Artigos de Conferência, Publicação

A Two-Tier Adaptive Data Aggregation Approach for M2M Group-Communication

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Network lifetime is the time interval in which the nodes are operational. Considering that machine-to-machine (M2M) devices have limited energy resources, an important challenge in M2M communications is to prolong the network lifetime. The constrained application protocol (CoAP) supports multi-target monitoring applications in M2M communications, allowing the creation and maintenance of groups, as well as their periodic communication. It is essential to aggregate the CoAP group-communication over the paths to increase the network lifetime of low-power M2M devices, since data aggregation reduces the use of energy-consuming hardware (e.g., central processing unit and wireless interface). However, the current data aggregation solutions do not specify how to support data aggregation with multiple CoAP-based groups in multi-target monitoring applications. In this paper, the proposed approach, called two-tier aggregation for multi-target applications (TTAMAs), aggregates the data originated from nodes belonging to either the same or different CoAP groups. Furthermore, TTAMA is an adaptive solution because it performs the data aggregation in accordance with the CoAP configurations, such as communication periodicity and data aggregation functions. We compare TTAMA with current data aggregation approaches that use minimum spanning tree and shortest path tree. The results show that TTAMA outperforms the related works in terms of network lifetime and energy consumption.

Artigos de Conferência, Publicação

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

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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

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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

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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

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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

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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.