Augusto Neto

A routing protocol based on energy and link quality for Internet of Things applications.

The Internet of Things (IoT) is attracting considerable attention from the universities, industries, citizens and governments for applications, such as healthcare, environmental monitoring and smart buildings. IoT enables network connectivity between smart devices at all times, everywhere, and about everything. In this context, Wireless Sensor Networks (WSNs) play an important role in increasing the ubiquity of networks with smart devices that are low-cost and easy to deploy. However, sensor nodes are restricted in terms of energy, processing and memory. Additionally, low-power radios are very sensitive to noise, interference and multipath distortions. In this context, this article proposes a routing protocol based on Routing by Energy and Link quality (REL) for IoT applications. To increase reliability and energy-efficiency, REL selects routes on the basis of a proposed end-to-end link quality estimator mechanism, residual energy and hop count. Furthermore, REL proposes an event-driven mechanism to provide load balancing and avoid the premature energy depletion of nodes/networks. Performance evaluations were carried out using simulation and testbed experiments to show the impact and benefits of REL in small and large-scale networks. The results show that REL increases the network lifetime and services availability, as well as the quality of service of IoT applications. It also provides an even distribution of scarce network resources and reduces the packet loss rate, compared with the performance of well-known protocols.

A Resource Reservation Protocol Supporting QoS-aware Multicast Trees for Next Generation Networks

It is expected that next generation of networks will handle new types of services which are destined to large audiences and have different QoS requirements. From the transport point of view, multicast is the most suitable technology for the required group communication services, since it avoids packets duplication and saves network resources. However, QoS-aware multicast content deliver raises several problems, such as the control of QoS trees in environments with asymmetric routing. This paper presents Multi-service Resource Allocation (MIRA), a multicast-aware resource reservation protocol for class-based networks that consider routing asymmetries. MIRA controls the resources of network classes associated to multicast sessions considering the QoS characteristics of the latter and network conditions of the available classes in the source-to-receivers path. A detailed description of the functionalities of MIRA and a conceptual analysis against RSVP and RMD-QoSM are presented. Finally, the session setup time, and the signalling and state overheard in comparison with RSVP are analyzed based on simulations.

Scalable Resource Provisioning for Multi-User Communications in Next Generation Networks

The great demand for real-time multimedia sessions encompassing groups of users (multi-user), associated with the limitations of the current Internet in providing quality assurance, has raised challenges for defining the best mechanisms to deploy the next generation of networks (NGN). There is a consensus that an efficient and scalable provisioning of network resources is crucial for the success of the NGN, mainly in what concerns access networks. Previous solutions for the control of multi-user sessions rely mostly on uncoordinated actions to allocate per-flow bandwidth and multicast trees. This paper introduces a multiuser aggregated resource allocation mechanism (MARA) that coordinates the control of class-based bandwidth and multicast resources in a scalable manner. In comparison with previous work, MARA significantly reduces signaling, state and processing overhead. The performance benefits of MARA are analyzed though simulations, which successfully demonstrated the significant optimization in the network performance.

MMC04-3: A Unifying Architecture for Publish-Subscribe Services in the Next Generation IP Networks

Next generation IP networks are envisioned to be heterogeneous, to provide a wide variety of services, and to support mobility of users with distinct requirements. Moreover, mobile communications are expected to expand from telephony to publish-subscribe services, such as real-time multimedia. With this goal, the University of Coimbra is working with DoCoMo Euro-Labs on a unifying control architecture for multimedia publish-subscribe services over an IP-based mobile system, where our proposal aims to control the quality of service and mobility across heterogeneous networks with no perceived service degradation to the users. This article highlights the requirements of a control architecture for publish-subscribe services, and presents our proposal, called QoS Architecture for Multi-user Mobile Multimedia (Q3M). The main components and functionality of the Q3M architecture are analysed from the user and network perspectives, and some simulation results concerning the analysis of the session setup times are presented.

Virtualization at the network edge: A performance comparison

The rapid growth of the Internet of Things (IoT) is driving the evolution of Cloud technologies towards resource distribution across multi-clouds and the inclusion of various heterogeneous devices. IoT specific applications may require the deployment of gateways at the network edge to enable its interaction with physical sensors, pre-processing data from these sensors, and synchronizing it with the cloud. The orchestration, deployment, and maintenance of the software running on the gateways in large-scale deployments is known to be challenging. In this paper we analyze two virtualization techniques commonly used for deployment and management of applications at the cloud, but on the context of IoT and network edge. A study was conducted to evaluate the performance of the container-based approach compared to a hypervisor-based virtualization when running on devices typically used at the network edge. The study was performed through the execution of several synthetic benchmarks providing an insight in the performance overhead introduced by Docker containers (lightweight-virtualization) and KVM VMs (hypervisor-virtualization) running at network edge devices.

