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  • Combining Optics and SDN In next Generation data centre Networks COSIGN

     Careglio, Davide
    Participation in a competitive project

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  • ILP modeling of many-to-many replicated multimedia communication

     Walkowiak, Krzysztof; Bulira, Damian; Careglio, Davide
    Journal of telecommunications and information technology
    Date of publication: 2013-09-01
    Journal article

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    On-line communication services were evolving from a simple text-based chats towards sophisticated videopresence appliances. The bandwidth consumption of those services is constantly growing due to the technology development and high user and business needs. That fact leads us to implement optimization mechanisms into the multimedia communication scenarios. In this paper, the authors concentrate on many-to-many (m2m) communication, that is mainly driven by the growing popularity of on-line conferences and telepresence applications. An overlay model where m2m flows are optimally established on top of a given set of network routes is formulated and a joint model where the network routes and the m2m flows are jointly optimized. In the models, the traffic traverses through replica servers, that are responsible for stream aggregation and compression. Models for both predefined replica locations and optimized server settlement are presented. Each model is being followed by a comprehensive description and is based on real teleconference systems.

    On-line communication services were evolving from a simple text-based chats towards sophisticated videopresence appliances. The bandwidth consumption of those services is constantly growing due to the technology development and high user and business needs. That fact leads us to implement optimization mechanisms into the multimedia communication scenarios. In this paper, the authors concentrate on many-to-many (m2m) communication, that is mainly driven by the growing popularity of on-line conferences and telepresence applications. An overlay model where m2m flows are optimally established on top of a given set of network routes is formulated and a joint model where the network routes and the m2m flows are jointly optimized. In the models, the traffic traverses through replica servers, that are responsible for stream aggregation and compression. Models for both predefined replica locations and optimized server settlement are presented. Each model is being followed by a comprehensive description and is based on real teleconference systems.

  • Eco-sustainable routing in optical networks

     Ricciardi, Sergio; Wang, Jiayuan; Palmieri, Francesco; Careglio, Davide; Manolova, Anna; Santos Boada, German
    Photonic network communications
    Date of publication: 2013-12-01
    Journal article

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    It is quite easy to foresee that in the next years, the future generation ultra-high speed network infrastructures and equipments will be no longer constrained only by their pure transport capacity, but also by their energy consumption costs and environmental effects. In particular, large network infrastructures are now widely recognized to play a fundamental role in the emission of green-house gases (GHG) in the atmosphere, significantly afecting the environmental sustainability of new evolutions in network architectures as well as technological developments in communication devices. In this paper, a novel eco-sustainable Routing and Wavelength Assignment (RWA) algorithm, based on shortest-path routing with an adaptive link weighting function relying on an extension of the OSPF-TE protocol to convey carbon footprint information, has been proposed to decrease the network ecological impact while balancing the traffic load and maintaining acceptable connection blocking rate. The trade-off between load balancing and carbon footprint is also analyzed to evaluate the efectiveness of the proposed strategy within the context of a real world network.

  • 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.

  • A GRASP with path-relinking heuristic for the survivable IP/MPLS-over-WSON multi-layer network optimization problem

     Pedrola Escriba, Oscar; Ruiz Ramírez, Marc; Velasco Esteban, Luis; Careglio, Davide; Gonzalez de Dios, Oscar; Comellas Colome, Jaume
    Computers & operations research
    Date of publication: 2013-12
    Journal article

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    In this paper we deal with the survivable internet protocol (IP)/multi-protocol label switching (MPLS)-over-wavelength switched optical network (WSON) multi-layer network optimization problem (SIMNO). This problem entails planning an IP/MPLS network layer over a photonic mesh infrastructure whilst, at the same time, ensuring the highest availability of services and minimizing the capital expenditures (CAPEX) investments. Such a problem is currently identified as an open issue among network operators, and hence, its solution is of great interest. To tackle SIMNO, we first provide an integer linear programming (ILP) formulation which provides an insight into the complexity of its managing. Then, a greedy randomized adaptive search procedure (GRASP) with path-relinking (PR) together with a biased random-key genetic algorithm (BRKGA) are specifically developed to help solve the problem. The performance of both heuristics is exhaustively tested and compared making use of various network and traffic instances. Numerical experiments show the benefits of using GRASP instead of BRKGA when dealing with highly complex network scenarios. Moreover, we verified that the use of GRASP with PR remarkably improves the basic GRASP algorithm, particularly in real-sized, complex scenarios such as those proposed in this paper.

