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  • 1.
    Chen, Jiajia
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Fotonik.
    Jirattigalachote, Amornrat
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Fotonik.
    Wosinska, Lena
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Fotonik.
    Thylén, Lars
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Fotonik.
    Novel Node Architectures for Wavelength-Routed WDM Networks with Wavelength Conversion Capability2008Ingår i: 34th European Conference and Exhibition on Optical Communication ECOC’08, 2008, 2008Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    We present and evaluate two novel node architectures based on optical switch matrices and wavelength converters (WCs). Relatively small and cheap switches are required while WCs efficiently improve blocking probability

  • 2.
    Furdek, Marija
    et al.
    University of Zagreb, Croatia.
    Jirattigalachote, Amornrat
    KTH, Skolan för informations- och kommunikationsteknik (ICT).
    Skorin-Kapov, Nina
    University of Zagreb, Croatia.
    Wosinska, Lena
    KTH, Skolan för informations- och kommunikationsteknik (ICT).
    Attack-aware optical networks planning: A cost analysis2011Ingår i: 13th International Conference on Transparent Optical Networks, 2011. ICTON'11., IEEE , 2011Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    Transparent optical networks (TONs) based on Wavelength Division Multiplexing (WDM) are the only viable future-proof solution for supporting rapidly growing traffic demands. In TONs, optical signals are propagated transparently between edge nodes without any O/E/O conversion. In this way, it is possible to reduce cost and energy consumption in the network, as well as obtain transparency to signal bit rates, modulation formats and protocols. However, the absence of O/E/O conversion makes it easier for erroneous signals to propagate through the network and affect existing traffic. This can be utilized to realize attacks exploiting the physical-layer characteristics of network elements. An example of such attacks is high-power jamming, where a high-powered signal is injected in the network aiming to deteriorate the signal quality on other, legitimate optical channels (referred to as lightpaths), as described in [1] and [2].

  • 3. Hasegawa, Hiroshi
    et al.
    Taniguchi, Y.
    Sato, K.
    Jirattigalachote, Amonrat
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Monti, Paolo
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Wosinska, Lena
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Design strategies for survivable Grouped Routing Entity (GRE)-based optical networks2013Ingår i: Design of Reliable Communication Networks (DRCN), 2013 9th International Conference on the, 2013, s. 148-154Konferensbidrag (Refereegranskat)
    Abstract [en]

    In bandwidth abundant optical networks, the Grouped Routing Entity (GRE) concept is a cost-efficient alternative used instead of waveband routing. It offers all the benefits of the waveband routing (i.e., reduced number of ports), without using expensive wavelength cross connects (WXCs) required in hierarchical optical networks. In fact in a GRE-based optical network wavelength channel add/drop operations are accomplished via Wavelength Selective Switches (WSS) or with optical couplers. The objective of this paper is to further investigate the benefits of GRE-based optical networks in a scenario where survivability is required. In this paper a dedicated protection scheme is proposed, where wavelength paths are efficiently routed using mostly disjoint working and backup GRE pipes (i.e., working and backup pipes are allowed to share some common nodes along their paths). Numerical experiments demonstrate that significant hardware scale reduction at the switching nodes can be obtained by using the proposed network design algorithm.

  • 4.
    Jirattigalachote, Amornrat
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Provisioning Strategies for Transparent Optical Networks Considering Transmission Quality, Security, and Energy Efficiency2012Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    The continuous growth of traffic demand driven by the brisk increase in number of Internet users and emerging online services creates new challenges for communication networks. The latest advances in Wavelength Division Multiplexing (WDM) technology make it possible to build Transparent Optical Networks (TONs) which are expected to be able to satisfy this rapidly growing capacity demand. Moreover, with the ability of TONs to transparently carry the optical signal from source to destination, electronic processing of the tremendous amount of data can be avoided and optical-to-electrical-to-optical (O/E/O) conversion at intermediate nodes can be eliminated. Consequently, transparent WDM networks consume relatively low power, compared to their electronic-based IP network counterpart. Furthermore, TONs bring also additional benefits in terms of bit rate, signal format, and protocol transparency. However, the absence of O/E/O processing at intermediate nodes in TONs has also some drawbacks. Without regeneration, the quality of the optical signal transmitted from a source to a destination might be degraded due to the effect of physical-layer impairments induced by the transmission through optical fibers and network components. For this reason, routing approaches specifically tailored to account for the effect of physical-layer impairments are needed to avoid setting up connections that don’t satisfy required signal quality at the receiver. Transparency also makes TONs highly vulnerable to deliberate physical-layer attacks. Malicious attacking signals can cause a severe impact on the traffic and for this reason proactive mechanisms, e.g., network design strategies, able to limit their effect are required. Finally, even though energy consumption of transparent WDM networks is lower than in the case of networks processing the traffic at the nodes in the electronic domain, they have the potential to consume even less power. This can be accomplished by targeting the inefficiencies of the current provisioning strategies applied in WDM networks.

