Artigos de Conferência, Publicação

vSDNBox: Um Hardware Especializado de Baixo Custo Gerenciado via SDN

Os switches whitebox vêm sendo uma alternativa vantajosa para o plano de dados SDN. Eles permitem tanto a redução nas despesas como também a ampliação dos níveis de heterogeneidade de fabricantes na infraestrutura de rede. Recentes ferramentas possibilitaram que os whiteboxes baseados em software-switches pudessem ampliar seus desempenhos apenas com otimizações feitas via softwares abertos em hardwares genéricos. A partir disso, propõe-se o vSDNBox, uma alternativa de whitebox software-switched para redes definidas por software, capaz de reduzir ainda mais os custos e ampliar o desempenho através de seu gerenciamento e otimizações feitas via software no espaço do usuário. Os resultados obtidos comprovam que a proposta consegue ter um desempenho igual ou aproximado de um whitebox hardwareswitched através de avaliações de vazão e latência.

Artigos de Conferência, Publicação

DLCP: A protocol for securing light client operation in blockchains

In blockchain, full nodes (FNs) are peers that store and verify entire chains of transactions, and light clients (LCs) are those which outsource chain verification to FNs (as they lack computing resources required to do so). In general, LCs perform simpler verification protocols, e.g. Simple Payment Verification (SPV), by offloading the execution of blockchain operations to FNs. To cope with byzantine faults (like malicious behavior), a current approach for blockchain transaction verification is requiring that LCs outsource their requests to multiple FNs, and compare received results. This approach, however, requires that LCs establish secure connections to each FN, which leads to client-side complexity and slower verification. To tackle this issue, we propose Distributed Lightweight Client Protocol (DLCP), a protocol for secure verification in blockchain. In summary, DLCP requires LCs to encrypt a request once, allowing a pre-determined set of FNs to access and process it. Through DLCP, LCs become able to verify whether FNs have agreed on the operation outcome. From some preliminary evaluation, we observed that DLCP decreased computing and communication overhead in LCs, while providing lower latency.

Artigos de Conferência, Publicação

Topology resilience enhancement for software defined networks

Software Defined Networks is a paradigm that flexibilizes the management of networking, separating the control and forwarding planes. This separation introduces new concerns towards the resilience of the network, which now presents different vulnerabilities related to the interaction between these planes. A resilience factor for Software Defined Networks is proposed, using multiple metrics to analyze intrinsic features of its architecture, serving as an indication for its resilience. Beyond that, topological augmentation algorithms are employed to increase the resilience of test topologies, as indicated by the proposed factor. Tests results demonstrate an improvement of the topologies’ resilience characteristics.

Artigos de Conferência, Publicação

FI-MApp: a web application for managing FI-WARE environments in internet of things

The FI-WARE project aims to create a core platform for the Future Internet. However, such a platform has failed to promote the centralization of its services, since it did not offer a unified development framework. In addition, it demands a great effort to use the platform, due to extensive, disordered and scattered documentation. In this context, the present work explored the FI-WARE service for enabling the Internet of Things (IoT). The main goal was to develop a Web application for an integrated visualization and management of the resources offered by FI-WARE IoT enabling services. Called FI-MApp, the proposed Web application acts as a bridge (middleware) between the FI-WARE IoT service and its managers. FI-MApp is shown as suitable solution in this scenario because the FI-WARE APIs have already been implemented following the RESTful Web service architecture. Through its simple and intuitive user interface, the FI-MApp Web application make it easy for both managing and visualizing FI-WARE IoT environments from different parts of the world by offering features, such as registering new IoT devices and data collection from both real and virtual sensors.

Artigos de Conferência, Publicação

Securing light clients in blockchain with DLCP

In blockchain, full nodes (FNs) are peers that store and verify entire chains of transactions. In contrast, light clients (LCs) are those with limited resources, and for this reason, they request only block headers from FNs for transac- tion verification—using protocols like Simple Payment Verification (SPV). In an approach to prevent FN tampering on transaction verification (byzantine fault), LCs request block headers from multiple FNs and compare received responses. One problem with this approach is that an LC must connect to each FN and per- form the same cryptographic operations with each one repeatedly, which leads to client-side complexity and slower response. We propose an alternate approach to tackle this issue, in which LCs can encrypt a request for block headers only once, and send that request to a predetermined set of FNs to access, process, and reply back in a single response. Our approach, called Distributed Lightweight Client Protocol (DLCP), enables LCs to verify with little effort if FNs have agreed on a response. From an experimental evaluation, we observed that DLCP pro- vided lower latency and reduced computing and communication overhead in comparison with the existing conventional approach.

