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  • 1. Abedifar, V.
    et al.
    Furdek, Marija
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Muhammad, Ajmal
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Eshghi, M.
    Wosinska, Lena
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Routing, modulation format, spectrum and core allocation in SDM networks based on programmable filterless nodes2018Inngår i: Optics InfoBase Conference Papers, Optics Info Base, Optical Society of America, 2018Konferansepaper (Fagfellevurdert)
    Abstract [en]

    An RMSCA approach based on binary particle swarm optimization is proposed for programmable filterless SDM networks, aimed at minimizing core and spectrum usage. Nearoptimal resource consumption.

  • 2. Abedifar, Vahid
    et al.
    Furdek, Marija
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Muhammad, Ajmal
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Eshghi, Mohammad
    Wosinska, Lena
    KTH, Skolan för elektroteknik och datavetenskap (EECS).
    Routing, Modulation and Spectrum Assignment in Programmable Networks based on Optical White Boxes2018Inngår i: Journal of Optical Communications and Networking, ISSN 1943-0620, E-ISSN 1943-0639, Vol. 10, nr 9, s. 723-735Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Elastic optical networks (EONs) can help overcome the flexibility challenges imposed by emerging heterogeneous and bandwidth-intensive applications. Among the different solutions for flexible optical nodes, optical white box switches implemented by architecture on demand (AoD) have the capability to dynamically adapt their architecture and module configuration to the switching and processing requirements of the network traffic. Such adaptability allows for unprecedented flexibility in balancing the number of required nodal components in the network, spectral resource usage, and length of the established paths. To investigate these trade-offs and achieve cost-efficient network operation, we formulate the routing, modulation, and spectrum assignment (RMSA) problem in AoD-based EONs and propose three RMSA strategies aimed at optimizing a particular combination of these performance indicators. The strategies rely on a newly proposed internal node configuration matrix that models the structure of optical white box nodes in the network, thus facilitating hardware-aware routing of connection demands. The proposed strategies are evaluated in terms of the number of required modules and the related cost, spectral resource usage, and average path length. Extensive simulation results show that the proposed RMSA strategies can achieve remarkable cost savings by requiring fewer switching modules than the benchmarking approaches, at a favorable trade-off with spectrum usage and path length.

  • 3. Abeywickrama, S.
    et al.
    Furdek, Marija
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab). University of Zagreb, Faculty of Electrical Engineering and Computing, Dept. of Telecommunications, Croatia.
    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).
    Nag, A.
    Wong, E.
    Dual-homing based protection for enhanced network availability and resource efficiency2014Inngår i: Asia Communications and Photonics Conference, ACP, 2014Konferansepaper (Fagfellevurdert)
    Abstract [en]

    An approach to enhance core network survivability by utilizing dual-homing capabilities of the access network. Results reveal significant improvements in core network resource utilization and connection availability, suggesting benefits to network operators and service providers.

  • 4. Abeywickrama, S.
    et al.
    Wong, E.
    Furdek, Marija
    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).
    Energy-efficient survivability for core networks using dual-homing2015Inngår i: Asia Communications and Photonics Conference, ACPC 2015, 2015Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper studies the energy efficiency of exploiting dual-homing in access network to provide core network survivability. Simulation results show reduced number of utilized wavelengths, suggesting significant energy saving opportunities in the core network. © 2015 OSA.

  • 5. Abeywickrama, Sandu
    et al.
    Furdek, Marija
    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).
    Wong, Elaine
    Protecting core networks with dual-homing: A study on enhanced network availability, resource efficiency, and energy-savings2016Inngår i: Optics Communications, ISSN 0030-4018, E-ISSN 1873-0310, Vol. 381, s. 327-335Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Core network survivability affects the reliability performance of telecommunication networks and remains one of the most important network design considerations. This paper critically examines the benefits arising from utilizing dual-homing in the optical access networks to provide resource-efficient protection against link and node failures in the optical core segment. Four novel, heuristic-based RWA algorithms that provide dedicated path protection in networks with dual-homing are proposed and studied. These algorithms protect against different failure scenarios (i.e. single link or node failures) and are implemented with different optimization objectives (i.e., minimization of wavelength usage and path length). Results obtained through simulations and comparison with baseline architectures indicate that exploiting dual-homed architecture in the access segment can bring significant improvements in terms of core network resource usage, connection availability, and power consumption.

  • 6. Aparicio Pardo, Ramon
    et al.
    Garcia Manrubia, Belen
    Pavon Marino, Pablo
    Skorin-Kapov, Nina
    Furdek, Marija
    Balancing CapEx reduction and network stability with stable routing-virtual topology capacity adjustment (SR-VTCA)2013Inngår i: Optical Switching and Networkning Journal, ISSN 1573-4277, E-ISSN 1872-9770, Vol. 10, nr 4, s. 343-353Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper investigates the merits of the SR–VTCA (stable routing–virtual topology capacity adjustment) approach as a mechanism to find a beneficial trade-off between network stability and reduction in capital expenditures (CapEx). These are two main objectives for the entities that own the optical infrastructure, such as network operators (NOs), and those also acting as Internet service providers (ISPs). The SR–VTCA scheme is a novel approach to adapt transparent optical networks to time-varying traffic by adjusting the number of lightpaths between node pairs, while keeping the IP routing unchanged. Lightpath bundling (LB) and anycast (AS) switching are combined in SR–VTCA operation to advertise lightpath additions/removals to the IP layer as mere adjustments (increments or decrements) in the capacity, allowing to keep the IP routing stable, and thus, simplifying control plane operations. On the contrary, a fully-reconfigurable (FR) network design, where IP routing can be also modified, would increase the burden in the control plane, but at a higher CapEx reduction, since the optical infrastructure is used more efficiently. In this work, we investigate the CapEx overprovision introduced by SR–VTCA with respect to a FR scheme. In order to do this, SR–VTCA planning problem is first modeled as a MILP formulation. A heuristic procedure based on traffic domination is then proposed to solve large instances of the problem. Exhaustive experiments are conducted comparing the SR–VTCA solutions obtained by the aforementioned MILP and heuristic proposal with solutions found by other optimization methods presented in the literature to solve the FR planning problem. Finally, the results show that SR–VTCA can achieve similar results to the FR case in terms of CapEx reduction, while a huge number of IP reroutings are saved by maintaining IP stability. Thus, SR–VTCA provides an advantageous balance between CapEx overprovisioning and the control plane overhead associated with IP rerouting.

  • 7. Archambault, Emile
    et al.
    Alloune, Nabih
    Furdek, Marija
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Xu, Zhenyu
    Tremblay, Christine
    Muhammad, Ajmal
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Chen, Jiajia
    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).
    Littlewood, Paul
    Belanger, Michel
    Routing and spectrum assignment in elastic filterless optical networks2016Inngår i: IEEE/ACM Transactions on Networking, ISSN 1063-6692, E-ISSN 1558-2566, Vol. 24, nr 6, s. 3578-3592Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Elastic optical networking is considered a promising candidate to improve the spectral efficiency of optical networks. One of the most important planning challenges of elastic optical networks is the NP-hard routing and spectrum assignment (RSA) problem. In this paper, we investigate offline RSA in elastic filterless optical networks, which use a passive broadcast-and-select architecture to offer network agility. Here elastic optical network is referred to as the optical network that can adapt the channel bandwidth, data rate, and transmission format for each traffic demand in order to offer maximum throughput. In elastic filterless networks, the presence of unfiltered signals resulting from the drop-and-continue node architecture must be considered as an additional constraint in the RSA problem. In this paper, first the RSA problem in elastic filterless networks is formulated by using integer linear program (ILP) to obtain optimal solutions for small networks. Due to the problem complexity, two efficient RSA heuristics are also proposed to achieve suboptimal solutions for larger networks in reasonable time. Simulation results show that significant bandwidth savings in elastic filterless networks can be achieved compared to the fixed-grid filterless solutions. The proposed approach is further tested in multi-period traffic scenarios and combined with periodical spectrum defragmentation, leading to additional improvement in spectrum utilization of elastic filterless optical networks.