    The work in this thesis addresses the three important aspects mentioned above. In particular, this thesis focuses on routing and wavelength assignment (RWA) strategies specifically devised to target: (i) the lightpath transmission quality, (ii) the network security (i.e., in terms of vulnerability to physical-layer attacks), and (iii) the reduction of the network energy consumption. Our contributions are summarized below.

    A number of Impairment Constraint Based Routing (ICBR) algorithms have been proposed in the literature to consider physical-layer impairments during the connection provisioning phase. Their objective is to prevent the selection of optical connections (referred to as lightpaths) with poor signal quality. These ICBR approaches always assign each connection request the least impaired lightpath and support only a single threshold of transmission quality, used for all connection requests. However, next generation networks are expected to support a variety of services with disparate requirements for transmission quality. To address this issue, in this thesis we propose an ICBR algorithm supporting differentiation of services at the Bit Error Rate (BER) level, referred to as ICBR-Diff. Our approach takes into account the effect of physical-layer impairments during the connection provisioning phase where various BER thresholds are considered for accepting/blocking connection requests, depending on the signal quality requirements of the connection requests. We tested the proposed ICBR-Diff approach in different network scenarios, including also a fiber heterogeneity. It is shown that it can achieve a significant improvement of network performance in terms of connection blocking, compared to previously published non-differentiated RWA and ICBR algorithms. 

    Another important challenge to be considered in TONs is their vulnerability to physical-layer attacks. Deliberate attacking signals, e.g., high-power jamming, can cause severe service disruption or even service denial, due to their ability to propagate in the network. Detecting and locating the source of such attacks is difficult, since monitoring must be done in the optical domain, and it is also very expensive. Several attack-aware RWA algorithms have been proposed in the literature to proactively reduce the disruption caused by high-power jamming attacks. However, even with attack-aware network planning mechanisms, the uncontrollable propagation of the attack still remains an issue. To address this problem, we propose the use of power equalizers inside the network nodes in order to limit the propagation of high-power jamming attacks. Because of the high cost of such equipment, we develop a series of heuristics (incl. Greedy Randomized Adaptive Search Procedure (GRASP)) aiming at minimizing the number of power equalizers needed to reduce the network attack vulnerability to a desired level by optimizing the location of the equalizers. Our simulation results show that the equalizer placement obtained by the proposed GRASP approach allows for 50% reduction of the sites with the power equalizers while offering the same level of attack propagation limitation as it is possible to achieve with all nodes having this additional equipment installed. In turn, this potentially yields a significant cost saving.   

    Energy consumption in TONs has been the target of several studies focusing on the energy-aware and survivable network design problem for both dedicated and shared path protection. However, survivability and energy efficiency in a dynamic provisioning scenario has not been addressed. To fill this gap, in this thesis we focus on the power consumption of survivable WDM network with dynamically provisioned 1:1 dedicated path protected connections. We first investigate the potential energy savings that are achievable by setting all unused protection resources into a lower-power, stand-by state (or sleep mode) during normal network operations. It is shown that in this way the network power consumption can be significantly reduced. Thus, to optimize the energy savings, we propose and evaluate a series of energy-efficient strategies, specifically tailored around the sleep mode functionality. The performance evaluation results reveal the existence of a trade-off between energy saving and connection blocking. Nonetheless, they also show that with the right provisioning strategy it is possible to save a considerable amount of energy with a negligible impact on the connection blocking probability.

    In order to evaluate the performance of our proposed ICBR-Diff and energy-aware RWA algorithms, we develop two custom-made discrete-event simulators. In addition, the Matlab program of GRASP approach for power equalization placement problem is implemented.

