Now showing items 1-10 of 10

    • After failure repair optimization in dynamic flexgrid optical networks 

      Ruiz Ramírez, Marc; Zotkiewicz, Mateusz; Castro Casales, Alberto; Klinkowski, Miroslaw; Velasco Esteban, Luis Domingo; Pioro, Michal (The Optical Society (OSA), 2014)
      Conference report
      Restricted access - publisher's policy
      We introduce the problem of reoptimizing the network after a link failure has been repaired as an effective way for reducing capacity usage and improving network performance. Numerical results show gains higher than 42%.
    • Column generation algorithm for RSA problems in flexgrid optical networks 

      Ruiz Ramírez, Marc; Pioro, Michal; Zotkiewicz, Mateusz; Klinkowski, Miroslaw; Velasco Esteban, Luis Domingo (2013-10)
      Article
      Restricted access - publisher's policy
      Finding optimal routes and spectrum allocation in flexgrid optical networks, known as the RSA problem, is an important design problem in transport communication networks. The problem is TeX -hard, and its intractability ...
    • Non-linear optimization for multi-path source routing in OBS networks 

      Klinkowski, Miroslaw; Pioro, Michal; Careglio, Davide; Marciniak, Marian; Solé Pareta, Josep (2007-12)
      Article
      Open Access
      Optical Burst Switching (OBS) architectures without buffering capabilities are sensitive to burst losses. A proper routing strategy may help to reduce such congestion. In this letter we present a novel approach for OBS ...
    • Optimization models for flexgrid elastic optical networks 

      Zotkiewicz, Mateusz; Pioro, Michal; Ruiz Ramírez, Marc; Klinkowski, Miroslaw; Velasco Esteban, Luis Domingo (Institute of Electrical and Electronics Engineers (IEEE), 2013)
      Conference report
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      In the paper we present integer programming (IP) optimization models for flexgrid elastic optical networks (EON). We consider several different basic assumptions regarding flexibility of EON that lead to a variety of IP ...
    • Planning fixed to flexgrid gradual migration: drivers and open issues 

      Ruiz Ramírez, Marc; Velasco Esteban, Luis Domingo; Lord, Andrew; Fonseca, Daniel; Pioro, Michal; Wessäly, Roland; Fernández-Palacios, Juan Pedro (2014-01)
      Article
      Restricted access - publisher's policy
      Flexgrid technology has recently been presented as the most promising option for upgrading the currently operating fixed grid optical networks and extending their capacity to be able to deal with the massive traffic volumes ...
    • Reoptimization of dynamic flexgrid optical networks after link failure repairs 

      Zotkiewicz, Mateusz; Ruiz Ramírez, Marc; Klinkowski, Miroslaw; Pioro, Michal; Velasco Esteban, Luis Domingo (Institute of Electrical and Electronics Engineers (IEEE), 2015-01-01)
      Article
      Open Access
      In dynamic flexgrid optical networks, the usage of capacity may not be optimal due to the permanent process of setting up and tearing down connections, which, if not controlled, leads to spectrum fragmentation and, as a ...
    • Solving large instances of the RSA problem in flexgrid elastic optical networks 

      Walkowiak, Krzysztof; Zotkiewicz, Mateusz; Klinkowski, Miroslaw; Pioro, Michal; Ruiz Ramírez, Marc; Velasco Esteban, Luis Domingo (Institute of Electrical and Electronics Engineers (IEEE), 2016-05-01)
      Article
      Open Access
      We present an optimization procedure that mixes advanced large-scale optimization methods and heuristics to solve large instances (with over 1.7 million integer variables) of the routing and spectrum allocation (RSA) ...
    • Spectrum allocation problem in elastic optical networks - a branch-and-price approach 

      Pioro, Michal; Klinkowski, Miroslaw; Zotkiewicz, Mateusz; Walkowiak, Krzysztof; Ruiz Ramírez, Marc; Velasco Esteban, Luis Domingo (Institute of Electrical and Electronics Engineers (IEEE), 2015)
      Conference report
      Restricted access - publisher's policy
      In the paper we present a branch and price approach to routing and spectrum allocation – a basic optimization problem in elastic optical networks. We formulate the problem as a mixed-integer program for which ...
    • Valid inequalities for the routing and spectrum allocation problem in elastic optical networks 

      Klinkowski, Miroslaw; Pioro, Michal; Zotkiewicz, Mateusz; Ruiz Ramírez, Marc; Velasco Esteban, Luis Domingo (Institute of Electrical and Electronics Engineers (IEEE), 2014)
      Conference report
      Restricted access - publisher's policy
      We deal with a natural integer-linear programming formulation of the routing and spectrum allocation (RSA) problem in elastic optical networks. We focus on strengthening the formulation with valid inequalities (cuts). For ...
    • Virtual topology design in OBS networks 

      Klinkowski, Miroslaw; Pedroso, Pedro; Pioro, Michal; Careglio, Davide; Solé Pareta, Josep (2010)
      Conference report
      Open Access
      The problem of burst losses in OBS networks has an impact on the service quality perceived by end users. In order to guarantee certain level of Service Quality (QoS) in terms of burst losses, wavelength resources have to ...