedded over the network substrate, we present an iterative optimization heuristic that appropriately embeds all virtual infrastructure demands in order to minimize both the physical substrate IT and optical resources needed to allocate them. For this purpose, the heuristic arranges the demands in descending order, based on the amount of resources they require. Then, it processes all demands, one after another, optimally embedding each one of them on the network substrate using Integer Linear Programming (ILP) techniques. The performance of the proposed heuristic is highlighted through illustrative results.

  • Virtual network embedding in optical infrastructures

     Pages Cruz, Albert; Perello Muntan, Jordi; Spadaro, Salvatore
    International Conference on Transparent Optical Networks
    Presentation's date: 2012-07-04
    Presentation of work at congresses

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  • Optimal allocation of virtual optical networks for the future internet

     Pages Cruz, Albert; Perello Muntan, Jordi; Spadaro, Salvatore; Garcia Espin, Joan Antoni; Ferrer Riera, Jordi; Figuerola, Sergi
    International Conference on Optical Networking Design and Modeling
    Presentation's date: 2012-04-17
    Presentation of work at congresses

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  • Access to the full text
    Service and resource differentiation in shared-path protection environments to maximize network operator's revenues  Open access

     Velasco Esteban, Luis; Ruiz Ramírez, Marc; Perello Muntan, Jordi; Spadaro, Salvatore; Comellas Colome, Jaume
    Journal of optical communications and networking
    Date of publication: 2011-02
    Journal article

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    Network operators are facing hard competition for opportunities in the telecommunications market, forcing network investments to be carefully evaluated before the decision-making process. A great part of core network operators’ revenues comes from the provisioned connectivity services. Taking this premise as our starting point, we first examine the provisioning of differentiated services in current shared-path protection (SPP) environments. This analysis reveals that current resource assignment policies are only able to provide a very poor grade of service to the supported best-effort traffic. Aiming to improve this performance, a novel resource partitioning scheme called diff-WS is proposed, which differentiates those wavelengths supporting each class of service in the network. As a major goal of this paper, the benefits of diff-WS over current resource assignment policies are assessed from an economic perspective. For this purpose, the network operator revenues maximization (NORMA) problem is presented to design the optical network such that the operator’s revenues are maximized. To solve NORMA, we derive statistical models to obtain, given a certain grade of service, the highest traffic intensity for each class of service and resource partitioning scheme. These models turn NORMA into a nonlinear problem, which is finally addressed as an iterative approach, solving an integer linear programming (ILP) subproblem at each iteration. The obtained numerical results on several network topologies illustrate that diff-WS maximizes resource utilization in the network and, thus, the network operator’s profit.

  • Enhanced domain disjoint backward recursive TE path computation for PCE-based multi-domain networks

     Hernandez Sola, Guillem; Perello Muntan, Jordi; Agraz Bujan, Fernando; Velasco Esteban, Luis; Spadaro, Salvatore; Junyent Giralt, Gabriel
    Photonic network communications
    Date of publication: 2011-04
    Journal article

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    The ability of computing optimal routes poses new challenges when extending it to larger multi-domain network scenarios, as the quality of these computed endto-end inter-domain routes depends on the selection of the domain sequence to be traversed. In the scope of the Internet Engineering Task Force (IETF), the Path Computation Element (PCE) Working Group has not provided definitive solutions to address the domain sequence selection problem, being still a work in progress. To this goal, the Path Computation Flooding (PCF) approach appears as a possible extension to Backward Recursive PCE-based Computation (BRPC) to calculate optimal end-to-end inter-domain paths without requiring a pre-configured domain sequence. Nonetheless, PCF presents major scalability issues in terms of network control overhead and path computation complexity, thus pleading for more accurate domain sequence selection techniques. This paper describes two novel mechanisms to establish inter-domain paths calculating the sequence of domains to be crossed when it is not known in advance. Both procedures make a good trade-off between the control overhead introduced and the accuracy of the computed end-to-end route. The obtained simulation results show the benefits of the proposed contributions, drastically reducing the control overhead while keeping the connection blocking probability close to the optimal values.