  • 5.
    Jirattigalachote, Amornrat
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Fotonik (Stängd 20120101).
    Cavdar, Cicek
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Fotonik (Stängd 20120101).
    Monti, Paolo
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Fotonik (Stängd 20120101).
    Wosinska, Lena
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Fotonik (Stängd 20120101).
    Tzanakaki, Anna
    Dynamic provisioning strategies for energy efficient WDM networks with dedicated path protection2011Ingår i: Optical Switching and Networkning Journal, ISSN 1573-4277, E-ISSN 1872-9770, Vol. 8, nr 3, s. 201-213Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Energy consumption in optical backbone networks is increasing due to two main reasons: (i) the exponential growth of bandwidth demands, and (ii) the increase in availability requirements in order to guarantee protection of the ultra high capacity optical channels provided by wavelength division multiplexing (WDM) networks. Although state of the art reliability mechanisms are very efficient in guaranteeing high availability, they do not consider the impact of the protection resources on the network's energy consumption. Dedicated (1:1) path protection (DPP) is a well-known mechanism that provides one extra link-disjoint path for the protection of a connection request. This secondary path is reserved and maintained in an active mode even though it is not utilized most of the time. This means that in-line optical amplifiers and switching nodes/ports are always consuming power even when they are not used to reroute any primary traffic. Moreover secondary paths are on average longer than their respective primary paths. These observations motivated us to investigate the energy savings, when all unused protection resources can be switched into a low-power, stand-by state (or sleep mode) during normal network operation and can be activated upon a failure. It is shown that significant reduction of power consumption (up to 25%) can be achieved by putting protection resources into sleep mode. Moreover, in order to enhance this energy saving figure, this paper proposes and evaluates different energy-efficient algorithms, specifically tailored around the sleep mode option, to dynamically provision 1:1 dedicated path protected connection. The trade-off between energy saving and blocking probability is discussed and an efficient mechanism to overcome this drawback is devised. Our results reveal that a 34% reduction of energy consumption can be obtained with a negligible impact on the network's blocking performance.

  • 6.
    Jirattigalachote, Amornrat
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Fotonik (Stängd 20120101).
    Katrinis, Kostas
    Athens Information Technology.
    Tzanakaki, Anna
    Athens Information Technology.
    Wosinska, Lena
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Fotonik (Stängd 20120101).
    Monti, Paolo
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Fotonik (Stängd 20120101).
    Quantifying the Benefit of BER-based Differentiated Path Provisioning in WDM Optical Networks2009Ingår i: ICTON: 2009 11TH INTERNATIONAL CONFERENCE ON TRANSPARENT OPTICAL NETWORKS, VOLS 1 AND 2, NEW YORK: IEEE , 2009, s. 1097-1100Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper we propose the use of Bit Error Rate (BER) as a differentiation of service parameter for connection provisioning in optical Wavelength Division Multiplexing (WDM) networks. This is achieved through the use of Impairment Constraint Based Routing (ICBR), whereby various BER thresholds are set for accepting/blocking requests at the connection provisioning phase, depending on QoS requirements. The performance of the proposed scheme is evaluated through simulations, using dynamic traffic demands as an input at 10 Gb/s bit rate. The evaluation results reveal significant improvement in term of connection blocking, as compared to non-differentiated conventional RWA and ICBR algorithms.

  • 7.
    Jirattigalachote, Amornrat
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Fotonik (Stängd 20120101).
    Monti, Paolo
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Fotonik (Stängd 20120101).
    Wosinska, Lena
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Fotonik (Stängd 20120101).
    Katrinis, Kostas
    Athens Information Technology.
    Tzanakaki, Anna
    Athens Information Technology.
    ICBR-Diff: An Impairment Constraint Based Routing Strategy with Quality of Signal Differentiation2010Ingår i: Journal of Networks, ISSN 1796-2056, E-ISSN 1796-2056, Vol. 5, nr 11, s. 1279-1289Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Latest advances in Wavelength Division Multiplexing (WDM) technology make it possible to build all-optical transparent networks, which are considered to be able to satisfy the rapidly growing capacity demand. However, in a transparent WDM network the optical signal transmitted from a source to a destination node might be degraded due to physical layer impairments induced by transmission through optical fibers and components. Several Impairment Constraint Based Routing (ICBR) algorithms have been proposed to consider physical layer impairments during the connection-provisioning phase in order to prevent selecting a lightpath with poor signal quality. However, these algorithms support only a single quality of transmission threshold for all connection requests, while next generation networks and the future Internet are expected to support a variety of services with potentially disparate QoS requirements. In this paper, we propose the use of bit error rate (BER) as a differentiation of service parameter for connection requests in optical WDM networks. This is achieved through the use of ICBR, whereby various BER thresholds are set depending on the QoS requirements for accepting/blocking the connection requests during the connection-provisioning phase. The evaluation results reveal that significant network performance improvement in terms of connection blocking can be achieved, compared to non-differentiated conventional routing and wavelength assignment (RWA) and ICBR algorithms.