    In this paper we deal with the survivable internet protocol (IP)/multi-protocol label switching (MPLS)-over-wavelength switched optical network (WSON) multi-layer network optimization problem (SIMNO). This problem entails planning an IP/MPLS network layer over a photonic mesh infrastructure whilst, at the same time, ensuring the highest availability of services and minimizing the capital expenditures (CAPEX) investments. Such a problem is currently identified as an open issue among network operators, and hence, its solution is of great interest. To tackle SIMNO, we first provide an integer linear programming (ILP) formulation which provides an insight into the complexity of its managing. Then, a greedy randomized adaptive search procedure (GRASP) with path-relinking (PR) together with a biased random-key genetic algorithm (BRKGA) are specifically developed to help solve the problem. The performance of both heuristics is exhaustively tested and compared making use of various network and traffic instances. Numerical experiments show the benefits of using GRASP instead of BRKGA when dealing with highly complex network scenarios. Moreover, we verified that the use of GRASP with PR remarkably improves the basic GRASP algorithm, particularly in real-sized, complex scenarios such as those proposed in this paper.

  • 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
    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.

  • Elastic spectrum allocation for time-varying traffic in flexgrid optical networks

     Klinkowski, Miroslaw; Ruiz Ramírez, Marc; Velasco Esteban, Luis; Careglio, Davide; López Álvarez, Victor; Comellas Colome, Jaume
    IEEE journal on selected areas in communications
    Date of publication: 2013-01
    Journal article

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  • 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
    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
    Participation in a competitive project

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  • (1537-744X) The scientific world journal

     Careglio, Davide
    Collaboration in journals

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  • Measurement methodology and tools

    Date of publication: 2013-09-01
    Book

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  • Towards service orchestration between smart grids and telecom networks

     Ricciardi, Sergio; Santos Boada, German; Klinkowski, Miroslaw; Careglio, Davide; Palmieri, Francesco
    European Conference on Energy Efficiency in Large Scale Distributed Systems
    Presentation's date: 2013-04
    Presentation of work at congresses

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    In the last years, the research efforts in smart grids (SG) and telecommunication networks (TN) have been considerable but never converged to a common view and, due to the lack of strong interactions between the two worlds, only limited benefits have been achieved. We envision in this paper that future TN (as well as any other ICT application) will interact with the SG, enabling (1) the TN to know the energy source and cost that is currently powering its equipment, (2) to turn the TN into an active client which can request to the SG the quantity and quality (e.g. green) of energy that it needs, and (3) a service orchestration between SG supply system and TN operations. As a consequence, the enabled interoperability between TN and SG would allow TN to take energy-aware management decisions in function of energy-related information provided by the SG. For example, TN can route packets with the objective of optimizing green criteria, while SG can route the energy towards the TN clients with the objective of not wasting surpluses of green energy. These new energy and data routing capabilities can be exploited not only by SG operators and telecom carriers but also by any energy consumer/producer within the ICT world. This may include industry and institutional ICT premises, datacenters, home automation, wireless and mobile cellular networks, which will be able to implement their own energy-aware management and operations (M&O) by considering the quantity, quality and cost of the energy currently provided by the smart grid.

  • Evaluating energy savings in WoL-enabled networks of PCs

     Ricciardi, Sergio; Santos Boada, German; Careglio, Davide; Palmieri, Francesco; Fiore, Ugo
    IEEE International Symposium on Industrial Electronics
    Presentation's date: 2013-05
    Presentation of work at congresses

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    In this paper we present EnergySave, a smart energy-saving system that, by leveraging the consolidated WoL (Wake on LAN) technology, allows the remote wake-up of PCs from a centralized management server, providing easy and secure power management capabilities for local or remote IP-based networks of personal computers (PCs). We also present a lightweight web-based platform implementing the remote management interface as less intrusively as possible. Finally, we model the mathematical saving functions to be used in order to evaluate through simulation the amount of potential energy savings, and hence the whole framework effectiveness, both in the general case and in a real case scenario. Results show that significant savings are achievable provided that the hardware supports the Wake-on-LAN specifications and that proper configuration of the Web server is set-up, allowing the WoL magic packet to travel to the destination hosts and wake them up only when they are really needed.

