Software-driven definition of virtual testbeds to validate emergent network technologies

This paper is an extended version of our paper published in XIII Jornadas de Ingeniería Telemática (JITEL 2017), Valencia, Spain, 27–29 September 2017, “Definición de Testbeds Virtualizados Utilizando Perfiles de Actividad de Red”The lack of privileged access to emergent and operational deployments is one of the key matters during validation and testing of novel telecommunication systems and technologies. This matter jeopardizes the repeatability of experiments, which results in burdens for innovation and research in these areas. In this light, we present a method and architecture to make the software-driven definition of virtual testbeds easier. As distinguishing features, our proposal can mimic operational deployments by using high-dimensional activity patterns. These activity patterns shape the effect of a control module that triggers agents for the generation of network traffic. This solution exploits the capabilities of network emulation and virtualization systems, which nowadays can be easily deployed in commodity servers. With this, we accomplish a reproducible definition of realistic experimental conditions and the introduction of real agent implementations in a cost-effective fashion. We evaluate our solution in a case study that is comprised of the validation of a network-monitoring tool for Voice over IP (VoIP) deployments. Our experimental results support the viability of the method and illustrate how this formulation can improve the experimentation in emergent technologies.This work has been partially funded by the SpanishMinistry of Economy and Competitiveness and the European Regional Development Fund under the projects TRÁFICA (MINECO/FEDER TEC2015-69417-C2-1-R) and RACING DRONES (MINECO/FEDER RTC-2016-4744-7

Estimation of the parameters of token-buckets in multi-hop environments

Bandwidth verification in shaping scenarios receives much attention of both operators and clients because of its impact on Quality of Service (QoS). As a result, measuring shapers’ parameters, namely the Committed Information Rate (CIR), Peak Information Rate (PIR) and Maximum Burst Size (MBS), is a relevant issue when it comes to assess QoS. In this paper, we present a novel algorithm, TBCheck, which serves to accurately measure such parameters with minimal intrusiveness. These measurements are the cornerstone for the validation of Service Level Agreements (SLA) with multiple shaping elements along an end-to-end path. As a further outcome of this measurement method, we define a formal taxonomy of multi-hop shaping scenarios. A thorough performance evaluation covering the latter taxonomy shows the advantages of TBCheck compared to other tools in the state of the art, yielding more accurate results even in the presence of cross-traffic. Additionally, our findings show that MBS estimation is unfeasible when the link load is high, regardless the measurement technique, because the token-bucket will always be empty. Consequently, we propose an estimation policy which maximizes the accuracy by measuring CIR during busy hours and PIR and MBS during off-peak hoursThis work was partially supported by the Spanish Ministry of Economy and Competitiveness and the European Regional Development Fund under the project Tráfica (MINECO/FEDER TEC2015-69417-C2-1-R

Definición de Testbeds Virtualizados Utilizando Perfiles de Actividad de Red

[ES] Un problema recurrente para los profesionales de la Ingeniería Telemática es la escasez de despliegues de tecnologías emergentes y las restricciones de acceso a redes operativas. Por ello, en este trabajo presentamos un método para la generación automática de carga siguiendo perfiles de actividad que facilita la replicación del comportamiento típico de una red. Este método se basa en un nodo de control que configura agentes de generación de tráfico, para aprovechar las capacidades de las plataformas de virtualización de red. Evaluamos esta propuesta en un caso de estudio que considera un despliegue de Voz sobre IP (Voice over IP, VoIP) en un único servidor de propósito general usando Mininet como entorno de virtualización ligera.Los resultados experimentales muestran que el método propuesto replica fidedignamente la dinámica de red especificada, y que los recursos físicos consumidos permiten su uso en equipamiento de coste reducido.Este trabajo ha sido parcialmente financiado por el Ministerio de Economía y Competitividad y el Fondo Europeo de Desarrollo Regional a traves de los proyectos ´ TRAFICA (MINECO / FEDER TEC2015-69417-C2-1-R) y RACING DRONES (MINECO / FEDER RTC-2016-4744-7).Muelas, D.; Ramos, J.; López De Vergara, J. (2018). Definición de Testbeds Virtualizados Utilizando Perfiles de Actividad de Red. En XIII Jornadas de Ingeniería telemática (JITEL 2017). Libro de actas. Editorial Universitat Politècnica de València. 272-277. https://doi.org/10.4995/JITEL2017.2017.6502OCS27227

Online detection of pathological TCP flows with retransmissions in high-speed networks

Online Quality of Service (QoS) assessment in high speed networks is one of the key concerns for service providers, namely to detect QoS degradation on-the-fly as soon as possible and avoid customers’ complaints. In this regard, a Key Performance Indicator (KPI) is the number of TCP retransmissions per flow, which is related to packet losses or increased network and/or client/server latency. However, to accurately detect TCP retransmissions the whole sequence number list should be tracked which is a challenging task in multi-Gb/s networks. In this paper we show that the simplest approach of counting as a retransmission a packet whose sequence number is smaller than the previous one is enough to detect pathological flows with severe retransmissions. Such a lightweight approach eliminates the need of tracking the whole TCP flow history, which severely restricts traffic analysis throughput. Our findings show that low False Positive Rates (FPR) and False Negative Rates (FNR) can be achieved in the detection of such pathological flows with severe retransmissions, which are of paramount importance for QoS monitoring. Most importantly, we show that live detection of such pathological flows at 10 Gb/s rate per processing core is feasibleThis work has been partially funded by the Spanish Ministry of Economy and Competitiveness and the European Regional Development Fund under the projects TRÁFICA (MINECO/ FEDER TEC2015-69417-C2-1-R), Preproceso Inteligente de Tráfico (MINECO / FEDER TEC2015-69417-C2-2-R) and RACING DRONES (MINECO / FEDER RTC-2016-4744-7

