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  • 251.
    Udalcovs, Aleksejs
    et al.
    KTH, School of Information and Communication Technology (ICT).
    Schatz, Richard
    KTH, School of Engineering Sciences (SCI), Applied Physics, Optics and Photonics, OFO.
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT).
    Monti, Paolo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Analysis of Spectral and Energy Efficiency Tradeoff in Single-Line Rate WDM Links2017In: Journal of Lightwave Technology, ISSN 0733-8724, E-ISSN 1558-2213, Vol. 35, no 10, p. 1847-1857Article in journal (Refereed)
    Abstract [en]

    This paper investigates, through simulations, the tradeoff between energy efficiency (EE) and the overall spectral efficiency (SE) of fiber optic links for a given capacity and a link length. The comparison is made for various modulation formats, span lengths, and with/without using forward error correction (FEC). The power consumption of the different system components is estimated from the data sheets of the state-of-the-art equipment. Results show that the use of long single-mode fiber spans (i.e., more than 40 km) improves EE when coherent modulation formats are used. However, with noncoherent formats, the span length must be selected depending on SE, aggregated traffic amount needs to be transmitted, and link length. For almost all modulation formats, FEC reduces the overall energy consumption despite being one of the main power consumers in fiber optic communication systems. The power consumption of 3Rs becomes particularly important when the linear crosstalk limits the system reach. In all other cases, the power consumption of transponders and optical line amplifiers is dominating, but their contribution changes depending on the aggregated traffic amount and system reach.

  • 252. Valcarenghi, L.
    et al.
    Inkret, R.
    Mikac, B.
    Pattavina, A.
    Tomatore, M.
    Pickavet, M.
    Wajda, K.
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Which Resilience for the Optical Internet?: An e-Photon/ONe+ Outlook2007In: ICTON 2007: PROCEEDINGS OF THE 9TH INTERNATIONAL CONFERENCE ON TRANSPARENT OPTICAL NETWORKS, VOL 3 / [ed] Marciniak, M, 2007, Vol. 3, p. 142-145Conference paper (Refereed)
    Abstract [en]

    The paper provides an overview of the resilient schemes currently adopted in network architectures based on IP over Automatically Switched Optical Networks (ASONs)/Generalized Multiprotocol Label Switching (GMPLS) based optical networks, namely the Optical Internet. In addition it outlooks the raising challenges and possible solutions in implementing advanced resilient schemes capable of satisfying the requirements of the different applications carried by a single multi-layer network infrastructure.

  • 253.
    Valcarenghi, Luca
    et al.
    Scuola Superiore Sant'Anna.
    Chincoli, Michele
    Scuola Superiore Sant'Anna.
    Castoldi, Piero
    Scuola Superiore Sant'Anna.
    Monti, Paolo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Improving energy efficiency in TDMA passive optical networks from theory to practice2012In: Photonics In Switching, 2012Conference paper (Other academic)
    Abstract [en]

     Passive optical networks are currently the major contributor to fixed optical networks energy consumption. Within PON, almost 65% of their energy consumption is due to the customer premises equipments (i.e., the ONUs).Standardisation authorities, industries and researchers are proposing several methods for decreasing ONU energy consumption. Cyclic sleep or fast sleep is one of the proposed methods that is based on cycles of sleep and waking periods. However, cyclic sleep, while decreasing ONU energy consumption, causes an increase in the delay experienced by the transmitted data. Based on the requested Quality of Service (QoS) such additional delay can be more or less detrimental for the carried service. Therefore, it is essential to optimally select when to sleep and for how long, based also on the services subscribed by the ONU.This presentation will outline a method for maximizing energy savings while providing services with delay guaranteed. The method exploits service-based variable sleep periods. Simulation results prove the method effectiveness with both Poisson and heavy-tailed traffic. The presentation will also provide an overview of the testbed implementation of the proposed approach

  • 254.
    Valcarenghi, Luca
    et al.
    Scuola Superiore Sant'Anna.
    Chincoli, Michele
    Scuola Superiore Sant'Anna.
    Monti, Paolo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Castoldi, Piero
    Scuola Superiore Sant'Anna.
    Energy efficient PONs with service delay guarantees2012In: 2012 Sustainable Internet and ICT for Sustainability, SustainIT 2012, IFIP , 2012, p. 1-8Conference paper (Refereed)
    Abstract [en]

    Passive Optical access Networks (PONs) are currently the major contributor to the energy consumption budget of fixed optical networks. In PON, the largest part of the energy consumption is due to the equipments at the customer premises. This paper proposes a method for maximizing energy savings while providing services with delay guarantees (i.e., frame delivery time and frame delay variation). The method combines service-based variable sleep period and a queueing theory model to compute the optimal sleep time. Simulation results prove the effectiveness of the method for a Poisson frame arrival process.

  • 255.
    Valcarenghi, Luca
    et al.
    Scuola Superiore Sant'Anna.
    Monti, Paolo
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101), Photonics (Closed 20120101).
    Cerutti, Isabella
    Scuola Superiore Sant'Anna.
    Castoldi, Piero
    Scuola Superiore Sant'Anna.
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101), Photonics (Closed 20120101).
    Issues and solutions in mobile WiMAX and wired backhaul network integration2009In: ICTON: 2009 11TH INTERNATIONAL CONFERENCE ON TRANSPARENT OPTICAL NETWORKS, VOLS 1 AND 2, 2009, p. 563-566Conference paper (Other academic)
    Abstract [en]

    This paper surveys the issues in implementing a wired backhaul optical network that supports mobility of broadband wireless access network users. In particular, the focus is on the functionalities and the performance in terms of delay, throughput, and reliability that the backhaul network must guarantee.

  • 256. Van, Dung Pham
    et al.
    Fiorani, Matteo
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Chen, Jiajia
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Adaptive Open-Shop Scheduling for Optical Interconnection Networks2017In: Journal of Lightwave Technology, ISSN 0733-8724, E-ISSN 1558-2213, Vol. 35, no 13, p. 2503-2513Article in journal (Refereed)
    Abstract [en]

    This paper deals with resource management in optical interconnection networks. It first proposes an optical resource management framework as a platform to develop and evaluate efficient solutions for multipoint-to-multipoint optical communication systems with a centralized controller. The paper then focuses on studying the optical resource scheduling (ORS) problem as a core element in the framework by applying the classical open-shop scheduling theory. The ORS problem can therefore be solved by adopting the existing preemptive and nonpreemptive open-shop scheduling algorithms. In an optical network with nonnegligible reconfiguration delay, a preemptive algorithm may incur high reconfiguration overhead resulting in worse performance compared to the nonpreemptive strategy. Motivated by this fact, this paper proposes an adaptive open-shop scheduling (AOS) algorithm that dynamically decides the optimal scheduling strategy according to traffic condition and system parameters, such as reconfiguration delay, nonpreemptive approximation ratio, and number of involved optical interfaces. The solution is assessed by means of an analytical model that allows to quantify the network performance in terms of packet delay and potential energy savings obtained by the sleep mode operation. As a possible application scenario, the inter- and intrarack optical interconnection networks in data centres are considered. Analytical results demonstrate how the proposed AOS outperforms the nonpreemptive and preemptive scheduling strategies for typical configurations used in data center networks. In addition, the reconfiguration delay and wake-up time of optical devices are identified as performance-determining factors.

