Artigos de Conferência, Publicação

Ipsflow–uma proposta de sistema de prevençao de intrusao baseado no framework openflow

The ideal Intrusion Prevention System (IPS) is the one that detects malicious traffic across the network and blocks it at its source. Conventional IPSs do not meet these requirements satisfactorily, because when operating in active mode cannot have a wide coverage on the network and just block the passing traffic. And while catching mirrored traffic, it can only block it when working together with switches from the same solution or vendor. In this scenario, this paper presents IPSFlow, an IPS solution for selective and distributed capture with automated blocking of malicious traffic based on OpenFlow.

Artigos de Conferência, Publicação

A mobile qoe architecture for heterogeneous multimedia wireless networks

One of the main requirements in this emerging wireless multimedia era is the Quality of Experience (QoE) assurance for 2D or 3D video applications in heterogeneous multi-operator environments. Therefore, this paper proposes a QoE Architecture for Heterogeneous Multimedia Wireless Networks, called QoEHand. QoEHand extends the Media Independent Handover (MIH)/IEEE 802.21 proposal with QoEawareness, seamless mobility, dynamic class of service mapping and a set of content adaptation schemes. The proposed solution allows the best connection and considers the QoE needs of mobile clients and available wireless resources in IEEE 802.11e and IEEE 802.16e service classes. Simulation experiments were carried out to show the impact and benefits of QoEHand on the user´s perception, by using objective and subjective QoE metrics.

Artigos de Conferência, Publicação

Real-time QoE prediction for multimedia applications in wireless mesh networks

As Wireless Mesh Networks (WMNs) are being increasingly deployed, there is an increasing demand for new quality assessment mechanisms that allow service operators to evaluate and optimize the utilization of network resources, while ensuring a good quality level on multimedia applications as perceived by end-users. However, existing real-time assessment schemes for WMNs are not capable of capturing the actual quality of received multimedia content with regard to user perception. Therefore, it is not possible to assure the user experience of content services. To address this problem, this paper introduces the Hybrid Quality of Experience (HyQoE) Prediction, which is a quality estimator specially designed to assess realtime multimedia applications. HyQoE is designed based on the framework of the widely used Pseudo-Subjective Quality Assessment (PSQA) Tool which exploits Random Neural Network (RNN). Crucial extension work has been implemented to achieve our objectives. A performance evaluation verifies the effectiveness and advantages of HyQoE in predicting users’ perception of multimedia content in WMNs over existing subjective and hybrid methods.

Artigos de Conferência, Publicação

A proposal management of the legacy network environment using OpenFlow control plane

The Future Internet will arise from the convergence of new network concepts and combine technologies, services, media and content. It will offer flexibility and diversity with scalable content and services that are accessible through a wide range of interfaces and devices. However, the biggest challenge now is how to enable and test the proposed approaches so that they can be validated without sacrificing the current production infrastructure. The OpenFlow protocol allows production networking environments such as campus networks, metropolitan networks or R&D networks, to be used as experimental infrastructure hosting, future Internet architectures, software and protocols, in parallel with the production traffic. During rollout, there is a practical problem that arises with Legacy networks that do not support OpenFlow and need to be replaced/upgraded or refined by means of costly network re-engineering. This paper proposes a new OpenFlow architecture with new components, capable of managing Legacynon-OpenFlow elements by offering a new solution that facilitates the management of Legacy technologies and allows them to be employed in FI experimentation environment and increase the number of experiment with the Legacy Network Environment using OpenFlow control.

Artigos de Conferência, Publicação

Video quality estimator for wireless mesh networks

As Wireless Mesh Networks (WMNs) have been increasingly deployed, where users can share, create and access videos with different characteristics, the need for new quality estimator mechanisms has become important because operators want to control the quality of video delivery and optimize their network resources, while increasing the user satisfaction. However, the development of in-service Quality of Experience (QoE) estimation schemes for Internet videos (e.g., real-time streaming and gaming) with different complexities, motions, Group of Picture (GoP) sizes and contents remains a significant challenge and is crucial for the success of wireless multimedia systems. To address this challenge, we propose a real-time quality estimator approach, HyQoE, for real-time multimedia applications. The performance evaluation in a WMN scenario demonstrates the high accuracy of HyQoE in estimating the Mean Opinion Score (MOS). Moreover, the results highlight the lack of performance of the well-known objective methods and the Pseudo-Subjective Quality Assessment (PSQA) approach.