On the dynamics of valley times and its application to bulk-transfer scheduling

Periods of low load have been used for the scheduling of non-interactive tasks since the early stages of computing. Nowadays, the scheduling of bulk transfers—i.e., large-volume transfers without precise timing, such as database distribution, resources replication or backups—stands out among such tasks, given its direct effect on both the performance and billing of networks. Through visual inspection of traffic-demand curves of diverse points of presence (PoP), either a network, link, Internet service provider or Internet exchange point, it becomes apparent that low-use periods of bandwidth demands occur at early morning, showing a noticeable convex shape. Such observation led us to study and model the time when such demands reach their minimum, on what we have named valley time of a PoP, as an approximation to the ideal moment to carry out bulk transfers. After studying and modeling single-PoP scenarios both temporally and spatially seeking homogeneity in the phenomenon, as well as its extension to multi-PoP scenarios or paths—a meta-PoP constructed as the aggregation of several single PoPs—, we propose a final predictor system for the valley time. This tool works as an oracle for scheduling bulk transfers, with different versions according to time scales and the desired trade-off between precision and complexity. The evaluation of the system, named VTP, has proven its usefulness with errors below an hour on estimating the occurrence of valley times, as well as errors around 10% in terms of bandwidth between the prediction and actual valley trafficThis work has been partially supported by the European Commission under the project H2020 METRO-HAUL (Project ID: 761727

Evaluación de equipamiento de bajo coste para realizar medidas de red en entornos domésticos

[ES] En la actualidad, la proliferación de dispositivos móviles y accesos a Internet utilizando tecnologías inalámbricas en los entornos domésticos obliga a cambiar las metodologías para la realización de medidas de red.Para que éstas representen fidedignamente las condiciones ofrecidas a los usuarios, las prestaciones del equipamiento de medida y el número de dispositivos empleados deben adaptarse a las condiciones reales de un despliegue.Para facilitar y abaratar el desarrollo de medidas en estas condiciones, este trabajo presenta una evaluación de las capacidades de varias plataformas de propósito general y bajo coste.Nuestros resultados muestran que, aunque aparecen limitaciones relacionadas con cómo son conectadas a la red y los protocolos empleados, son aptas para medir una gran variedad de situaciones.Este trabajo ha sido parcialmente financiado por el Ministerio de Economía y Competitividad y del Fondo Europeo de Desarrollo Regional a traves de los proyectos ´ TRAFICA (MINECO / FEDER TEC2015-69417-C2-1-R) ´ y RACING DRONES (MINECO / FEDER RTC-2016- 4744-7). Los autores tambien agradecen al Ministerio de Educacion Cultura y Deporte por la beca de colaboración del primer autor.Miravalls Sierra, E.; Muelas, D.; López De Vergara, J.; Ramos, J.; Aracil, J. (2018). Evaluación de equipamiento de bajo coste para realizar medidas de red en entornos domésticos. En XIII Jornadas de Ingeniería telemática (JITEL 2017). Libro de actas. Editorial Universitat Politècnica de València. 118-123. https://doi.org/10.4995/JITEL2017.2017.6501OCS11812

ERK5 signalling pathway is a novel target of sorafenib: Implication in EGF biology

© 2021 The Authors.Sorafenib is a multikinase inhibitor widely used in cancer therapy with an antitumour effect related to biological processes as proliferation, migration or invasion, among others. Initially designed as a Raf inhibitor, Sorafenib was later shown to also block key molecules in tumour progression such as VEGFR and PDGFR. In addition, sorafenib has been connected with key signalling pathways in cancer such as EGFR/EGF. However, no definitive clue about the molecular mechanism linking sorafenib and EGF signalling pathway has been established so far. Our data in HeLa, U2OS, A549 and HEK293T cells, based on in silico, chemical and genetic approaches demonstrate that the MEK5/ERK5 signalling pathway is a novel target of sorafenib. In addition, our data show how sorafenib is able to block MEK5-dependent phosphorylation of ERK5 in the Ser218/Tyr220, affecting the transcriptional activation associated with ERK5. Moreover, we demonstrate that some of the effects of this kinase inhibitor onto EGF biological responses, such as progression through cell cycle or migration, are mediated through the effect exerted onto ERK5 signalling pathway. Therefore, our observations describe a novel target of sorafenib, the ERK5 signalling pathway, and establish new mechanistic insights for the antitumour effect of this multikinase inhibitor.This work was supported by grants from Fundación Leticia Castillejo Castillo, Ministerio de Ciencia, Innovación y Universidades (MCIU), Agencia Estatal de Investigación (AEI) and Fondo Europeo de Desarrollo Regional (FEDER) (RTI2018-094093-B-I00) to RSP and MJRH. OR holds a contract for accessing the Spanish System of Science, Technology, and Innovation (SECTI) funded by the University of Castilla-La Mancha (UCLM) and received partial support from the European Social Fund (FSE) through its Operative Program for Castilla-La Mancha (2007–2013). RSP and MJRH's Research Institute, and the work carried out in their laboratory, received partial support from the European Community through the FEDER. RPS and EAL hold a research predoctoral contract cofounded by the European Social Fund and UCLM. The Spanish Ministry of Economy and Competitiveness (MINECO, Project RTI2018-096724-B-C21) and the Generalitat Valenciana (PROMETEO/2016/006) support work in the Encinar´s laboratory. Authors are grateful to Dr.G- Ferrer Mayorga for her assistance in the transwell assays, and to the ‘Centro de Computación Científica’ (CCC-UAM) for letting us to take advantage of the computer cluster Cibeles (https://www.ccc.uam.es/) and for providing computing facilities