A quality of experience handover system for heterogeneous multimedia wireless networks

The convergence of emerging real-time multimedia services, the increasing coverage of wireless networks and the ever-growing popularity of mobile devices, are leading to an era of user-centric multimedia wireless services. In this scenario, heterogeneous communications will co-exist and ensure that the end-user is always best connected. However, the Quality of Experience (QoE) support for emerging video applications in multi-operator environments remains a significant challenge and is crucial for the success of wireless multimedia systems. This paper presents a Quality of Experience Handover Architecture for Converged Heterogeneous Wireless Networks, called QoEHand. QoEHand allows users of multimedia content to be always best connected in IEEE 802.11e and IEEE 802.16e environments. Simulation results show the impact and benefit of the proposed solution in multi-access and multi-operator wireless scenarios by using objective and subjective QoE metrics.

Mobility management for multi-user sessions in next generation wireless systems

Mobility management and ubiquitous access for real-time multi-user sessions with Quality of Service (QoS) support are major requirements to the success of next generation wireless systems. In this context, Multi-User Session Control (MUSC) is proposed to allow fixed and mobile users to access multi-user sessions ubiquitously, while providing QoS mapping, QoS adaptation and connectivity control in heterogeneous environments with mobile receivers and static senders. By interacting with resource allocation controllers, MUSC allows the construction of QoS-aware distribution trees over networks with different QoS models and aims to keep sessions with an acceptable quality of experience in congestion periods. Furthermore, by interacting with mobility controllers, MUSC assures the session continuity with QoS and connectivity support. MUSC was evaluated in a simulation and in an experimental environment to analyze its convergence time as well as its efficiency in allowing seamless mobility and in keeping sessions with an acceptable quality level during handover.

QoS Mapping and Adaptation in Next Generation Networks

The end-to-end quality of service (QoS) control is one of the key factors to the success of next generation networks. Therefore, this paper presents a session-aware QoS mapping and adaptation mechanism that maps the session QoS requirements into the most suitable network service class across heterogeneous mobile networks as well as it adapts the session to the current network conditions. The proposed scheme allows mobile operators to keep network internals sufficiently opaque and to reduce operational costs by mapping and/or adapting sessions to groups of heterogeneous mobile users. Concurrently, the proposed scheme assures acceptable quality levels to on-going sessions, independently of the movement of users. In addition, an experimental evaluation in a QoS mobile multicast environment is presented

Advanced multicast class-based bandwidth over-provisioning

Dynamic bandwidth aggregate over-provisioning has been proposed to provide differentiated services with scalable Quality of Service (QoS) control. Previous research showed that efficient over-reservation control allows minimizing QoS control overhead with reduced waste of bandwidth and blocking probability. However, existing over-reservation centric solutions are still inefficient in the face of network dynamics, as they are not able to accommodate the dynamic service demands, thus failing to optimize the bandwidth usage. This paper proposes a new Advanced Class-based resource Over-Reservation (ACOR) solution for multicast sessions, which seeks increased network resources utilization while minimizing QoS control overhead. More specifically, ACOR is able to dynamically update the share of bandwidth between different classes of service, providing improved results with less complexity than current solutions. Our analytical and simulation results prove the cost-effective and scalable QoS control capabilities of ACOR in decentralized networks with multiple distributed ingress routers coordinating the QoS control.

A New Strategy for Efficient Decentralized Network Control

The limited scope of Internet architecture forced network providers implementing centralized mechanisms (QoS, group communication, mobility, etc) to support attractive value added sessions. Besides ease to manage, performance aspects of such mechanisms, mainly in terms of scalability, robustness and availability, are shortcoming. In this sense, decentralization is promising, since complex networking operations may be provided throughout the nodes, increasing the network performance. However, current distributed solutions implement their own strategies for decentralization (e.g. synchronization, resilience, etc.), which contributes to increase Internets complexity and damage overall performance. This paper introduces a cost-effective strategy for scalable decentralization of control operations in current Internet, called Self-Organizing Multiple Edge Nodes (SOMEN) mechanism. SOMEN enables multiple distributed network Control Decision Points -CDPs- (e.g. network borders) to jointly exploit control data inside a network with low signaling load. The effectiveness of SOMEN was proved through analytical modeling and simulation, which demonstrated significant minimization of control overhead.