Xavi Masip-Bruin

The EuQoS system: a solution for QoS routing in heterogeneous networks [Quality of Service based Routing Algorithms for Heterogeneous Networks]

EuQoS is the acronym for end-to-end quality of service support over heterogeneous networks, which is a European research project aimed at building an entire QoS framework, addressing all the relevant network layers, protocols, and technologies. This framework, which includes the most common access networks (xDSL, UMTS, WiFi, and LAN) is being prototyped and tested in a multidomain scenario throughout Europe, composing what we call the EuQoS system. In this article we present the novel QoS routing mechanisms that are being developed and evaluated in the framework of this project. The preliminary performance results validate the design choices of the EuQoS system, and confirm the potential impact this project is likely to have in the near future

An efficient and lightweight method for Service Level Agreement assessment

Traditional approaches to on-line end-to-end Service Level Agreement (SLA) assessment have focused on the estimation of network QoS parameters. These approaches, however, face a trade-off between accuracy and the amount of resources needed to achieve such accuracy. This paper offers an alternative approach, where instead of estimating QoS parameters, we propose an effective and lightweight solution for directly detecting SLA violations. Our solution monitors the Inter-Packet Arrival Time (IPAT) at an end-point, wherein current IPAT distributions are periodically compared with a set of reference IPAT distributions as the main basis for detecting SLA violations. A mapping of the IPAT distribution with the current network conditions is derived, and a training algorithm that dynamically acquires the set of reference IPAT distributions is designed. For the comparison of the IPAT distributions, we propose a variant of the Hausdorff Distance algorithm. Our variant provides a better accuracy than the traditional Hausdorff Distance, while presenting linear complexity. Our proposal is validated in a real testbed, by comparing the SLA violations detected and the resources required in terms of bandwidth, with other existing alternatives as well as with perfect knowledge of current network QoS status.

Do we all really know what a fog node is? Current trends towards an open definition

Fog computing has emerged as a promising technology that can bring cloud applications closer to the physical IoT devices at the network edge. While it is widely known what cloud computing is, how data centers can build the cloud infrastructure and how applications can make use of this infrastructure, there is no common picture on what fog computing and particularly a fog node, as its main building block, really is. One of the first attempts to define a fog node was made by Cisco, qualifying a fog computing system as a “mini-cloud” located at the edge of the network and implemented through a variety of edge devices, interconnected by a variety, mostly wireless, communication technologies. Thus, a fog node would be the infrastructure implementing the said mini-cloud. Other proposals have their own definition of what a fog node is, usually in relation to a specific edge device, a specific use case or an application. In this paper, we first survey the state of the art in technologies for fog computing nodes, paying special attention to the contributions that analyze the role edge devices play in the fog node definition. We summarize and compare the concepts, lessons learned from their implementation, and end up showing how a conceptual framework is emerging towards a unifying fog node definition. We focus on core functionalities of a fog node as well as in the accompanying opportunities and challenges towards their practical realization in the near future.

Towards Distributed Service Allocation in Fog-to-Cloud (F2C) Scenarios

The novel Fog-to-Cloud (F2C) computing paradigm has been recently proposed aiming at the enhanced integration of Fog Computing and Cloud Computing through the coordinated management of underlying resources, taking into account the peculiarities inherent to each computing model, and enabling the parallel and distributed execution of services into distinct fog/cloud resources. Nevertheless, studies on F2C are still premature and several issues remain unsolved yet. For instance, in an F2C scenario service allocation must cope with the specific aspects associated to cloud and fog resource models, requiring distinct strategies to properly map IoT services into the most suitable available resources. In this paper, we propose a QoS-aware service distribution strategy contemplating both service requirements and resource offerings. We model the service allocation problem as a multidimensional knapsack problem (MKP) aiming at an optimal service allocation taking into consideration delay, load balancing and energy consumption. The presented results, demonstrate that the adopted strategy may be applied by F2C computing reducing the service allocation delay, while also diminishing load and energy consumption on cloud and fog resources.

