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  • 1.
    Ahmed, Jawwad
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Dynamic Resource Provisioning and Survivability Strategies in Optical Networks2013Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Optical networks based on Wavelength Division Multiplexing (WDM) technology show many clear benefits in terms of high capacity, flexibility and low power consumption. All these benefits make WDM networks the preferred choice for today’s and future transports solutions which are strongly driven by a plethora of emerging online services.

    In such a scenario, capability to provide high capacity during the service provisioning phase is of course very important, but it is not the only requirement that plays a central role. Traffic dynamicity is another essential aspect to consider because in many scenarios, e.g., in the case of real time multimedia services, the connections are expected to be provisioned and torn down quickly and relatively frequently. High traffic dynamicity may put a strain on the network control and management operations (i.e., the overhead due to control message exchange can grow rapidly) that coordinate any provisioning mechanisms. Furthermore, survivability, in the presence of new failure scenarios that goes beyond the single failure assumption, is still of the utmost importance to minimize the network disruptions and data losses. In other words, protection against any possible future failure scenario where multiple faults may struck simultaneously, asks for highly reliable provisioning solutions.

    The above consideration have a general validity i.e., can be equally applied to any network segment and not just limited to the core part. So, we also address the problem of service provisioning in the access paradigm. Long reach Passive Optical Networks (PONs) are gaining popularity due to their cost, reach, and bandwidth advantages in the access region. In PON, the design of an efficient bandwidth sharing mechanism between multiple subscribers in the upstream direction is crucial. In addition, Long Reach PONs (LR-PONs) introduces additional challenges in terms of packet delay and network throughput, due to their extended reach. It becomes apparent that effective solutions to the connection provisioning problem in both the core and access optical networks with respect to the considerations made above can ensure a truly optimal end-to-end connectivity while making an efficient usage of resources.

    The first part of this thesis focuses on a control and management framework specifically designed for concurrent resource optimization in WDM-based optical networks in a highly dynamic traffic scenario. The framework and the proposed provisioning strategies are specifically designed with the objective of: (i) allowing for a reduction of the blocking probability and the control overhead in a Path Computation Element (PCE)-based network architecture, (ii)  optimizing resource utilization for a traffic scenario that require services with diverse survivability requirements which are achieved by means of  dedicated and shared path-protection, and (iii) designing provisioning mechanism that guarantees high connection availability levels in Double Link Failures (DLF) scenarios. The presented results show that the proposed dynamic provisioning approach can significantly improve the network blocking performance while making an efficient use of primary/backup resources whenever protection is required by the provisioned services. Furthermore, the proposed DLF schemes show good performance in terms of minimizing disruption periods, and allowing for enhanced network robustness when specific services require high connection availability levels.

    In the second part of this thesis, we propose efficient resource provisioning strategies for LR-PON. The objective is to optimize the bandwidth allocation in LR-PONs, in particular to: (i) identify the performance limitations associated with traditional (short reach) TDM-PON based Dynamic Bandwidth Allocation (DBA) algorithms when employed in long reach scenarios, and (ii) devise efficient DBA algorithms that can mitigate the performance limitations imposed by an extended reach. Our proposed schemes show noticeable performance gains when compared with conventional DBA algorithms for short-reach PON as well as specifically devised approaches for long reach.

  • 2.
    Ahmed, Jawwad
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    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).
    A Dynamic Bulk Provisioning Framework for Concurrent Optimization in PCE-Based WDM Networks2012Inngår i: Journal of Lightwave Technology, ISSN 0733-8724, E-ISSN 1558-2213, Vol. 30, nr 14, 2229-2239 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A centralized network control and management plane, such as the one based on a path computation element (PCE), is highly beneficial in terms of resource optimization in wavelength division multiplexing optical networks. Benefits of centralized provisioning are even more evident when connection requests are provisioned in batches, i.e., they allow a better use of network resources via concurrent optimization. In this study, a dynamic bulk provisioning framework is presented with the objective of optimizing the use of network resources that also presents, as an additional benefit, the ability to yield a reduction of the control plane overhead. The rationale behind the proposed framework is based on a mechanism in which the PCE client is allowed to bundle and simultaneously send multiple labeled switch path (LSP) requests to the PCE where, in turn, several bundles can be concurrently processed together as a single bulk. From the network deployment perspective, a PCE-based network architecture is proposed to practically realize this approach. For dynamic bulk provisioning of optical LSP requests, a time-efficient integer linear programming (ILP) model (LSP BP ILP) is presented to minimize the request blocking, the network resource consumption, and the network congestion. In addition, a heuristic based on a greedy randomized adaptive search procedure (GRASP), namely LSP_BP_GRASP, is also proposed as a scalable alternative. The presented results demonstrate significant advantages of the proposed PCE bulk provisioning framework based on concurrent optimization in terms of reduced blocking probability and control overhead when compared with conventional dynamic connection provisioning approaches processing a single connection request at a time.