  • 257.
    Van, Dung Pham
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Rimal, Bhaskar Prasad
    Chen, Jiajia
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Monti, Paolo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Maier, Martin
    Power-Saving Methods for Internet of Things over Converged Fiber-Wireless Access Networks2016In: IEEE Communications Magazine, ISSN 0163-6804, E-ISSN 1558-1896, Vol. 54, no 11, p. 166-175Article in journal (Refereed)
    Abstract [en]

    The IoT has been emerging as the next big leap in the information and communication technology sector. Providing a unified communication platform to support billions of smart connected devices seamlessly alongside existing voice and Internet services is vitally challenging. This article leverages converged fiber-wireless (FiWi) access networks to design a shared communication infrastructure for supporting both IoT applications and traditional services. Given the paramount importance of energy efficiency in both IoT and access networks, the article discusses the possibilities and potential challenges of designing and implementing power-saving mechanisms to prolong battery life of IoT devices while reducing energy consumption of the optical backhaul network. In-depth technical guidelines are provided through end-to-end power-saving solutions proposed for typical IoT deployment scenarios.

  • 258.
    Varasteh, Amir
    et al.
    Tech Univ Munich, Dept Elect & Comp Engn, Chair Commun Networks, Munich, Germany..
    De Andrade, Marilet
    KTH, School of Electrical Engineering and Computer Science (EECS), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Machuca, Carmen Mas
    Tech Univ Munich, Dept Elect & Comp Engn, Chair Commun Networks, Munich, Germany..
    Wosinska, Lena
    KTH, School of Electrical Engineering and Computer Science (EECS), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Kellerer, Wolfgang
    Tech Univ Munich, Dept Elect & Comp Engn, Chair Commun Networks, Munich, Germany..
    Power-Aware Virtual Network Function Placement and Routing using an Abstraction Technique2018In: 2018 IEEE Global Communications Conference, GLOBECOM 2018 - Proceedings, IEEE, 2018, article id 8647538Conference paper (Refereed)
    Abstract [en]

    The Network Function Virtualization (NFV) is very promising for efficient provisioning of network services and is attracting a lot of attention. NFV can be implemented in commercial off-the-shelf servers or Physical Machines (PMs), and many network services can be offered as a sequence of Virtual Network Functions (VNFs), known as VNF chains. Furthermore, many existing network devices (e.g., switches) and collocated PMs are underutilized or over-provisioned, resulting in low power-efficiency. In order to achieve more energy efficient systems, this work aims at designing the placement of VNFs such that the total power consumption in network nodes and PMs is minimized, while meeting the delay and capacity requirements of the foreseen demands. Based on existing switch and PM power models, we formulate an Integer Linear Programming (ILP) model to find the optimal solution. We also propose a heuristic based on the concept of Blocking Islands (BI), and a baseline heuristic based on the Betweenness Centrality (BC) property of the graph. Both heuristics and the ILP solutions have been compared in terms of total power consumption, delay, demands acceptance rate, and computation time. Our simulation results suggest that BI-based heuristic is superior compared with the BC-based heuristic, and very close to the optimal solution obtained from the ILP in terms of total power consumption and demands acceptance rate. Compared to the ILP, the proposed BI-based heuristic is significantly faster and results in 22% lower end-to-end delay, with a penalty of consuming 6% more power in average.

  • 259. Velasco, L.
    et al.
    Jirattigalachote, Amornrat
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Ruiz, M.
    Monti, Paolo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Junyent, G.
    Statistical Approach for Fast Impairment-Aware Provisioning in Dynamic All-Optical Networks2012In: Journal of Optical Communications and Networking, ISSN 1943-0620, E-ISSN 1943-0639, Vol. 4, no 2, p. 130-141Article in journal (Refereed)
    Abstract [en]

    Physical layer impairments (PLIs) need to be considered in the routing and wavelength assignment (RWA) process of all-optical networks to ensure the provisioning of good quality optical connections (i.e., lightpaths). A convenient way to model the impact of PLIs on the signal quality is to use the so-called Q-factor. In a dynamic provisioning environment, impairment-aware RWA (IA-RWA) algorithms include Q-factor evaluation in their on-line decisions on whether to accept a connection request or not. The Q-factor can be computed in either an approximated or an exact way. IA-RWA algorithms using an approximated Q-factor estimation (i.e., worst case) can be very fast and allow for a short setup delay. However, connection request blocking can be unnecessarily high because of the worst-case assumption for the Q-factor parameters. In contrast, an exact Q-factor computation results in a better blocking performance at the expense of a longer setup delay, mainly due to the time spent for the Q-factor computation itself. Moreover, an exact Q-factor approach requires extensions of the generalized multi-protocol label switching suite. To overcome these problems, we propose a statistical approach for fast impairment-aware RWA (SAFIR) computation. The evaluation results reveal that SAFIR improves the blocking probability performance compared to the worst-case scenario without adding extra computational complexity and, consequently, without increasing the connection setup delay.

  • 260.
    Velasco, Luis
    et al.
    Universitat Politècnica de Catalunya (UPC).
    Jirattigalachote, Amornrat
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101), Photonics (Closed 20120101).
    Monti, Paolo
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101), Photonics (Closed 20120101).
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101), Photonics (Closed 20120101).
    Spadaro, Salvatore
    Universitat Politècnica de Catalunya (UPC).
    Junyent, Gabriel
    Universitat Politècnica de Catalunya (UPC).
    Probabilistic-based approach for fast impairments-aware RWA in all-optical networks2010In: 2010 Conference on Optical Fiber Communication, Collocated National Fiber Optic Engineers Conference, OFC/NFOEC 2010, 2010, p. 5465402-Conference paper (Refereed)
    Abstract [en]

    We devised a probabilistic model to compute the number of used wavelengths in every link of a transparent optical network. Based on this model, a novel approach for impairments-aware RWA algorithm is proposed and evaluated.

  • 261. Vázquez, C.
    et al.
    Montalvo, J.
    Moeyaert, V.
    Yuksel, K.
    Caucheteur, C.
    Gravey, P.
    Loukina, T.
    Larrabeiti, D.
    Ennser, K.
    Franzl, G.
    Hauske, F.
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101), Photonics (Closed 20120101).
    Monti, Paolo
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101), Photonics (Closed 20120101).
    Ahmed, Jawwad
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101), Photonics (Closed 20120101).
    Lazaro, J.
    Signal Processing, Management and Monitoring in Transmission Networks2011In: Optical Transmission: FP7 BONE Project Experience, Springer Publishing Company, 2011, 1, p. 53-122Chapter in book (Other academic)
  • 262.
    Wang, Kun
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab). RISE Acreo.
    Gavler, Anders
    RISE Acreo.
    Mas Machuca, Carmen
    Technical University of Munich.
    Wosinska, Lena
    KTH, School of Electrical Engineering and Computer Science (EECS), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Brunnström, Kjell
    RISE Acreo.
    Chen, Jiajia
    KTH, School of Electrical Engineering and Computer Science (EECS), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Migration Strategies for FTTx Solutions based on Active Optical Networks2016In: IEEE Communications Magazine, ISSN 0163-6804, E-ISSN 1558-1896, Vol. 54, no 2, p. 78-85Article in journal (Refereed)
    Abstract [en]

    AON, one of the most deployed fiber access solutions in Europe, needs to be upgraded in order to satisfy the ever growing bandwidth demand driven by new applications and services. Meanwhile, network providers want to reduce both capital expenditures and operational expenditures to ensure that there is profit coming from their investments. This article proposes several migration strategies for AON from the data plane, topology, and control plane perspectives, and investigates their impact on the total cost of ownership.