Artigos de Conferência, Publicação

FHDRA: Uma Proposta para Reduçao da Latência de Handoff Layer-3 em Redes Sem Fio de Multiplos Saltos

Nos últimos anos houve expressivo esforço em prol de soluções de mobilidade para redes sem fio tradicionais, tais como redes de celulares e IEEE 802.11. Outro tipo de rede sem fio que vem se destacando mais recentemente são as redes de múltiplos saltos. Porém a questão da mobilidade neste tipo de rede não é uma simples extensão das redes sem fio tradicionais. Assim, são necessárias soluções específicas de mobilidade que atendam os requisitos dessas novas redes. Visando este objetivo, o presente trabalho propõe uma adaptação ao DHCP, voltado para redes sem fio de múltiplos saltos. A proposta agrega inteligência ao agente DHCP relay, tornando-o capaz de acelerar o processo de configuração de endereço IP aos clientes móveis durante o handoff.

Artigos de Conferência, Publicação

IPSFlow–uma proposta de IPS distribuído para captura e bloqueio seletivo de tráfego malicioso em redes definidas por software

Os tradicionais sistemas de prevenção de intrusão (Intrusion Prevention Systems–IPS) possuem limitações em sua atuação. Quando operam no modo ativo, não possuem uma ampla cobertura na rede, e quando capturam tráfego espelhado, só bloqueiam o tráfego malicioso se atuarem em conjunto com equipamentos de rede do mesmo fabricante ou solução. Neste contexto, propomos neste artigo o IPSFlow, um framework de IPS para Redes Definidas por Software (Software Defined Networks-SDN) que, através do protocolo Openflow, possibilita a criação de um IPS com ampla cobertura na rede, permitindo a captura seletiva e o bloqueio automatizado de tráfego malicioso o mais próximo de sua origem, através da combinação dos resultados de diferentes técnicas de análise de tráfego.

Artigos de Conferência, Publicação

A parametric QoE video quality estimator for Wireless Networks

The development of real-time quality estimator schemes for emerging Internet videos with different content types remains a significant challenge and is crucial for the success of wireless multimedia systems. However, currently in-service assessment schemes fail in capturing subjective aspects of multimedia content related to the user perception. Therefore, this paper proposes an on-the-fly parametric video quality estimator approach (called MultiQoE) for real-time video streaming applications. Experiments in a Wireless Mesh Network (WMN) scenario were carried out to show the accuracy, benefit, and impact of MultiQoE compared to widely used Quality of Experience (QoE) subjective, objective and parametric methods.

Artigos de Conferência, Publicação

A hybrid prediction and assessment quality of experience approach for videostreaming applications over wireless mesh networks

As Wireless Mesh Networks (WMNs) have been increasingly deployed, the need of new quality measurement schemes became essential since operators want to control and optimize their network resources, while keeping users of multimedia applications with a good quality level. However, currently WMN in-service assessment schemes fails in capturing subjective aspects of real-time multimedia content related to the user perception. Therefore, this paper proposes a new on-the-fly quality estimator approach, called Hybrid Quality of Experience (HyQoE) Prediction, for real-time videostreaming applications. Moreover, performance evaluation results present the benefits and accuracy of HyQoE in predicting the user perception compared to well-know subjective and objective methods in a WMN scenario.

Artigos de Conferência, Publicação

Mecanismo para aprovisionamento dinâmico e escalável em redes em malha sem fio para suporte de aplicações com alta demanda de recursos

The success of mobile and ubiquitous computing, coupled with the increasing demand for applications with high Quality of Service (QoS) and Quality of Experience (QoE) requirements, has brought great challenges to the future access networks. Thus, wireless mesh networks distinguish due to its flexibility, redundancy, low-cost and broadband capacity. However, aspects as scalability, availability and reliability, are still challenging. Following the limitations of existing proposals, this paper proposes the Multi-Service Resource Allocation in Wireless Mesh Networks (MIRA-WMN) for provisioning resources of wireless mesh networks compliant with IEEE 802.11 e/s standard. The MIRA-WMN proposes a single solution to integrate QoS control and connectivity resources to support multi-user sessions with high requirements. The MIRA-WMN was evaluated by simulations, which demonstrated its benefits in the data and control plane, as well as user’s perception.

