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Lopez V.,Autonomous University of Madrid | Hernandez J.A.,Charles III University of Madrid | Gonzalez De Dios O.,Telefnica ID | Fernandez Palacios J.,Telefnica ID | Aracil J.,Autonomous University of Madrid
Journal of Optical Communications and Networking | Year: 2010

Network operators are migrating their networks to IP over WDM architectures. In such multilayer networks, it is necessary to define mechanisms that efficiently use the resources available from both layers in a coordinated manner. Thanks to the development of the control plane (GMPLS), it is feasible to both set up and tear down lightpaths automatically. Thus the WDM layer can now adapt its configuration to both meet a set of resource constraints and fulfill some predefined quality-of-service (QoS) requirements. To this end, we define a multilayer traffic engineering algorithm that efficiently manages the resources from both layers. This algorithm, which is based on Bayesian decision theory, finds the optimal number of label-switched paths that must be switched over the optical and electronic domains. Such an optimal value is found by trading off the QoS required by the users and the limited availability of network resources. © 2009 OSA.


Alvarez D.,Autonomous University of Madrid | Lopez V.,Autonomous University of Madrid | Anamuro J.L.,Autonomous University of Madrid | De Vergara J.L.,Autonomous University of Madrid | And 2 more authors.
2011 International Conference on the Network of the Future, NOF 2011 - Proceedings | Year: 2011

In recent years, Path Computation Element (PCE) architecture has been standardized as a suitable solution for path computation in multi-domain network scenarios. The Traffic Engineering Database (TED) of the PCE is updated with the information of the control plane. However, there is a delay from the PCE replies to a request, until the TED is updated with the network status information. This delay includes not only the control plane delay, but also Path Computation Element Protocol (PCEP) information exchange. This desynchronization in the TED and the real status information leads to an extra blocking situation when the Label Switch Router (LSR) tries to reserve a path, but it has been previously reserved by other LSR. To solve such problem, a recent draft is submitted to the IETF proposing new PCEP extensions for a pre-reservation of the computed path resources for a certain period. This work implements in C three multi-domain algorithms: Per-domain Path Computation, Backward-Recursive PCE-based Computation and Hierarchical Path Computation Element and it assesses their performance with and without mechanisms to reduce this extra blocking probability due to the uncertainty of the TED information. © 2011 IEEE.


Crdenas J.P.,Technical University of Madrid | Mouronte M.L.,Telefnica ID | Moyano L.G.,Telefnica ID | Vargas M.L.,Telefnica ID | Benito R.M.,Technical University of Madrid
Physica A: Statistical Mechanics and its Applications | Year: 2010

Complex networks are considered robust against random failures but sensitive to failures in target. Under this perspective we analyze the robustness of the Spanish telecommunication networks for digital transmission, the Synchronous Digital Hierarchy (SDH), considering failures in the equipments that control the flow of information. Our results suggest that the robustness depends not only on the connectivity of equipments removed but also on the capacity and types of links associated with that removal. We have also observed that the robustness of SDH networks depends on the particular initial design and evolution of each Spanish province. © 2010 Elsevier B.V. All rights reserved.


De-Frutos-Lopez M.,Charles III University of Madrid | Orellana-Quiros D.,PRODYS S.L. | Pujol-Alcolado J.C.,Telefnica ID | Pujol-Alcolado J.C.,Charles III University of Madrid | Diaz-De-Maria F.,Charles III University of Madrid
Signal Processing: Image Communication | Year: 2010

In this article, an improved version of one of the most cited intra mode decision algorithms in H.264/AVC video coding is proposed with the aim to improve its efficiency and performance. The reference algorithm determines the interpolation/extrapolation spatial direction (mode) for achieving the best intra prediction using the Sobel gradient calculation. The proposed algorithm suggests reducing the number of gradients calculated and changing the Sobel operator to that of Roberts. In addition to this, it also proposes including the previously encoded neighboring block modes among the evaluated modes. Experimental results show that the proposed algorithm reduces the computational load of the original algorithm and substantially improves its rate-distortion performance. © 2010 Elsevier B.V. All rights reserved.


Gmez-Prez J.M.,Intelligent Software Components ISOCO S.A. | Erdmann M.,Ontoprise GmbH | Greaves M.,Vulcan Inc. | Corcho O.,Technical University of Madrid | Benjamins R.,Telefnica ID
International Journal of Human Computer Studies | Year: 2010

The development of knowledge-based systems is usually approached through the combined skills of software and knowledge engineers (SEs and KEs, respectively) and of subject matter experts (SMEs). One of the most critical steps in this task aims at transferring knowledge from SMEs' expertise to formal, machine-readable representations, which allow systems to reason with such knowledge. However, this process is costly and error prone. Alleviating such knowledge acquisition bottleneck requires enabling SMEs with the means to produce the target knowledge representations, minimizing the intervention of KEs. This is especially difficult in the case of complex knowledge types like processes. The analysis of scientific domains like Biology, Chemistry, and Physics uncovers: (i) that process knowledge is the single most frequent type of knowledge occurring in such domains and (ii) specific solutions need to be devised in order to allow SMEs to represent it in a computational form. We present a framework and computer system for the acquisition and representation of process knowledge in scientific domains by SMEs. We propose methods and techniques to enable SMEs to acquire process knowledge from the domains, to formally represent it, and to reason about it. We have developed an abstract process metamodel and a library of problem solving methods (PSMs), which support these tasks, respectively providing the terminology for SME-tailored process diagrams and an abstract formalization of the strategies needed for reasoning about processes. We have implemented this approach as part of the DarkMatter system and formally evaluated it in the context of the intermediate evaluation of Project Halo, an initiative aiming at the creation of question answering systems by SMEs. © 2010 Elsevier Ltd. All rights reserved.