  • 263.
    Wang, Kun
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab). RISE Acreo.
    Mas Machuca, Carmen
    Technical University of Munich.
    Wosinska, Lena
    KTH, School of Electrical Engineering and Computer Science (EECS), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Urban, Patryk J.
    Ericsson.
    Gavler, Anders
    RISE Acreo.
    Brunnström, Kjell
    RISE Acreo.
    Chen, Jiajia
    KTH, School of Electrical Engineering and Computer Science (EECS), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Techno-Economic Analysis of Active Optical Network Migration Toward Next-Generation Optical Access2017In: Journal of Optical Communications and Networking, ISSN 1943-0620, E-ISSN 1943-0639, Vol. 9, no 4, p. 327-341Article in journal (Refereed)
    Abstract [en]

    Active optical networks (AONs) have been one of the most deployed fiber access solutions in Europe. However, with the increasing traffic demand, the capacity of the existing AONs is becoming insufficient. For the legacy AONs, there are two major variants of architectures, namely, point-to-point and active star. Considering the different characteristics of these two AON architectures, this paper proposes and analyzes several migration paths toward next-generation optical access (NGOA) networks offering a minimum 300 Mbit/s sustainable bit rate and 1 Gbit/s peak bit rate to every end customer. Furthermore, this paper provides detailed descriptions of the network cost modeling and the processes for AON migration. The total cost of ownership (TCO) is evaluated for the proposed migration paths, taking into account different migration starting times, customer penetration, node consolidation, and business roles in the fiber access networks. The migration from AON to NGOA can be economically feasible. The results indicate that a network provider plays a key business role and is responsible for the major part of the TCO for AON migration. Moreover, performing node consolidation during AON migration can be beneficial from a cost point of view, especially in rural areas.

  • 264.
    Wang, Meiqian
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Furdek, Marija
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Monti, Paolo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Restoration with service degradation and relocation in optical cloud networks2015In: Asia Communications and Photonics Conference, ACPC 2015, 2015Conference paper (Refereed)
    Abstract [en]

    The paper studies the improvement of cloud service restoration by combining the service degradation and relocation concepts. Results demonstrate that it is possible to achieve improvements in both cloud service availability and restorability performance. © 2015 OSA.

  • 265.
    Wang, Meiqian
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Furdek, Marija
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Monti, Paolo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Wavelength overprovisioning strategies for enhanced optical path restoration2016In: International Conference on Transparent Optical Networks, IEEE Computer Society, 2016Conference paper (Refereed)
    Abstract [en]

    This paper proposes two wavelength overprovisioning strategies that can be used to improve the performance of path restoration in optical core networks under dynamic traffic conditions while considering single fiber link failure scenarios. The study presented in the paper shows that with the two proposed schemes it is possible to achieve nearly the same level of average connection availability and restorability typical of dedicated path protection schemes (i.e., 100%) with, on the other hand, better blocking probability performance.

  • 266. Wiatr, P
    et al.
    Chen, Jiajia
    KTH, School of Electrical Engineering and Computer Science (EECS), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Monti, Paolo
    KTH, School of Electrical Engineering and Computer Science (EECS), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Wosinska, Lena
    KTH, School of Electrical Engineering and Computer Science (EECS), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Yuan, D.
    Device reliability performance awareness: Impact of RWA on EDFA failure reparation cost in optical networks2017In: Proceedings of 2017 9th International Workshop on Resilient Networks Design and Modeling, RNDM 2017, Institute of Electrical and Electronics Engineers Inc. , 2017Conference paper (Refereed)
    Abstract [en]

    High reliability performance of network is essential to minimize the possible network service interruption time, particularly in optical backbone networks where a large amount of data can be affected by a single failure. The existing studies on improvement of network reliability performance assume that failures of network devices are not related to the traffic load, which on the other hand, is not always true. For example, the lifetime of erbium doped fiber amplifier (EDFA) depends on the number of amplified lightpaths passing through. Encouraged by this observation, in this paper, we investigate the impact of used routing and wavelength assignment (RWA) algorithm on the number of failures in the network, and as a consequence on the network operational cost related to the failure reparation. We propose and evaluate a novel RWA approach, referred to as reliability performance aware RWA (RA-RWA), taking into account particular EDFA reliability performance characteristics with the goal of reducing the number of EDFA failures. The assessment results show that the operational cost related to EDFA failure reparation is impacted by the chosen RWA. The proposed RA-RWA provides 6% reduction, while other analyzed RWA algorithm, i.e., least loaded path (LLP), causes significant rise (up to 27%) of EDFA related failure reparation cost compared to the classical shortest path (SP) approach. In addition, RA-RWA offers further benefits in terms of reduced blocking probability compared to the SP. Concluding, we show that considering device reliability performance characteristics in RWA is important for the optical network operators as it can impact the network operational cost related to EDFA failure reparation.

  • 267.
    Wiatr, Pawel
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Chen, Jiajia
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Monti, Paolo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Energy efficiency and reliability tradeoff in optical core networks2014In: Optical Fiber Communication Conference, OFC 2014, Optical Society of America, 2014Conference paper (Refereed)
    Abstract [en]

    We assess the highest allowable reliability performance degradation of active components caused by applying energy-efficient mechanisms. EDFAs are identified as the most critical devices where energy saving might not cover the potential additional reparation cost.

  • 268.
    Wiatr, Pawel
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Chen, Jiajia
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Monti, Paolo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Energy Efficiency Versus Reliability Performance in Optical Backbone Networks2015In: Journal of Optical Communications and Networking, ISSN 1943-0620, E-ISSN 1943-0639, Vol. 7, no 3, p. A482-A491Article in journal (Refereed)
    Abstract [en]

    Improving the energy efficiency in telecommunication networks has been one of the main research topics of the past few years. As a result, many energy efficient algorithms have been proposed, some focusing on maximizing only the energy savings, others considering also the impact that green strategies have on other network performance metrics, e.g., delay, utilization of network resources, and blocking probability. The aim of this paper is to provide new insight on the impact of energy efficient strategies, i.e., investigating the trade-off between green network operations and the reliability performance of optical backbone devices. The study is motivated by the intuition that energy efficient strategies are usually based on putting unutilized devices in power saving (sleep) mode, which can have some side effects (e.g., frequent on/sleep switching, and/or high fiber link utilization) that may affect the working conditions of a device. To better understand these phenomena, this paper presents a number of models aimed at estimating the reliability performance changes of a device as a function of its average working temperature, of its temperature variations, and of its average occupancy. These models are then used to carry out a study both at the component and at the network levels. The study at the component level shows that erbium-doped fiber amplifiers (EDFAs) are critical devices, i.e., their achievable energy savings might not cover the additional reparation costs resulting from their reliability performance degradation. Similar findings are reached also with the network level study. In summary, it can be concluded that the use of energy efficient routing algorithms based on setting EDFAs in sleep mode may not always be beneficial.