  • GMPLS control plane network design with resilience guarantees

     Ruiz Ramírez, Marc; Perello Muntan, Jordi; Velasco Esteban, Luis; Spadaro, Salvatore; Comellas Colome, Jaume; Junyent Giralt, Gabriel
    Journal of lightwave technology
    Date of publication: 2011-01-01
    Journal article

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    A one-to-one association between data and control channels has traditionally existed in transport networks. Being the control plane embedded in the data plane, the design of the former, as well as its resilience, has been addressed in the latter’s one. However, a main GMPLS architectural requirement is to provide a clean separation between control and data planes. In this sense, the control plane in GMPLS networks may describe a different topology than the data plane, even realized over a separated IP network. As a consequence of this, data and control network design become no more linked in such scenarios. To the best of our knowledge, no works in the literature have addressed an independent design of the control plane in GMPLS-enabled networks regardless of the data plane. In this paper, we provide a method to obtain the optimal GMPLS control plane design, minimizing the network Capital Expenditures (CAPEX) while matching specific resilience requirements. To this goal, the problem of finding an optimal control plane topology that ensures a certain resilience level is formulated as a non-linear combinatorial model. This model, however, does not scale properly for large backbone networks. In view of this, a constructive linear method is also presented and its optimality validated through simulations on several reference network scenarios. Furthermore, its benefits in terms of total execution time are also highlighted.

  • Experimental Demonstration of an Impairment Aware Network Planning and Operation Tool for Transparent/Translucent Optical Networks

     Azodolmolky, Siamak; Perello Muntan, Jordi; Angelou, Marianna; Agraz Bujan, Fernando; Velasco Esteban, Luis; Spadaro, Salvatore; Pointurier, Yvan; Francescon, Antonio; Saradhi, Chava Vijaya; Kokkinos, Panagiotis; Varvarigos, Emmanouel A.; Al Zahr, Sawsan; Gagnaire, Maurice; Gunkel, Mathias; Klonidis, Dimitrios; Tomkos, Ioannis
    Journal of lightwave technology
    Date of publication: 2011-02-15
    Journal article

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  • Future Internet testbeds/experimentation between BRazil and Europe - EU

     Junyent Giralt, Gabriel; Perello Muntan, Jordi; Spadaro, Salvatore
    Participation in a competitive project

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  • A GMPLS/OBS network architecture enabling QoS-aware end-to-end burst transport

     Pedroso, Pedro; Perello Muntan, Jordi; Klinkowski, Miroslaw; Careglio, Davide; Spadaro, Salvatore; Sole Pareta, Josep
    International Conference on High Performance Switching and Routing
    Presentation of work at congresses

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  • Experimental demonstration of an enhanced impairment-aware path computation element

     Spadaro, Salvatore; Perello Muntan, Jordi; Agraz Bujan, Fernando; Azodolmolky, Siamak; Angelou, Marianna; Qin, Yixuan; Nejabati, Reza; Simeonidou, Dimitra; Kokkinos, Pannagiotis; Varvarigos, Emmanouel; Ye, Yabin; Tomkos, Ioannis
    Optical Fiber Communication Conference and Exposition
    Presentation's date: 2011-03-08
    Presentation of work at congresses

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  • Scalable hybrid path computation procedure for PCE-based

     Hernandez Sola, Guillem; Perello Muntan, Jordi; Agraz Bujan, Fernando; Spadaro, Salvatore; Comellas Colome, Jaume; Junyent Giralt, Gabriel
    International Conference on Transparent Optical Networks
    Presentation's date: 2011-06-27
    Presentation of work at congresses

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  • Dynamic Impairment-Aware Optical Networking: Some Experimental Results of the EU DICONET Project

     Spadaro, Salvatore; Perello Muntan, Jordi; Agraz Bujan, Fernando; Angelou, Marianna; Azodolmolky, Siamak; Qin, Yixuan; Nejabati, Reza; Simeonidou, Dimitra; Tomkos, Ioannis
    International Conference on Transparent Optical Networks
    Presentation's date: 2011-06-29
    Presentation of work at congresses

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  • Experimental evaluation of centralized failure restoration in a dynamic impairment-aware all-optical network

     Perello Muntan, Jordi; Spadaro, Salvatore; Agraz Bujan, Fernando; Angelou, Marianna; Azodolmolky, Siamak; Qin, Yixuan; Nejabati, Reza; Simeonidou, Dimitra; Kokkinos, Panagiotis; Varvarigos, Emmanouel A.; Al Zahr, Sawsan; Gagnaire, Maurice; Tomkos, Ioannis
    Optical Fiber Communication Conference and Exposition
    Presentation's date: 2011-03-08
    Presentation of work at congresses

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  • Power management of optoelectronic interfaces for dynamic optical networks

     Morea, Annalisa; Spadaro, Salvatore; Rival, Olivier; Perello Muntan, Jordi; Agraz Bujan, Fernando; Verchere, Dominique
    European Conference and Exposition on Optical Communications
    Presentation's date: 2011-09-21
    Presentation of work at congresses

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  • Experimental comparison of impairment-aware RWA algorithms in a GMPLS-controlled dynamic optical network