  • 3.
    Ahmed, Jawwad
    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).
    An Optimal Model for LSP Bundle Provisioning in PCE-based WDM Networks2011Inngår i: 2011 Optical Fiber Communication Conference and Exposition and the National Fiber Optic Engineers Conference, OFC/NFOEC 2011, Washington: Optical Society of America , 2011Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A time-efficient resource optimization model for dynamic concurrent provisioning of connection requests at PCE is proposed. It is shown that a significant performance improvement can be achieved without noticeable increase in connection setup-time.

  • 4.
    Ahmed, Jawwad
    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).
    Bulk provisioning of LSP requests with shared path protection in a PCE-based WDM network2011Inngår i: ONDM 2011 - 15th Conference on Optical Network Design and Modeling, 2011Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The Path Computation Element (PCE) is a network entity utilized for network path computation operations, especially useful in optical networks based on wavelength division multiplexing (WDM). In the PCE paradigm, the communication between a node and the PCE is specified by the Path Computation Element Communication Protocol (PCEP). According to PCEP protocol, multiple LSP (Label Switched Path) requests can be bundled together before being sent to the PCE in order to reduce the control overhead. Multiple bundles received by the PCE can then be provisioned at once as a single bulk. Enabling bulk provisioning of LSP requests at the PCE in a concurrent manner can bring significant improvements in terms of higher network resource utilization and control plane overhead reduction. However, these advantages come at a cost of a longer connection setup-time and of an instantaneous increase in the network load, which may lead to a degradation of the network performance, e.g. blocking probability. In this study pros and cons of bulk provisioning are explored in shared path protection (SPP) by comparing sequential and concurrent path computation strategies. An efficient meta-heuristic named GRASP-SPP-BP (Greedy Random Adoptive Search Procedure for Shared Path Protection with Bulk Provisioning) is proposed for concurrent provisioning of primary and shared backup path pairs. GRASP-SPP-BP minimizes the backup resource consumption while requiring minimal path computation time. The presented results demonstrate that, in a SPP network scenario, a significant reduction in the PCEP control overhead, network blocking probability and backup resource consumption can be achieved via LSP bulk provisioning at the PCE with the proposed GRASP-SPP-BP approach.

  • 5.
    Ahmed, Jawwad
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Cavdar, Cicek
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Radio Systems Laboratory (RS 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).
    Hybrid Survivability Schemes Achieving High Connection Availability With a Reduced Amount of Backup Resources2013Inngår i: Journal of Optical Communications and Networking, ISSN 1943-0620, E-ISSN 1943-0639, Vol. 5, nr 10, A152-A161 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Maximizing connection availability in WDM networks is critical because even small disruptions can cause huge data losses. However, there is a trade-off between the level of network survivability and the cost related to the backup resources to be provided. The 100% survivability can be achieved by dedicated path protection with multiple pre-reserved protection paths for each provisioned connection, i.e., DPP (1:N). Unfortunately, the blocking probability performance of DPP (1:N) is negatively affected by the large number of pre-reserved backup wavelengths standing-by unutilized. On the other hand, path restoration (PR)-based solutions ensure good blocking performance at the expense of lower connection availability.

    The work in this paper aims at finding hybrid network survivability strategies that combine the benefits of both techniques (i.e., high availability with low blocking rate). More specifically, the paper focuses on a double link failure scenario and proposes two strategies. The first one, couples dedicated path protection DPP (1:1) with path restoration (referred to as DPP + PR) to minimize the number of dropped connections. The second scheme adds up the concept of backup reprovisioning (BR), referred to as DPP + BR + PR, in order to further increase the connection availability achieved by DPP + PR. Integer Linear Programming (ILP) models for the implementation of the proposed schemes are formulated. Extensive performance evaluation conducted in a PCE-based WDM network scenario shows that DPP + BR + PR and DPP + PR can significantly lower the blocking probability value compared to DPP (1:2) without compromising too much in terms of connection availability.