  • 8.
    Jirattigalachote, Amornrat
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Monti, Paolo
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Wosinska, Lena
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Taniguchi, Yuki
    Ban, Toshinori
    Hasegawa, Hiroshi
    Sato, Ken-ichi
    Design of Grouped Routing Entity (GRE)-based Optical Networks with 100% Signal Quality Guarantee2014Ingår i: 2014 International Conference on Optical Network Design and Modeling, ONDM 2014, 2014, s. 174-179Konferensbidrag (Refereegranskat)
    Abstract [en]

    In bandwidth abundant optical networks it is important to develop design strategies that are not only cost effective but also able to account for the inherent characteristics of the optical transmission medium responsible for the signal quality degradation. With this objective in mind, the paper proposes a design algorithm able to determine an appropriate placement of regenerators in Grouped Routing Entity (GRE)-based optical networks. The objective of the algorithm is to guarantee a certain signal quality level to all connections while minimizing the number of fibers and switching ports required in the network The proposed design strategy relies on a physical-layer impairment model, specifically introduced in the paper for this purpose, able to estimate the signal quality of an optical path in a GRE-based optical network Simulation results indicate that compared with a single layer optical path network the proposed design algorithm can reduce at least 87% of the switch ports while the increment in the number of fibers is lower than 10%.

  • 9.
    Jirattigalachote, Amornrat
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    Skorin-Kapov, Nina
    University of Zagreb.
    Furdek, Marija
    University of Zagreb.
    Chen, Jiajia
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    Monti, Paolo
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    Wosinska, Lena
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    Limiting physical-layer attack propagation with power equalization placement in transparent WDM networks2010Ingår i: 2010 Asia Communications and Photonics Conference and Exhibition, ACP 2010, 2010, s. 363-364Konferensbidrag (Refereegranskat)
    Abstract [en]

    We propose and evaluate a Greedy Randomized Adaptive Search Procedure applied to minimize the number of power equalizers (GRASP-PE) needed to limit the propagation of high-power jamming attacks in WDM networks. Simulation results show that GRASP-PE significantly reduces the required number of power equalizers when compared to a greedy approach.

  • 10.
    Jirattigalachote, Amornrat
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Fotonik (Stängd 20120101).
    Skorin-Kapov, Nina
    Furdek, Marija
    Chen, Jiajia
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    Monti, Paolo
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS. KTH, Skolan för informations- och kommunikationsteknik (ICT), Centra, KTH Center för Trådlösa System, Wireless@kth.
    Wosinska, Lena
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    Sparse power equalization placement for limiting jamming attack propagation in transparent optical networks2011Ingår i: Optical Switching and Networkning Journal, ISSN 1573-4277, E-ISSN 1872-9770, Vol. 8, nr 4, s. 249-258Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The latest advances in Wavelength Division Multiplexing (WDM) technology are making it possible to build all-optical transparent WDM networks, which are expected to be able to satisfy the rapid growth of today's capacity demand. However, the transparency of such networks makes them highly vulnerable to deliberate attacks, specifically targeting the physical layer. Physical-layer attacks, such as high-power jamming, can cause severe service disruption or even service denial, enhanced by their capability to propagate through a transparent optical network. Several attack-aware routing and wavelength assignment algorithms have been proposed to reduce the possible disruption caused by high-power jamming attacks. However, even with network planning approaches which take network security, specifically physical-layer attacks, into account, resilience to deliberate attacks in such scenarios remains an issue. In this paper, we propose the use of wavelength-selective attenuators as power equalizers inside network nodes to limit the propagation of high-power jamming attacks. Due to the increased cost of optical switching nodes associated with the addition of power equalizers, we aim at minimizing their number through sparse power equalization placement. We developed a set of greedy algorithms to solve what we call the Power Equalization Placement (PEP) problem with the objective of minimizing the number of power equalizers needed to reduce, to a desired level, the propagation of high-power jamming attacks for a given routing scheme. We further improved upon these results by proposing a GRASP (Greedy Randomized Adaptive Search Procedure) heuristic with a somewhat longer execution time, but with significantly superior results. The performance evaluation results indicate that the proposed GRASP heuristic can achieve the same attack propagation reduction as can be obtained by equipping all nodes with power equalizers by placing them at less than 50% of the nodes on average, potentially yielding significant cost savings.

