Artigos de Conferência, Publicação

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

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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

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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

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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

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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

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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

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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

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

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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.