  • 269.
    Wiatr, Pawel
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Chen, Jiajia
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Monti, Paolo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Energy saving in access networks: Gain or loss from the cost perspective?2013In: 2013 15th International Conference on Transparent Optical Networks (ICTON), IEEE conference proceedings, 2013, p. 6603014-Conference paper (Refereed)
    Abstract [en]

    Energy consumption in telecommunication networks has become a significant problem during the last few years. Many energy efficient mechanisms have been proposed and evaluated with respect to their impact on the overall network performance (e.g., delay, blocking probability, quality of transmission). Most of these mechanisms are based on the sleep mode functionality, i.e., a "low power" state of network devices that can be utilized in low traffic conditions. On the other hand, a frequent switching between a working and a sleeping state may increase the probability of failures in a device, which in turn makes the operational cost related to fault reparation higher. This paper discusses how sleep mode-based energy saving mechanisms can impact the reliability performance of network equipment by pointing out several physical phenomena that may lead to an increase of the failure rate. In order to quantify such effects we propose a methodology that estimates to what extent energy savings can be maximized without exceeding the extra reparation cost caused by the degradation of the reliability performance of network equipment due to frequent switching on and off. We perform a number of simulative studies focused on an optical access segment and show that the cost saved by reducing the energy consumption (i.e., as the result of a power efficient mechanism) may be easily overcome by the extra expenses related to reparation of network equipment and service interruption for business users.

  • 270.
    Wiatr, Pawel
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Chen, Jiajia
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Monti, Paolo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Green WDM-PONs: Exploiting traffic diversity to guarantee packet delay limitation2013In: 2013 17th International Conference On Optical Networking Design And Modeling (ONDM), IEEE , 2013, p. 229-234Conference paper (Refereed)
    Abstract [en]

    In this paper we propose a scheme tailored for WDM-PONs, which employs dozing mode in transceivers not only at the user side but also at the central office. The objective is to reduce the energy consumption while minimizing the impact on the total packet delay. The proposed scheme is able to take into account the diverse delay requirement of multiple traffic classes by adapting the wakeup time of the transmitter. Simulation results confirm that the proposed scheme can significantly improve the power efficiency in WDM-PONs while maintaining the maximum packet delay at an acceptable level, in particular in cases where multiple traffic classes are considered.

  • 271.
    Wiatr, Pawel
    et al.
    Uppsala Univ, Dept Informat Technol, Uppsala, Sweden..
    Chen, Jiajia
    KTH, School of Electrical Engineering and Computer Science (EECS), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Monti, Paolo
    KTH, School of Electrical Engineering and Computer Science (EECS), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Wosinska, Lena
    KTH, School of Electrical Engineering and Computer Science (EECS), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Yuan, Di
    Uppsala Univ, Dept Informat Technol, Uppsala, Sweden..
    Routing and wavelength assignment vs. EDFA reliability performance in optical backbone networks: An operational cost perspective2019In: Optical Switching and Networkning Journal, ISSN 1573-4277, E-ISSN 1872-9770, Vol. 31, p. 211-217Article in journal (Refereed)
    Abstract [en]

    A failure in optical backbone network can cause tremendous consequences as a substantial number of connections often each carrying a large amount of data can be interrupted. Therefore, high reliability performance is essential for the network operators. Many existing works that aim at improving network reliability performance implicitly assume that the lifetime of devices is constant and independent of the traffic load. However, the reliability performance of a device is related to its occupancy. For example, the failure rate of erbium doped fiber amplifier (EDFA) can be expressed as a function of the number of amplified wavelengths. On the other hand, the choice of routing and wavelength assignment (RWA) algorithm impacts the link load and, as a consequence, can influence the number of EDFA failures in the network. In this paper we examine how RWA can impact the failure reparation related network operational costs. Several types of RWA approaches are considered, namely load-balancing, energy-awareness, and reliability-awareness. Among all the considered RWA algorithms, the reliability-aware RWA (RA-RWA) approach leverages on EDFA reliability profile to reduce the number of EDFA failures in the network and the related operational costs. The simulation results show that the RWA algorithm impacts in a significant way the operational costs caused by EDFA failures. The cost associated with reparation of an EDFA decreases by 7.8% (in case of RA-RWA) and increases by up to 40% (in case of a load-balancing approach) compared to the classical Shortest Path (SP) approach. Moreover, the cost caused by connection rerouting due to link unavailability triggered by EDFA failure exhibits a 20% decrease (RA-RWA) and up to 94% increase (energy-aware algorithm). We also analyze some key network performance metrics that may be affected by RWA, including blocking probability, link occupancy distribution, and path length.

  • 272.
    Wiatr, Pawel
    et al.
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101).
    Monti, Paolo
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101), Photonics (Closed 20120101).
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101).
    Green lightpath provisioning in transparent WDM networks: Pros and cons2010In: IEEE 4th International Symposium on Advanced Networks and Telecommunication Systems (ANTS), 2010, IEEE , 2010, p. 10-12Conference paper (Other academic)
    Abstract [en]

    Despite their intrinsic power efficiency, transparent wavelength division multiplexing (WDM) networks have additional potentials to save energy, and have attracted the interest of researchers with many power-aware (PA) routing and wavelength assignment (RWA) solutions being proposed in the literature. These approaches seem to have, however, an adverse effect on network blocking probability performance. This paper aims at providing a different insight to the PA-RWA problem. The idea is based on the intuition that power minimization and resource blocking can be jointly treated. The proposed approach, called Weighted Power-Aware RWA (WPA-RWA), has been tested using a continental core network and the performance evaluation confirms the presence of a trade-off between power saving and blocking probability.

  • 273.
    Wiatr, Pawel
    et al.
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101). KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Monti, Paolo
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101), Photonics (Closed 20120101). KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101). KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Power Savings versus Network Performance in Dynamically Provisioned WDM Networks2012In: IEEE Communications Magazine, ISSN 0163-6804, E-ISSN 1558-1896, Vol. 50, no 5, p. 48-55Article in journal (Refereed)
    Abstract [en]

    The role of the ICT sector in our daily life is causing a significant growth of the power consumed by the network equipment. In this context, transparent WDM networks represent a promising solution for reducing the power consumption of telecom networks. For this reason transparent WDM networks attract a lot of interest and several power-aware routing and wavelength assignment algorithms are available in the literature. These approaches, however, seem to consider power minimization as the only parameter to be optimized. Little or no attention is given to other important network aspects, e. g., connection requests blocking. Such approaches may not always be advisable, especially in core WDM networks where high performance levels must be considered in the first place. This article aims at providing a different insight to the PA-routing problem. It follows the intuition that in some cases relaxing the power minimization constraint can have beneficial effects on the overall network performance, especially on the blocking probability. A novel approach, referred to as Weighted Power-Aware Lightpath Routing (WPA-LR), is proposed and evaluated using two continental core networks. Our results confirm the presence of a trade-off between power savings and blocking probability.

  • 274.
    Wiatr, Pawel
    et al.
    Uppsala Univ, Dept Informat Technol, Uppsala, Sweden..
    Yuan, Di
    Uppsala Univ, Dept Informat Technol, Uppsala, Sweden..
    Wosinska, Lena
    KTH, School of Electrical Engineering and Computer Science (EECS), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Chen, Jiajia
    KTH, School of Electrical Engineering and Computer Science (EECS), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Optical Interconnect Architectures for Datacenters2018In: 2018 IEEE PHOTONICS CONFERENCE (IPC), IEEE , 2018Conference paper (Refereed)
    Abstract [en]

    This paper highlights the challenges faced by the current datacenter tworks, where using photonic technology offers a numbers of obvious vantages. Some existing optical intra-datacenter network architectures ll be presented along with new ideas allowing for reduction of energy nsumption and required spectrum resources.

