549 research outputs found

    Robust Energy Management for Green and Survivable IP Networks

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    Despite the growing necessity to make Internet greener, it is worth pointing out that energy-aware strategies to minimize network energy consumption must not undermine the normal network operation. In particular, two very important issues that may limit the application of green networking techniques concern, respectively, network survivability, i.e. the network capability to react to device failures, and robustness to traffic variations. We propose novel modelling techniques to minimize the daily energy consumption of IP networks, while explicitly guaranteeing, in addition to typical QoS requirements, both network survivability and robustness to traffic variations. The impact of such limitations on final network consumption is exhaustively investigated. Daily traffic variations are modelled by dividing a single day into multiple time intervals (multi-period problem), and network consumption is reduced by putting to sleep idle line cards and chassis. To preserve network resiliency we consider two different protection schemes, i.e. dedicated and shared protection, according to which a backup path is assigned to each demand and a certain amount of spare capacity has to be available on each link. Robustness to traffic variations is provided by means of a specific modelling framework that allows to tune the conservatism degree of the solutions and to take into account load variations of different magnitude. Furthermore, we impose some inter-period constraints necessary to guarantee network stability and preserve the device lifetime. Both exact and heuristic methods are proposed. Experimentations carried out with realistic networks operated with flow-based routing protocols (i.e. MPLS) show that significant savings, up to 30%, can be achieved also when both survivability and robustness are fully guaranteed

    Energy management in communication networks: a journey through modelling and optimization glasses

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    The widespread proliferation of Internet and wireless applications has produced a significant increase of ICT energy footprint. As a response, in the last five years, significant efforts have been undertaken to include energy-awareness into network management. Several green networking frameworks have been proposed by carefully managing the network routing and the power state of network devices. Even though approaches proposed differ based on network technologies and sleep modes of nodes and interfaces, they all aim at tailoring the active network resources to the varying traffic needs in order to minimize energy consumption. From a modeling point of view, this has several commonalities with classical network design and routing problems, even if with different objectives and in a dynamic context. With most researchers focused on addressing the complex and crucial technological aspects of green networking schemes, there has been so far little attention on understanding the modeling similarities and differences of proposed solutions. This paper fills the gap surveying the literature with optimization modeling glasses, following a tutorial approach that guides through the different components of the models with a unified symbolism. A detailed classification of the previous work based on the modeling issues included is also proposed

    Needed Actions within Defense Acquisitions Based on a Forecast of Future Mobile Information and Communications Technologies Deployed in Austere Environments

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    The purpose of this research was twofold. First, it developed a forecast of future mobile information and communications technologies (ICT) suitable for use by military forces in austere environments in 5-10, 10-20, and beyond 20 years. Secondly, it explored whether or not current acquisitions practices will be adequate to meet the needs of warfighters who depend on mobile ICT. These questions were explored by conducting utilization of the Delphi technique. Eight panelists from within the private sector conducted three rounds of iterative feedback. This research resulted in a technology forecast for the three timeframes aforementioned, and the potential impacts to the defense acquisitions community. First, current acquisitions practices are unlikely to meet the needs of warfighters dependent upon mobile ICT and streamlining efforts are not likely to result in sufficient lessening of development timelines to maintain technological currency. Secondly, it is foreseeable that military forces will become increasingly dependent upon technologies developed by the private sector. An acquisitions model which exploits technological advances in the form of smart phones and tablets and a secure repository for approved applications and data services is feasible and may help defense acquisitions to maintain technological currency as they replace dedicated, single-purpose equipment. Finally, it suggested that developing the organizational flexibility to adapt to emerging technological trends will become more important than detailed planning and budgeting beyond 10 years

    The Future of Mobile Information and Communication Technology in Austere Environments: A Command and Control Technology Integration Perspective

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    The information and communications technology (ICT) field is undergoing a period of tremendous and rapid change. As ICT develops more rapidly, the United States Air Force needs to remain responsive and adaptive to maintain military advantages. The need to integrate ICT developments sooner than our adversaries prompted an assessment of guidelines evaluating how well the AF is doctrinally positioned from a Command and Control perspective to support integration of emerging ICT. A Delphi Study was commissioned by the 689th CCW to forecast the future of mobile Information and Communication Technology (ICT) in austere environments. Using the ICT forecast data as a basis, the panel provided inputs on the integration concerns the forecasted trends invoked and the effects of the forecast on the Measures of Effectiveness outlined in AF doctrine

    Special Issue on Survivable and Resilient Communication Networks and Services

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    Communication networks and services play a vital role in our modern lives. This importance is expected to continue to grow in future decades. More and more business, healthcare or government organizations will become increasingly dependent on the communication between their offices and people. Not only does modern society depend on these services in terms of availability but also in terms of proper functioning in all circumstances. These services having stringent requirements with respect to protection of privacy and security. Anonymity (such as e-health) cannot accept, for example, temporary leakage of confidential information by accident whether a result of human error or technical problems. The information and communication network technology itself have also been evolving with tremendous breakthroughs. Users have more and more different types of mobile devices that interconnect them to the Internet. These mobile devices provide incentives to generate novel technology paradigms that enable more flexible provisioning, network virtualization, or improved power efficiency. The robustness and fault tolerance of these novel evolutions is as crucial as ever

    Software Defined Applications in Cellular and Optical Networks

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    abstract: Small wireless cells have the potential to overcome bottlenecks in wireless access through the sharing of spectrum resources. A novel access backhaul network architecture based on a Smart Gateway (Sm-GW) between the small cell base stations, e.g., LTE eNBs, and the conventional backhaul gateways, e.g., LTE Servicing/Packet Gateways (S/P-GWs) has been introduced to address the bottleneck. The Sm-GW flexibly schedules uplink transmissions for the eNBs. Based on software defined networking (SDN) a management mechanism that allows multiple operator to flexibly inter-operate via multiple Sm-GWs with a multitude of small cells has been proposed. This dissertation also comprehensively survey the studies that examine the SDN paradigm in optical networks. Along with the PHY functional split improvements, the performance of Distributed Converged Cable Access Platform (DCCAP) in the cable architectures especially for the Remote-PHY and Remote-MACPHY nodes has been evaluated. In the PHY functional split, in addition to the re-use of infrastructure with a common FFT module for multiple technologies, a novel cross functional split interaction to cache the repetitive QAM symbols across time at the remote node to reduce the transmission rate requirement of the fronthaul link has been proposed.Dissertation/ThesisDoctoral Dissertation Electrical Engineering 201
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