  • 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
    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.

  • Special issue: green networking and computing, part 1 of 2

     Careglio, Davide; Monti, Paolo; Klinkowski, Miroslaw
    Journal of high speed networks
    Date of publication: 2012
    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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  • 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
    Date of publication: 2012-07-05
    Journal article

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  • Value optimization of survivable multilayer IP/MPLS-over-WSON networks

     Velasco Esteban, Luis; González de Dios, Óscar; Ricciardi, Sergio; Castro Casales, Alberto; Muñoz, Fernando; Careglio, Davide; Comellas Colome, Jaume
    Photonic network communications
    Date of publication: 2012-05-01
    Journal article

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  • Dynamic routing and spectrum (re)allocation in future flexgrid optical networks

     Castro Casales, Alberto; Velasco Esteban, Luis; Ruiz Ramírez, Marc; Klinkowski, Miroslaw; Fernández Palacios, Juan Pedro; Careglio, Davide
    Computer networks
    Date of publication: 2012-08-16
    Journal article

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  • CAPEX study for a multilayer IP/MPLS-over-flexgrid optical network

     Pedrola Escriba, Oscar; Castro Casales, Alberto; Velasco Esteban, Luis; Ruiz Ramírez, Marc; Careglio, Davide
    Journal of optical communications and networking
    Date of publication: 2012-08
    Journal article

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

     Sole Pareta, Josep; Subramaniam, Suresh; Careglio, Davide; Spadaro, Salvatore
    Proceedings of the IEEE
    Date of publication: 2012-05
    Journal article

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  • Measurement-based research: methodology, experiments, and tools

     Papadimitriou, Dimitri; Fàbrega Soler, LLuís; Vilà Talleda, Pere; Careglio, Davide; Demeester, Piet
    Computer communication review
    Date of publication: 2012-10
    Journal article

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    In this paper, we report the results of the workshop organized by the FP7 EULER project on measurement-based research and associated methodology, experiments and tools. This workshop aimed at gathering all Future Internet Research and Experimentation (FIRE) experimental research projects under this thematic. Participants were invited to present the usage of measurement techniques in their experiments, their developments on measurement tools, and their foreseeable needs with respect to new domains of research not currently addressed by existing measurement techniques and tools.

  • 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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  • Optimized monitor placement for accurate QoT assessment in core optical networks

     Angelou, Marianna; Pointurier, Yvan; Careglio, Davide; Spadaro, Salvatore; Tomkos, Ioannis
    Journal of optical communications and networking
    Date of publication: 2012-01
    Journal article

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

     Pedrola Escriba, Oscar
    Defense's date: 2012-11-30
    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.

  • 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
    Presentation's date: 2012-07-02
    Presentation of work at congresses

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  • Green-aware routing in GMPLS networks

     Wang, Jiayuan; Ruepp, Sarah; Manolova Vasileva, Anna; Dittman, Lars; Ricciardi, Sergio; Careglio, Davide
    Workshop on Cost, Reliability, Energy Requirements and Constraints in Next Generation Networks
    Presentation's date: 2012-01-30
    Presentation of work at congresses

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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 optimization in Optical Networks  Open access

     Angelou, Marianna
    Defense's date: 2012-04-16
    Department of Computer Architecture, Universitat Politècnica de Catalunya
    Theses