  • 8.
    da Silva, Carlos Natalino
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Yayimli, Aysegul
    Istanbul University of Technology.
    Wosinska, Lena
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Furdek, Marija
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Assessing the effects of physical layer attacks on content accessibility and latency in optical CDNs2017Inngår i: 19th International Conference on Transparent Optical Networks (ICTON), Girona, Spain: IEEE conference proceedings, 2017, artikkel-id 8024993Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Content Delivery Networks (CDNs) are a major enabler of large-scale content distribution for Internet applications. Many of these applications require high bandwidth and low latency for a satisfactory user experience, e.g., cloud gaming, augmented reality, tactile Internet and vehicular communications. Replication is one of the most prominent solutions to meet the requirements of latency-sensitive applications. However, infrastructure disruptions can greatly degrade the performance of such applications, or even cease their proper execution. The extent of degradation can be exacerbated by malicious attackers that target the critical elements of the CDN physical infrastructure to disconnect or severely degrade services.

  • 9.
    da Silva, Carlos Natalino
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Yayimli, Aysegul
    Istanbul University of Technology.
    Wosinska, Lena
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Furdek, Marija
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Content Accessibility in Optical Cloud Networks Under Targeted Link Cuts2017Inngår i: 2017 21st International Conference on Optical Network Design and Modeling, ONDM 2017 - Conference Proceedings, Institute of Electrical and Electronics Engineers (IEEE), 2017, artikkel-id 7958546Konferansepaper (Fagfellevurdert)
    Abstract [en]

    One of the key enablers of the digital society is a highly reliable information infrastructure that can ensure resiliency to a wide range of failures and attacks. In cloud networks, replicas of various content are located at geographically distributed data centers, thus inherently enhancing cloud network reliability through diversification and redundancy of user accessibility to the content. However, cloud networks rely on optical network infrastructure which can be a target of deliberate link cuts that may cause service disruption on a massive scale. This paper investigates the dependency between the extent of damage caused by link cuts and a particular replica placement solution, as a fundamental prerequisite of resilient cloud network design that lacks systematic theoretical quantification and understanding. To quantify the vulnerability of optical cloud networks based on anycast communication to targeted link cuts, we propose a new metric called Average Content Accessibility (ACA). Using this metric, we analyze the impact of the number and the placement of content replicas on cloud network resiliency and identify the best and the worst case scenarios for networks of different sizes and connectivity. We evaluate the efficiency of simultaneous and sequential targeted link cuts, the latter reassessing link criticality between subsequent cuts to maximize disruption. Comparison with Average Two-Terminal Reliability (A2TR), an existing robustness measure for unicast networks, shows great discrepancy in the vulnerability results, indicating the need for new measures tailored to anycast-based networks.

  • 10. Dobrijevic, O.
    et al.
    Natalino, Carlos
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Furdek, Marija
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Hodzic, H.
    Dzanko, M.
    Wosinska, Lena
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Another price to pay: An availability analysis for SDN virtualization with network hypervisors2018Inngår i: Proceedings of 2018 10th International Workshop on Resilient Networks Design and Modeling, RNDM 2018, Institute of Electrical and Electronics Engineers Inc. , 2018Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Communication networks are embracing the software defined networking (SDN) paradigm. Its architectural shift assumes that a remote SDN controller (SDNC) in the control plane is responsible for configuring the underlying devices of the forwarding plane. In order to support flexibility-motivated network slicing, SDN-based networks employ another entity in the control plane, a network hypervisor (NH). This paper first discusses different protection strategies for the control plane with NHs and presents the corresponding availability models, which assume possible failures of links and nodes in the forwarding plane and the control plane. An analysis of these protection alternatives is then performed so as to compare average control plane availability, average path length for the control communication that traverses NH, and infrastructure resources required to support them. Our results confirm the intuition that the NH introduction generally results in a reduction of the control plane availability, which stresses the need for appropriate protection. However, the availability achieved by each of the considered strategies is impacted differently by the node availability and the link failure probability, thus calling for a careful selection that is based on the infrastructure features.

  • 11. Dzanko, M.
    et al.
    Furdek, Marija
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Gonzalez, N. A.
    Zervas, G.
    Mikac, B.
    Simeonidou, D.
    Experimental demonstration and benefits of self-healing hard-wired and synthetic ROADMs2014Inngår i: Optical Fiber Communication Conference, OFC 2014, Optical Society of America, 2014Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Novel hard-wired and synthetic ROADM architectures with self-healing capabilities are experimentally demonstrated. Simulation results show significant improvements of availability and recovery time due to node-level restoration, with reduced mean down time and operator revenue losses.

  • 12. Dzanko, M.
    et al.
    Furdek, Marija
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Mikac, B.
    Zervas, G.
    Hugues-Salas, E.
    Simeonidou, D.
    Synthesis, resiliency and power efficiency of function programmable optical nodes2015Inngår i: Proceedings of the 13th International Conference on Telecommunications, IEEE , 2015Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Due to the large transmibion speeds and enormous volumes of transferred data, network availability performance is one of the key ibues in optical long-haul networks, comprising nodes implemented by optical crob-connects (OXCs). In this context, the design of OXCs is becoming very challenging since they have to support both legacy lower bit-rates and future highspeed super-channels by means of flexible allocation of spectral resources, and at the same time provide high availability of established connections. In this paper we study the availability and power consumption of different node architectures. We focus on the design of the new generation of synthetic programmable OXCs based on the Architecture on Demand concept which can reduce the number of utilized node components when a certain part of signals is switched at the fibre level, resulting in lower mean down time and power consumption compared to traditional node architectures.

  • 13. Dzanko, Matija
    et al.
    Furdek, Marija
    Amaya, Norberto
    Zervas, Georgios
    Mikac, Branko
    Simeonidou, Dimitra
    Self-healing optical networks with Architecture on Demand nodes2013Inngår i: 39th European Conference and Exhibition on Optical Communication, ECOC 2013, IEEE conference proceedings, 2013Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Architecture on Demand (AoD) can provide self-healing at the optical node level due to its flexibility and the ability to employ idle components for failure recovery. We study the impact of AoD on network availability at different traffic switching granularities, showing significant improvements compared to traditional static node architecture.