  • 6.
    Ahmed, Jawwad
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    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).
    Survivability strategies for PCE-based WDM networks offering high reliability performance2013Inngår i: 2013 Optical Fiber Communication Conference and Exposition and the National Fiber Optic Engineers Conference, OFC/NFOEC 2013, Optical Society of America, 2013, 6532695- s.Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Two approaches based on backup reprovisioning and path restoration are proposed for dynamic failure recovery in survivable, PCE-based, WDM networks. Results show that proposed schemes can achieve high connection availability in double link failure scenarios.

  • 7.
    Ahmed, Jawwad
    et al.
    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).
    Chen, Biao
    Department of Optical Engineering, Zhejiang University.
    Mukherjee, Biswanath
    Efficient Inter-Thread Scheduling Scheme for Long-Reach Passive Optical Networks2013Inngår i: IEEE Communications Magazine, ISSN 0163-6804, E-ISSN 1558-1896, Vol. 51, nr 2, S35-S43 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    These days there is a clear trend toward extending the reach of passive optical networks to cover large geographical areas, which enables reduction of the number of central offices and hence has the potential of cost saving in network operation. On the other hand, this reach extension necessitates the design of efficient dynamic bandwidth allocation schemes in order to tackle performance degradation caused by the increased propagation delay in long reach PONs. Among many existing approaches, the multi-thread-based DBA scheme where several bandwidth allocation processes are performed in parallel is considered one of the most effective options to improve network performance in LRPONs. We have found that without proper intercommunication between the overlapped threads, multi-thread DBA may lose efficiency and even perform worse than the conventional single-thread algorithm. With this in mind, this article reviews different inter-thread scheduling schemes for LR-PONs, and proposes a novel approach of integrating the key ideas of the existing ones. Extensive simulation results confirm that our proposed scheme can significantly improve DBA performance for LR-PONs under a variety of scenarios with consideration of different values of network load and reach.

  • 8.
    Ahmed, Jawwad
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Monti, Paolo
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Wosinska, Lena
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Mikroelektronik och tillämpad fysik, MAP.
    Benefits of Connection Request Bundling in a PCE-based WDM Network2009Inngår i: Proc. of European Conference on Networks and Optical Communications (NOC), 2009Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    The  Path  Computation  Element  (PCE)  concept  is  considered  to  be  beneficial  in  the network  connection  setup  operations,  especially  in  optical  networks  based  on wavelength  division  multiplex  (WDM)  transport  technology.  In  the  PCE  paradigm, communication  between  a  node  and  the  PCE  is  specified  by  the  Path  Computation Element  Communication  Protocol  (PCEP).  PCEP  allows  the  PCC  (Path  Computation Client) to send to the PCE more than one LSP (path computation) request at a time, i.e., multiple LSP requests can be bundled together before being sent to the PCE. Enabling bundling, and consequently the concurrent optimization of a large set of LSP requests at the PCE, may result in significant improvements in terms of network optimization and reduced  control  plane  overhead.  However,  these  advantages  come  at  a  cost  of increased  connection  setup-delay.  This  paper  explores  pros  and  cons  of  enabling bundling of LSP requests in terms of both control plane overhead reduction and benefits of  sequential  vs.  concurrent  path  computation  operations.  A  variety  of  scenarios  are analyzed,  including  a  WDM  mesh  network  providing  LSPs  with  both  dedicated  and shared  path  protection.  Results  demonstrate  significant  gains  in  terms  of  reduced control  overhead  using  LSP  bundling,  and  reduction  in  blocking  probability  using concurrent processing of bundled LSP requests at the PCE.

  • 9.
    Ahmed, Jawwad
    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).
    Concurrent processing of multiple LSP request bundles on a PCE in a WDM network2010Inngår i: 2010 Conference on Optical Fiber Communication, Collocated National Fiber Optic Engineers Conference, OFC/NFOEC, New York: IEEE , 2010, 5465298- s.Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Concurrent RWA algorithm for differentiated services to process multiple LSP bundles at PCE is proposed. Significant blocking probability reduction has been observed at the expense of slightly increased LSP setup-time compared to a sequential approach.

