El Acceso de usuario a Internet de banda ancha

Peer Reviewe

El Acceso de usuario a Internet de banda ancha

Peer Reviewe

Les Autopistes de la informació : l'eix vertebral de la societat de la informació

Peer Reviewe

Introducing ethics by design in engineering education: designing COVID-19 tracing apps

Including ethical concepts and considerations in engineering education has attracted significant interest in recent years, mainly due to the impact of some AI applications in different areas of our life. The use of case studies in teaching ethics is a well-known and useful approach. The debate related with a given case study helps students think about the implications, motivations and foreseeable impact of the technologies. This fact is in contrast with the common easy-thinking that technologies are neutral and that an engineer should not bother about ethics and does not have any responsibility at all. While many basic technologies may be considered neutral, more developed and complex systems are not so neutral; they have a motivation and some foreseeable impact and consequences. Thence, the main message is that engineers have a responsibility when developing these systems. This paper presents a case study used in a course for Ph.D. students in a Technical University to introduce the concept of ethics by design and to stress the idea of responsible conduct in engineering. The case under study is the design and development of tracing applications for fighting against the Covid-19 pandemic in 2020. The analysis of the case requires to understand the basic technologies proposed, the different alternatives considered at that time, the basic facts related with the contagion chain and the main factors to be addressed, the consideration of the balance between public health rights and individual privacy rights, and the social aspects related with the acceptability by citizens

An analytical model for Loc/ID mappings caches

Concerns regarding the scalability of the interdomain routing have encouraged researchers to start elaborating a more robust Internet architecture. While consensus on the exact form of the solution is yet to be found, the need for a semantic decoupling of a node's location and identity is generally accepted as a promising way forward. However, this typically requires the use of caches that store temporal bindings between the two namespaces, to avoid hampering router packet forwarding speeds. In this article, we propose a methodology for an analytical analysis of cache performance that relies on the working-set theory. We first identify the conditions that network traffic must comply with for the theory to be applicable and then develop a model that predicts average cache miss rates relying on easily measurable traffic parameters. We validate the result by emulation, using real packet traces collected at the egress points of a campus and an academic network. To prove its versatility, we extend the model to consider cache polluting user traffic and observe that simple, low intensity attacks drastically reduce performance, whereby manufacturers should either overprovision router memory or implement more complex cache eviction policies.Peer ReviewedPostprint (author's final draft

Evaluation of joint controller placement for latency and reliability-aware control plane

The separation of the forwarding and control planes in software-defined networking provides flexibility for network management. The Controller Placement Problem (CPP) is an important issue affecting network performance. This paper presents an evaluation of the Joint Latency and Reliability-Aware Controller Placement (LRCP) optimization model. LRCP provides network administrators with flexible choices to simultaneously achieve a trade-off between the switch-To-controller latency and the controller-To-controller latency, including the reliability aspect using alternative backup paths. Control plane latency (CPL) is used as the evaluation metric and it is defined as the sum of average switch-To-controller latency and the average inter-controller latency. For each optimal placement in the network, the control plane latency using the real latencies of the real network topology is computed. Results from the control plane latency metric show how the number and location of controllers influence the reliability of the network. In the event of a single link failure, the real CPL for LRCP placements is computed and assesses how good the LRCP placements are. The CPL metric is used to compare with other models using latency and reliability metrics.This publication is part of the Spanish I+D+i project TRAINER-A (ref. PID2020-118011GB-C21), funded by MCIN/AEI/10.13039/501100011033. This work has been also partially funded by the Spanish Ministry of Economy and Competitiveness, under contract TEC 2017-90034-C2-1-R (ALLIANCE).Peer ReviewedPostprint (author's final draft

A study of packet losses in the EuQoS network

As Internet usage grows, more efforts are put into analyzing its internal performance, usually such analysis comes through simulation using different models. While simulation can provide a good approximation of network behavior, modeling such a complex network as the Internet is very difficult if not impossible. This paper studies the network’s performance from an experimental point of view using the EuQoS project’s overlay network as a testbed. In the framework of the EuQoS project, many performance tests have been done for proving the reliability of the data transmission. The tests show some rough edges which need further analysis, the most important being random packet losses in UDP flows, and a great amount of out of order packets. This paper focuses on the study of such packet losses, searching for their causes, and more importantly, to show their effects on real-time traffic such as VoIP. As a basis for comparison, the paper also uses TCP traffic to relate the performance of bulk data transfer versus the sustained rate of UDP/RTP flows used for real-time applications. To achieve this goal, several applications are used to generate and capture such traffic and measure its behavior at network level.Peer ReviewedPostprint (author’s final draft