556 research outputs found

    Computer-Aided Conceptual Design Through TRIZ-based Manipulation of Topological Optimizations

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    Organised by: Cranfield UniversityIn a recent project the authors proposed the adoption of Optimization Systems [1] as a bridging element between Computer-Aided Innovation (CAI) and PLM to identify geometrical contradictions [2], a particular case of the TRIZ physical contradiction [3]. A further development of the research has revealed that the solutions obtained from several topological optimizations can be considered as elementary customized modeling features for a specific design task. The topology overcoming the arising geometrical contradiction can be obtained through a manipulation of the density distributions constituting the conflicting pair. Already two strategies of density combination have been identified as capable to solve geometrical contradictions.Mori Seiki – The Machine Tool Compan

    Demonstration of dynamic restoration in segment routing multi-layer SDN networks

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    Dynamic traffic recovery is designed and validated in a multi-layer network exploiting an SDN-based implementation of Segment Routing. Traffic recovery is locally performed from the node detecting the failure up to the destination node without involving the SDN controller. Experimental results demonstrate recovery time within 50 ms

    Introducing database communication technologies for TED replication in multi-domain networks

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    In multi-domain transport networks, exchange of Traffic Engineering information is required to enable effective end-to-end service provisioning and restoration by efficiently utilizing network resources. So far, several solutions have been proposed by the communication community such as the Hierarchical Path Computation Element (H-PCE) architecture. Using the H-PCE architecture a parent PCE is responsible for inter-domain path computation, while a dedicated child PCE performs intra-domain path computation within each domain. However, this approach can introduce scalability concerns especially under dynamic traffic condition such as during restoration because all path computation procedures are coordinated by the parent PCE and may require the exchange of many control messages. This paper proposes a standard communication among database systems located at the child PCEs, to exchange and share YANG-based Traffic Engineering information in multi-domain networks. By exploiting currently available database technologies, scalable and predictable performance is demonstrated for both replication mechanisms among child PCEs and information retrieval from the stored databases. Thus, this proposal enables the sharing of intra-domain information at each cPCE that can be locally used, upon failure, to speed-up the recovery procedure

    A Survey on the Path Computation Element (PCE) Architecture

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    Quality of Service-enabled applications and services rely on Traffic Engineering-based (TE) Label Switched Paths (LSP) established in core networks and controlled by the GMPLS control plane. Path computation process is crucial to achieve the desired TE objective. Its actual effectiveness depends on a number of factors. Mechanisms utilized to update topology and TE information, as well as the latency between path computation and resource reservation, which is typically distributed, may affect path computation efficiency. Moreover, TE visibility is limited in many network scenarios, such as multi-layer, multi-domain and multi-carrier networks, and it may negatively impact resource utilization. The Internet Engineering Task Force (IETF) has promoted the Path Computation Element (PCE) architecture, proposing a dedicated network entity devoted to path computation process. The PCE represents a flexible instrument to overcome visibility and distributed provisioning inefficiencies. Communications between path computation clients (PCC) and PCEs, realized through the PCE Protocol (PCEP), also enable inter-PCE communications offering an attractive way to perform TE-based path computation among cooperating PCEs in multi-layer/domain scenarios, while preserving scalability and confidentiality. This survey presents the state-of-the-art on the PCE architecture for GMPLS-controlled networks carried out by research and standardization community. In this work, packet (i.e., MPLS-TE and MPLS-TP) and wavelength/spectrum (i.e., WSON and SSON) switching capabilities are the considered technological platforms, in which the PCE is shown to achieve a number of evident benefits

    A Tutorial on Machine Learning for Failure Management in Optical Networks

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    Failure management plays a role of capital importance in optical networks to avoid service disruptions and to satisfy customers' service level agreements. Machine learning (ML) promises to revolutionize the (mostly manual and human-driven) approaches in which failure management in optical networks has been traditionally managed, by introducing automated methods for failure prediction, detection, localization, and identification. This tutorial provides a gentle introduction to some ML techniques that have been recently applied in the field of the optical-network failure management. It then introduces a taxonomy to classify failure-management tasks and discusses possible applications of ML for these failure management tasks. Finally, for a reader interested in more implementative details, we provide a step-by-step description of how to solve a representative example of a practical failure-management task
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