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    Network planning and operation in core optical networks require processes that lead to a cost-effective network able to effectively accommodate the given traffic demands. Crosslayer techniques that exploit information coming from the transport plane to serve either the network planning or the operation phases have been proposed to achieve optimal resource utilization and network performance. Dynamic impairment-aware networking refers to a solution that utilizes the dynamicity as well as the valuable physical-layer information of a reconfigurable WDM network to provide a smooth transition from the quasi-static networking of today to an intelligent reconfigurable and physical impairment-aware architecture. The concept of physical layer awareness allows intelligent techniques to offer optimal planning, dynamic configuration and management of the network while ensuring strong quality of transmission (QoT). A physical-layer performance estimating tool called Q-tool, has been designed and developed to deliver fast and accurate QoT assessments in dynamic single line-rate WDM networks employing 10 Gb/s OOK systems. The Q-tool was developed so as to feed with QoT evaluations the various cross-layer modules including offline RWA, monitor placement, regenerator placement, online RWA and failure handling. The significance of the physical-layer awareness and the role of Q-tool in the online routing strategy have been experimentally investigated using an impairment-enabled control-plane testbed. A cross-layer module that utilizes physical layer information to optimize the planning phase of single line-rate networks has been also developed; a monitor placement scheme was designed that takes into account partial monitoring information coming from the physical layer to decide the optimum number and locations of the optical monitoring devices. A techno-economic analysis was also conducted to explore the cost implications stemming from the resource optimization of a dynamic single line-rate network. Impairment aware and impairment-unaware algorithms along with the developed QoT tool were used to compare the planning solutions in terms of CapEx and OpEx. The challenges arising in the core networks of the next generation have also been addressed. Flexible optical networking has been introduced by the research community as a way to offer efficient utilization of the available optical resources while offering ultra-high speed rates. As opposed to the rate-specific and fixed-grid solution of a mixed line-rate (MLR) network, flexible networks are bandwidth agnostic and have the ability to adapt on- demand the delivered bit-rate. Yet, the increased level of flexibility imposes complex requirements; during network operation traffic is changing with time, leaving windows of spectrum of variable size unused. Moreover, interference from the neighbouring channels has to be taken into account and sufficient guard-bands ought to be considered. In such context the physical layer requirements for a spectrum-flexible optical superchannel were experimentally investigated by implementing a set of networking scenarios. The importance of the result is that it can act as input for cognitive algorithms that will enable a novel networking paradigm. Finally next generation core networks were evaluated from a cost, spectral and energy perspective so as to give a comprehensive view of the potential of the proposed technologies. The resource optimization achieved by flexible networks has been compared to single and mixed line-rate networks under the prism of cost and energy efficiency. It was shown that the capability of flexible networks to allocate efficiently the available spectrum, counterbalances the additional capital expenditures that are required to migrate to a multi-carrier system. In addition flexible networks achieve low energy per bit as they use just the amount of network resources needed for the given input traffic.

  • Energy-Oriented Optimizations Towards Sustainable Internet

     Ricciardi, Sergio
    Defense's date: 2012-11-22
    Department of Computer Architecture, Universitat Politècnica de Catalunya
    Theses

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  • Measurement-based experimental research methodology

     Papadimitriou, Dimitri; Fàbrega Soler, LLuís; Vilà Talleda, Pere; Careglio, Davide; Demeester, Piet M.A.
    European Workshop on Measurement Methodology and Tools
    Presentation's date: 2012-05
    Presentation of work at congresses

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    Aiming at creating a dynamic between elaboration, realization, and validation by means of iterative cycles of experimentation, Future Internet Research and Experimentation (FIRE) projects have been rapidly confronted to the lack of systematic experimental research methodology. Moreover, the "validation by experimentation" objective involves a broad spectrum of experimentation tools ranging from simulation to field trial prototypes together with their associated measurement tools. As experimental measurement results and corresponding tools play a fundamental role in experimental research, devising a systematic experimentation and measurement methodology becomes thus crucial for experimental research projects to achieve this objective for their various realizations, including protocols, systems and components. In turn, and in order to meet scientific validity criteria, the measurement results obtained when performing experimental research implies the availability of reliable and verifiable measurement tools, including on-line measurement data analysis and mining.