  • 275. Wong, E.
    et al.
    Machuca, C. M.
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Survivable architectures for power-savings capable converged access networks2016In: 2016 IEEE International Conference on Communications, ICC 2016, IEEE conference proceedings, 2016, p. 365-371, article id 7510719Conference paper (Refereed)
    Abstract [en]

    The reliance on the loss-of-signal (LOS) of upstream transmissions to indicate fiber/component failure is potentially unsuitable in networks that implement sleep/doze mode operation. In such networks, the transition into sleep/doze mode would result in no signal transmission, and when used in conjunction with conventional LOS to indicate network failure, would result in erroneous triggering of false alarm and subsequently protection switching. Recently, converged access networks using a hybrid passive optical architecture, have been favored as a low-cost and high-bandwidth solution to deliver high-bandwidth applications to both fixed access and mobile users. These networks are referred to as Hybrid PON Converged Access Networks. Protection against fiber/equipment failures in these networks is critical considering the customer base, network span, and traffic supported. This paper proposes four survivable architectures for such converged access networks. These architectures combine rapid fault detection and protection switching against high impact failures but without the need to rely on upstream transmissions for LOS detection. A comparison of the four architectures across three different area densities under three deployment scenarios, is presented. Guidance for selecting the best protection architecture to be deployed, considering area densities and deployment scenarios, is provided.

  • 276. Wong, Elaine
    et al.
    Grigoreva, Elena
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Machuca, Carmen Mas
    Enhancing the Survivability and Power Savings of 5G Transport Networks Based on DWDM Rings2017In: Journal of Optical Communications and Networking, ISSN 1943-0620, E-ISSN 1943-0639, Vol. 9, no 9, p. D74-D85Article in journal (Refereed)
    Abstract [en]

    So much has been promised by the fifth generation (5G), the revolution of mobile communications that allows for flexible, speedy, and efficient delivery of unlimited data and information sharing between people located anywhere and at any time. The road toward making 5G a reality, however, requires concerted efforts in designing both the underlying infrastructure and the enabling technologies to simultaneously satisfy not only capacity but also reliability, low latency, synchronization, security, and energy consumption requirements. In that respect, the transport segment of a 5G network, i.e., the backhaul network of mobile base stations (BSs) or fronthaul of remote radio units (RRUs), must not be overlooked. Further, any future design of a resilient 5G transport network must also consider the potential exploitation of switching on and off network resources such as RRUs and BSs to improve energy efficiency. At present, there are few inroads on 5G transport networks that provide resilience during sleep mode operation. Therefore, the focus of this workis aimed specifically at providing solutions to enhance both the survivability and power savings of mobile transport networks that implement sleep mode operation. We develop our solutions around a dense wavelength-division multiplexed (DWDM) optical ring transport network that has been previously proven to be energy efficient as a 5G transport network. Further, we propose two survivable schemes that exploit the inherent resiliency of the ring network. In conjunction with cw monitoring signals and highly sensitive monitoring modules, these schemes facilitate for the first time continuous monitoring of the network at all times, even during idle periods of transmission when transceivers are sleeping. That is, our proposed schemes enable network energy savings through sleep mode operation without having to compromise on failure detection time. Compared to a conventional ring architecture, our survivable schemes provide enhanced connection availability and power savings at less than 0.2% incremental network cost. Based on performance evaluations for brownfield, duct reuse, and greenfield deployments, we provide guidance on the most suitable scheme for each considered scenario, thus driving the future choices of mobile network operators.

  • 277. Wong, Elaine
    et al.
    Machuca, Carmen Mas
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Survivable Hybrid Passive Optical Converged Network Architectures Based on Reflective Monitoring2016In: Journal of Lightwave Technology, ISSN 0733-8724, E-ISSN 1558-2213, Vol. 34, no 18, p. 4317-4328Article in journal (Refereed)
    Abstract [en]

    Hybrid passive optical converged access networks (HPCANs) are recognized as a cost-efficient and high-bandwidth solution to address the exponentially increasing demands of both fixed access and mobile users. HPCANs are expected to support high client count with different bandwidth requirements, long network spans, and high traffic. In that respect, survivability of such networks against fiber/equipment failures is a critical deployment feature. Consequently, rapid fault detection and subsequent restoration of services to users are gaining importance. Four survivable architectures that are compliant with the aforementioned HPCAN specifications are presented in this work. These architectures do not need to rely on upstream transmissions for loss-of-signal (LOS) activation, thereby making them suitable for use with sleep/doze mode transceivers for power saving. In networks that implement sleep/doze upstream transceivers, the transition into sleep/doze mode would result in no upstream signal transmission. If using conventional LOS activation rather than our proposed architectures to indicate equipment/fiber failure in the network, the absence of upstream transmission would result in erroneous triggering of false LOS alarm and subsequently unnecessary protection switching. We compare the four survivable HPCAN architectures against an unprotected HPCAN using illustrative examples of three different population densities, namely covering dense urban, urban, and rural areas, and three different deployment scenarios, namely brownfield, duct reuse, and greenfield. We perform detailed evaluations of connection availability, failure impact factor, yearly network energy consumption, and total network cost. Results from this study provide guidance for the choice of the best survivable HPCAN architecture to serve each of the three considered area densities under each of the three deployment scenarios.

  • 278.
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Information Technology, IMIT.
    Connection availability in WDM mesh networks with multiple failures2006In: ICTON 2006: 8th International Conference on Transparent Optical Networks, Vol 3, Proceedings / [ed] Marciniak, M, 2006, p. 126-129Conference paper (Refereed)
    Abstract [en]

    Wavelength Division Multiplexed (WDM) technology has revolutionized wide-area networks. As the amount of traffic carried is very large, any single failure can be catastrophic. Thus, survivability of a network that refers to a network's capability to provide continuous service in the presence of failures has become crucial in such networks. Communication networks are usually designed to survive single failure. However, in large networks the occurrence of multiple concurrent failures cannot be neglected. Therefore, in this paper we study connection availability in WDM networks assuming failures of any multiplicity. Shared Path Protection (SPP) scheme is an efficient network recovery mechanism in terms of network resource utilization and in many related works the SPP scheme has been studied to solve a single failure problem. We apply SPP scheme and propose an analytical model for calculation of connection unavailability in WDM mesh networks with multiple failure assumption. We have evaluated our model by simulations and show that the connection unavailability obtained by simulations is very close to the theoretical value obtained by our algorithm, which proves the accuracy of our model.

  • 279.
    Wosinska, Lena
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Optimization of optical networks: Price and value of reliability2004In: ICTON 2004: 6TH INTERNATIONAL CONFERENCE ON TRANSPARENT OPTICAL NETWORKS, PROCEEDINGS, VOL 1 / [ed] Marciniak, M, NEW YORK: IEEE , 2004, p. 53-58Conference paper (Refereed)
    Abstract [en]

    In this paper we consider reliability optimization in optical networks. We present both a general view and our recent results in the field. It is shown that monitoring of optical signal can significantly improve network reliability performance and, in some cases, can be considered as a cost effective alternative for achieving a certain level of connection availability. Finally, the presented sensitivity analysis gives a guideline for improving network reliability in a cost effective way.