Artigos de Conferência, Publicação

Legacyflow: Bringing openflow to legacy network environments

The OpenFlow protocol allows production networking environments such as campus networks, metropolitan networks or R&D networks, to be used as experimental infrastructure hosting, future internet architectures, softwares and protocols, in isolation to the production traffic. During rollout, one practical problem arises with legacy switches that do not support the OpenFlow protocol and need to be replaced/upgraded or worked around by means of costly network re-engineering. This poster proposes a new OpenFlow datapath, which is able to interact with non OpenFlow legacy equipment, creating a new approach to hybrid OpenFlow networks.

Artigos de Conferência, Publicação

Pesquisa experimental para a internet do futuro: Uma proposta utilizando virtualização e o frame-work openflow

A Internet é um enorme sucesso mundial e vem mudando a forma como interagimos, trabalhamos e nos divertimos. Boa parte deste sucesso se deve à grande flexibilidade da tecnologia IP. Apesar de todo o sucesso da Internet, a tecnologia básica IP é a causa das suas próprias limitações que se tornam cada vez mais evidentes. Um dos principais objetivos da atividade conhecida como Internet do Futuro (IF) é a formulação e avaliação de arquiteturas alternativas para substituir o protocolo IP. Nesse contexto, duas abordagens estão sendo discutidas e investigadas: a primeira denominada limpa (Clean Slate), que visa substituir a arquitetura atual por uma nova totalmente reconstruída, e a outra chamada evolucionária (Evolutionary) que pretende evoluir a arquitetura atual sem perder a compatibilidade com a anterior.

Artigos de Conferência, Publicação

A multimedia-based fuzzy queue-aware routing approach for wireless mesh networks

The proliferation of multimedia content and Wireless Mesh Networks (WMNs) are changing the Internet facilities and life style of fixed and mobile users. For the success of the next generation wireless networks, novel multimedia approaches with quality level assurance are required to allow the distribution of video-streaming, video conference, gaming, multimedia social networking, green multimedia content and other entrainment applications for thousand of users in ubiquitous wireless (mesh) systems. In this context, new routing schemes are needed to provide end-to-end Quality of Service (QoS) and Quality of Experience (QoE) support for delay/loss/jitter-sensitive multimedia applications in WMNs. The well-known OLSR (Optimized Link State Routing) protocol with ETX (Expected Transmission Count) metric bring many benefits for the path selection process, but present a drawback in the queue availability management and reduce the system performance. Therefore, multimedia-related packets will suffer with loss/delay/jitter and the system overall performance will decrease. This paper proposes the Queue-based OLSR ETX (QoETX) approach to overcome the limitations of OLSR-ETX regarding queue availability by using a cross-layer scheme and supporting QoS and QoE assurance. QoETX optimizes network and user-based parameters by coordinating queue availability, QoS and fuzzy issues in the routing decision process as a way to allocate the best paths for multimedia applications. In order to present the benefits of the proposed solution compared with existing routing schemes, namely OLSR-ETX, OLSR-FLC, OLSR-MD and HWMP (IEEE 802.11s standard), regarding QoS (block probability and throughput) and QoE (PSNR, SSIM, VQM and MOS) parameters, performance evaluations were carried by using the Network Simulator (NS-2.34).

Artigos de Conferência, Publicação

Abaré: Um framework para implantação, monitoramento e gerenciamento coordenado e autônomo para redes em malha sem fio

The Wireless Mesh Networks (WMNs) have been gaining ground as a solution to provide last mile indoors and outdoors Internet access, because of their technical and economic feasibility. However, the existence of open source and proprietary approaches that are not interoperable and the delay in the standardization process make deployment of a large-scale WMN timeconsuming and complex. This paper presents an extension of the framework Abaré with autonomic capability and performance evaluation results regarding load balance issues. Abaré defines a set of components and practices in order to optimize the implementation and management of WMN systems, as well as to provide autonomic features in routers to decrease and facilitate the manager workload.

Artigos de Conferência, Publicação

Mitigação Inteligente de Ataques DDoS em Redes O-RAN Utilizando Aprendizado de Máquina

A transição das redes móveis para o 5G estimulou a adoção de tecnologias como NFVs, SDN, slices e de padrões abertos e interoperáveis como o Open RAN (O-RAN). Em relação à segurança, as redes O-RAN se encontram nos estágios iniciais para garantir a integridade e confiabilidade. Diante deste cenário, este trabalho propõe o SID-xApp (Slice Intelligent Defender xApp), uma aplicação integrada ao controlador de quase tempo real da rede (Near-RT RIC), com o objetivo de identificar e mitigar ataques DDoS que possam comprometer os slices presentes na O-RAN. A solução proposta é projetada para permitir o desenvolvimento de forma modular e suportar o recebimento de métricas dos dispositivos conectados à rede, identificar padrões por meio de modelos de aprendizado de máquina (AM) e desassociar usuários mal-intencionados, proporcionando uma camada de segurança ao open fronthaul da O-RAN.