Artigos de Conferência, Publicação

Fator de Resiliência para Aprimoramento Topológico em Redes Definidas por Software

Redes Definidas por Software é um paradigma que exibilizaa gerência de redes de computadores ao separar os planos de controle e de dados. Essa separação introduz novas preocupações quanto a resiliência da rede, que passa a apresentar diferentes vulnerabilidades relacionadas a interação entre os planos. É proposto um fator de resiliência para Redes Definidas por Software, utilizando múltiplas métricas para analisar características intrínsecas da arquitetura, servindo como indicativo de resiliência da rede. Além disso, algoritmos de aprimoramento topológico são empregados para aperfeiçoar a resiliência das topologias utilizadas. Os resultados de monstram melhoria nas características de resiliência.

Artigos de Conferência, Publicação

Busca de caminhos como serviço em vSDNs

As Redes virtuais Definidas por Software (vSDNs) são a junção de SDN e Virtualização. Neste contexto, o hipervisor de rede é responsável pela gestão da rede física, enquanto a rede SDN não virtualizada mantém esta função no controlador. Este artigo apresenta o Search Path, um buscador de caminhos baseado em grafos que evita traduções desnecessárias entre o hipervisor de rede e os controladores no contexto de vSDNs. A fatia encaminhada pelo hipervisor de rede é recebida pelo Search Path em forma de grafos, facilitando o desenvolvimento de lógicas de encaminhamento específicas para cada rede, através da manipulação de grafos. Os testes realizados demonstram que o Search Path possui resultados melhores quando comparado com hipervisor de rede e controlador tradicionais.

Artigos de Conferência, Publicação

Tag-and-Forward: A source-routing enabled data plane for OpenFlow Fat-Tree Networks

Software-Defined Networking (SDN) has turned the Data Center Network (DCN) environment into a more flexible one by decoupling control plane from data plane, allowing an innovative and easily extensible network management solutions. Nowadays, OpenFlow is the most successful protocol for SDN. However, SDN based on OpenFlow protocol presents performance issues on forwarding table increasing and packet match cost. Our proposal named Tag-and-Forward (TF) is a data plane that reduces the number of flow table required in the Fat-Tree software-defined DCNs to optimize forwarding. The results noticebly outperformed RTT and packet transmission rate when compared to usual OpenFlow data plane.

Artigos de Conferência, Publicação

Cache-Aware Interest Routing: Impact Analysis on Cache Decision Strategies in Content-Centric Networking

Information-Centric Networking (ICN) is one of the most promising model for dealing with the cern of the current Internet scenario, that is content. In this model, either routers or user devices in the network are capable of storing content in cache, where a client device pull a content by expressing an interest of the desired content name. One of the most sucessfull implementation of ICN is Content-Centric Networking (CCN) proposed by PARC. In CCN, the forwarding strategy pushes interest packets torwards a content server through a route determined by the Shortest-Path Route (SPR) strategy. However, SPR cannot fully exploit the network caching benefits, because the caching process only happens within the path without considering cache saturation level. Therefore, we propose Least Cache Routing (LCR) cache-aware strategy. Besides being based on SPR, LCR is constantly looking for the least saturated paths. The results shows that, a slight improvement on forwarding strategy is capable of improving LCE and LCD cache decision policies. Our results shows 150% and 53% performance gain on cache hit probability when LCR is jointly running with, respectively, LCE and LCD on Torus network.

Artigos de Conferência, Publicação

On the Benchmarking Mainstream Open Software-Defined Networking Controllers

Software-Defined Networking (SDN) has been one of the most successfull networking model over the past few years. The model decouples the network control and forwarding functions enabling the underlying infrastructure complexity to be programmed by applications. Although control plane is the cern for all the benefits, it is also the most crucial drawback of the SDN model to keep up working. Therefore, this paper presents a performance analysis on mainstream open-source SDN controllers. The results show that a well-perfomed control plane not only depends on controller throughput and response time, but also relies on topology discovery time. Our results show that Beacon controller has the highest performance on controller troughput because it uses multicore feature better than others. However, there is a few difference on topology building delay when compared to ONOS, Floodlight and OpenDaylight, which are also Java-based controllers. The worst one is Ryu for building network topology.