  • 280.
    Wosinska, Lena
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS.
    Reliability study of fault-tolerant multiwavelength nonblocking optical cross connect based on InGaAsP/InP laser-amplifier gate-switch arrays1993In: IEEE Photonics Technology Letters, ISSN 1041-1135, E-ISSN 1941-0174, Vol. 5, p. 1206-1209Article in journal (Refereed)
    Abstract [en]

    Reliability studies for a multiwavelength nonblocking optical cross connect (OXC) are presented. Calculations are based on available reliability data for commercial components as well as expected life lengths for new components and systems developed for application in the OXC. Reliability of the electronic control system is not considered here. Average OXC downtime below 2 min/year can be obtained. In general for switching systems it is required that average downtime is held below 3 min/year. As the OXC is proposed to be utilized in telecommunication in optical transport networks it is extremely important to know if this OXC exhibits reliability properties acceptable for this purpose.<>

  • 281.
    Wosinska, Lena
    et al.
    KTH, School of Information and Communication Technology (ICT), Centres, Kista Photonics Research Center, KPRC. KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Chen, JiaJia
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics. KTH, School of Information and Communication Technology (ICT), Centres, Kista Photonics Research Center, KPRC.
    Contention resolution in an asynchronous all-optical packet switch2006In: 2006 International Conference on Photonics in Switching, Proceedings, NEW YORK: IEEE , 2006, p. 161-163Conference paper (Refereed)
    Abstract [en]

    We propose an asynchronous optical packet switching node architecture, where congestion resolution is based on shared optical buffers and tuneable wavelength converters. We evaluated our switch by simulations and show that decreasing packet loss probability obtained by optical buffers can be efficiently boosted by adding a few shared tuneable wavelength converters, which allows for reduction of all-optical buffer size. The smaller switch size the larger impact of wavelength conversion on packet loss probability was observed. Furthermore it can be noticed that for the proposed node architecture the higher number of buffer positions the larger improvement caused by applying tuneable wavelength converters can be achieved.

  • 282.
    Wosinska, Lena
    et al.
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Chen, Jiajia
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    How Much to Pay for Protection in Fiber Access Networks: Cost and Reliability Tradeoff2009In: 2009 IEEE 3RD INTERNATIONAL SYMPOSIUM ON ADVANCED NETWORKS AND TELECOMMUNICATION SYSTEMS (ANTS 2009), NEW YORK: IEEE , 2009, p. 28-30Conference paper (Refereed)
    Abstract [en]

    The economical aspects are most critical in the access part of the networks because of the low sharing factor of the total cost. It makes the deployment of fiber access networks relatively slow due to the high investment cost involved. Several fiber access network architectures such as homerun (sometimes referred to as point-to-point P2P), active optical networks (AONs) and passive optical networks (PONs) have been developed to support the growing bandwidth demand from both residential and business customers. Meanwhile, fault management and reliable service delivery becomes more significant due to increased dependency on electronic services all over society and the growing importance of reliable service delivery. However, there is a tradeoff between the cost of protection and the level of service reliability. Obviously, in the access part of the networks, improving reliability performance by duplication of network resources (and capital expenditures CAPEX) can be too expensive. Therefore, a real challenge for an access network operator is to operate a cost-efficient, yet reliable network that provides leading edge services at low price and with minimal downtime. In this paper we present the evolution of fiber access networks and compare reliability performance in relation to investment and management cost for some representative cases. We consider both standard and novel architectures for deployment in both sparse and dense populated areas. While some recent works focused on PON protection schemes with reduced CAPEX the current and future effort is put on minimizing the operational expenditures (OPEX) during the access network lifetime.

  • 283.
    Wosinska, Lena
    et al.
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101), Photonics (Closed 20120101).
    Chen, Jiajia
    KTH, School of Information and Communication Technology (ICT), Microelectronics and Applied Physics, MAP.
    Reliability Performance Analysis vs. Deployment Cost of Fiber Access Networks2008In: 2008 7TH INTERNATIONAL CONFERENCE ON THE OPTICAL INTERNET (COIN), NEW YORK: IEEE , 2008, p. 161-162Conference paper (Refereed)
    Abstract [en]

    In this paper the availability and deployment cost analysis of different fiber access networks is presented. We consider both standard and novel architectures for two deployment scenarios, namely in dense and sparse populated areas referred to as collective and dispersive case respectively. In order to demonstrate the cost efficiency of different access network architectures we introduce a cost-reliability measure CRM parameter. For our calculations we assumed the typical values for component reliability and cost. Furthermore, we assume a decrease of the cost by 5% per year (4% for fiber). Our results reveal that the decrease of component cost does not make any significant difference because burying fiber is the dominating part of the network deployment cost and it does not decrease over the years.

  • 284.
    Wosinska, Lena
    et al.
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics.
    Chen, JiaJia
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics.
    Reliability performance of passive optical networks2007In: ICTON 2007: Proceedings of the 9th International Conference on Transparent Optical Networks, Vol 3 / [ed] Marciniak, M, 2007, p. 121-124Conference paper (Refereed)
    Abstract [en]

    In this paper reliability performance analysis of some representative protection schemes for Passive Optical Networks PONS is presented. We study three PON architectures defined by ITU-T as well as two architectures that provide reliable connections to business customers and compare connection availability in order to select the most promising protection scheme for the future access solution. Our results show that for the considered architectures a sufficient connection availability level can be obtained only in the scheme with full duplication of network resources.

  • 285.
    Wosinska, Lena
    et al.
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics.
    Chen, JiaJia
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics.
    Kantor, Miroslaw
    Wajda, Krzysztof
    Reliability and cost analysis of passive optical networks2007In: 2007 ICTON Mediterranean Winter Conference, 2007, p. 273-273Conference paper (Refereed)
    Abstract [en]

    In this talk the cost of building resilient passive optical networks (PONs) is analyzed in relation to the connection availability performance. Both standard and several novel PON protection architectures are considered [1 - 6]. A new measure for cost efficiency of protection is proposed to compare different protection architectures in order to select the most appropriate ones for particular groups of clients. Fault management in communication networks becomes more significant due to the increasing demand for reliable service delivery. On the other hand, access network providers need to keep capital and operational expenditures (CAPEX and OPEX) low in order to be able to offer economical solutions for the customers. Improving network reliability performance by adding redundant components and systems is expensive and thus, not always very suitable for cost-sensitive access networks. The evolution of protection schemes for PONs can be divided into two phases. In the first one, the standard protection architectures were defined by ITU-T [1] around a decade ago. They are based on duplication of the network resources and are referred to as type A, B, C and D. In Type A only the feeder fiber (FF) is redundant. Type B protection duplicates the shared part of the PON, i.e., FF and optical interfaces at the OLT. In Type B the primary optical interface at OLT is normally working while the second one is used as a cold standby. Type C represents 1+1 dedicated path protection with full duplication of the PON resources. In Type C both the primary and secondary interfaces are normally working (hot standby), which allows for very fast recovery time. Type D protection specifies the independent duplication of FF and distribution fibers (DFs) and thus, it enables network provider to deliver services for different users with different reliability. Obviously, the ITU-T standard Type C and Type D with full protection offer relatively high connection availability but unfortunately they require duplication of all network resources (and investment cost) to realize the protection, which may result in CAPEX that is too high for the cost-sensitive access networks. Therefore, in the second phase of the PON protection scheme evolution the effort was put on the development of cost-efficient architectures [2 - 6]. To evaluate the different PON protection schemes we propose a cost-reliability measure (CRM) in order to capture the trade-off between the deployment cost and reliability performance. The CRM values obtained for each considered protection scheme allow for selecting the most cost-efficient protection for PON customers.