  • 14. Dzanko, Matija
    et al.
    Furdek, Marija
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab). University of Zagreb, Croatia.
    Zervas, Georgios
    Simeonidou, Dimitra
    Evaluating Availability of Optical Networks Based on Self-Healing Network Function Programmable ROADMs2014Inngår i: Journal of Optical Communications and Networking, ISSN 1943-0620, E-ISSN 1943-0639, Vol. 6, nr 11, s. 974-987Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Due to the large transmission speeds and enormous volume of transferred data, network reliability performance and cost-efficiency are among the key concerns in optical network design. Reducing the number of used optical components with higher failure probability within nodes represents a promising approach for achieving reliable and cost-effective optical network operation as it reduces the correlated risk of connection failures and enables reusing idle components as redundancy for failure recovery. This can result in greater overall network availability and lower loss of data and related revenue. Recently introduced synthetic network function programmable optical nodes implemented by architecture on demand (AoD) support the aforementioned approach by offering high levels of flexibility, modularity, and scalability. In AoD nodes, an optical backplane (i.e., optical switch) hosts optical components and enables arbitrary node configurations by cross-connecting attached modules. As a result, each lightpath passing through the node uses only the components necessary for fulfilling the switching and processing requirements. AoD nodes can perform switching at the wavelength and waveband granularity and also support switching of lightpaths at the fiber level by connecting an input fiber directly to the targeted output, referred to as fiber switching (FS). The latter functionality is particularly beneficial for the availability aspect, as it helps decrease the number of failure-prone components traversed by each lightpath, allowing them to be reused as redundancy. In this paper we demonstrate and evaluate self-healing capabilities of AoD nodes arising from their flexibility and ability to employ idle components for failure recovery. To improve efficiency of self-healing by increasing the number of idle components within nodes, we propose a routing algorithm which obtains a targeted portion of lightpaths switched at the fiber level, called the enforced FS (EFS) algorithm. We study the impact of AoD on network availability at different traffic switching granularities and compare it to traditional hard-wired node architecture via simulation. The results show significant improvements of availability and recovery time due to node-level restoration, with reduced network outage time and operator revenue losses. Finally, to the best of our knowledge, for the first time we experimentally demonstrate two novel hard-wired and synthetic reconfigurable optical add-drop multiplexer architectures with redundancy and all-optical self-healing capabilities.

  • 15. Dzanko, Matija
    et al.
    Mikac, Branko
    Furdek, Marija
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Dedicated path protection for optical networks based on function programmable nodes2018Inngår i: Optical Switching and Networkning Journal, ISSN 1573-4277, E-ISSN 1872-9770, Vol. 27, s. 79-87Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Due to the constantly increasing volumes and tightening reliability requirements of network traffic, survivability is one of the key concerns in optical network design. Optical "white box" nodes based on the Architecture on Demand (AoD) paradigm allow for self-healing of nodal component failures due to their architectural flexibility and the ability to employ idle components for failure recovery. By incorporating node-level survivability with network-level protection from link failures, resiliency of optical networks can be significantly improved. To this end, we propose a survivable routing algorithm for AoD-based networks called Dedicated Path Protection with Enforced Fiber Switching (DPP-EFS), which combines self-healing at the node level with dedicated path protection at the network level. The algorithm aims at improving the self-healing capabilities of the nodes by increasing the percentage of fiber switching (FS). Namely, fiber-switched lightpaths require a minimal amount of processing within the node (i.e. only signal switching), while other aspects of processing (e.g. demultiplexing, bandwidth virtualization) and the related components (i.e. demultiplexers, splitters, wavelength selective switches) remain unused and may be used as redundancy. On the other hand, lightpaths that are not eligible for FS have to be re-routed to alternative, longer paths in order to allow for FS between certain ports within the node. Therefore, the proposed algorithm pursues an advantageous trade-off between the increase of the number of idle components which can be used as redundancy at the node level and the unwanted length increase of lightpaths re-routed to render components redundant. For particular cases when DPP-EFS is not able to reduce the mean down time (MDT) in the network merely by increasing the percentage of fiber switching, we propose an algorithm for Dedicated Path Protection with Fixed Shortest Path routing and added Redundancy (DPP-FSP-RED) which adds additional spare components at strategic nodes to ensure that all connections have at least one redundant node component along their path. Simulation results show a significant reduction in MDT with minimal extra capital expenses.

  • 16.
    Furdek, Maria
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Džanko, Matija
    Wosinska, Lena
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Resilience of optical networks based on architecture on demand nodes2014Konferansepaper (Fagfellevurdert)
  • 17.
    Furdek, Maria
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Skorin-Kapov, N
    Wosinska, Lena
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Shared path protection under the risk of high power jamming2014Inngår i: 2014 19th European Conference on Networks and Optical Communications, NOC 2014, 2014, s. 23-28Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Transparent optical networks are sensitive to high-power jamming which can degrade legitimate user signals via out-of-band effects in optical fibers and amplifiers, and in-band crosstalk in optical switches. Jamming signals can be inserted in the network either deliberately as an attack, with the intention to deteriorate service, or accidentally, due to component miscon-figuration. This type of attack/failure can potentially propagate through the network causing high data and revenue losses, requiring tailored survivability approaches which take these harmful effects into consideration. Namely, conventional network survivability approaches which protect transmission in case of component faults might not provide adequate protection from jamming since the working and backup paths of a connection may both be within reach of the same jamming signal, even if they are link/node disjoint. Previously, we proposed the concept of an Attack Group (AG) of an all-optical connection (referred to as a lightpath), comprised of all other lightpaths which potentially can affect it in case they carry a high-power jamming signal. Furthermore, we developed a jamming attack-aware dedicated path protection algorithm which establishes AG-disjoint working and backup paths for each connection. Herein, we extend this work by proposing an approach for Jamming-Aware Shared Path Protection (JA-SPP) to achieve survivability in the presence of jamming signals in a more resource-efficient way. We formulate the JA-SPP problem as an Integer Linear Problem (ILP) to obtain optimal solutions for smaller network instances. Comparison with standard SPP for single component faults (without jamming-awareness) shows that JA-SPP obtains solutions which offer protection from high-power jamming, in addition to single component faults, while using the same amount of resources (in terms of link and wavelength usage) as the standard SPP.

  • 18.
    Furdek, Maria
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Skorin-Kapov, N.
    Zsigmond, S.
    Wosinska, Lena
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Vulnerabilities and security issues in optical networks2014Inngår i: Transparent Optical Networks (ICTON), 2014 16th International Conference on, IEEE conference proceedings, 2014, s. 1-4Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The paper provides a comprehensive overview of security issues in state-of-the-art optical networks. It identifies and describes the main vulnerabilities of today’s and future networks and outlines potential methods of attack which could exploit these vulnerabilities.

  • 19.
    Furdek, Marija
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Dzanko, M.
    Matanic, M.
    Boric, I.
    Wosinska, Lena
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Mikac, B.
    Multi-hour network provisioning utilizing function programmable ROADMs2015Inngår i: International Conference on Transparent Optical Networks, IEEE Computer Society, 2015, Vol. 2015, artikkel-id 7193722Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The study focuses on optimization of optical networks based on function programmable ROADMs implemented by Architecture on Demand (AoD) under a multi-hour traffic scenario. The objective is to minimize the cost and energy consumption by reducing the number of active modules inside the nodes, and to investigate the impact of network reconfiguration frequency to potential savings and lightpath availability. The results indicate that AoD nodes combined with tailored routing can reduce cost and increase availability with no traffic disruptions during transitions between periods.

  • 20.
    Furdek, Marija
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Dzanko, Matija
    Glavica, Patrik
    Wosinska, Lena
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Can Architecture on Demand nodes with self-healing capabilities improve reliability of optical networks?2014Inngår i: Optics InfoBase Conference Papers, 2014Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Architecture on Demand (AoD) nodes enable bypass of unneeded node components and support self-healing of node failures. We analyze how AoD impacts network reliability and propose a novel survivable lightpath routing strategy for AoD-based networks.