    Aiming at creating a dynamic between elaboration, realization, and validation by means of iterative cycles of experimentation, Future Internet Research and Experimentation (FIRE) projects have been rapidly confronted to the lack of systematic experimental research methodology. Moreover, the “validation by experimentation” objective involves a broad spectrum of experimentation tools ranging from simulation to field trial prototypes together with their associated measurement tools. As experimental measurement results and corresponding tools play a fundamental role in experimental research, devising a systematic experimentation and measurement methodology becomes thus crucial for experimental research projects to achieve this objective for their various realizations, including protocols, systems and components. In turn, and in order to meet scientific validity criteria, the measurement results obtained when performing experimental research implies the availability of reliable and verifiable measurement tools, including on-line measurement data analysis and mining.

    Postprint (author’s final draft)

  • Iterative research method applied to the design and evaluation of a dynamic multicast routing scheme

     Papadimitriou, Dimitri; Coras, Florin-tudorel; Rodriguez Natal, Alberto; Carela Español, Valentin; Careglio, Davide; Fàbrega Soler, LLuís; Vilà Talleda, Pere; Demeester, Piet M.A.
    European Workshop on Measurement Methodology and Tools
    Presentation's date: 2012-05
    Presentation of work at congresses

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    Following the iterative research cycle process, this chapter elaborates a methodology and documents the steps followed for the design of a dynamic multicast routing algorithm, referred to as Greedy Compact Multicast Routing. Starting from the design of the dynamic multicast routing algorithm, we then evaluate by simulation on large-scale topologies its performance and compare them with the Abraham compact multicast routing scheme and two other reference schemes, namely the Shortest Path Tree (SPT) and the Steiner Tree (ST) algorithm. Performance evaluation and comparison include i) the stretch of the multicast routing paths also referred to as multicast distribution tree (MDT), ii) the memory space required to store the resulting routing table entries, and iii) the total communication or messaging cost, i.e., the number of messages exchanged to build the MDT. However, such performance evaluation is a necessary but not a sufficient condition to meet in order to expect deployment of multicast routing. Indeed, if one can determine that traffic exchanges are spatially and temporally concentrated, this would provide elements indicating the relevance for the introduction of such scheme in the Internet. Otherwise (if traffic exchanges are spatially and temporally diverse, i.e., highly distributed), then very few of them would benefit from a (shared) point-to-multipoint routing paths and multicast routing scheme would be less useful. For this purpose, we have conducted a multicast tree inference study. In turn, data and results obtained from these studies provides more realistic scenarios for emulation experiments against the currently deployed approach combining MBGP and PIMdeployed in IPTV or mVPN context.

    Following the iterative research cycle process, this chapter elaborates a methodology and documents the steps followed for the design of a dynamic multicast routing algorithm, referred to as Greedy Compact Multicast Routing. Starting from the design of the dynamic multicast routing algorithm, we then evaluate by simulation on large-scale topologies its performance and compare them with the Abraham compact multicast routing scheme and two other reference schemes, namely the Shortest Path Tree (SPT) and the Steiner Tree (ST) algorithm. Performance evaluation and comparison include i) the stretch of the multicast routing paths also referred to as multicast distribution tree (MDT), ii) the memory space required to store the resulting routing table entries, and iii) the total communication or messaging cost, i.e., the number of messages exchanged to build the MDT. However, such performance evaluation is a necessary but not a sufficient condition to meet in order to expect deployment of multicast routing. Indeed, if one can determine that traffic exchanges are spatially and temporally concentrated, this would provide elements indicating the relevance for the introduction of such scheme in the Internet. Otherwise (if traffic exchanges are spatially and temporally diverse, i.e., highly distributed), then very few of them would benefit from a (shared) point-to-multipoint routing paths and multicast routing scheme would be less useful. For this purpose, we have conducted a multicast tree inference study. In turn, data and results obtained from these studies provides more realistic scenarios for emulation experiments against the currently deployed approach combining MBGP and PIMdeployed in IPTV or mVPN context.