     Angelou, Marianna; Agraz Bujan, Fernando; Kokkinos, Panagiotis; Perello Muntan, Jordi; Azodolmolky, Siamak; Varvarigos, Emmanouel; Spadaro, Salvatore; Tomkos, Ioannis
    Future Network and MobileSummit
    Presentation's date: 2011-06-15
    Presentation of work at congresses

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  • Experimental evaluation of a full-meshed domain abstraction design model for reduced state information dissemination in multi-domain PCE-based WSONs

     Pagès, Albert; Casellas, Ramón; Perello Muntan, Jordi; Martinez, Ricardo; Spadaro, Salvatore; Muñoz González, Raul
    European Conference and Exposition on Optical Communications
    Presentation's date: 2011-09-21
    Presentation of work at congresses

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    A novel full-meshed domain abstraction model for scalable state information in PCEbased WSONs is presented. We experimentally evaluate the state information update reduction and the blocking improvement with regard to a shortest path model.

  • Scalable hybrid path computation procedure for PCE-based multi-domain WSON networks

     Hernandez Sola, Guillem; Perello Muntan, Jordi; Agraz Bujan, Fernando; Spadaro, Salvatore; Comellas Colome, Jaume; Junyent Giralt, Gabriel
    International Conference on Transparent Optical Networks
    Presentation's date: 2011
    Presentation of work at congresses

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    In the Hierarchical Path Computation Element (H-PCE) architecture, an optimum end-to-end path is computed using a hierarchical relationship among PCEs. An H-PCE-based path computation procedure provides low network blocking probability meanwhile it results on a great amount of control overhead messages. In this paper we propose a hybrid path computation procedure based on the H-PCE architecture and the Backward Recursive PCE-Based Computation (BRPC). Extensive simulation results show that the proposed approach performs better than H-PCE in terms of network control overhead.

  • A feedback-based hybrid OBS/OCS architecture with fast-over-slow capability

     Khodashenas, Pooria Saiyad; Perello Muntan, Jordi; Spadaro, Salvatore; Comellas Colome, Jaume; Junyent Giralt, Gabriel
    International Conference on Optical Network Design and Modeling
    Presentation's date: 2011-02-08
    Presentation of work at congresses

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  • Deployment and validation of GMPLS-controlled multi-layer integrated routing over the ASON/GMPLS CARISMA test-bed

     Agraz Bujan, Fernando; Velasco Esteban, Luis; Perello Muntan, Jordi; Ruiz Ramírez, Marc; Spadaro, Salvatore; Junyent Giralt, Gabriel; Comellas Colome, Jaume
    Journal of networks
    Date of publication: 2010-11
    Journal article

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  • Scalable path computation flooding approach for PCE-based multi-domain networks

     Perello Muntan, Jordi; Hernandez Sola, Guillem; Agraz Bujan, Fernando; Spadaro, Salvatore; Comellas Colome, Jaume
    ETRI journal
    Date of publication: 2010-08
    Journal article

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  • Using updated neighbor state information for efficient contention avoidance in OBS networks

     Perello Muntan, Jordi; Agraz Bujan, Fernando; Spadaro, Salvatore; Comellas Colome, Jaume; Junyent Giralt, Gabriel
    Computer communications
    Date of publication: 2010-01
    Journal article

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  • Experimental UpdateLess Evolutive Routing

     Perello Muntan, Jordi; Spadaro, Salvatore; Sole Pareta, Josep; Cabellos Aparicio, Alberto; Careglio, Davide
    Participation in a competitive project

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  • projecte GEYSERS

     Junyent Giralt, Gabriel; Spadaro, Salvatore; Comellas Colome, Jaume; Perello Muntan, Jordi
    Participation in a competitive project

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  • Experimental UpdateLess Evolutive Routing

     Junyent Giralt, Gabriel; Comellas Colome, Jaume; Cabellos Aparicio, Alberto; Careglio, Davide; Perello Muntan, Jordi; Sole Pareta, Josep; Spadaro, Salvatore
    Participation in a competitive project

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  • Scalable, Tunable and Resilient Optical Networks Guaranteeing Extremely-high Speed Transport

     Spadaro, Salvatore; Sole Pareta, Josep; Perello Muntan, Jordi; Careglio, Davide; Velasco Esteban, Luis; Junyent Giralt, Gabriel; Comellas Colome, Jaume
    Participation in a competitive project

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  • Access to the full text
    A GMPLS/OBS network architecture enabling QoS-aware end-to-end burst transport  Open access

     Pedroso, Pedro; Klinkowski, Miroslaw; Perello Muntan, Jordi; Spadaro, Salvatore; Careglio, Davide; Sole Pareta, Josep
    Date: 2010-07-01
    Report