  • 286.
    Wosinska, Lena
    et al.
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics. KTH, School of Information and Communication Technology (ICT), Centres, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Chen, Jiajia
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics. KTH, School of Information and Communication Technology (ICT), Centres, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Larsen, Claus Popp
    Fiber Access Networks: Reliability Analysis and Swedish Broadband Market2009In: IEICE transactions on communications, ISSN 0916-8516, E-ISSN 1745-1345, Vol. E92B, no 10, p. 3006-3014Article in journal (Refereed)
    Abstract [en]

    Fiber access network architectures such as active optical networks (AONs) and passive optical networks (PONS) have been developed to support the growing bandwidth demand. Whereas particularly Swedish operators prefer AON, this may not be the case for operators in other countries. The choice depends on a combination of technical requirements, practical constraints, business models, and cost. Due to the increasing importance of reliable access to the network services, connection availability is becoming one of the most crucial issues for access networks. which should be reflected in the network owner's architecture decision. In many cases protection against failures is realized by adding backup resources. However, there is a trade off between the cost of protection and the level of service reliability since improving reliability performance by duplication of network resources (and capital expenditures CAPEX) may be too expensive. In this paper we present the evolution of fiber access networks and compare reliability performance in relation to investment and management cost for some representative cases. We consider both standard and novel architectures for deployment in both sparsely and densely populated areas. While some recent works focused on PON protection schemes with reduced CAPEX the current and future effort should be put on minimizing the operational expenditures (OPEX) during the access network lifetime.

  • 287.
    Wosinska, Lena
    et al.
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics. KTH, School of Information and Communication Technology (ICT), Centres, Zhejiang-KTH Joint Research Center of Photonics, JORCEP. KTH, School of Information and Communication Technology (ICT), Centres, Kista Photonics Research Center, KPRC.
    Chen, Jiajia
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics. KTH, School of Information and Communication Technology (ICT), Centres, Zhejiang-KTH Joint Research Center of Photonics, JORCEP.
    Machuca, Carmen Mas
    Techno-economical evaluation of selected passive optical network architectures2008In: ICTON 2008: PROCEEDINGS OF 2008 10TH ANNIVERSARY INTERNATIONAL CONFERENCE ON TRANSPARENT OPTICAL NETWORKS, VOL 3 / [ed] Marciniak, M, NEW YORK: IEEE , 2008, p. 1-1Conference paper (Refereed)
  • 288.
    Wosinska, Lena
    et al.
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Chen, Jiajia
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Machuca, Carmen Mas
    Kantor, Miroslaw
    Impact of Protection Mechanisms on Cost in PONs2009In: ICTON: 2009 11TH INTERNATIONAL CONFERENCE ON TRANSPARENT OPTICAL NETWORKS, VOLS 1 AND 2 , NEW YORK: IEEE , 2009, p. 728-731Conference paper (Refereed)
    Abstract [en]

    Passive optical networks (PONs) are considered as a promising solution for broadband access networks. Due to the growing demand for reliable service delivery, fault management in the network is becoming very significant. However, there is a trade off between the cost of protection and the level of service reliability. Since economical aspects are most critical in the access part of the networks, improving reliability performance by duplication of network resources can be too expensive. Therefore, some recent works focused on PON protection schemes with reduced capital expenditures (CAPEX). The future trend will probably migrate towards minimizing the operational expenditures (OPEX) during the access network lifetime. This work presents a cost comparison of different protection mechanisms that can be applied in passive optical networks. The impact that different protection approaches have on the cost related both to the equipment to be deployed and the failure reparation and service penalties to be paid is evaluated.

  • 289.
    Wosinska, Lena
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Chen, Jiajia
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Monti, Paolo
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Next Generation Optical Access Network Architectures: What is the Best Option?2013Conference paper (Other academic)
  • 290.
    Wosinska, Lena
    et al.
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101), Photonics (Closed 20120101).
    Chen, Jiajia
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101), Photonics (Closed 20120101).
    Monti, Paolo
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101), Photonics (Closed 20120101).
    What Photonics Can Do for Switching in Transparent Optical Networks2010In: European Conference on Networks  and Optical Communications (NOC), 2010Conference paper (Other academic)
    Abstract [en]

    Transparent optical networks, based on WDM technology, are considered as the mostpromising candidates for future high capacity communication networks because of theirscalability and energy efficiency. In such networks, switching functions will be carriedout directly in the optical domain so that high speed optical signals will traverse thenetwork without any optical-to-electrical conversion. Different switching paradigms canbe applied, such as optical circuit switching OCS, optical burst switching OBS andoptical packet switching OPS, offering different switching granularities and performance.A number of challenges are associated with each of the switching paradigm. This talkwill highlight some of these challenges and review pros and cons of using photonictechnology for switching in communication networks. The optical circuit switching (OCS) is based on a course switching granularity (mostly atwavelength level). It provides end-to-end optical channels (lightpaths) between sourceand destination nodes. The basic function of OCS network is solving routing andwavelength assignment (RWA) problem, i.e. finding a suitable physical path for eachlightpath request and assigning an available wavelength to it. A suitable OCS nodearchitecture and technology can significantly improve network performance.On the other hand, switching in OPS networks should be done on per packet basisproviding high switching granularity, which in turn gives a potential for better resourceutilization compared with OCS. However, several fundamental problems need to besolved in order to implement OPS networks. In particular, packet contention at the OPSnodes needs to be efficiently handled in order to guarantee required networkperformance. However, lack of flexible optical memory makes the contentionresolution in optical domain very difficult.

  • 291.
    Wosinska, Lena
    et al.
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101), Photonics (Closed 20120101).
    Colle, D.
    Demeester, P.
    Katrinis, K.
    Lackovic, M.
    Lapcevic, O.
    Lievens, I.
    Markidis, G.
    Mikac, B.
    Pickavet, M.
    Puype, B.
    Skorin-Kapov, Nina
    Staessens, D.
    Tzanakaki, Anna
    Network resilience in future optical networks2009In: Towards Digital Optical Networks, Springer, 2009, p. 253-284Conference paper (Refereed)
    Abstract [en]

    Network resilience is an issue of deep concern to network operators being eager to deploy high-capacity fibre networks, since a single failure in the network could result in significant losses of revenue. The importance of network reliability will keep pace with the steadily increasing network capacity. For very-high-capacity future optical networks, carrying multitudes of 10 Gbit/s channels per fibre strand, a failure of optical connection will interrupt a vast amount of services running on-line, making the connection availability a factor of great significance. Therefore the ultrahigh capacity future optical networks will face a challenge of providing very efficient and fast survivability mechanisms. In this chapter we review the terminology and basic resilience techniques along with the results of research work on optical network survivability performed in the frame of COST291 cooperation. Our research work was focused on reliability performance improvement and on recovery in multilayer optical networks.