Securing combined Fog-to-Cloud system Through SDN Approach

Future IoT services execution may benefit from combining resources at cloud and at the edge. To that end, new architectures should be proposed to handle IoT services in a coordinated way at either the edge of the network, the cloud, or both. Reacting to that need, the Fog-to-Cloud concept has been recently proposed. A key aspect in the F2C design refers to security, since F2C raises security issues besides those yet unsolved in fog and cloud. Thus, we envision the need for new security strategies to handle all components in the F2C architecture. In this paper we propose an SDN-based (mater/slave) security architecture leveraging a centralized controller on the cloud, and distributed controllers at the edge of the network. We argue that the proposed architecture brings more security and privacy to the cloud users by reducing the distance between them and, therefore, reducing the risks of the so called man-in-the-middle attacks. The proposed security architecture is analyzed in some critical infrastructure scenarios in order to illustrate their potential benefits.

FRA: A new fuzzy-based routing approach for optical transport networks

Providing networks with QoS guarantees is one of the key issues to support current and future expected clients demands. In this scenario, QoS routing is definitely critical as being responsible for defining those optimal routes supporting traffic forwarding throughout the whole network. This paper proposes two new QoS-aware RWA algorithms dealing with the routing inaccuracy problem, aiming at reducing blocking probability while limiting signaling overhead and balancing network load. The proposed algorithms extend the work already published by the authors on prediction based routing by adding a novel fuzzy-based technique featuring a powerful tool for modeling uncertainty. The proposed algorithms are compared with a well-known RWA algorithm and results show the benefit of introducing the fuzzy techniques in the RWA selection.

Will it be cloud or will it be fog? F2C, A novel flagship computing paradigm for highly demanding services

Cloud computing has been lately extended by fog computing. The main aim of fog computing is to shift computing resources to the edge of the network, hence generating proximate rich infrastructures highly matching common latency and privacy requirements for IoT services. Recently, fog computing and cloud computing have been merged in a collaborative computing model referred to as Fog-to-Cloud computing (F2C). F2Cs aim is to make the most out of the set of distributed and heterogeneous resources found at fog and cloud premises, hence building a global stack of resources, offered for an optimized service performance. The F2C paradigm is then based on providing services with those resources best matching their demands. In this paper, we illustrate how F2C may be used for a particular ehealth scenario with specific constraints in mobility, also including future research lines in the area.

Towards the scalability of a service-oriented PCE architecture for IoT scenarios

Despite the increasing number of mobile heterogeneous network elements (NEs) interconnected through the Internet, all of them setting the foundations for an agile IoT development, many issues remain still unsolved. The scalability of the current host-oriented Internet model is one of these problems. In this paper, we present a novel service-oriented architecture dealing with the scalability problem leveraging the Path Computation Element (PCE) concept. PCE has already been proved as an efficient technology to decouple the control tasks from the forwarding nodes, what undoubtedly impacts on scalability growth. Given the importance of control solutions for IoT, we propose to enrich the current host-oriented PCE model to become a Service-oriented PCE (SPCE). Results obtained after running several evaluation tests show that the proposed PCE-based solution may support a higher number of Network Elements (NEs).

Metrics and QoE assessment in P2PTV applications

Peer-to-peer P2P is a growing technology offering an affordable platform to deploy distributed services and streaming of multimedia content through peer-to-peer television P2PTV. Nevertheless, to promote such technology it is necessary to provide a solid streaming quality assessment mechanism. In this context, legacy solutions tied to service level agreements are no longer suitable, as for P2P systems, the service consumers become an active part by assisting in the service delivery. To overcome this limitation, we present a generic multi-layer monitoring and management framework to assess the quality of service QoS and the quality of experience QoE of multimedia traffic in any P2PTV streaming application. We also demonstrate the usefulness of our solution, by analysing the performance of a real streaming application in a P2PTV environment.

Quality of Experience Aware Multimedia Provisioning with Cross-Layer Network Management

This paper presents a Cross-layer Network Management System (NMS) that allows Service Providers (SPs) to perform cost-effective network resource reservations with their Network Operators (NOs). The novelty of our NMS is that it offers a fresh and promising approach to use the end-users satisfaction level as the metric to perform the resource management. We show that our system is capable of achieving considerable reductions in the operational costs of SPs, while keeping proper bounds in the end-user satisfaction for the offered multimedia services.