Artigos de Conferência, Publicação

OCClient: Ferramenta para Gerenciamento integrado de Dispositivos em Redes SDN

A tarefa de integração com APIs pode ser onerosa, tanto em tempo como por conta de custo com pessoal. No caso de Redes Definidas por Software (SDN), que utilizam o controlador ONOS, essa situação é especialmente problemática já que ele não possui um SDK. Este trabalho apresenta uma solução para gerenciamento de dispositivos, denominada OCClient. Inicialmente a solução foi desenvolvida para ser uma ferramenta de apoio ao grupo de trabalho da UFPA, durante a fase 1, do programa OpenRAN@Brasil. Posteriormente, notou-se um interesse da comunidade por uma ferramenta que pudesse auxiliar na interação com o controlador. Por tratar-se de um binário, pode ser executado na maioria dos ambientes, sem a necessidade de instalação, facilitando a adoção em fluxos automatizados de gerenciamento de configuração de redes, tal como acontece na abordagem GitOps. Para os testes foi provisionado um laboratório com dispositivos emulados pelo CNETLAB e um controlador, um arquivo JSON, contendo as declarações dos dispositivos e respectivos links foi utilizado para aplicar as configurações de registro dos dispositivos no controlador. Posteriormente, a ferramenta também foi utilizada para realizar a remoção dos dispositivos do controlador. E por fim, foi realizada uma comparação entre aplicar as configurações através da ferramenta ou por meio de uma implementação direta utilizando utilizando uma linguagem de programação.

Artigos de Conferência, Publicação

Detecção de Ataques DDoS em Redes SDN Utilizando Aprendizado de Máquina: Uma Abordagem em Microsserviços

Ainda hoje, a segurança é um desafio crítico nas Redes Definidas por Software (SDN), incluindo ameaças como ataques de negação de serviço distribuído (DDoS). Nesse cenário, o uso de aprendizado de máquina é promissor para detectar e mitigar tais ataques, onde devem ser considerados não apenas o desempenho do modelo, como também, o seu impacto no desempenho do controlador da rede. Este trabalho propõe uma abordagem baseada em microsserviços, avaliando cinco modelos de aprendizado de máquina para detecção. Os resultados identificaram o Random Forest como mais eficaz com F1-Score de 98.65%. Além disso, a abordagem de microsserviços permitiu a utilização de modelos mais complexos sem prejudicar o desempenho do controlador SDN.

Artigos de Conferência, Publicação

AID-SDN: Advanced Intelligent Defense for SDN Using P4 and Machine Learning

The advent of protocol independent packet processor (P4) programming allows devices, such as switches, to determine how data is processed at the data plane. P4 opens up the possibility of using lightweight machine learning models (ML) to support intelligent security services over software-defined networks (SDN). However, it is challenging to integrate ML models into P4-based switches to detect attacks, mainly due to the internal limitations of the P4 architecture. It is also challenging to combine P4-based detection with old-fashioned detection, where attack classification is performed at the edge of the network. To overcome this challenge, this paper proposes Advanced Intelligent Defense for SDN (AID-SDN). It is a hybrid solution that supports and coordinates two layers of ML classification for attack detection. The first layer runs on P4-based switches and the second layer runs at the edge of the network. The proposed solution aims to benefit from the faster detection of P4-based classification and also from the accuracy and scope of conventional ML classification. AID-SDN has been implemented in a simulated environment to evaluate the performance of the system and assess its ability to accurately detect different types of attacks considering different ML methods. The results show that AID-SDN achieves high performance considering ML metrics and classification time for each attack tested.

Artigos de Conferência, Publicação

Redes Definidas por Software para a Orquestração de Diferentes Domínios Tecnológicos

Current and next generation mobile networks (5G and 6G) fully virtualized and based on open software and hardware solutions demand a flexible and programmable control plane capable of handling technologies from different technological domains. In this context, this work investigates the use of the Software Defined Networking (SDN) paradigm to orchestrate the technological domains of data networks, with Programmable Packet Data Plane (PPDP), Software-Defined Passive Optical Networks (SD-PON) and Wavelength Division Multiplexing (WDM) networks. For this, an SDN environment was created, using the ONOS controller to manage data plane devices from different technological domains. As a result, the research proved the viability of using SDN technology in the orchestration of multidomain devices.