  • 21.
    Furdek, Marija
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Dzanko, Matija
    Glavica, Patrik
    Wosinska, Lena
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Mikac, Branko
    Amaya, Norberto
    Zervas, Georgios
    Simeonidou, Dimitra
    Efficient Optical Amplification in Self-Healing Synthetic ROADMs2014Inngår i: 2014 International Conference on Optical Network Design and Modeling, ONDM 2014, 2014, s. 150-155Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Optical backbone networks are carrying enormous amount of traffic and therefore, network reliability performance is extremely important to minimize the service interruption time and loss of data. Besides, increasing energy consumption of the ICT sector makes network energy efficiency gain a lot of attention. Reducing the usage of components in the network is a promising strategy to both make network more energy efficient and reliable as it allows N putting idle components into a power-saving, or sleep, mode and (ii) reusing them as redundancy for failure recovery. The new generation of synthetic reconfigurable optical add-drop multiplexers (ROADMs) implemented by Architecture on Demand (AoD) supports the above functionalities by offering unprecedented flexibility and self-healing capabilities. In AoD nodes, components are interconnected via high-port-count optical switch serving as optical backplane, and each connection uses only the components necessary to fulfill the switching and processing requirements. In this paper, we aim at improving optical network availability and reducing power consumption by minimizing the number of optical amplifiers used in AoD nodes. To this end, a decision on the necessity of signal amplification is made for every connection according to the power level at each node. Unnecessary amplifiers are bypassed and put into sleep mode, decreasing the overall power consumption of the network This also reduces the associated risk of connection failure, while reuse of idle amplifiers for failure recovery further improves connection availability. To gain greater insight into the benefits of our approach, we analyze the performance of the NSF and EON network deploying AoD nodes with different optical backplane implementations, i.e. 3D MEMS and piezoelectric optical switch (POS), and compare them with networks deploying hard-wired ROADMs. Simulation results show that deployment of synthetic AoD nodes with POS as optical backplane can reduce the network mean down time and power consumption of EDFAs by up to 63% and 38%, respectively, on average over all test cases.

  • 22.
    Furdek, Marija
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Džanko, Matija
    Skorin-Kapov, Nina
    Wosinska, Lena
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Planning of optical networks based on programmable ROADMs2015Inngår i: Asia Communications and Photonics Conference, ACPC 2015, 2015Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Synthetic programmable ROADMs enable great architectural flexibility and offer remarkable opportunities for network optimization. This paper summarizes the benefits and network planning challenges introduced by this technology and outlines optimization approaches to utilize its advantages. © 2015 OSA.

  • 23.
    Furdek, Marija
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Muhammad, Ajmal
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Skorin-Kapov, N.
    Survivable manycast, anycast and replica placement in optical inter-datacenter networks2017Inngår i: 2017 19th International Conference on Transparent Optical Networks (ICTON), IEEE Computer Society, 2017, artikkel-id 8024994Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Inter-datacenter networks need to support datacenter communication with the end-users, as well as content replication and synchronization between datacenters in a reliable manner. This paper presents a survivable manycast, anycast and replica placement strategy for optical inter-datacenter networks resulting in reduced overall network resource consumption.

  • 24.
    Furdek, Marija
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Muhammad, Ajmal
    KTH, Skolan för informations- och kommunikationsteknik (ICT).
    Zervas, Georgios
    Alloune, Nabih
    Tremblay, Christine
    Wosinska, Lena
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Programmable Filterless Network Architecture Based on Optical White Boxes2016Inngår i: 20TH INTERNATIONAL CONFERENCE ON OPTICAL NETWORK DESIGN AND MODELING (ONDM 2016), IEEE conference proceedings, 2016Konferansepaper (Fagfellevurdert)
    Abstract [en]

    We propose and evaluate a novel architecture enabling high-capacity, resource efficient and agile elastic optical networks. It is based on sliceable bandwidth-variable transponders and optical white box switches which route optical signals without filtering them. Instead of using active filtering components, each node is equipped with an optical white box based on a programmable optical switch that serves as an optical backplane. It provides interconnections between input/output ports and passive splitters and couplers. Due to signal broadcast and the absence of filtering (so-called drop-and-waste transmission), some of the signals appear on unintended links which can lead to an overhead in spectrum usage. To address this issue, we formulate the problem of signal routing, modulation format and spectrum assignment in programmable filterless networks based on optical white boxes as an integer linear program (ILP) with the objective to minimize the total spectrum usage. Simulation results indicate that our proposed solution obtains a beneficial tradeoff between component usage and spectrum consumption, using a drastically lower number of active switching elements than the conventional networks based on hard-wired reconfigurable add/drop multiplexers, and lowering the maximum used frequency slot by up to 48% compared to existing passive filterless networks.

  • 25.
    Furdek, Marija
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Muhammad, Ajmal
    KTH, Skolan för informations- och kommunikationsteknik (ICT).
    Zervas, Georgios
    Tremblay, Christine
    Wosinska, Lena
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Performance Evaluation of Programmable Filterless Networks Implemented by Optical White Boxes2016Inngår i: 2016 18TH INTERNATIONAL CONFERENCE ON TRANSPARENT OPTICAL NETWORKS (ICTON), IEEE, 2016Konferansepaper (Fagfellevurdert)
    Abstract [en]

    To support the immense traffic growth and enable scalable on-demand provisioning of service requests, optical networks must deliver great agility and reconfigurability in a cost-and resource-efficient manner. The progress in elastic coherent transmission [1] has enabled simplifications in the optical network architecture by, for example, replacing the costly wavelength switches in the add/drop part of colorless reconfigurable add/drop multiplexers (ROADMs) with passive couplers. The concept of passive filterless networking further proposes the elimination of wavelength switching in the transport function as well. It is based on completely passive interconnections realized by passive splitters and combiners, essentially forming fiber trees spanning the network nodes [2]. In such networks, transmission follows the Drop&Waste ( or Drop&Continue) scheme where each signal is broadcasted to all branches downstream of the source node in a tree, while a copy of signal continues to propagate downstream of the destination node [3]. Thus, the simplification of the nodal architecture comes at the expense of increased spectrum usage due to the presence of unfiltered signals. Moreover, the broadcasting of signals to inadvertent nodes raises confidentiality issues. An additional drawback stems from the inability of the passive, fixed interconnection of nodes to allow for topology reconfiguration. The optical white boxes, or programmable optical switches (also referred to as architecture-on-demand) can provide unparalleled switching and architectural flexibility [4]. Unlike in conventional ROADMs, optical modules (e.g., passive couplers, amplifiers or WSSs) inside an optical white box are not interconnected in a hard-wired manner, but are selected on demand by a reconfigurable optical backplane (OB), implemented by, e.g., a piezoelectric switch or 3D MEMs. An arbitrary nodal architecture can be configured by setting up the interconnections of the OB as per traffic requirements, and swiftly reconfigured to accommodate changing traffic demands, scale capacity, and ease migration and upgrade. Combining the agile filterless transmission with flexible optical white boxes into a programmable filterless network architecture, recently proposed in [5], integrates the agility of filterless operation with the high flexibility enabled by white boxes. The nodes in a programmable filterless network are equipped with a programmable OB hosting only passive couplers to route the connections. The preliminary study of routing, modulation format and spectrum assignment (RMSA) in programmable filterless networks aimed at spectrum usage minimization [5] shows that they are capable of reducing the amount of unfiltered signals compared to passive filterless networks and can significantly decrease spectrum usage. Due to the moderately-sized switches deployed for the OB, this architecture also offers the potential of diminishing the nodal costs compared to the conventional ROADM-based networks. In addition, when striving to minimize the spectrum usage, connections tend to get routed over fewer splitters as they are the cause of broadcasted, unfiltered signals. This may lead to a decrease in the total number and degree of passive couplers traversed by connections, which can reduce the signal losses and lower the amplification requirements. This talk will outline the operational principles of programmable filterless network architecture and their benefits in terms of spectrum and component usage. We will also present possible technological and optimization approaches to further enhance the performance of white box based filterless networks and the related preliminary results.

