Paving roads towards eGov inclusion: a portuguese inter-municipal case study

http://www.echallenges.org/e2008/This paper presents a Portuguese inter-municipal project - Vale do Minho Digital (VMD), framed by the Digital Cities and Regions (DCR) initiative. The project aims to contribute to the Inclusive eGov roadmap providing an integrated ICT solution that spans five sparse municipalities in North Portugal. Taking an orthogonal view of the VMD building blocks, from the communication infrastructure to the citizen-centric services, the discussion highlights the challenges and strategies of the VMD project design. Key development aspects and good practices to foster multiregional eGov projects implementation, deployment and success are also discussed

Enabling self-adaptive QoE/QoS control

Handling quality requirements of multimedia services and the expectations of end-users regarding the perceived service quality is currently a major issue for service providers in order to sustain service diversity and improve competitiveness. In this context, this paper presents ongoing work toward a service-oriented architecture for QoE/QoS evaluation and control, which can be deployed to assist the provision of multi-constrained services. Considering the users' QoE perspective and the negotiated service levels, the architecture lays on per service class online monitoring to assist self-adaptive control of multimedia flows entering the network. To perform online monitoring, a distributed and versatile QoS monitoring tool oriented to multiservice networks is proposed. Preliminary results shows that the presented control strategy is effective in providing consistent quality levels to heterogeneous services

Análise de utilização de WLANs universitárias

A recente aposta das universidades europeias nas redes locais sem fios - Wireless Local Area Networks (WLANs), como forma de disponibilizar à comunidade académica um serviço de mobilidade, trouxe inúmeras vantagens, mas é de extrema importância perceber até que ponto é que os seus utilizadores tiram proveito desta tecnologia e qual é o seu comportamento. Neste trabalho foram analisadas as WLANs de dois campi universitários pertencentes às Universidades do Minho e de Vigo. O estudo realizado tem por objectivo identificar padrões de comportamento dos utilizadores e o grau de utilização dos recursos de rede, respondendo à questão: qual a utilização efectiva das WLANs em análise? Os resultados deste trabalho, aqui reportados para o caso da Universidade do Minho, demonstram que o local de acesso tem influência no número de utilizadores associados, no volume de tráfego gerado, no número e duração das sessões, fornecendo importantes indicadores para o planeamento, dimensionamento e investimento nas WLANs universitárias

Distributed admission control for QoS and SLS management

This article proposes a distributed admission control (AC) model based on on-line monitoring to manage the quality of Internet services and Service Level Specifications (SLSs) in class-based networks. The AC strategy covers intra- and interdomain operation, without adding significant complexity to the network control plane and involving only edge nodes. While ingress nodes perform implicit or explicit AC resorting to service-oriented rules for SLS and QoS parameters control, egress nodes collect service metrics providing them as inputs for AC. The end-to-end operation is viewed as a cumulative and repetitive process of AC and available service computation.We discuss crucial key points of the model implementation and evaluate its two main components: themonitoring process and the AC criteria. The results show that, using proper AC rules and safety margins, service commitments can be efficiently satisfied, and the simplicity and flexibility of the model can be explored to manage successfully QoS requirements of multiple Internet services.(undefined

Ensuring IP services consistency through lightweight monitoring-based admission control

This paper evaluates the performance of a distributed and lightweight AC model based on per-class edge-to-edge monitoring feedback for ensuring the quality of multiple services in class-based IP networks. The model resorts to service-dependent AC rules for controlling QoS parameters and SLSs utilization, both intradomain and end-to-end. To provide a proof-of-concept of the proposed AC solution, a prototype of the AC model has been developed and tested using a simulation platform. The devised test scenarios aim at exploring the AC criteria's ability in satisfying each service class QoS levels and existing SLSs commitments. Generically, the results show that the proposed AC model, using a two-rule AC criterion defined on a service class basis, is able to control service levels and achieve high network utilization, without adding significant complexity to the network elements. The use of systematic edge-to-edge on-line monitoring and of a controlled degree of overprovisioning proved to be essential design aspects contributing for reaching a good compromise between simplicity and performance.Fundação para a Ciência e Tecnologia FC

Mobilidade em Redes IP

Jornal Expresso: Caderno de Informática "Tecnologias wireless - rápida evolução

Toward scalable management of multiple service levels in IP networks

This paper analyzes and discusses the role of a distributed and simple admission control (AC) model in achieving scalable management of multiple network service levels. The model design, covering explicit and implicit AC, exhibits relevant properties which allow managing QoS and SLSs in multiservice IP networks in a flexible and scalable manner. These properties stem from the way service-dependent AC and on-line service performance monitoring are proposed and articulated in the model's architecture and operation. The scalability debate, carried out at these two levels, highlights key steps toward performing self-adaptive service-oriented AC and low overhead multiservice monitoring. The performance evaluation results, illustrating the role and relevance of the defined AC rules, show that QoS and SLSs requirements can be efficiently satisfied or bounded, proving that the simplicity, flexibility and self-adaptability of the model can be explored to manage multiple service guarantees successfully

Enhancing QoS metrics estimation in multiclass networks

This paper discusses the problematic of QoS monitoring, suggesting the use of on-line multipurpose active monitoring in multiclass networks as a powerful tool to efficiently assist and enhance the control of multiple service levels. To improve the simultaneous estimation of one-way QoS metrics, we propose a flexible probing source able to adjust probing patterns to the measurement requirements of each service class, exploring pattern coloring to better sense packet loss. The proof-of-concept provided shows that the proposed solution improves the estimation accuracy of multiple QoS metrics significantly, with a reduced probing overhead.info:eu-repo/semantics/publishedVersio

Admission control in multiservice IP networks : architectural issues and trends

The trend toward the integration of current and emerging applications and services in the Internet has launched new challenges regarding service deployment and management. Within service management, admission control (AC) has been recognized as a convenient mechanism to keep services under controlled load and assure the required QoS levels, bringing consistency to the services offered. In this context, this article discusses the role of AC in multiservice IP networks and surveys current and representative AC approaches. We address and compare the architectural principles of these AC approaches and their main features, virtues and limitations that impact on the quality control of network services. We identify important design aspects that contribute to the successful deployment of flexible and scalable AC solutions in multiservice networks

The role of admission control in assuring multiple services quality

Considering that network overprovisioning by itself is not always an attainable and everlasting solution, Admission Control (AC) mechanisms are recommended to keep network load controlled and assure the required service quality levels. This article debates the role of AC in multiservice IP networks, providing an overview and discussion of current and representative AC approaches, highlighting their main characteristics, pros and cons regarding the management of network services quality. In this debate, particular emphasis is given to an enhanced monitoring-based AC proposal for assuring multiple service levels in multiclass networks.Centro de Ciências e Tecnologias da Computação do Departamento de Informática da Universidade do Minho (CCTC