  • 292.
    Wosinska, Lena
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Furdek, Marija
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS, Optical Network Laboratory (ON Lab).
    Dzanko, Matija
    Reliability Performance of Optical Networks Based on Programmable ROADMs2016In: 2016 18TH INTERNATIONAL CONFERENCE ON TRANSPARENT OPTICAL NETWORKS (ICTON), IEEE, 2016Conference paper (Refereed)
  • 293.
    Wosinska, Lena
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS. KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Glick, Madeleine
    Call for Papers: Photonics in Switching2006In: Journal of Optical Networking, ISSN 1536-5379, Vol. 5, no 4, p. 293-294Article in journal (Refereed)
  • 294.
    Wosinska, Lena
    et al.
    KTH, School of Information and Communication Technology (ICT), Communication Systems, CoS. KTH, School of Information and Communication Technology (ICT), Optics and Photonics, Photonics.
    Glick, Madeleine
    Photonics in Switching: introduction to the feature issue2007In: Journal of Optical Networking, ISSN 1536-5379, Vol. 6, no 11, p. 1244-1246Article in journal (Other academic)
  • 295.
    Wosinska, Lena
    et al.
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Haralson, Joanna
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Thylén, Lars
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Öberg, Johnny
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Hessmo, Björn
    KTH, Superseded Departments, Microelectronics and Information Technology, IMIT.
    Benefit of Implementing Novel Optical Buffers in an Asynchronous Photonic Packet Switch2004In: Proceedings of ECOC-04, 2004Conference paper (Refereed)
  • 296. Wosinska, Lena
    et al.
    Jirattigalachote, A.
    Monti, P.
    Tzanakaki, A.
    Katrinis, K.
    Energy Efficient Approach for Survivable WDM Optical Networks2011In: 2010 12TH INTERNATIONAL CONFERENCE ON TRANSPARENT OPTICAL NETWORKS (ICTON), 2011Conference paper (Refereed)
  • 297.
    Wosinska, Lena
    et al.
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101), Photonics (Closed 20120101).
    Jirattigalachote, Amornrat
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101), Photonics (Closed 20120101).
    Monti, Paolo
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101), Photonics (Closed 20120101).
    Tzanakaki, A.
    Katrinis, K.
    Lightpath routing considering differentiated physical layer constraints in transparent WDM networks2009In: Network Architectures, Management, and Applications VII, 2009, p. 76331D-Conference paper (Refereed)
    Abstract [en]

    Wavelength division multiplexing (WDM) technology is considered to be the ultimate answer to the rapidly growing capacity demand of next generation networks. Many routing and wavelength assignment (RWA) algorithms, proposed for lightpath provisioning, base their routing decisions on the availability of network resources, and assume that optical fibers and components are ideal. In reality, physical impairments degrade the quality of the optical signal propagating through fiber segments and optical components. To cope with this problem, Impairment Constraint Based Routing (ICBR) algorithms, that consider physical impairments during connection provisioning, are currently proposed to prevent selecting lightpaths with poor signal quality. However, these algorithms support only a single (highest) quality of transmission threshold, the same one for all connection requests. This does not fit well with the variety of services, with potentially disparate QoS requirements, that the next generation networks are expected to support. Consequently, the efficiency of network resource utilization is reduced. This paper demonstrates that a significant improvement, in terms of blocking probability, can be achieved when using an ICBR algorithm with differentiated physical layer constraints. Performance is compared with conventional impairment aware routing approaches when unprotected, shared path protected (SPP), and dedicated path protected (DPP) connection requests are considered. The achieved improvement is a result of more efficient resource utilization as unnecessary connection blocking can be avoided by selecting network resources offering optical signal quality that is "good enough" to satisfy a specific connection request.

  • 298.
    Wosinska, Lena
    et al.
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101), Photonics (Closed 20120101).
    Jirattigalachote, Amornrat
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101), Photonics (Closed 20120101).
    Monti, Paolo
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101), Photonics (Closed 20120101).
    Tzanakaki, Anna
    Athens Information Technology.
    Katrinis, Kostas
    Athens Information Technology.
    Energy efficient approach for survivable WDM optical networks2010In: 2010 12th International Conference on Transparent Optical Networks (ICTON), 2010Conference paper (Other academic)
    Abstract [en]

    The traffic volume that needs to be handled by communication networks is growing very fast due to the continuously increasing number of end-users and to the new and emerging services that can be accessed on the Internet. This reflects into a need for increased network capacity, which in turn introduces higher energy consumption of the network infrastructure. In view of the scale of the network of the future, it becomes evident that investigation of technologies, methodologies and approaches that can offer energy savings are of the utmost importance. It is widely accepted that optical network technologies will have a central role in the formation and the support of the network of the future. Therefore, it is important to explore novel solutions with respect to their energy efficiency. Several attempts to reduce power consumption in optical networks can be found in the literature. However, so far, no attention is paid to the impact of resilience in the overall network power consumption. On the other hand, wavelength division multiplexing (WDM) networks consist of very high capacity links and nodes where a single failure may disrupt an enormous number of services. Therefore, backup resources need to be provided for the purpose of survivability. Regardless of the network status, optical amplifiers and switching nodes along the backup paths are always active (i.e. switched on). Moreover, backup paths are typically longer than their respective primary paths, and therefore the total energy consumed by the spare resources in the network may be relatively high. This paper proposes a novel approach to save energy in survivable optical networks. The approach is based on appropriately handling protection resources, where a trade-off between recovery time and energy consumption is exploited. The proposed idea has been tested through simulations using a Pan-European (COST 239) and Pan-American (NSFNet) network topology. For benchmarking purposes, results for the proposed energy-a- - ware approach are compared against a conventional one, based on shortest path routing. With the proposed approach, more than 40% energy saving has been observed in case of the COST 239 network and more than 30% in the NSFNet. To further increase the energy savings in the network, a routing algorithm (specifically tailored for the proposed energy-aware approach) is also presented, showing that an additional 20% in energy reduction is achievable.

  • 299.
    Wosinska, Lena
    et al.
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101), Photonics (Closed 20120101).
    Jirattigalachote, Amornrat
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101), Photonics (Closed 20120101).
    Monti, Paolo
    KTH, School of Information and Communication Technology (ICT), Optics and Photonics (Closed 20120101), Photonics (Closed 20120101).
    Tzanakaki, Anna
    Athens Information Technology.
    Katrinis, Kostas
    Athens Information Technology.
    Lightpath routing considering differentiated physical layer constraints in transparent WDM networks2009In: 2009 Asia Communications and Photonics Conference and Exhibition, ACP 2009, 2009Conference paper (Other academic)
    Abstract [en]

    We investigate WDM network performance improvement by applying routing algorithms taking into account service differentiation in terms of signal quality requirement. We consider network survivability based on dedicated and shared path protection where both working and protection paths are calculated according to our algorithm. A significant improvement is obtained compared with the conventional algorithms.

  • 300.
    Wosinska, Lena
    et al.
    KTH.
    Lin, Rui
    KTH.
    Cheng, Yuxin
    KTH.
    Chen, Jiajia
    KTH.
    Optical Network Architectures and Technologies for Datacenters2017In: 2017 IEEE PHOTONICS SOCIETY SUMMER TOPICAL MEETING SERIES (SUM), IEEE , 2017, p. 111-112, article id 8012675Conference paper (Refereed)
    Abstract [en]

    The paper highlights the challenges related to the increasing importance of datacenter services, leading to dramatically growing datacenter traffic. The advantages of using photonic technology in intra-datacenter networks are discussed and a cross-layer view for network architecture design is presented.

34567 251 - 300 of 337
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