  • 26.
    Furdek, Marija
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Natalino, Carlos
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Schiano, Marco
    Telecom Italia, Turin, Italy..
    Di Giglio, Andrea
    Telecom Italia, Turin, Italy..
    Experiment-based detection of service disruption attacks in optical networks using data analytics and unsupervised learning2019Inngår i: METRO AND DATA CENTER OPTICAL NETWORKS AND SHORT-REACH LINKS II / [ed] Srivastava, AK Glick, M Akasaka, Y, SPIE-INT SOC OPTICAL ENGINEERING , 2019, artikkel-id 109460DKonferansepaper (Fagfellevurdert)
    Abstract [en]

    The paper addresses the detection of malicious attacks targeting service disruption at the optical layer as a key prerequisite for fast and effective attack response and network recovery. We experimentally demonstrate the effects of signal insertion attacks with varying intensity in a real-life scenario. By applying data analytics tools, we analyze the properties of the obtained dataset to determine how the relationships among different optical performance monitoring (OPM) parameters of the signal change in the presence of an attack as opposed to the normal operating conditions. In addition, we evaluate the performance of an unsupervised learning technique, i.e., a clustering algorithm for anomaly detection, which can detect attacks as anomalies without prior knowledge of the attacks. We demonstrate the potential and the challenges of unsupervised learning for attack detection, propose guidelines for attack signature identification needed for the detection of the considered attack methods, and discuss remaining challenges related to optical network security.

  • 27. Furdek, Marija
    et al.
    Skorin-Kapov, Nina
    Attack-survivable routing and wavelength assignment for high-power jamming2013Inngår i: 2013 17TH INTERNATIONAL CONFERENCE ON OPTICAL NETWORKING DESIGN AND MODELING (ONDM), IEEE conference proceedings, 2013Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Transparent optical networks (TONs) are vulnerable to high-power jamming attacks aimed at service disruption by exploiting the inherent characteristics of optical fibers, amplifiers and switches. In this type of attack, a high-power jamming signal is injected in the network to degrade the quality of legitimate user signals. Conventional survivability approaches which protect transmission in occurrences of component faults might not provide protection from attacks as the working and the backup path of a connection might both be within the reach of the attacking signal. In this paper, we propose a novel concept of identifying a so-called Attack Group (AG) of each lightpath and develop a dedicated path protection approach which ensures that the primary and the backup path of each connection be attack group disjoint, i.e., not within the reach of a same potential attacker. Furthermore, the proposed attack-survivable routing and wavelength assignment is aimed at reducing the maximum potential damage from these attacks, measured by an objective criterion called Attack Radius (AR), as well as minimizing the number of used wavelengths to be resource-effective. In comparison with generic dedicated path protection without attack awareness, the proposed approach shows a significant enhancement of network survivability in the presence of attacks at a small trade-off of increased wavelength usage.

  • 28. Furdek, Marija
    et al.
    Skorin-Kapov, Nina
    Grbac, Masa
    Attack-aware wavelength assignment for localization of in-band crosstalk attack propagation2010Inngår i: Journal of Optical Communications and Networking, ISSN 1943-0620, E-ISSN 1943-0639, Vol. 2, nr 11, s. 1000-1009Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The high data rates employed by wavelength division multiplexing transparent optical networks make them most suitable for today's growing network traffic demands. However, their transparency imposes several vulnerabilities in network security, enabling malicious signals to propagate from the source to other parts of the network without losing their attacking capabilities. Furthermore, detecting, locating the source, and localizing the spreading of such physical-layer attacks is more difficult since monitoring must be performed in the optical domain. While most failure and attack management approaches focus on network recovery after a fault or an attack has already occurred, we suggest a novel safety strategy, proposing a prevention-oriented method to aid attack localization and source identification in the planning phase. In this paper, we propose attack-aware wavelength assignment that minimizes the worst-case potential propagation of in-band crosstalk jamming attacks. We define a new objective criterion for the wavelength assignment (WA) problem, called the propagating crosstalk attack radius (P-CAR), and develop heuristic algorithms aimed at minimizing both the P-CAR and the number of wavelengths used. Our aim is to achieve better protection, but without the need for extra resources. We compare our algorithms with existing WA approaches, illustrating their benefits with respect to transparent optical networks' security, as well as the associated wavelength utilization.

  • 29.
    Furdek, Marija
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Skorin-Kapov, Nina
    Wosinska, Lena
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Attack-aware dedicated path protection in optical networks2016Inngår i: Journal of Lightwave Technology, ISSN 0733-8724, E-ISSN 1558-2213, Vol. 34, nr 4, s. 1050-1061Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Due to the high data rates in optical networks,physical-layer attacks targeting service degradation, such as powerjamming, can potentially lead to large data and revenue losses.Conventional network survivability approaches which establishlink-disjoint working and backup paths to protect from componentfaults may not provide adequate protection for such attacks.Namely, the working and the backup paths, although link-disjoint,might both be affected by a single attack scenario due to specificattack propagation characteristics. To enhance the existing survivabilityapproaches, we utilize the concept of an attack group(AG) which incorporates these characteristics to identify connectionswhich can simultaneously be affected by a single attack. Weapply this concept to dedicated path protection (DPP) and developattack-aware DPP (AA-DPP) approaches which aim to establishAG-disjoint primary and backup paths in a cost-effective manner.We provide a two-step ILP formulation for the routing and wavelengthassignment of the working and backup paths, as well as aheuristic for larger problem instances. Numerical results indicatethat the proposed approaches provide dedicated path protectionschemes with enhanced attack protection without using more resources(i.e., wavelengths, average path lengths) than standardDPPmethods.

  • 30.
    Furdek, Marija
    et al.
    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).
    Goscien, Roza
    Manousakis, Konstantinos
    Aibin, Michal
    Walkowiak, Krzysztof
    Ristov, Sashko
    Gushev, Marjan
    Marzo, Jose L.
    An overview of security challenges in communication networks2016Inngår i: PROCEEDINGS OF 2016 8TH INTERNATIONAL WORKSHOP ON RESILIENT NETWORKS DESIGN AND MODELING (RNDM), IEEE, 2016, s. 43-50Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The ongoing transition towards a networked society requires reliable and secure network infrastructure and services. As networks evolve from simple point to point systems towards complex, software-defined, ultra-high capacity and reach, and distributed cloud environments, new security challenges emerge. The EU-funded RECODIS project aims at coordinating and fostering research collaboration in Europe on disaster resiliency in communication networks. One of the disaster types, considered by RECODIS Working Group (WG) 4, are deliberate human-made attacks aimed at gaining unauthorized access to the network or disrupting the service. In order to develop methods for increasing network security in the presence of attacks, it is crucial to first identify the security vulnerabilities and attack methods that exploit them, as well as the capabilities and shortcomings of existing security schemes. To this end, the members of RECODIS WG4 performed a comprehensive overview of attack methods and security approaches from the literature. This overview covers the security vulnerabilities inherent to the underlying physical layer, the implications of software-defined networking to security, and security challenges in cloud networks spanning geographically distributed data centers.