  • Cross-layer enabled translucent optical network with real-time impairment awareness

     Pedrola Escriba, Oscar; Bathula, Balagangadhar G.; Wang, Michael; Ahsan, Atiyah K M; Careglio, Davide; Bergman, Keren
    IEEE Global Communications Conference
    Presentation's date: 2012-12
    Presentation of work at congresses

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    The existing dimensioning strategy for translucent, sub-wavelength switching architectures relies on over-provisioning, and consequently, overuse of costly, power-consuming optical-electrical-optical (O/E/O) regenerators. In addition, due to a variety of external phenomena, many physical layer impairments are time-varying, and hence, can strongly degrade network performance. In this work, we introduce a Cross-Layer Optical Network Element (CLONE) used for the dynamic management of physical layer impairments in the network. We investigate the impact of real-time impairment aware routing in a CLONE-enabled optical network with sub-wavelength switching. Simulation results show that the CLONE-enabled network architecture provides improvements in: (1) energy efficiency by optimizing the usage of regenerators, and (2) network performance in terms of the packet loss probability.

    The existing dimensioning strategy for translucent, sub-wavelength switching architectures relies on over-provisioning, and consequently, overuse of costly, power-consuming optical-electrical-optical (O/E/O) regenerators. In addition, due to a variety of external phenomena, many physical layer impairments are time-varying, and hence, can strongly degrade network performance. In this work, we introduce a Cross-Layer Optical Network Element (CLONE) used for the dynamic management of physical layer impairments in the network. We investigate the impact of real-time impairment aware routing in a CLONE-enabled optical network with sub-wavelength switching. Simulation results show that the CLONE-enabled network architecture provides improvements in: (1) energy efficiency by optimizing the usage of regenerators, and (2) network performance in terms of the packet loss probability.

  • GPON and EP2P: a techno-economic study

     Ricciardi, Sergio; Santos Boada, German; Careglio, Davide; Domingo Pascual, Jordi
    European Conference on Networks and Optical Communications
    Presentation's date: 2012-06-20
    Presentation of work at congresses

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    New services like Video on demand/Internet Protocol Television, Voice over IP and high speed Internet access demand very high bandwidth to provide Triple Play services to the customers. The ADSL/ADLS2+ and the VDSL/VDSL2 copper- wire technologies deteriorate quickly with the distance and will be soon obsolete for supporting the ultra-high bandwidth requirements of the next future. One suitable long term solution for such a high bandwidth demand is employing optical fibers to customers premises (FTTH). In particular, two optical distribution network architectu res, GPON (gigabit passive optical network) and EP2P (E thernet point-to-point), are competing for the network access segment. This paper surveys the two technologies and evalua tes them from a quantitative techno-economic point of view, tr ying to identify which market scenarios are best served by EP2P and which are best served by GPON architectures for supporting the requirement of Triple Play applications .

  • Energy-aware routing optimization in dynamic GMPLS controlled optical networks

     Wang, J; Ricciardi, Sergio; Fagertun, A.M.; Ruepp, Sarah; Careglio, Davide; Dittmann, L.
    International Conference on Transparent Optical Networks
    Presentation's date: 2012
    Presentation of work at congresses

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    In this paper, routing optimizations based on energy sources are proposed in dynamic GMPLS controlled optical networks. The influences of re-routing and load balancing factors on the algorithm are evaluated, with a focus on different re-routing thresholds. Results from dynamic network simulations show that re-routing strategies can lower CO2 emissions compared to the basic energy source routing scheme, and a lower re-routing threshold achieves more savings. The increased blocking probability brought by using re-routing schemes can be compensated by applying load balancing criteria. A trade-off between blocking probability and obtained CO2 savings is studied.

    In this paper, routing optimizations based on energy sources are proposed in dynamic GMPLS controlled optical networks. The influences of re-routing and load balancing factors on the algorithm are evaluated, with a focus on different re-routing thresholds. Results from dynamic network simulations show that re-routing strategies can lower CO2 emissions compared to the basic energy source routing scheme, and a lower re-routing threshold achieves more savings. The increased blocking probability brought by using re-routing schemes can be compensated by applying load balancing criteria. A trade-off between blocking probability and obtained CO2 savings is studied.