Periódicos, Publicação

Uma estratégia para o serviço de cálculo de caminhos em redes definidas por software

O paradigma de redes definidas por software (SDN) está sendo investigado como a solução mais promissora para o atual engessamento da internet, uma vez que propõe a dissociação entre o plano de dados e o plano de controle, proporcionando maior programabilidade às redes de computadores. No entanto, ainda há lacunas em serviços disponíveis nessa arquitetura, dentre as quais se observa o serviço de cálculos de caminhos, que não está evoluindo consideravelmente entre os controladores. Por exemplo, a reserva de recursos, a partir dos requisitos necessários de cada aplicação, permanece como um desafio a ser vencido. Este artigo apresenta uma estratégia de cálculo de caminhos para redes SDN. O objetivo é oferecer um serviço mais flexível no estabelecimento de fluxos OpenFlow, além de possibilitar restrições determinísticas de qualidade vindas das aplicações. A proposta contribui também com uma arquitetura que pode ser aplicada a controladores SDN, um algoritmo de busca, baseado em uma métrica de qualidade de serviço (QoS), e uma análise de desempenho, mostrando que o algoritmo é capaz de minimizar o tempo de busca, processamento e consumo de memória pelo controlador na rede SDN.

Periódicos, Publicação

NVP: A Network Virtualization Proxy for Software Defined Networking

The combination of Network Function Virtualization (NFV) and Software Defined Networking (SDN) can improve the control and utilization of network resources. However, this issue still requires proper solutions to virtualize large-scale networks, which would allow the use of SDN and Virtualization in real environments.Thus, this paper proposes a virtualization architecture for SDN that relies on a proxy-based approach. The NVP (Network Virtualization Proxy) is a virtualization proxy that intercepts messages exchanged between controllers and switches SDN enabling network virtualization. An implementation of the proposal was developed as a proof of concept and load testing was performed showing that the solution can provide network virtualization in a scalable manner, using less than 2.5 MB of memory to manage 100 switches performing simultaneous requests, whereas FlowVisor requires more than 200 MB.

Artigos de Conferência, Publicação

A MultiCriteria Caching Decision for information centric networks

Information Centric Networks (ICN) has been a new network paradigm and it has attracted a lot of attention recently. In this new model, contents are retrieved by their name, not by IP address, shifting from host-to-host to a host-to-content approach. In networking-caching plays a very important role in ICN, which enables routers to cache content in the path between a user and the permanent server, for instance. These intermediate nodes use a caching scheme to decide whether to store a content or not. However, most of the current caching schemes are only-one-criterion based and, given the dynamics of the network, this only one criterion may not be suitable, resulting in both low network hit ratio and performance. Therefore, we designed a MultiCriteria Caching Decision scheme for ICN, which not only considers one criterion for caching decision, but it aggregates three of them to better distribute content over the network and provide user’s requests. Our results got a much higher cache hit ratio than the other evaluated schemes and a reasonable download time.

Artigos de Conferência, Publicação

How to automatically collect oriented object metrics: A study based on systematic review

Aim: Getting information to automatically collect object oriented metrics (OO metrics) in order to assist the comprehension and assessment of software products. Method: It was developed a study based on a systematic review and 37 primary studies were selected from 577 papers retrieved in 3 databases. Result: 177 metrics that can be automatically collected were cataloged. Besides, 27 from such total were the most referenced. The cataloged metrics were classified according to the quality characteristics which were related; 18 collection tools have been identified. This way, it was concluded that there is a set of common procedures for collecting OO metrics and the Java and C++ are the languages with the largest number of tools on which is possible to extract metrics.

Artigos de Conferência, Publicação

Building an infrastructure for experimentation between Brazil and Europe to enhance research collaboration in future Internet

This paper describes the experience of RNP, the Brazilian research and education network, in creating a large scale research facility for experimentation on Future Internet as a member of the FIBRE (Future Internet testbeds experimentation between BRazil and Europe) project. Its main goal is to create common space between Brazil and EU for Future Internet experimental research into network infrastructure and distributed applications, by building and operating a federated EU-Brazil Future Internet experimental facility. The FIBRE testbed is currently composed by a federation of 13 local testbeds (a.k.a. experimental islands), located in different R&E organizations. The FIBRE infrastructure combines heterogeneous physical resources and different technologies, including OpenFlow, wireless and optical communications. We also present the architecture of FIBRE, which allows users to access the testbed through an integrated interface for either experimental or control planes, and provides a common access to the different underlying Control and Monitoring Frameworks (CMFs) for Future Internet experimentation.

Artigos de Conferência, Publicação

Fibre-an international testbed for future internet experimentation

This paper describes the FIBRE testbed, a large-scale research facility for experimentation on Future Internet. The current testbed is a federation of 13 local testbeds (aka experimental islands), located in different R&E organizations. The FIBRE infrastructure combines heterogeneous physical resources and different technologies, including OpenFlow, wireless and optical communications. This paper discusses the architecture of FIBRE, which includes different Control Management Frameworks, and describes how the testbed can be used in research and education to experiment with networking and distributed systems.