  • 31. Goscien, R.
    et al.
    Natalino, Carlos
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Wosinska, Lena
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Furdek, Marija
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Impact of high-power jamming attacks on SDM networks2018Inngår i: 22nd Conference on Optical Network Design and Modelling, ONDM 2018 - Proceedings, Institute of Electrical and Electronics Engineers (IEEE), 2018, s. 77-81Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Space Division Multiplexing (SDM) is a promising solution to provide ultra-high capacity optical network infrastructure for rapidly increasing traffic demands. Such network infrastructure can be a target of deliberate attacks that aim at disrupting a large number of vital services. This paper assesses the effects of high-power jamming attacks in SDM optical networks utilizing Multi-Core Fibers (MCFs), where the disruptive effect of the inserted jamming signals may spread among multiple cores due to increased Inter-Core CrossTalk (ICo-XT). We first assess the jamming-induced reduction of the signal reach for different bit rates and modulation formats. The obtained reach limitations are then used to derive the maximal traffic disruption at the network level. Results indicate that connections provisioned satisfying the normal operating conditions are highly vulnerable to these attacks, potentially leading to huge data losses at the network level.

  • 32. Grigoreva, Elena
    et al.
    Wong, Elaine
    Furdek, Marija
    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).
    Mas Machuca, Carmen
    Energy Consumption and Reliability Performance of Survivable Passive Optical Converged Networks: Public ITS Case Study2017Inngår i: Journal of Optical Communications and Networking, ISSN 1943-0620, E-ISSN 1943-0639, Vol. 9, nr 4, s. C98-C107Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Access networks are evolving fast by increasing their capacity and coverage area, coping with a larger number of users and variety of terminals. Operators aim at keeping high network performance and quality of service but limiting their capital and operational expenditures by, e.g., minimizing investments and energy consumption using power saving at the network components. To address these challenges this paper evaluates the energy consumption, connection availability, and failure detection time of three protection schemes applicable for converged access networks: disjoint fiber protection, energy-efficient disjoint fiber protection, and reflective disjoint fiber protection. The schemes are assessed by a case study considering a public intelligent transport system (ITS). The studied ITS deploys a dedicated short-range communications radio access network connected to the service server through a protected passive access network. Comparison with unprotected architecture shows that reflective disjoint fiber protection offers low energy consumption and high connection availability, while it significantly reduces the failure detection time and, hence, the connection interruption time.

  • 33. Izquierdo-Zaragoza, J. -L
    et al.
    Furdek, Marija
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Nag, A.
    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).
    Pavon-Marino, P.
    On the dimensioning of survivable optical metro/core networks with dual-homed access2016Inngår i: IEEE International Conference on High Performance Switching and Routing, HPSR, IEEE Computer Society, 2016, artikkel-id 7483089Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Long-reach passive optical networks (LR-PONs) are able to effectively support the growing demand of traffic originating from residential and business customers. Failures of metro/core (M/C) nodes serving the traffic to/from the access networks covered by LR-PONs, may potentially affect hundreds or thousands of customers. One way of guaranteeing 100% survivability from single-node failures is to apply dual-homing, where each LR-PON is connected to two M/C nodes, and combine it with node-disjoint dedicated-path protection (DPP). In this paper, we present a new approach to provide network survivability against single M/C node failures. Instead of applying dedicated path protection (DPP) strategy, which can require huge amount of extra resources, we combine an unprotected network design with a dynamic multilayer restoration algorithm. Our aim is to determine a suitable amount of resource overbuild (in terms of extra transponders) needed to provide average connection availability close to that guaranteed by DPP. Preliminary results show that dimensioning for the worst-case scenario among a set of predefined M/C node failures, i.e., the one disrupting the highest number of connections, yields to a cost-effective strategy requiring up to 35% less transponders than DPP, while offering the same average connection availability.

  • 34. Licciardello, M.
    et al.
    Fiorani, Matteo
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Furdek, Marija
    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).
    Raffaelli, C.
    Wosinska, Lena
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Performance evaluation of abstraction models for orchestration of distributed data center networks2017Inngår i: 2017 19th International Conference on Transparent Optical Networks (ICTON), IEEE Computer Society, 2017, artikkel-id 8025184Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Cloud computing is increasingly based on geographically distributed data centers interconnected by high performance networks. Application of Software Defined Networking (SDN) is studied as an emerging solution to support dynamic network resource management for distributed data centers (DCs) jointly with extensive use of Network Function Virtualization (NFV). SDN/NFV operation takes advantage of orchestration of network control functions according to distributed DCs communication needs. Orchestration relies on a set of logical information related to the underlying infrastructure, called abstraction, which offers different levels of visibility of available resources, depending on the abstraction strategy adopted.

  • 35. Machuca, C. M.
    et al.
    Wong, E.
    Furdek, Marija
    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).
    Energy consumption and reliability performance of survivable hybrid passive optical converged networks2014Inngår i: Optics InfoBase Conference Papers, OSA - The Optical Society , 2014Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The paper provides the methodology to evaluate the tradeoff between the consumed energy, the connection availability and the connection interruption time for survivable hybrid passive optical converged networks in different deployment areas.

  • 36. Mas Machuca, Carmen
    et al.
    Wong, Elaine
    Furdek, Marija
    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).
    Energy consumption and reliability performance of survivable hybrid passive optical converged network2016Inngår i: Optics InfoBase Conference Papers, OSA - The Optical Society , 2016Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The paper provides the methodology to evaluate the tradeoff between the consumed energy, the connection availability and the connection interruption time for survivable hybrid passive optical converged networks in different deployment areas.

  • 37. Mikac, B.
    et al.
    Dzanko, M.
    Furdek, Marija
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab). University of Zagreb, Croatia .
    Hugues-Salas, E.
    Zervas, G.
    Simeonidou, D.
    Availability aspects of self-healing optical nodes designed by architecture on demand2014Inngår i: International Conference on Transparent Optical Networks, 2014Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The paper demonstrates the concept of optical networks with nodes implemented by the architecture on demand (AoD) and proposes a procedure for finding out possible benefits of AoD application, related to node and network availability. AoD node structure enables efficient failure management by creating a set of redundant components, which can be used for self-healing of optical nodes after failure. Availability evaluation procedure is based on Monte Carlo simulation of times to failure/repair of network components. A case study network with AoD nodes is compared to the network with hard-wired nodes in regard to availability performance, and results are presented.

  • 38. Muhammad, A.
    et al.
    Furdek, Marija
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab). University of Zagreb, Croatia.
    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).
    Forchheimer, R.
    An optimization model for dynamic bulk provisioning in elastic optical networks2014Inngår i: Asia Communications and Photonics Conference, ACPC 2014, 2014Konferansepaper (Fagfellevurdert)
    Abstract [en]

    We investigate benefits of setup-delay tolerance in elastic optical networks and propose an optimization model for dynamic and concurrent connection provisioning. Simulation shows that the proposed strategy offers significant improvement of the network blocking performance.