  • On the performance of flexgrid-based optical networks

     Velasco Esteban, Luis; Ruiz Ramírez, Marc; Pedrola Escriba, Oscar; Castro Casales, Alberto; Klinkowski, Miroslaw; Careglio, Davide; Comellas Colome, Jaume
    International Conference on Transparent Optical Networks
    Presentation's date: 2012-07
    Presentation of work at congresses

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  • Access to the full text
    CAPEX study for grid dependent multi-layer IP/MPLS-over-EON using relative BV-WSS costs  Open access

     Pedrola Escriba, Oscar; Velasco Esteban, Luis; Fernández-Palacios, Juan Pedro; Castro Casales, Alberto; Careglio, Davide; Junyent Giralt, Gabriel
    Optical Fiber Communication Conference and Exposition and National Fiber Optic Engineers Conference
    Presentation's date: 2012-03
    Presentation of work at congresses

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    The impact of the frequency grid on the CAPEX required to deploy a multi-layer IP/MPLS-over-EON is analyzed. Results showing significant savings at the electronic layer motivate the introduction of narrower grids with enhanced BV-WSS.

  • OSPF-TE extensions for green routing in optical networks

     Wang, Jiayuan; Ricciardi, Sergio; Manolova Vasileva, Anna; Ruepp, Sarah; Careglio, Davide; Dittmann, L.
    Opto-Electronics and Communications Conference
    Presentation's date: 2012-07-02
    Presentation of work at congresses

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    This paper proposes extensions to the OSPF-TE protocol to enable green routing in GMPLS-controlled optical networks. Simulation results show a remarkable reduction in CO 2 emissions by preferring network elements powered by green energy sources in the connection routing.

  • 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
    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.

  • Access to the full text
    Survivable IP/MPLS-Over-WSON multilayer network optimization  Open access

     Ruiz Ramírez, Marc; Pedrola Escriba, Oscar; Velasco Esteban, Luis; Careglio, Davide; Fernández Palacios, Juan Pedro; Junyent Giralt, Gabriel
    Journal of optical communications and networking
    Date of publication: 2011-08-01
    Journal article

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    Network operators are facing the problem of dimensioning their networks for the expected huge IP traffic volumes while keeping constant or even reducing the connectivity prices. Therefore, new architectural solutions able to cope with the expected traffic increase in a more cost-effective way are needed. In this work, we study the survivable IP/multi-protocol label switching (MPLS) over wavelength switched optical network (WSON) multilayer network problem as a capital expenditure (CAPEX) minimization problem. Two network approaches providing survivability against optical links, IP/MPLS nodes, and opto-electronic port failures are compared: the classical overlay approach where two redundant IP/MPLS networks are deployed, and the new joint multilayer approach which provides the requested survivability through an orchestrated interlayer recovery scheme which minimizes the over-dimensioning of IP/MPLS nodes. Mathematical programming models are developed for both approaches. Solving these models, however, becomes impractical for realistic networks. In view of this, evolutionary heuristics based on the biased random-key genetic algorithm framework are also proposed. Exhaustive experiments on several reference network scenarios illustrate the effectiveness of the proposed approach in minimizing network CAPEX.

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

     Mendonça Pedroso, Pedro Miguel
    Defense's date: 2011-12-16
    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.

  • 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
    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.

  • 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
    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.

  • 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
    Date of publication: 2011-09
    Journal article

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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
    Date of publication: 2011-11-15
    Journal article

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  • Offline impairment-aware RWA and regenerator placement in translucent optical networks

     Garcia Manrubia, Bélen; Pavón Mariño, Pablo; Aparicio Pardo, Ramon; Klinkowski, Miroslaw; Careglio, Davide
    Journal of lightwave technology
    Date of publication: 2011
    Journal article

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  • 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
    Date of publication: 2011-01
    Journal article

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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
    Participation in a competitive project

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  • 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
    Presentation's date: 2011-05-13
    Presentation of work at congresses

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  • A routing and spectrum assignment problem in optical OFDM networks

     Klinkowski, Miroslaw; Careglio, Davide
    European Teletraffic Seminar
    Presentation's date: 2011
    Presentation of work at congresses

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