  • 10.
    Ahmed, Jawwad
    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).
    LSP Request Bundling in a PCE-Based WDM Network2009Inngår i: OFC: 2009 Conference on Optical Fiber Communication, IEEE , 2009, 989-991 s.Konferansepaper (Fagfellevurdert)
    Abstract [en]

    LSP requests may be bundled to improve the network optimization process at the expense of an increased connection setup delay. A detailed study is conducted to evaluate the pros and cons of the bundling approach.

  • 11.
    Ahmed, Jawwad
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Fotonik (Stängd 20120101).
    Solano, Fernando
    Warsaw University of Technology.
    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).
    Traffic re-optimization strategies for dynamically provisioned WDM networks2011Inngår i: ONDM 2011 - 15th Conference on Optical Network Design and Modeling, Bologna, 2011Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In Wavelength Division Multiplexed (WDM) networks with dynamic lightpath provisioning, connection requests are served without any prior knowledge of their arrival and departure times. As time passes, network resources may become fragmented because of the network dynamism. Under these circumstances it is highly beneficial to re-optimize (i.e., de-fragment) the existing lightpath configuration at some specific time instances to improve the network resource utilization and reduce the risk that future connection requests will be blocked. Assuming that this de-fragmentation process occurs during a re-optimization phase, this paper presents a set of strategies which govern the time instances when this re-optimization phase should be triggered as well as a set of strategies to decide which of the currently active lightpaths should be optimized at any given re-optimization phase. These strategies are referred to as when-to-re-optimize (when-t-r) and what-to-re-optimize (what-t-r) strategies, respectively. During the evaluation process particular attention is devoted to study the impact that when-t-r and what-t-r strategies have on the traffic disruption metrics (i.e., number of total disrupted connections, disruption time, reconfiguration time) inherent with the re-optimization process. Based on the evaluation results, it can be concluded that the choice of an optimal "when" and an optimal "what" to re-optimize strategy is dependent upon the performance objective (e.g. lower blocking probability or network disruption) in a given network scenario.

  • 12.
    Chen, Jiajia
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Fotonik. KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    De Andrade, M.
    Skubic, Björn
    Ericsson Research.
    Ahmed, Jawwad
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    Wosinska, Lena
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    Enhancing IPACT with limited service for multi-thread DBA in long-reach EPON2010Inngår i: Communications and Photonics Conference and Exhibition (ACP), 2010 Asia, 2010, 629-630 s.Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this paper we propose an enhanced IPACT with limited service for multi-thread DBA in long-reach EPON. We evaluate our scheme by simulations in single-thread and double-thread cases and show that the DBA performance in terms of average delay and jitter can be significantly improved by the proposed algorithm.

  • 13.
    De Andrade, Marilet
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT).
    Chen, Jiajia
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Skubic, Björn
    Ahmed, Jawwad
    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).
    Enhanced IPACT: solving the over-granting problem in long-reach EPON2013Inngår i: Telecommunications Systems, ISSN 1018-4864, E-ISSN 1572-9451, Vol. 54, nr 2, 137-146 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this paper we address an issue referred to as "over-granting problem", which is inherent in the existing dynamic bandwidth allocation algorithms for Ethernet-based Passive Optical Networks (EPON), in particular when deployed for multi-threaded scheme in long-reach scenario. In order to solve this problem we design a scheme for the algorithm of Interleaved Polling with Adapted Cycle Time (IPACT) with the limited service discipline. We evaluate the proposed scheme through simulations for single-thread and double-thread cases and demonstrate that, the network performance can be significantly improved by our solution in terms of average delay, jitter, and throughput.