Artigos de Conferência, Publicação

Model of organization and distribution of applications for software defined networks: SDNrepo

One way to provide more flexibility for computer networks is through software defined networks (SDN). This paradigm supports network applications, whose behavior is defined by the controllers. However, management applications SDN is a solution under explored, such applications are scattered in various repositories codes on-line, or are still embedded in the factory switches. This article proposes a model of organization and distribution of applications, called SDNrepo, may specify and model all the way that applications must do to reach the end user, in this case the controllers.

Artigos de Conferência, Publicação

RepoSDN: An repository organization and coordination method of software defined networks applications

This paper describes the experience of RNP, the Brazilian research and education network, in creating a large scale research facility for experimentation on Future Internet as a member of the FIBRE (Future Internet testbeds experimentation between BRazil and Europe) project. Its main goal is to create common space between Brazil and EU for Future Internet experimental research into network infrastructure and distributed applications, by building and operating a federated EU-Brazil Future Internet experimental facility. The FIBRE testbed is currently composed by a federation of 13 local testbeds (a.k.a. experimental islands), located in different R&E organizations. The FIBRE infrastructure combines heterogeneous physical resources and different technologies, including OpenFlow, wireless and optical communications. We also present the architecture of FIBRE, which allows users to access the testbed through an integrated interface for either experimental or control planes, and provides a common access to the different underlying Control and Monitoring Frameworks (CMFs) for Future Internet experimentation

Artigos de Conferência, Publicação

Context-aware adaptation mechanism for video dissemination over Flying Ad-Hoc Networks

The user experience on watching live video sequences transmitted over a Flying Ad-Hoc Networks (FANETs) must be considered to drop packets in overloaded queues, in scenarios with high buffer overflow and packet loss rate. In this paper, we introduce a context-aware adaptation mechanism to manage overloaded buffers. More specifically, we propose a utility function to compute the dropping probability of each packet in overloaded queues based on video context information, such as frame importance, packet deadline, and sensing relevance. In this way, the proposed mechanism drops the packet that adds the minimum video distortion. Simulation evaluation shows that the proposed adaptation mechanism provides real-time multimedia dissemination with QoE support in a multi-hop, multi-flow, and mobile network environments.

Artigos de Conferência, Publicação

Additions to the ETArch control plane to support multimedia QoS-guaranteed content transport over OpenFlow-enabled SDN future internet systems

The Future Internet approach requires new solutions to support novel usage scenarios driven by the technological evolution and the new service demands. However, this paradigm shift requires deeper changes in the existing systems, which makes Internet providers reluctant in deploying the full transformation required for the Future Internet. The Entity Title Architecture (ETArch) is a holistic clean-slate Future Internet system embedding new services for these scenarios leveraging the Software Defined Networking (SDN) concept materialized by the OpenFlow. However, legacy ETArch deploys a fully per-flow approach to provision the same transport model for all sessions (equivalent to the Internet best-effort), while suffering with performance drawbacks and lacking Quality of Service (QoS) control. To that, we evolved ETArch with SMART (Support of Mobile Sessions with High Transport Network Resource Demand) QoS control approach, which coordinates admission control and dynamic control of super-dimensioned resources to accommodate multimedia sessions with QoS-guaranteed over time, while keeping scalability/performance and users with full Quality of Experience (QoE). The SMART-enabled ETArch system evaluation was carried out using a real Testbed of the OFELIA Brazilian Island, confirming its benefits in both data and control planes over the legacy ETArch.

Artigos de Conferência, Publicação

Filling the gap between Software Defined Networking and Wireless Mesh Networks

Software Defined Networking (SDN) has emerged as a new paradigm that highly increase the network management flexibility through simple but powerful abstractions. The key idea is decoupling the control plane, which makes the forward decisions, from the data plane, which effectively makes the forward. However, the OpenFlow, the main SDN enabler, is designed mainly by wired networks characteristics. As consequence, Wireless Mesh Networks (WMNs) is not suitable for operating as control plane and many wireless networks features are neglected in the OpenFlow, e.g.: power control and network ID. In addition, there are few effort research to extend SDN to wireless networks and these existing works focus on very specific issues of this integration. In this paper, we propose an architecture to extent the OpenFlow functionalities in order to proper deal with wireless networks, including an approach for transporting the control plane over wireless multihop networks. The extensions include new rules, actions, and commands, which bring the network management flexibility to the wireless context. We validated our proposal by implementing and testing some extensions in a small real world testbed. As a proof of concept, we illustrate the OpenFlow capability of isolation between research and production traffics in a wireless backhaul.