  • 39. Muhammad, Ajmal
    et al.
    Furdek, Maria
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab). University of Zagreb, Croatia .
    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).
    Forchheimer, Robert
    Dynamic provisioning utilizing redundant modules in elastic optical networks based on architecture on demand nodes2014Inngår i: Optical Communication (ECOC), 2014 European Conference on, 2014, s. 1-3Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Survivable synthetic ROADMs are equipped with redundant switching modules to support failure recovery. The paper proposes a dynamic connection provisioning strategy which exploits these idle redundant modules to provision regular traffic resulting in a substantial improvement in the blocking performance.

  • 40.
    Muhammad, Ajmal
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Furdek, Marija
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Zervas, G.
    Wosinska, Lena
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Filterless networks based on optical white boxes and SDM2016Inngår i: ECOC 2016 42th European Conference on Optical Communication Proceedings, September 18 - 22, 2016, Düsseldorf, Germany, Institute of Electrical and Electronics Engineers (IEEE), 2016, s. 893-895Konferansepaper (Fagfellevurdert)
    Abstract [en]

    We propose an agile and programmable multicore fiber (MCF)-based filterless network that exploits the flexibility offered by spatial domain multiplexing and programmable optical switches to eliminate the waste of spectrum due to unfiltered transmission.

  • 41.
    Muhammad, Ajmal
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Skorin-Kapov, Nina
    Furdek, Marija
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Manycast, Anycast, and Replica Placement in Optical Inter-Datacenter Networks2017Inngår i: Journal of Optical Communications and Networking, ISSN 1943-0620, E-ISSN 1943-0639, Vol. 9, nr 12, s. 1161-1171Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The expanding adoption of cloud-based services in recent years puts stringent requirements on datacenters (DCs) and their interconnection networks. Optical inter-datacenter networks represent the only viable option for satisfying the huge bandwidth required to replicate and update content for cloud-based services across geographically dispersed datacenters. In addition to content replication and synchronization, optical inter-datacenter networks must also support communication between datacenters and end-users. The resulting new traffic patterns and the enormous traffic volumes call for new capacityefficient approaches for inter-datacenter network designs that incorporate both transport and datacenter resource planning. This paper introduces an integrated approach to optimally place content replicas across DCs by concurrently solving the routing and wavelength assignment (RWA) problem for both inter-DC content replication and synchronization traffic following the manycast routing paradigm, and end-user-driven user-to-DC communication following the anycast routing paradigm, with the objective to reduce the overall network capacity usage. To attain this goal, the manycast, anycast, and replica placement (MARP) problem is formulated as an integer linear program to find optimal solutions for smaller problem instances. Due to the problem complexity, a scalable and efficient heuristic algorithm is developed to solve larger network scenarios. Simulation results demonstrate that the proposed integrated MARP strategy can significantly reduce the network capacity usage when compared to the benchmarking replica placement and RWA schemes aimed at minimizing the resources consumed by either of the two types of traffic independently.

  • 42.
    Munjal, Rashmi
    et al.
    Auckland Univ Technol, Sch Engn Comp & Math Sci, Auckland, New Zealand..
    Liu, William
    Auckland Univ Technol, Sch Engn Comp & Math Sci, Auckland, New Zealand..
    Li, Xue Jun
    Auckland Univ Technol, Sch Engn Comp & Math Sci, Auckland, New Zealand..
    Gutierrez, Jairo
    Auckland Univ Technol, Sch Engn Comp & Math Sci, Auckland, New Zealand..
    Furdek, Marija
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    Sustainable Massive Data Dissemination by Using Software Defined Connectivity Approach2017Inngår i: 2017 27th International Telecommunication Networks and Applications Conference, ITNAC 2017, Institute of Electrical and Electronics Engineers (IEEE), 2017, s. 454-459Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The traditional world has transformed into a digital society where almost anything can be accessed from anywhere. However, this digital society is responsible for an explosive growth of high-volume, high-velocity and high-variety information assets, with high demand for "Big Data". A Software Defined Connectivity (SDC) is an emerging paradigm, which promises to simplify network management, to provide the flexibility to program the network through centralized network control by providing new abstractions in networking with all real objects for reliable and energy efficient data transmission. In a SDC architecture, the connectivity controller decides the forwarding rules as per the demands and objectives of users when transmitting information to the intended destination through either internet or existing transport infrastructure. The key idea is to have flexibility in the network to utilize existing transport infrastructure to shift traffic from the internet towards public bus services as per the current users requirements. The numerical studies reported in this paper confirm that this new opportunity helps to achieve efficient resource utilization and high performance with significant savings of energy.

  • 43. Nag, Avishek
    et al.
    Furdek, Marija
    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.
    Ruffini, Marco
    Exploiting Dual Homing in Access Networks to Improve Resiliency in Core Networks2016Inngår i: Journal of Optical Communications and Networking, ISSN 1943-0620, E-ISSN 1943-0639, Vol. 8, nr 11, s. 854-862Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We propose a network architecture consisting of long-reach passive optical network-based access and a transparent optical core network. The end users are connected to the remote node or the local exchange (LE) through an optical distribution network, and the remote node is connected by disjoint feeder fiber links to central offices located in two distinct metro/ core (MC) nodes. This method of connecting a single remote node to two geographically separate MC nodes for dedicated protection in case of feeder fiber failure is referred to as dual homing. In this work, we explore the benefits of dual homing in the access in simultaneously providing better resilience and load balancing in the core network considering connections between LEs. While looking into the benefits of dual homing in terms of network resiliency, we also explore whether the path redundancies added by dual homing play a role in providing efficient distribution of load across the core network and thereby reduce the cost of provisioning capacity in terms of number of lightpaths, transponders, etc. Dual homing at both the source and destination LEs offers more options for paths between LEs through the core network. Our results show that dual-homed access proves to be advantageous over single-homed access in terms of enhancing both core network resiliency and facilitating better load balancing.

  • 44.
    Natalino, Carlos
    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).
    Franca, Luis
    Furdek, Marija
    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).
    Frances, Carlos R. L.
    Costa, Joao C. W. A.
    Dimensioning Optical Clouds with Shared-Path Shared-Computing (SPSC) Protection2015Inngår i: High Performance Switching and Routing (HPSR), 2015 IEEE 16th International Conference on, IEEE conference proceedings, 2015Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Service relocation represents a promising strategy to provide flexible and resource efficient resiliency from link failures in the optical cloud environment. However, when a failure affects a node hosting a datacenter (DC), service relocation from the affected DC is not possible. One alternative to protect against DC failures relies on using design strategies that duplicate the IT (i.e., storage and processing) resources in a backup DC at the expense of increasing resource overbuild (i.e., cost) of the network. This work proposes a dimensioning strategy based on the shared-path shared-computing (SPSC) concept able to protect against any single link, server, or DC failure scenario with minimal resource overbuild for the network and IT infrastructures. SPSC is based on the intuition that only storage units need complete replication in backup DC, while processing units can be instantiated only after the occurrence of a failure, leaving the design strategy some leeway to minimize their number. As result, the proposed SPSC design shows a considerable reduction in the amount of backup resources when compared to the dedicated protection strategies.

  • 45.
    Natalino, Carlos
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Schiano, M.
    Di Giglio, A.
    Wosinska, Lena
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Furdek, Marija
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Field Demonstration of Machine-Learning-Aided Detection and Identification of Jamming Attacks in Optical Networks2018Inngår i: European Conference on Optical Communication, ECOC, Institute of Electrical and Electronics Engineers Inc. , 2018Konferansepaper (Fagfellevurdert)
    Abstract [en]

    We develop a machine-learning-aided framework for detection and identification of optical network jamming signal attacks of varying intensities. Trained with data gathered in our field-deployed experimental setup, the approach achieves 93% accuracy on average over the considered attack scenarios.