  • 14.
    Monti, Paolo
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Natalino, Carlos
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS, Optical Network Laboratory (ON Lab).
    Ahmed, Jawwad
    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, Renato
    Restoring optical cloud services using relocation2014Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Optical cloud is a very popular concept by which storage and computing resources (i.e., IT resources) are distributed over different datacenter (DC) locations interconnected via high-speed optical wavelength division multiplexing (WDM) links. In this paradigm cloud services are provisioned in an anycast fashion, where only the source node needs to be specified in the routing and resource assignment phase, while any DC (with enough IT resources) can be used to accommodate a cloud service. Anycast provisioning has a number of advantages already recognized by optical cloud providers [1][2]. This kind of provisioning paradigm allows, for example, for the live relocation of the already provisioned cloud services, referred to as the service relocation concept. It means that if the DC location is not essential for the execution of a certain cloud service, multiple relocations of the job to other DC locations are possible. This allows for a more efficient management of both the cloud and the transport network resources. Service relocation has also the potential to bring an extra degree of flexibility to survivability strategies. By providing the option for relocating a cloud service it is possible to use a backup path terminating at a DC that is different from the one used by the primary path. This benefit has been assessed in the literature showing the ability to improve resources efficiency by using service relocation in conjunction with path protection strategies [1]. Another instance in which service relocation might be beneficial is when it is combined with restoration-based survivability strategies. These strategies are very efficient in using backup resources, i.e., they are dynamically provisioned only upon a failure, but restoration-based approaches suffer from a certain risk that the backup network resources might not be available when needed [3]. Service relocation can potentially alleviate this problem. This talk presents a study where the objective is to inves- igate if relocating a cloud service disrupted by a network failure is beneficial in terms of both restorability and average connection availability. To this end the talk will present a number of results based on the solution of an efficient and scalable heuristic algorithm able to jointly solve the restoration and service relocation problem. These results are also benchmarked against the performance of an integer linear programming (ILP) model [4] optimizing the same objective function as the heuristic. In summary it can be concluded that by using relocation the average service availability can be significantly improved requiring only a minimal fraction of the cloud services to be relocated. In addition the proposed heuristic behaves very closely to the optimal ILP results in terms of both restorability and average connection availability.

  • 15. Skubic, Björn
    et al.
    Chen, Biao
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Fotonik (Stängd 20120101). Zhejiang University, China.
    Chen, Jiajia
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Fotonik (Stängd 20120101).
    Ahmed, Jawwad
    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).
    Improved scheme for estimating T-CONT bandwidth demand in status reporting DBA for NG-PON2009Inngår i: Network Architectures, Management, and Applications VII, SPIE - International Society for Optical Engineering, 2009, 76330E- s.Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A scheme for estimating T-CONT bandwidth demand within dynamic bandwidth allocation (DBA) for next-generation passive optical network (NG-PON) is proposed and evaluated. Estimating T-CONT bandwidth demand is considered as a main challenge in gigabit-capable passive optical network (GPON) DBA. The proposed minimum guaranteed T-CONT content (MGTC) scheme allows for a more conservative estimate of bandwidth demand. It is shown that at high load significant improvements in delay, jitter and bandwidth utilization can be achieved with the proposed scheme. For light loads the conventional scheme shows better delay performance. However, this may be overcome by controlled overgranting in the MGTC scheme.

  • 16. Skubic, Björn
    et al.
    Chen, Biao
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Fotonik.
    Chen, Jiajia
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Fotonik.
    Ahmed, Jawwad
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Fotonik.
    Wosinska, Lena
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Fotonik.
    Improved scheme for estimating T-CONT bandwidth demand in status reporting DBA for NG-PON2009Inngår i: 2009 Asia Communications and Photonics Conference and Exhibition, ACP 2009, 2009, Vol. 2009-SupplementKonferansepaper (Fagfellevurdert)
    Abstract [en]

    A scheme for estimating T-CONT bandwidth demand within dynamic bandwidth allocation (DBA) for next-generation passive optical network (NG-PON) is proposed and evaluated. Estimating T-CONT bandwidth demand is considered as a main challenge in gigabit-capable passive optical network (GPON) DBA. The proposed minimum guaranteed T-CONT content (MGTC) scheme allows for a more conservative estimate of bandwidth demand. It is shown that at high load significant improvements in delay, jitter and bandwidth utilization can be achieved with the proposed scheme. For light loads the conventional scheme shows better delay performance. However, this may be overcome by controlled over-granting in the MGTC scheme.