  • 11.
    Jirattigalachote, Amornrat
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Fotonik (Stängd 20120101).
    Wosinska, Lena
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Fotonik (Stängd 20120101).
    Monti, Paolo
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Fotonik (Stängd 20120101).
    Katrinis, Kostas
    Tzanakaki, A.
    Impairment aware routing with service differentiation in heterogeneous WDM networks2009Ingår i: Network Architectures, Management, and Applications VII, SPIE - International Society for Optical Engineering, 2009, s. 763307-Konferensbidrag (Refereegranskat)
    Abstract [en]

    In transparent Wavelength Division Multiplexing (WDM) networks, the signal is transported from source to destination in the optical domain through all-optical channels, or lightpaths. A lightpath may traverse several fiber segments and optical components that in general degrade the optical signal. This effect introduces the need for considering physical layer impairments during the connection-provisioning phase. Physical layer impairments can be divided into linear and non-linear. Both types of impairments are highly dependent on the fiber characteristics, which in turn are sensitive to length, temperature and age. A close look at the fiber infrastructure of today's network operators reveals a situation where old and newly deployed fibers coexist in the network. This heterogeneous fiber plant presents a challenge. A tradeoff should be found between the QoS requirements of connection requests and the use of the available (old and new) network resources. This calls for a provisioning mechanism able to adapt to the various fiber composition scenarios. In parallel, given the need for service differentiation, the authors recently proposed an Impairment Constraint Based Routing (ICBR) algorithm, referred to as ICBR-Diff, supporting differentiation of services at the BER (Bit Error Rate) level in a network with a homogeneous fiber infrastructure. In this paper the ICBR-Diff algorithm is extended to heterogeneous network; particularly, it is evaluated in WDM networks with fiber links having varying Polarization Mode Dispersion characteristics, i.e., with old and new fiber coexisting. Simulation results show that the ICBR-Diff algorithm exhibits high adaptability in a heterogeneous fiber composition scenario. This translates into improved performance in terms of blocking probability, when compared to traditional impairment aware routing algorithms.

  • 12.
    Jirattigalachote, Amornrat
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Fotonik (Stängd 20120101).
    Wosinska, Lena
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Fotonik (Stängd 20120101).
    Monti, Paolo
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Fotonik (Stängd 20120101).
    Katrinis, Kostas
    Athens Information Technology.
    Tzanakaki, Anna
    Athens Information Technology.
    Impairment aware routing with service differentiation in heterogeneous WDM networks2009Ingår i: 2009 Asia Communications and Photonics Conference and Exhibition, ACP 2009, 2009, s. 1-2Konferensbidrag (Refereegranskat)
    Abstract [en]

    We evaluate an Impairment Constraint Based Routing algorithm with service differentiation (ICBR-Diff) applied in WDM networks with fiber links having varying Polarization Mode Dispersion characteristics. Simulation results show high adaptability of the ICBR-Diff approach to this heterogeneous fiber scenario when compared to conventional routing schemes.

  • 13.
    Jirattigalachote, Amornrat
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Fotonik (Stängd 20120101).
    Wosinska, Lena
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Fotonik (Stängd 20120101).
    Monti, Paolo
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Fotonik (Stängd 20120101).
    Katrinis, Kostas
    Athens Information Technology.
    Tzanakaki, Anna
    Athens Information Technology.
    Impairment Constraint Based Routing (ICBR) with service differentiation in survivable WDM networks2009Ingår i: European Conference on Optical Communication, ECOC, 2009, s. 1-2Konferensbidrag (Refereegranskat)
    Abstract [en]

    We propose and evaluate a novel survivable impairment constraint based routing (ICBR) algorithm with service differentiation at the bit error rate level. Simulations show significant improvement in connection blocking compared to conventional ICBR solutions.