Artigos de Conferência, Publicação

Agregaçao e Desagregaçao de Dados IoT em Redes Definidas por Software Utilizando P4

Low-Power Internet-of-Things (LPIoT) networks are characterized by a large number of IoT nodes with resource limitations. Due to its limitations, it is common to use data aggregation techniques in LPIoT data traffic. However, any aggregated payload needs to be disaggregated before the data is delivered to IoT applications. This work proposes a new strategy for aggregating and disaggregating IoT data in software-defined networks (SDN) using the P4 language.

Artigos de Conferência, Publicação

Planejamento e Avaliaçao de Redes de Computadores Utilizando Cópias Digitais: Estudo da Rede Metropolitana de Belém (MetroBel)

The MetroBel network was a pioneer network in the national context, launched in 2007, connecting several teaching and research institutions in the metropolitan region of Belem/PA. Designed 15 years ago, it is still in produc- ´ tion, but needs to evolve to meet the new demands of user institutions. One of the obstacles to this evolution is the difficulty in carrying out tests to verify new configurations and adoption of new technologies. An innovative approach to overcoming these challenges is the use of Digital Shadow to address real-world problems. This approach uses digital techniques to represent real-world objects, has been gaining popularity in the industry and is beginning to be used in different scenarios. This paper proposes a four-step strategy to create a Digital Copy as an alternative to planning and evaluating computer networks. A case study of the MetroBel network is carried out to validate the proposal.

Artigos de Conferência, Publicação

Fatias (Leves) como um Serviço: Uma Solução para Dispositivos Móveis na Borda da Rede

Cloud Network Slicing (CNS) is the process of isolating end-to-end, on-demand, independently controlled, managed, and/or orchestrated cloud and network resources, which are called slices. In this context, one can consider devices with low computational power, such as mobile devices, to provide resources for slices, thus bringing services even closer to the end users. However, platforms that provide Slice as a Service (SlaaS) do not allocate mobile devices as part of the slice. In this sense, this paper presents a SlaaS platform that allocates mobile devices as part of the slice. For this, lightweight virtualization is used instead of full virtualization to do the slice instantiation. The results show it is possible to allocate mobile devices as part of the slice. The results obtained show that the solution is promising because of better performance in lightweight virtualization compared to full virtualization.

Artigos de Conferência, Publicação

Uma Abordagem de Aprendizado de Máquina Para Detecção Híbrida de Ataques no Plano de Dados SDN

The programmability of the SDN data plane allows users to write algorithms that define how network devices should process packets, including the use of programming interfaces (APIs) to take advantage of the network controller. With this great flexibility, the use of machine learning applications has been proposed for packet classification and attack detection. In this scenario, trained models are used to complete the action and correspondence table of pipeline P4 offering equal detection and processing time. Another approach used is network telemetry, which allows obtaining information on the state of the network and using it by applications running on the controller or external agent. In contrast, this work advances the state of the art by proposing a hybrid AM management architecture for SDN networks, combining the use of the P4 pipeline and strategic agents in the network to provide detection of multilevel attacks.

Artigos de Conferência, Publicação

Proposta de planejamento, gerência e otimização de recursos de redes em tempo de execução utilizando Gêmeo Digital

The Digital Twin is a promising concept, which is being adopted by several industrie by integrating a number of technologies. However, the adoption of this approach in computer networks is still timidy. Thus, this paper proposes a digital twin system structured in four layer that uses a multilayer SDN testbed as the physical entity, the CNetLab emulator as the digital twin and a data processing environment as the intermediate layer establishing a bidirectional connection between these environments.

Artigos de Conferência, Publicação

Qualidade de Serviço Absoluta em Redes OBS baseadas no GMPLS

Este artigo apresenta uma proposta para oferecer Qualidade de Serviço (QoS) absoluta em redes OBS baseadas no plano de controle GMPLS. Nessa proposta, as técnicas de engenharia de tráfego do GMPLS são usadas para proporcionar QoS absoluta de maneira eficiente através da otimização do uso dos recursos da rede e procurando minimizar o desfavorecimento das classes de menor prioridade. Para validar a proposta são realizadas simulações utilizando a plataforma NS-2 (Network Simulator).