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    This paper introduces a Generalized Multi-Protocol Label Switching (GMPLS)-enabled Optical Burst Switched (OBS) network architecture featuring end-to-end QoS-aware burst transport services. This is achieved by setting up burst Label Switched Paths (LSPs) properly dimensioned to match specific burst drop probability requirements. These burst LSPs are used for specific guaranteed QoS levels, whereas the remaining network capacity can be left for best-effort burst support. Aiming to ensure the requested burst drop probability figures even under bursty traffic patterns, burst LSPs’ performance is continuously monitored. Therefore, GMPLS-driven capacity reconfigurations can be dynamically triggered whether unfavorable network conditions are detected. Through the paper, the GMPLS/OBS architecture is firstly detailed, followed by the presentation of the optimized methods used for the initial burst LSP dimensioning. The successful network performance is finally illustrated by simulations on several network scenarios.

  • Access to the full text
    Performance evaluation of a hybrid OBS/OCS network with QoS differentiation based on packet loss/delay requirements  Open access

     Perello Muntan, Jordi; Guinea, Nuria de; Spadaro, Salvatore; Junyent Giralt, Gabriel; Comellas Colome, Jaume
    International Conference on Transparent Optical Networks
    Presentation's date: 2010-06-28
    Presentation of work at congresses

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    This paper introduces and evaluates a hybrid OBS/OCS switch for Quality of Service (QoS) differentiation in next-generation all-optical transport networks. Depending on their QoS requirements, incoming IP packets are collected in delay-sensitive or loss-sensitive assembly queues. Once assembled, those departing delay or losssensitive bursts are sent to the destination over a parallel all-optical hybrid network, where a set of switch ports and wavelengths are dedicated to delay-sensitive OBS-like transmission based on Just Enough Time (JET), whereas the remainder are dedicated to loss-sensitive OCS-like transmission. The obtained results validate the differentiated transport services in the deployed reference network scenario. Moreover, they show that circuit set-up retries are mandatory in OCS to carry loss-sensitive traffic efficiently.

  • Access to the full text
    Experimental evaluation of path restoration for a centralised impairment-aware GMPLS-controlled all-optical network  Open access

     Agraz Bujan, Fernando; Perello Muntan, Jordi; Angelou, Marianna; Azodolmolky, Siamak; Velasco Esteban, Luis; Spadaro, Salvatore; Kokkinos, Panagiotis; Varvarigos, Emmanouel A.; Tomkos, Ioannis
    European Conference and Exposition on Optical Communications
    Presentation's date: 2010-09-21
    Presentation of work at congresses

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    This paper evaluates a centralised impairment-aware path restoration approach for GMPLScontrolled transparent optical networks. Experimental results on a 14-node network test-bed show successful QoT compliant path restoration of around 3.6 seconds.

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    Experimental demonstration of centralized and distributed impairment-aware control plane schemes for dynamic transparent optical networks  Open access

     Agraz Bujan, Fernando; Azodolmolky, Siamak; Angelou, Marianna; Perello Muntan, Jordi; Velasco Esteban, Luis; Spadaro, Salvatore; Francescon, Antonio; Saradhi, Chava Vijaya; Pointurier, Yvan; Kokkinos, Panagiotis; Varvarigos, Manos; Gunkel, Mathias; Tomkos, Ioannis
    Optical Fiber Communication, collocated National Fiber Optic Engineers Conference
    Presentation's date: 2010-03-25
    Presentation of work at congresses

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    In transparent optical networks, the signal experiences the impact of various phenomena that degrade its quality. Considering the impact of physical layer impairments (PLIs) on transparent [1] and highly dynamic optical networks [2] has received much attention recently. The main innovation of the DICONET project [3] is the development of a dynamic Network Planning and Operation Tool (NPOT) that incorporates real-time assessments of the optical layer performance into Impairment Aware Routing and Wavelength Assignment (IA-RWA) algorithms. The NPOT is integrated into a unified extended Generalized Multi-Protocol Label Switching (GMPLS)-based control plane. The work in [1] reported the result of a centralized integration scheme for transparent networks considering various PLIs, while [4] only investigated a distributed GMPLS integration for translucent networks. This paper demonstrates the performance of centralized and distributed impairment-aware control plane approaches over a realistic 14-node experimental test-bed under dynamic traffic conditions.Initial simulation results were reported in [5] and experimental results are reported here. The test-bed integrates the developed NPOT engine, the extended GMPLS control protocols required for supporting the innovative DICONET solutions and the various communication protocols to allow all DICONET building blocks run in an orchestrated fashion. To the best of our knowledge, for the first time, impairment-aware control plane schemes with integrated real-time Quality of Transmission (QoT) estimator are demonstrated.