  • 17. Skubic, Björn
    et al.
    Chen, Jiajia
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Fotonik.
    Ahmed, Jawwad
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Fotonik.
    Chen, Biao
    Wosinska, Lena
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Fotonik.
    Mukherjee, Biswanath
    Dynamic Bandwidth Allocation for Long-Reach PON: Overcoming Performance Degradation2010Inngår i: IEEE Communications Magazine, ISSN 0163-6804, E-ISSN 1558-1896, Vol. 48, nr 11, 100-108 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A passive optical network, with its inherent point to multi-point structure, allows for centralized placement of active equipment and possible extension of its boundary towards core networks. This property of the PON can be exploited for node consolidation where multiple central offices are replaced by a single one covering a larger service area. Such node consolidation is being particularly driven by the need for network operational cost saving, and is offering significant challenges to PONs. The degree of node consolidation that can be achieved is limited by the reach of conventional PON systems. In order to achieve a larger degree of node consolidation, an extension of the PON reach, beyond the conventional 20 km, is required. This article addresses the challenges of the dynamic bandwidth allocation, where increased reach results in a degradation of DBA performance and quality of service support. This degradation is a consequence of the increased propagation delay of the DBA messages exchanged between different PON elements. A potential solution to the performance degradation is the introduction of a multi-threaded DBA. In this article, we examine for both Gigabit PON and Ethernet PON, the extent to which DBA performance degradation can be reduced by exploiting multi-threading. It is found that for both standards, multi-threading, if done properly, can be used to mitigate the performance degradation due to the increased reach. To make bandwidth allocation efficient, new schemes for coordinating the multiple threads are required in long reach PON.

  • 18. Skubic, Björn
    et al.
    Chen, Jiajia
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    Ahmed, Jawwad
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    Wosinska, Lena
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Kommunikationssystem, CoS.
    Mukherjee, Biswanath
    A Comparison of Dynamic Bandwidth Allocation for EPON, GPON, and Next-Generation TDM PON2009Inngår i: IEEE Communications Magazine, ISSN 0163-6804, E-ISSN 1558-1896, Vol. 47, nr 3, S40-S48 s.Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Dynamic bandwidth allocation in passive optical networks presents a key issue for providing efficient and fair utilization of the PON upstream bandwidth while supporting the QoS requirements of different traffic classes. In this article we compare the typical characteristics of DBA, such as bandwidth utilization, delay, and jitter at different traffic loads, within the two major standards for PONs, Ethernet PON and gigabit PON. A particular PON standard sets the framework for the operation of DBA and the limitations it faces. We illustrate these differences between EPON and GPON by means of simulations for the two standards. Moreover, we consider the evolution of both standards to their next-generation counterparts with the bit rate of 10 Gb/s and the implications to the DBA. A new simple GPON DBA algorithm is used to illustrate GPON performance. It is shown that the length of the polling cycle plays a crucial but different role for the operation of the DBA within the two standards. Moreover, only minor differences regarding DBA for current and next-generation PONs were found.

  • 19.
    Skubic, Björn
    et al.
    Ericsson Research, Ericsson AB, Stockholm, Sweden.
    Chen, Jiajia
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Fotonik.
    Chen, Biao
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Fotonik.
    Ahmed, Jawwad
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Fotonik.
    Wosinska, Lena
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik, Fotonik.
    Dynamic bandwidth allocation in EPON and GPON2010Inngår i: Convergence of Mobile and Stationary Next-Generation Networks / [ed] Krzysztof Iniewski, John Wiley & Sons, 2010Kapittel i bok, del av antologi (Fagfellevurdert)
  • 20. Vázquez, C.
    et al.
    Montalvo, J.
    Moeyaert, V.
    Yuksel, K.
    Caucheteur, C.
    Gravey, P.
    Loukina, T.
    Larrabeiti, D.
    Ennser, K.
    Franzl, G.
    Hauske, F.
    Wosinska, Lena
    KTH, 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).
    Ahmed, Jawwad
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Fotonik och optik (Stängd 20120101), Fotonik (Stängd 20120101).
    Lazaro, J.
    Signal Processing, Management and Monitoring in Transmission Networks2011Inngår i: Optical Transmission: FP7 BONE Project Experience, Springer Publishing Company, 2011, 1, 53-122 s.Kapittel i bok, del av antologi (Annet vitenskapelig)
1 - 20 of 20
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