Artundo I.,Polytechnic University of Valencia | Tymecki A.,Orange S.A. | Ortego E.,Telefnica ID | Ortega B.,Polytechnic University of Valencia
Optical Fiber Technology | Year: 2011

To analyze the costs of deploying any optical fiber network, it is critical to know the evolution of prices of its individual components in time. In this paper we investigate on the pricing and installation costs of several passive optical components, focusing as an example on optical fiber connectors, and present reliable data price trends for them. We then propose future costs based on parametric methods and the application of the extended learning curve model. The key contributions of this analysis are the accurate learning coefficients extracted for each type of optical component, ranging from 0.66 to 0.96 for fiber connectors or 0.88 for fiber cables, which can serve as valuable inputs to more complex, higher-level techno-economical models. Large price drops of 33% for splitters and 78% for attenuators have been also identified with these methods for the following years. © 2011 Elsevier Inc. All rights reserved.


Kiss Kallo C.,Intune Networks | Shields J.,Intune Networks | O'Malley C.,Intune Networks | Carley R.,Intune Networks | And 2 more authors.
2012 16th International Conference on Optical Networking Design and Modelling, ONDM 2012 | Year: 2012

This paper summarises the modelling results obtained with a sub-wavelength optical packet switching technology, called OPST (Optical Packet Switch and Transport), when compared against an IPoDWDM solution. In particular, the impact of data centre location in the network on the network cost is studied for two architectures based on different technologies. Data centre location, routing strategies, service mix, traffic growth and subscriber service take-up is modelled to obtain a broad view about the cost sensitivities in these networks. The main contribution of the paper is to demonstrate that resilience to data centre location and changing traffic patterns enable the sub-wavelength packet optical solution to achieve cost savings of 150% when compared to the IPoDWDM approach. Such flexibility of the packet optical solution also enables 100-300% of power consumption cost reduction and an average 150% savings on rack cabinets for typical configurations. © 2012 IEEE.


Kallo C.K.,Intune Networks | Dunne J.,Intune Networks | Carley R.,Intune Networks | O'Malley C.,Intune Networks | And 2 more authors.
2012 16th International Conference on Optical Networking Design and Modelling, ONDM 2012 | Year: 2012

In this paper the uncertainties and the implied level of risk associated with next-generation network architectures is modelled using Monte Carlo simulation, aimed at understanding network economics evolution. A high number of network parameters - like incremental network deployment, data centre location, network architecture, service mix, traffic growth and subscriber take-up - are modelled. A wide range of values is used for these parameters to gain understanding of their impact on network cost. Such an approach provides insight into the risk level undertaken by operators when building their network infrastructure based on a specific forecast. Thus, the core result of this analysis is that a sub-wavelength optical packet forwarding technology can de-risk network investments by 500% when compared to a next-generation IPoDWDM solution. Second, in a scaled network scenario the sub-wavelength solution also provides 150% capital savings. Finally, on the medium and long term the sub-wavelength approach yields a cost benefit for 99.8% of the configurations, when compared to an IPoDWDM architecture. © 2012 IEEE.


De Dios O.G.,Telefnica ID | Jimenez Chico F.J.,Telefnica ID | Fernandez Palacios J.P.,Telefnica ID | Oliveira Guerra S.,Telefnica ID | Rodriguez C.M.A.,Telefnica ID
2011 Optical Fiber Communication Conference and Exposition and the National Fiber Optic Engineers Conference, OFC/NFOEC 2011 | Year: 2011

This paper shows the CAPEX benefits of an IP over reconfigurable WDM network architecture, which combines most of the benefits of IP Offloading theory while entailing a minimal impact in current IP core networks design. © 2011 Optical Society of America.


Vercher J.B.,Telefnica ID | Hernandez-Munoz J.M.,Telefnica ID | Gomez L.H.,Technical University of Madrid | Sepulveda A.T.,Telefnica ID
2011 Future Network and Mobile Summit, FutureNetw 2011 | Year: 2011

Providing experimental facilities for the Internet of Things (IoT) world is of paramount importance to materialise the Future Internet (FI) vision. The level of maturity achieved at the networking level in Sensor and Actuator networks (SAN) justifies the increasing demand on the research community to shift IoT testbed facilities from the network to the service and information management areas. In this paper we present an Experimental Platform fulfilling these needs by: integrating heterogeneous SAN infrastructures in a homogeneous way; providing mechanisms to handle information, and facilitating the development of experimental services. It has already been used to deploy applications in three different field trials: smart metering, smart places and environmental monitoring and it will be one of the components over which the SmartSantander project, that targets a large-scale IoT experimental facility, will rely on. © 2011 IIMC.

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