Armando Ferro

• University of the Basque Country

The solutions to many optimization paradigms arising from different application domains can be modeled as a tree graph, in such a way that nodes represent the variables to be optimized and edges evince topological relationships between such variables. In these problems the goal is to infer an optimal tree graph interconnecting all nodes under a mea...

The high data volumes being managed by and transferred through mobile networks in the last few years are the main rationale for the upsurge of research aimed at finding efficient technical means to offload exceeding traffic to alternative communication infrastructures with higher transmission bandwidths. This idea is solidly buttressed by the proli...

Tree based optimization problems stand for those paradigms where solutions can be arranged within a tree-like graph whose nodes represent the optimization variables of the problem at hand and their interconnecting edges topological and/or hierarchical relationships between such variables. In this context, a research line of increasing interest duri...

This paper deals with the analysis of user perceived visual quality for mobile multimedia services. H.264/AVC is selected for low resolution video encoding, and 3G UMTS is considered for mobile data services. From subjective tests results, the combined impact of different service- and network-level parameters is inferred. As a result, different cro...

In the NGN environment, networks are designed to be multiservice, supporting a wide range of premium services. Each of these services may have different QoS requirements based on the overall end user’s perception. New QoS policies are required that adapt the traditional QoS regulatory model to this emerging context. This article presents a user-cen...

This paper proposes the deployment of a network software platform for experimentation called LabQoS that will allow the scientific community to establish scientific experiments relating to measure the performance of applications and services on the Internet and other network environments. Previous experiences have already deployed measurement syste...

Quality of service has become one of the most important factors among Internet service providers. The implementation of appropriate QoS policies is essential in order to maintain customer loyalty and fulfill regulators' requirements. ITU-T recommendation E.802 provides a framework for the identification of QoS criteria relevant to users and ISPs. T...

The growth of emerging multimedia applications with different quality requirements has made the objective network QoS (NQoS) to be commonly considered as an inadequate metric for quality assessment in telecommunication services, being the quality of experience (QoE) concept the most predominant alternative. However, most QoE-related research studie...

This paper presents an implementation of the BGP/MPLS IP VPN functionalities for GNU/Linux. First, we briefly review the operation mode described in the IETF RFC 4364 and show the characteristics that are supported by this implementation. Afterwards, we provide some implementation details of the forwarding plane for the kernel 2.6.18.1. This implem...

Traffic monitoring is an increasingly important discipline for nowadays networking, as Accounting, Security and also Quality of Service (QoS) lay on it. Besides, traffic bandwidth has increased exponentially in the last few years, and high-speed network monitoring is a challenging aim. Performance requirements are highly relevant for monitoring sys...

Simulation models have been developed in order to foresee characteristics of networks, systems or protocols when carrying out tests in laboratories is very expensive or even impossible. This paper presents a simulation model of a multiprocessor network traffic analysis system. The model, which is based on closed networks of queues, evaluates the ef...

RESUMEN. Actualmente, un aspecto clave tanto para usuarios como operadores de redes de comunicaciones es la calidad de servicio prestada en las redes de datos y servicios asociados. De hecho, según la legislación actual, los proveedo-res que operen en el mercado europeo pueden estar sujetos a la obligación de publicar informa-ción sobre la calidad...

This paper presents a comprehensive model intended to analyze quality of service in telecommunications services and its causes. Although many works have been published in this area, both from a technical viewpoint as well as taking into consideration subjective concerns, they have not resulted in a unique methodology to assess the experienced quali...

Simulation models have been developed in order to foresee characteristics of networks, systems or protocols when doing tests in laboratories are very expensive or even impossible. This paper presents a simulation model of a multiprocessor network traffic analysis system. The model, which is based on closed networks of queues, evaluates the efficien...

This paper offers an approach to the definition of access speed measurements. An ever growing increase of Internet Service Providers (ISP) and different types of technologies in the Internet access, makes it difficult for users to decide which is the best or most suitable connection to satisfy their needs. From these considerations, the possibility...

This document describes several design proposals to enhance net-work sensor performance on multiprocessor architectures. Our main contributions are related to the design of an autonomous sensor and to the idea of per-forming some parallelization of the analysis. These proposals can be implemented in network sensors such as intrusion detection syste...

This article describes an activity and time management tool that allows any member of a virtual learning environment to have their timetables and activities planned or scheduled in such a way, that deadlines and personal preference criteria are both met. First of all, a general overview of the day-to-day difficulties that students, particularly dis...

RESUMEN En este documento se presenta una solución para integrar dispositivos de control en redes eléctricas de alta tensión basándose en las tecnologías de las comunicaciones. Este trabajo está basado en la experiencia adquirida en el desarrollo de un proyecto PROFIT en cooperación con General Electric Power Management y otras empresas industriale...

Quality of service (QoS) has become one of the most important factors among Internet service providers (ISPs). The implementation of appropriate QoS policies is essential in order to maintain customer loyalty and fulfill regulators' requirements. ITU-T Recommendation E.802 provides a framework for the identification of QoS criteria relevant to the...

This article describes the development of an activity and time management tool specifically tuned to satisfy needs associated with distant learning techniques in virtual environments. Therefore, this tool's main objective is obtaining a software able to perform an automatic scheduling of planned tasks, i.e., offer to its end-users an easy way to ma...

With the increase of the rate in networks, computational ability of network resources and principal servers could be inadequate. In order to prove the performance of networks, network resources and servers there have to be traffic generators. These generate traffic flows with different characteristics. It is also necessary to have network monitorin...

This paper presents a comprehensive model intended to analyse general quality in telecommunications services centred in end users' perceived quality (PQoS). The proposed model allows us to estimate the quality experienced by end users, while offering detailed conclussions regarding the responsibility of the different agents involved in the service...

The most common shortcoming in the existing architectures in Intrusion Detection Systems is that they are built around a single monolithic entity that does most of the data collection and processing. This paper presents an architecture for a distributed Intrusion Detection System based on multiple independent entities working collectively called Au...