  • 46.
    Natalino, Carlos
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Sousa, A. D.
    Wosinska, Lena
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Furdek, Marija
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    On the trade-offs between user-to-replica distance and CDN robustness to link cut attacks2018Inngår i: Proceedings of 2018 10th International Workshop on Resilient Networks Design and Modeling, RNDM 2018, Institute of Electrical and Electronics Engineers Inc. , 2018Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Content Delivery Networks (CDNs) are a key enabler for geographically-distributed content delivery with high throughput and low latency. As CDNs utilize the underlying optical core network infrastructure, they inherit its vulnerability to targeted link cut attacks which can cause severe service degradation. One of the fundamental problems in CDN configuration is deciding on the placement of content replicas across the underlying network of data centers, which should obtain balance among multiple, often conflicting performance criteria. This paper investigates the implications of minimizing the average distance between the users and the content replicas on the CDN robustness to targeted link cuts.To this end, we compute Pareto-optimal replica placement solutions with minimal user-to-replica distance and maximal robustness to link cut attacks of the highest damaging potential. k-best replica placement solutions in terms of the user-to-replica distance are calculated by formulating the problem as an Integer Linear Programming (ILP) exact method. For each replica placement solution, the worst case link cut attack scenario is identified by defining the Critical Link Set Detection (CLSD) problem. CLSD returns the link set whose cutting disconnects the maximal number of nodes from the content. We develop an ILP model for the CLSD and evaluate the robustness of the resulting CDN attack scenario in terms of mean content accessibility. The approach is evaluated through extensive simulations on real-world reference topologies, indicating that it is possible to improve the robustness to link cuts at the expense of small user-to-replica distance penalties. Moreover, the improvement of robustness is more significant for topologies with smaller average node degree and when cuts involve a larger number of links.

  • 47.
    Natalino, Carlos
    et al.
    KTH.
    Yayimli, A.
    Wosinska, Lena
    KTH, Skolan för industriell teknik och management (ITM), Lärande.
    Furdek, Marija
    KTH.
    Link addition framework for optical CDNs robust to targeted link cut attacks2017Inngår i: Proceedings of 2017 9th International Workshop on Resilient Networks Design and Modeling, RNDM 2017, Institute of Electrical and Electronics Engineers Inc. , 2017Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Content Delivery Networks (CDNs) are a key en-abler for the distribution of large amounts of data with high capacity and low latency. For instance, content streaming companies extensively use geographical distribution and replication to meet the ever-growing demand for media. Optical networks are the only future-proof technology available that meets the reach and capacity requirements of CDNs. However, the robustness of optical networks becomes a point of concern, as they can be a target of deliberate link cuts that can severely degrade network connectivity and cause large-scale service disruption. To mitigate the vulnerabilities, actions can be taken in the optical and/or cloud infrastructures. The replication of content across geographically diverse data centers results in an intrinsic increase of content accessibility. At the network infrastructure level, robustness to attacks can be enhanced by increasing the topology connectivity through link addition. This work focuses on the latter approach and its effectiveness in increasing content accessibility in the presence of deliberate link cuts. The paper proposes a framework for evaluation and enhancement of content accessibility in CDNs by sparse link addition. First, a content accessibility measure called μ-ACA is introduced to gauge the content accessibility of a given network topology under a set of link cut attack scenarios. Based on this measure, a new link addition strategy is defined aimed at maximizing the content accessibility for a given number of extra links. Simulation results on real-world reference topologies show that the proposed strategy can significantly improve content accessibility by adding a very limited number of optical fiber links.

  • 48.
    Natalino, Carlos
    et al.
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Yayimli, Aysegul
    Valparaiso Univ, Comp & Informat Sci Dept, Indiana, PA USA..
    Wosinska, Lena
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Furdek, Marija
    KTH, Skolan för elektroteknik och datavetenskap (EECS), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Infrastructure upgrade framework for Content Delivery Networks robust to targeted attacks2019Inngår i: Optical Switching and Networkning Journal, ISSN 1573-4277, E-ISSN 1872-9770, Vol. 31, s. 202-210Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Content Delivery Networks (CDNs) are crucial for enabling delivery of services that require high capacity and low latency, primarily through geographically-diverse content replication. Optical networks are the only available future-proof technology that meets the reach and capacity requirements of CDNs. However, the underlying physical network infrastructure is vulnerable to various security threats, and the increasing importance of CDNs in supporting vital services intensifies the concerns related to their robustness. Malicious attackers can target critical network elements, thus severely degrading network connectivity and causing large-scale service disruptions. One way in which network operators and cloud computing providers can increase the robustness against malicious attacks is by changing the topological properties of the network through infrastructure upgrades. This work proposes a framework for CDN infrastructure upgrade that performs sparse link and replica addition with the objective of maximizing the content accessibility under targeted link cut attacks. The framework is based on a newly defined content accessibility metric denoted as mu-ACA which allows the network operator to gauge the CDN robustness over a range of attacks with varying intensity. Two heuristics, namely Content-Accessibility Aware Link Addition Heuristic (CAA-LAH), and Content-Accessibility-Aware Replica Addition Heuristic (CAA-RAH) are developed to perform strategic link and replica placement, respectively, and hamper attackers from disconnecting users from the content even in severe attack scenarios. Extensive experiments on real-world reference network topologies show that the proposed framework effectively increases the CDN robustness by adding a few links or replicas to the network.

  • 49.
    Natalino, Carlos
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Yayimli, Aysegul
    Wosinska, Lena
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Furdek, Marija
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Link Addition Framework for Optical CDNs Robust to Targeted Link Cut Attacks2017Bok (Annet vitenskapelig)
    Abstract [en]

    Content Delivery Networks (CDNs) are a key enabler for the distribution of large amounts of data with high capacity and low latency. For instance, content streaming companies extensively use geographical distribution and replication to meet the ever-growing demand for media. Optical networks are the only future-proof technology available that meets the reach and capacity requirements of CDNs. However, the robustness of optical networks becomes a point of concern, as they can be a target of deliberate link cuts that can severely degrade network connectivity and cause large-scale service disruption. To mitigate the vulnerabilities, actions can be taken in the optical and/or cloud infrastructures. The replication of content across geographically diverse data centers results in an intrinsic increase of content accessibility. At the network infrastructure level, robustness to attacks can be enhanced by increasing the topology connectivity through link addition. This work focuses on the latter approach and its effectiveness in increasing content accessibility in the presence of deliberate link cuts. The paper proposes a framework for evaluation and enhancement of content accessibility in CDNs by sparse link addition. First, a content accessibility measure called mu-ACA is introduced to gauge the content accessibility of a given network topology under a set of link cut attack scenarios. Based on this measure, a new link addition strategy is defined aimed at maximizing the content accessibility for a given number of extra links. Simulation results on real-world reference topologies show that the proposed strategy can significantly improve content accessibility by adding a very limited number of optical fiber links.

  • 50. Nooruzzaman, Md
    et al.
    Alloune, Nabih
    Nabet, Feriel
    Archambault, Emile
    Tremblay, Christine
    Furdek, Marija
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Chen, Jiajia
    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).
    Littlewood, Paul
    Bélanger, Michel
    Agile filterless submarine networks2016Konferansepaper (Fagfellevurdert)
12 1 - 50 of 78
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