  • 14.
    Jirattigalachote, Amornrat
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Yamada, Yoshiyuki
    Nagoya University.
    Cavdar, Cicek
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Monti, Paolo
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Wosinska, Lena
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Hasegawa, Hiroshi
    Nagoya University.
    Sato, Ken-ichi
    Nagoya University.
    Impairment-Aware Routing and Waveband Assignment for Efficient Optical Transport Networks2012Ingår i: 2012 Optical Fiber Communication Conference and Exposition and the National Fiber Optic Engineers Conference, OFC/NFOEC 2012, 2012, s. 6192131-Konferensbidrag (Refereegranskat)
    Abstract [en]

    We demonstrate the importance of considering physical impairments in waveband-based optical networks. We propose and evaluate an Impairment-Aware waveband-routing and waveband-assignment (IA-RWBA) algorithm achieving significant improvement in both impairment satisfaction rate and total network cost.

  • 15.
    Monti, Paolo
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Fotonik.
    Wiatr, Pawel
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik.
    Jirattigalachote, Amornrat
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik.
    Wosinska, Lena
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik.
    Trading Power Savings for Blocking Probabilityin Dynamically Provisioned WDM Networks2010Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    In those networking scenarios (e.g., the stationary/mobile wireless paradigm) where limited energy storagecapabilities is a limiting factor, power efficiency has been studied extensively for a long time. In the last fewyears, the steadily growing power consumption figures of ICT [1][2] along with a recent public awareness of thepossible environmental effects, broadened the focus of the research efforts towards more power conscioussolutions also for wired networks. One promising solution going in this direction is represented by transparentwavelength division multiplexing (WDM) networks, where all-optical circuits (or lightpaths) carry the networktraffic from the source to the destination node in the optical domain, i.e. without any optical-to-electrical(O-E-O) conversion. To further improve network power efficiency, several approaches have been proposed inthe literature attempting to reduce the power consumption in transparent WDM networks [3][4]. Among them,power aware (PA) routing and wavelength assignment (RWA) algorithms are receiving a lot of attention. Onepossible solution for the PA-RWA problem is to limit the number of devices in the network that need to bepowered-on to support the lightpath requests [5]. These methods, however, have an adverse impact on the lengthof the provisioned lightpaths. In order to efficiently use as much powered-on network resources as possible, thepath length is, on average, longer than the one found with traditional (and less power efficient) shortest pathsolutions. This is in contradiction with the goal of classical RWA algorithms that tend to minimize the resourceusage (i.e., wavelengths and fibers) within the network, in order to minimize the blocking probability. Whenavailability of network resources becomes something that cannot be overlooked, a trade off needs to be assessedbetween power savings and blocking probability.In this talk, a non-conventional solution to the PA-RWA problem is presented. It is based on the intuitionthat, in some cases, relaxing the power minimization constraint can have beneficial effects on the overallnetwork performance, i.e., it can contribute to the reduction of resource fragmentation in the network and, in thisway, lower the blocking probability. The proposed algorithm leverages on a cost function that considers both thepower status of network elements (in this particular case the in-line optical amplifiers on fiber links only) and theinformation about wavelength usage. The algorithm has been tested using a Pan-European core network (i.e.,COST 239). Performance results confirm the presence of a trade-off between energy saving and blockingprobability. They also suggest that a “binary” approach using only the powered-on/powered-off informationmight not always be the best choice.

  • 16. Skorin-Kapov, Nina
    et al.
    Jirattigalachote, Amonrat
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Wosinska, Lena
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    An integer linear programming formulation for power equalization placement to limit jamming attack propagation in transparent optical networks2014Ingår i: Security and Communication Networks, ISSN 1939-0114, E-ISSN 1939-0122, Vol. 7, nr 12, s. 2463-2468Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Transparent optical networks can be highly vulnerable to various physical-layer attacks, such as high-power jamming, which can cause widespread service disruption and even service denial. The propagation of such attacks can be thwarted with wavelength-selective attenuators, referred to as power equalizers, installed at the network nodes. However, employing all nodes with power equalization functionality can lead to substantial costs. In previous work, we proposed a heuristic approach for sparse power equalization placement to limit jamming attack propagation cost-effectively. The approach provides suboptimal solutions quickly; however, it does not guarantee optimality. Because placement of such power equalization is a long-term planning problem affecting the capital expenditures of the network operator, solution quality is more critical than execution time. Thus, in this paper, we propose an integer linear programming formulation for the problem to guarantee optimality in terms of the number of power equalizers placed. Evaluation results show that our proposed integer linear programming formulation is able to solve moderately sized problems in reasonable time. These results also support the efficiency of our previously proposed heuristic by confirming its ability to find optimal solutions for the cases tested.