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    Analysis of traffic engineering information dissemination strategies in PCE-based multi-domain optical networks  Open access

     Spadaro, Salvatore; Perello Muntan, Jordi; Hernandez Sola, Guillem; Moreno, A.; Agraz Bujan, Fernando; Comellas Colome, Jaume; Junyent Giralt, Gabriel
    International Conference on Transparent Optical Networks
    Presentation's date: 2010-06-28
    Presentation of work at congresses

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    This paper presents and compares different TE information dissemination strategies between Path Computation Elements (PCEs) in multi-domain optical networks. In such network context, recent studies have found that path computation only with local domain visibility yields poor network performance. Accordingly, certain visibility between domains seems necessary. Aiming to fit the confidentiality requirements of the composing domains while improving the final network blocking probability, novel link aggregation techniques have been proposed, which summarize the state of network domains resources efficiently. This aggregated link information is afterwards disseminated to all the remainder domains in the network. To this end, we introduce different update triggering policies to make a good trade-off between routing information scalability and inaccuracy. The performance of all contributions has been supported by illustrative simulation results.

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    An analytical model for GMPLS control plane resilience quantification  Open access

     Ruiz Ramírez, Marc; Perello Muntan, Jordi; Velasco Esteban, Luis; Spadaro, Salvatore; Comellas Colome, Jaume
    IEEE communications letters
    Date of publication: 2009-12
    Journal article

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    This paper concentrates on the resilience of the Generalized Multi-Protocol Label Switching (GMPLS) enabled control plane. To this end, the problem of control plane resilience in GMPLS-controlled networks is firstly stated and previous work on the topic reviewed. Next, analytical formulae to quantify the resilience of generic meshed control plane topologies are derived. The resulting model is validated by simulation results on several reference network scenarios.

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    Design and implementation of a GMPLS-controlled grooming-capable optical transport network  Open access

     Agraz Bujan, Fernando; Velasco Esteban, Luis; Perello Muntan, Jordi; Ruiz Ramírez, Marc; Spadaro, Salvatore; Junyent Giralt, Gabriel; Comellas Colome, Jaume
    Journal of optical communications and networking
    Date of publication: 2009-07
    Journal article

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    Aiming at better resource utilization, an important requirement of future optical transport networks is the capability to accommodate subwavelength client flows efficiently. This can be put into action thanks to the enhanced traffic engineering (TE) protocols provided within the generalized multiprotocol label switching (GMPLS) standardization. The present paper concentrates on the design and implementation of a GMPLS-controlled grooming-capable transport infrastructure, namely, the automatically switched optical network (ASON)ÕGMPLS CARISMA test bed. Through the paper, the operation of a GMPLS-controlled multilayer network architecture is introduced, subsequently highlighting implementation issues that come to light. Special attention is devoted to a centralized flow reallocation module deployed in the CARISMA test bed to minimize the overall network cost. In this context, an integer linear programming (ILP) formulation to obtain its optimal cost is derived and low-weighted metaheuristics providing a nearly optimal solution are additionally proposed. All contributions in the paper are supported by illustrative experimental results.

  • Controlled loops for quality-of-service differentiation in delay-sensitive optical burst switching networks

     Perello Muntan, Jordi; Spadaro, Salvatore; Comellas Colome, Jaume; Junyent Giralt, Gabriel
    IET communications
    Date of publication: 2009-08
    Journal article

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  • Performance issues in Optical Burst/Packet Switching

     Careglio, Davide; Aracil, Javier; Azodolmolky, Siamak; García Haro, Joan; Gunreben, Sebastian; Hu, Guoqiang; Izal, Mikel; Kimsas, Andreas; Klinkowski, Miroslaw; Köhn, Martin; Magaña, Eduardo; Morató, Daniel; Pavón Mariño, Pablo; Perello Muntan, Jordi; Scharf, Joachim; Tomkos, Ioannis; Spadaro, Salvatore; Tzanakaki, Anna; Veiga Gontán, Javier
    Date of publication: 2009-04-01
    Book chapter

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    This chapter summarises the activities on optical packet switching (OPS) and optical burst switching (OBS) carried out by the COST 291 partners in the last 4 years. It consists of an introduction, five sections with contributions on five different specific topics, and a final section dedicated to the conclusions. Each section contains an introductive state-of-the-art description of the specific topic and at least one contribution on that topic. The conclusions give some points on the current situation of the OPS/OBS paradigms.