Artigos de Conferência, Publicação

Flowvisorqos: Aperfeicoando o flowvisor para aprovisionamento e recursos em redes virtuais definidas por software

. On the context of OpenFlow networks, the FlowVisor has emerged as a tool to enable the network virtualization, creating an environment for running multiple concurrent and independent experiments. However, this solution still has some limitations, such as the definition of mechanisms to allocate resources to different virtual networks. Although newer versions of the tool allow the queue assignment network slice, to provide resource control among them, device configurations are on the dependency of external tools. Therefore, this article aims to propose a solution to extend the FlowVisor functionality, creating a structure to allow traffic control configuration parameters in the network device, to ensure resource isolation and interference mitigation between the different virtual networks.

Artigos de Conferência, Publicação

Control of multiple packet schedulers for improving QoS on OpenFlow/SDN networking

Packet scheduling is essential to properly support applications on Software-Defined Networking (SDN) model. However, on OpenFlow/SDN, QoS is only performed with bandwidth guarantees and by a well-known FIFO scheduling. Facing this limitation, this paper presents the QoSFlow proposal, which controls multiple packet schedulers of Linux kernel and improve the flexibility of QoS control. The paper assesses QoSFlow performance, by analysing response time of packet scheduler operations running on datapath level, maximum bandwidth capacity, hardware resource utilization rate, bandwidth isolation and QoE. Our outcomes show an increase more than 48% on PSNR value of QoE by using SFQ scheduling.

Artigos de Conferência, Publicação

Cim-sdn: A common information model extension for software-defined networking

The increase in complexity of computer networks and their services have boosted the development of standardizations, models, and solutions for network management over the years. Lately, the Distributed Management Task Force (DMTF) defined the Common Information Model (CIM) for describing computational entities and businesses on the Internet. This paper proposes an extension of the CIM for Software-Defined Networking (SDN) by adding new elements (Controllers, Apps, Slices and others) to improve the system management performance. Furthermore, we define a metamodel to help the process of creating and understanding the proposed model. The proposal was validated by creating a script that generates the FlowVisor configuration file using the network model as input and using Object Constraint Language (OCL) to find inconsistencies in the network.

Artigos de Conferência, Publicação

Integrating legacy forwarding environment to OpenFlow/SDN control plane

Currently, there is a philosophical problem that arises between the real need for current support to OpenFlow and legacy network infrastructure. Among them, the legacy networking has not been compatible with OpenFlow network, and for that, it needs to be replaced or a few cases upgraded, as a consequence there are additional spending with new equipment OpenFlow-based. This paper introduces a proposal of hybrid SDN solution based on OpenFlow protocol and called of LegacyFlow, which is able to control Legacy equipment (non-OpenFlow) through OpenFlow protocol 1.0. Results show that it is possible used the LegacyFlow together with OpenFlow switches keeping a good performance time with OpenFlow application.

Artigos de Conferência, Publicação

Uma proposta de arquitetura para o provisionamento de circuitos dinâmicos sobre redes definidas por software

The OpenFlow technology enables the creation of a programmable layer over the control-plane of a network, in this way dictating the data-plane forwarding behaviour through the use of applications plugged to a network controller. Dynamic Circuit Network is an architecture that permits the scheduling of network resources on virtual circuits, such as bandwidth, over multiple domains with heterogeneous technologies. Recently, researches were conducted in order to integrate both technologies so that dynamic circuits can be dynamically provisioned over OpenFlow domains. The objective of this work is to propose an architecture that enables such provision, maintaining the QoS requisites of a DCN architecture.

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

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

ETXMULT: A routing metric for multimedia applications in wireless mesh networks

In a near future, wireless mesh networks (WMNs) and multimedia content will be abundant technologies/applications in the Internet. Hence, in order to keep and attract new customers, as well as, reduce operational costs, the development of new quality level control schemes are needed and it is one of the key requirements for the success of next generation wireless multimedia systems. With this goal in mind, this paper presents a new routing metric with focused on estimation error on wireless links, named ETXMULT (Expected Transmission Count for Multimedia Content), to assure high-quality paths on multi-hop wireless networks for multimedia traffic. Simulations were carried out, by using Network Simulator 2 (NS-2), to demonstrate the behavior and benefits of the proposed metric with Optimized Link State Routing (OLSR) routing protocol. The results presented improvements in the distribution of multimedia content compared to the original Expected Transmission Count (ETX) metric, by analyzing well-know QoS and QoE metrics.

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.