  • 17.
    Tzanakaki, Anna
    et al.
    Athens Information Technology.
    Georgakilas, Kostas
    Athens Information Technology.
    Katrinis, Kostas
    Athens Information Technology.
    Wosinska, Lena
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Fotonik (Stängd 20120101).
    Jirattigalachote, Amornrat
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Fotonik (Stängd 20120101).
    Monti, Paolo
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Fotonik (Stängd 20120101).
    Network performance improvement in survivable WDM networks considering physical layer constraints2009Ingår i: ICTON: 11th International Conference on Transparent Optical Networks, 2009, s. 1089-1092Konferensbidrag (Övrigt vetenskapligt)
    Abstract [en]

    This paper focuses on survivable optical networks and studies in detail the network performance improvement that can be achieved when jointly considering network resilience and physical layer constraints. The protection scheme used is path-based shared protection known as backup multiplexing. In the proposed solution routing and wavelength assignment for both primary and protection paths are jointly performed considering their physical performance. Simulations comparing the proposed solution with alternative schemes aiming at maximising sharing of protection resources have shown substantial network performance improvement in terms of blocking probability reduction when jointly addressing resilience and physical layer performance requirements.

  • 18. Velasco, L.
    et al.
    Jirattigalachote, Amornrat
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Ruiz, M.
    Monti, Paolo
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Wosinska, Lena
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Junyent, G.
    Statistical Approach for Fast Impairment-Aware Provisioning in Dynamic All-Optical Networks2012Ingår i: Journal of Optical Communications and Networking, ISSN 1943-0620, E-ISSN 1943-0639, Vol. 4, nr 2, s. 130-141Artikel i tidskrift (Refereegranskat)
    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.

  • 19.
    Velasco, Luis
    et al.
    Universitat Politècnica de Catalunya (UPC).
    Jirattigalachote, Amornrat
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Fotonik (Stängd 20120101).
    Monti, Paolo
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Fotonik (Stängd 20120101).
    Wosinska, Lena
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Fotonik (Stängd 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 networks2010Ingår i: 2010 Conference on Optical Fiber Communication, Collocated National Fiber Optic Engineers Conference, OFC/NFOEC 2010, 2010, s. 5465402-Konferensbidrag (Refereegranskat)
    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.

  • 20.
    Wosinska, Lena
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Fotonik (Stängd 20120101).
    Jirattigalachote, Amornrat
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Fotonik (Stängd 20120101).
    Monti, Paolo
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Fotonik (Stängd 20120101).
    Tzanakaki, A.
    Katrinis, K.
    Lightpath routing considering differentiated physical layer constraints in transparent WDM networks2009Ingår i: Network Architectures, Management, and Applications VII, 2009, s. 76331D-Konferensbidrag (Refereegranskat)
    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.

  • 21.
    Wosinska, Lena
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Fotonik (Stängd 20120101).
    Jirattigalachote, Amornrat
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Fotonik (Stängd 20120101).
    Monti, Paolo
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Fotonik (Stängd 20120101).
    Tzanakaki, Anna
    Athens Information Technology.
    Katrinis, Kostas
    Athens Information Technology.
    Energy efficient approach for survivable WDM optical networks2010Ingår i: 2010 12th International Conference on Transparent Optical Networks (ICTON), 2010Konferensbidrag (Övrigt vetenskapligt)
    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.

  • 22.
    Wosinska, Lena
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Fotonik (Stängd 20120101).
    Jirattigalachote, Amornrat
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Fotonik (Stängd 20120101).
    Monti, Paolo
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Fotonik (Stängd 20120101).
    Tzanakaki, Anna
    Athens Information Technology.
    Katrinis, Kostas
    Athens Information Technology.
    Lightpath routing considering differentiated physical layer constraints in transparent WDM networks2009Ingår i: 2009 Asia Communications and Photonics Conference and Exhibition, ACP 2009, 2009Konferensbidrag (Övrigt vetenskapligt)
    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.

1 - 22 av 22
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