Artigos de Conferência, Publicação

A Model of Signaling for Establishing of LSPs for Multicast Communication over GMPLS Networks

Label switching, which in IP networks is exemplified by MPLS and its extensions MPLambdaS and GMPLS, appears as one of the best alternatives to offer a reliable and flexible control plane for WDM networks, since it allows the integration of the IP Protocol with WDM technology, when lambdas are associated with labels, implements powerful traffic-engineering mechanisms, and provides several alternative schemes for fault-tolerance, as well as support for quality of service (QoS). However, almost all the definitions and standardizations for MPLS are restricted to unicast communication, leaving support for multicast communication for future work. In the specific case of the triggering problem for LSPs (Label Switched Paths), there is still no consensus about the best strategy for multicast communication. This paper proposes an algorithm for traffic-driven triggering of LSPs, based on MFCs (Multicast Forwarding Caches), and has the advantage of being a schema which is compatible with several multicast routing protocols. To validate the proposed algorithm we carry out simulation studies using the NS-2 (Network Simulator) simulation platform.

Artigos de Conferência, Publicação

Log analysis based mechanism fornetwork security incidents identification

The increasing use and importance of networks in today’s economic and social context have also led to a rise in the number of malicious activities that violate privacy and security policies of institutional networks. There are several approaches aimed at detecting such activities, such as the use of intrusion detection systems. The goal of this paper is to present an alternative approach to detecting malicious activities based on querying and correlating the events recorded in system logs. The purpose of this approach is to identify the hosts responsible for these malicious activities. Experiments conducted at the Brazilian National Research and Educational Network’s Point of Presence in the State of Pará have shown that this proposal can accurately detect the hosts responsible for malicious activities while requiring low computational resources.

Artigos de Conferência, Publicação

Performance analysis of Ethernet passive optical networks with high load through a hybrid analytical/simulated model

This paper presents a hybrid analytical/simulated model to analyze the performance of upstream flows in Ethernet Optical Passive Networks (EPON) based on frame’s total delay. The modeling was done using Stochastic Colored Petri Networks (SCPN), from where the average queue size is obtained. Then, this average is used to analytically obtain the total delay. An improvement in the scheduling strategy based on weights of classes of traffic (CoS) is also proposed so as not to penalize too much the best-effort (BE) class type.

Artigos de Conferência, Publicação

Provisionamento Automático de Conexões Determinísticas para Redes GOBS

This paper proposes an architecture for the automatic establishment of connections that match the performance constraints for grid applications. This architecture is based on optical burst switching and on the utilization of protocols with traffic engineering functionalities. It propose an element called GOBS (Grid Optical Burst Switching) Server that stores and collects information about grid metrics and network resources and helps in the calculation of deterministic routes. Simulations show that the proposal is able to minimize the burst blocking, thus guaranteeing the established service levels, and it allowing better utilization of the grid and network resources.

Artigos de Conferência, Publicação

A multiple-metric approach for routing in wireless mesh networks

We present a multiple-metric approach in order to improve routing in Wireless Mesh Networks (WMNs). It is based on the proactive Optimized Link State Routing (OLSR) protocol to deal with applications with high Quality of Service (QoS) demands. Since routing with multiple metrics is an NPcomplete problem, we use the Analytic Hierarchy Process (AHP) and Pruning techniques to perform such routing. The proposal, dubbed here OLSR-MM (Multiple-Metric), offers the best available routes based on the considered metrics and is evaluated on Network Simulator 2.31.

Artigos de Conferência, Publicação

Reactive Management of Quality of Service in Multimedia OBS Networks Based on GMPLS

This paper presents a proposal for dynamic control of Quality of Service (QoS) in optical networks based on optical burst switching (OBS) using a GMPLS control plane. In this proposal, monitoring agents are used to verify the QoS experienced by the burst classes and to deploy reactive mechanisms in order to guarantee absolute performance levels. Using GMPLS traffic engineering, these agents also offer idle resources to traffic flows whose service level is not being achieved. Simulation results show that the proposal can minimize the blocking probability when there are violations of burst flow parameters.

