1,688 research outputs found

    Q-Andrew: a consolidated QOS management framework

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    Tese de mestrado em Segurança Informática, apresentada à Universidade de Lisboa, através da Faculdade de Ciências, 2008As redes IP convergentes são compostas por uma diversidade de tecnologias que suportam múltiplos tipos de serviços com diferentes características. Cada fabricante de equipamento activo de rede usa sistemas de manutenção proprietários, incompatíveis com equipamentos de outros fabricantes. Para um operador de telecomunicações a gestão da Qualidade de Serviço, numa rede composta por vários fabricantes, é uma tarefa complexa e dispendiosa. Algumas tarefas requerem configuração manual para garantir a compatibilidade entre configurações de equipamentos de fabricantes diferentes. Melhorar a resposta operacional e reduzir os custos de operação nestas circunstâncias é apenas possível com a consolidação da gestão de rede. Para responder a este desafio, propomos: Um conjunto de mecanismos geradores de configurações de Qualidade de Serviço, consistentes entre equipamentos de diversos fabricantes; A definição de um modelo abstracto de representação destas configurações, reutilizável em futuras aproximações de gestão consolidada de rede; Por fim, descrevemos uma aplicação de demonstração onde algumas das propostas apresentadas são concretizadas, tendo como objectivo futuro a sua utilização numa rede real de um operador de telecomunicações nacional, onde são utilizados equipamentos de diversos fabricantes.Converged IP networks consist of diverse technologies and support both legacy and emerging services. Different vendors use separate management systems to achieve similar goals. Manual provisioning today represents a large portion of the total effort required to manage a complex IP network. A consolidated Quality-of-Service policy is difficult to implement in heterogeneous networks. Creating and maintaining such policies is very demanding in terms of operations. For this reason, reducing operational costs while improving Quality-of-Service Management is only possible through a consolidated approach to network management. To leverage operations in converged IP networks, we propose the following: A mechanism to automatically generate consistent configurations across a network with equipment from different vendors; A framework definition such that network element configurations can be specified using a common model; Applying some of the methods proposed to an application that can be used in a real network with diverse technologies and equipment vendors

    Time Driven Priority Router Implementation and First Experiments

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    This paper reports on the implementation of Time-Driven Priority (TDP) scheduling on a FreeBSD platform. This work is part of a TDP prototyping and demonstration project aimed at showing the implications of TDP deployment in packet-switched networks, especially benefits for real-time applications. This paper focuses on practical aspects related to the implementation of the technology on a Personal Computer (PC)-based router and presents the experimental results obtained on a testbed network. The basic building blocks of a TDP router are described and implementation choices are discussed. The relevant results achieved and here presented can be categorized into two types: qualitative results, including the successful integration of all needed blocks and the insight obtained on the complexity related to the implementation of a TDP router, and quantitative ones, including measures of achievable network utilization and of jitter experienced on a fully-loaded TDP network. The outcome demonstrates the effectiveness of the presented implementation while confirming TDP points of strengt

    A novel approach to quality-of-service provisioning in trusted relay Quantum Key Distribution networks

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    In recent years, noticeable progress has been made in the development of quantum equipment, reflected through the number of successful demonstrations of Quantum Key Distribution (QKD) technology. Although they showcase the great achievements of QKD, many practical difficulties still need to be resolved. Inspired by the significant similarity between mobile ad-hoc networks and QKD technology, we propose a novel quality of service (QoS) model including new metrics for determining the states of public and quantum channels as well as a comprehensive metric of the QKD link. We also propose a novel routing protocol to achieve high-level scalability and minimize consumption of cryptographic keys. Given the limited mobility of nodes in QKD networks, our routing protocol uses the geographical distance and calculated link states to determine the optimal route. It also benefits from a caching mechanism and detection of returning loops to provide effective forwarding while minimizing key consumption and achieving the desired utilization of network links. Simulation results are presented to demonstrate the validity and accuracy of the proposed solutions.Web of Science28118116

    Buffer Sizing for 802.11 Based Networks

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    We consider the sizing of network buffers in 802.11 based networks. Wireless networks face a number of fundamental issues that do not arise in wired networks. We demonstrate that the use of fixed size buffers in 802.11 networks inevitably leads to either undesirable channel under-utilization or unnecessary high delays. We present two novel dynamic buffer sizing algorithms that achieve high throughput while maintaining low delay across a wide range of network conditions. Experimental measurements demonstrate the utility of the proposed algorithms in a production WLAN and a lab testbed.Comment: 14 pages, to appear on IEEE/ACM Transactions on Networkin

    A Survey on the Contributions of Software-Defined Networking to Traffic Engineering

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    Since the appearance of OpenFlow back in 2008, software-defined networking (SDN) has gained momentum. Although there are some discrepancies between the standards developing organizations working with SDN about what SDN is and how it is defined, they all outline traffic engineering (TE) as a key application. One of the most common objectives of TE is the congestion minimization, where techniques such as traffic splitting among multiple paths or advanced reservation systems are used. In such a scenario, this manuscript surveys the role of a comprehensive list of SDN protocols in TE solutions, in order to assess how these protocols can benefit TE. The SDN protocols have been categorized using the SDN architecture proposed by the open networking foundation, which differentiates among data-controller plane interfaces, application-controller plane interfaces, and management interfaces, in order to state how the interface type in which they operate influences TE. In addition, the impact of the SDN protocols on TE has been evaluated by comparing them with the path computation element (PCE)-based architecture. The PCE-based architecture has been selected to measure the impact of SDN on TE because it is the most novel TE architecture until the date, and because it already defines a set of metrics to measure the performance of TE solutions. We conclude that using the three types of interfaces simultaneously will result in more powerful and enhanced TE solutions, since they benefit TE in complementary ways.European Commission through the Horizon 2020 Research and Innovation Programme (GN4) under Grant 691567 Spanish Ministry of Economy and Competitiveness under the Secure Deployment of Services Over SDN and NFV-based Networks Project S&NSEC under Grant TEC2013-47960-C4-3-

    EVEREST IST - 2002 - 00185 : D23 : final report

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    Deliverable públic del projecte europeu EVERESTThis deliverable constitutes the final report of the project IST-2002-001858 EVEREST. After its successful completion, the project presents this document that firstly summarizes the context, goal and the approach objective of the project. Then it presents a concise summary of the major goals and results, as well as highlights the most valuable lessons derived form the project work. A list of deliverables and publications is included in the annex.Postprint (published version

    Design and Implementation of a Measurement-Based Policy-Driven Resource Management Framework For Converged Networks

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    This paper presents the design and implementation of a measurement-based QoS and resource management framework, CNQF (Converged Networks QoS Management Framework). CNQF is designed to provide unified, scalable QoS control and resource management through the use of a policy-based network management paradigm. It achieves this via distributed functional entities that are deployed to co-ordinate the resources of the transport network through centralized policy-driven decisions supported by measurement-based control architecture. We present the CNQF architecture, implementation of the prototype and validation of various inbuilt QoS control mechanisms using real traffic flows on a Linux-based experimental test bed.Comment: in Ictact Journal On Communication Technology: Special Issue On Next Generation Wireless Networks And Applications, June 2011, Volume 2, Issue 2, Issn: 2229-6948(Online
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