Artigos de Conferência, Publicação

Um modelo de componentes para aplicações telemáticas e ubíquas

Esta tese descreve CM-tel, um modelo de componentes para aplicações telemáticas e ubíquas.
CM-tel é neutro em termos de tecnologia, sendo especificado por meio da linguagem UML (Unified
Modeling Language). Componentes CM-tel são capazes de executar em plataformas destinadas tanto
a computadores tradicionais quanto a dispositivos com limitado poder computacional tais como dispositivos móveis. CM-tel define os três tipos de interfaces prescritas pelo Modelo de Referência para
Processamento Distribuído Aberto (RM-ODP), as interfaces operacional, de sinal e de fluxo contínuo.
Interfaces de fluxo contínuo são fundamentais para o desenvolvimento de aplicações telemáticas. A
arquitetura do contêiner CM-tel integra componentes e agentes móveis em um único ambiente computacional. Esta integração permite que aplicações implementem suas funcionalidades combinando
componentes e agentes móveis. Esta tese propõe ainda uma arquitetura para plataformas de software
que suportam o modelo CM-tel. A arquitetura utiliza XSLT (XML Stylesheet Language Transformation) para transformação de modelos e geração de código. Uma plataforma baseada na tecnologia
CORBA (Common Object Request Broker Architecture) e uma aplicação na área de laboratórios virtuais foram implementadas com a finalidade de avaliar o modelo CM-tel

Artigos de Conferência, Publicação

Difusão Seletiva em Inter-Redes IP Baseadas em Redes Ópticas

A difusão seletiva e os recentes avanços na tecnologia de transmissão
óptica, mais especificamente na multiplexação por comprimento de onda
(“Wavelength Division Multiplexing-WDM”), aliados à consolidação do IP como
protocolo dominante das redes convergentes, vêm oferecendo novas perspectivas
para as futuras gerações de inter-redes. Este trabalho faz uso da evolução dessas
tecnologias para propor um conjunto de adaptações à difusão seletiva, em especial
ao IP Multicast, denominado MIRROR (“Multicast IP para Redes baseadas em
Rajadas Ópticas Rotuladas”). A proposta MIRROR sugere modificações e
adequações para tornar o IP Multicast menos complexo, mais escalável em
relação ao número de grupos ativos simultaneamente e mais adequado às redes
baseadas em comutação óptica. Basicamente, MIRROR revê a necessidade de
todos os roteadores ao longo da árvore de distribuição multiponto manterem
informações de estado relacionadas a esta, bem como sugere adequações na forma
como os caminhos multiponto são estabelecidos quando se emprega comutação
baseada em rótulos na difusão seletiva. Para avaliar a proposta MIRROR,
investiu-se em duas frentes distintas, uma baseada na análise comparativa entre a
MIRROR e algumas alternativas ao IP Multicast apresentadas na literatura, e
outra baseada no desenvolvimento de um protótipo da proposta no simulador NS
(“Network Simulator”), com o intuito de referendar os resultados da análise
comparativa. Na análise comparativa, confronta-se parâmetros como: requisitos
de informações de estado, custo com informações de controle, custo de
encaminhamento dos pacotes e custo da árvore de multiponto. O desenvolvimento
do protótipo envolveu a criação de uma nova estrutura de nó e a alteração de
módulos já existentes no NS, para tornar possível a simulação de redes comutadas
por rajadas ópticas rotuladas no contexto da difusão seletiva.

Artigos de Conferência, Publicação

IP Multicast for Optical Burst-Switched Networks

New research perspectives opened up by the combination of IP and WDM technologies present an excellent opportunity for reformulating certain aspects of multicast transmission, bringing them more in line with the needs of future generations of IP internetworking. This paper analyses MIRRORS, which proposes modifications to traditional IP Multicast in order to improve its scalability as a function of the number of simultaneously active groups, as well as making it more appropriate for use in optically switched networks. In this analysis, MIRRORS is compared with other major multicast alternatives, using such parameters as: information state requirements, control overhead, cost of packet forwarding and cost of the multicast distribution tree.

Artigos de Conferência, Publicação

IP Multicast for Optically Switched Networks

New research perspectives opened up by the combination of IP and WDM technologies present an excellent opportunity for reformulating certain aspects of multicast transmission, bringing them more in line with the needs of future generations of IP internetworking. This paper analyses MIRROR, which proposes modifications to traditional IP Multicast in order to improve its scalability as a function of the number of simultaneously active groups, as well as making it more appropriate for use in optically switched networks. In this analysis, MIRROR is compared with other major multicast alternatives, using such parameters as: information state requirements and the costs of control information, packetforwarding and storing the distribution tree topology.