eHDDP: Enhanced Hybrid Domain Discovery Protocol for network topologies with both wired/wireless and SDN/non-SDN devices

Handling efficiently both wired and/or wireless devices in SDN networks is still an open issue. eHDDP comes as an enhanced version of the Hybrid Domain Discovery Protocol (HDDP) that allows the SDN control plane to discover and manage hybrid topologies composed by both SDN and non-SDN devices with wired and/or wireless interfaces, thus opening a path for the integration of IoT and SDN networks. Moreover, the proposal is also able to detect both unidirectional and bidirectional links between wireless devices. eHDDP has been thoroughly evaluated in different scenarios and exhibits good scalability properties since the number of required messages is proportional to the number of existing links in the network topology. Moreover, the obtained discovery and processing times give the opportunity to support scenarios with low mobility devices since the discovery times are in the range of hundreds of milliseconds.Comunidad de MadridJunta de Comunidades de Castilla-La Manch

HDDP: Hybrid Domain Discovery Protocol for heterogeneous devices in SDN

Computer networks are adopting the new Software-Defined Networking (SDN) architecture, however not all devices can support it, mainly due to power and computational constraints. This paper proposes the Hybrid Domain Discovery Protocol (HDDP), a new discovery protocol that enhances theexisting OpenFlow Discovery Protocol (OFDP). HDDP allows thediscovery of hybrid network topologies composed of both SDNand non-SDN devices, which no other state-of-the-art protocolcan achieve. HDDP has been implemented in a software switchand emulated in diverse networks, where it discovers hybrid topologies by using a number of messages similar to competitors,as they only discover SDN devices.Comunidad de MadridUniversidad de Alcal

A hybrid SDN switch based on standard P4 code

This paper presents an enhanced hybrid Software-Defined Networking (SDN) layer-2 switch whose behavior is specified by the Programming Protocol-independent Packet Processors (P4) language. Its SDN capabilities are enabled by using P4Runtime as control plane protocol to specify the forwarding rules used by its programmable data plane. Additionally, the device is also able to exploit P4 registers for an autonomous self-definition of its forwarding capabilities, with the goal of avoiding an overload of the SDN control plane. Its performance is better than other P4 proposals based on non-standard externs and similar to other platform-dependent implementations.Comunidad de MadridJunta de Comunidades de Castilla-La ManchaUniversidad de Alcal

Analysis of P4 and XDP for IoT programmability in 6G and beyond

Recently, two technologies have emerged to provide advanced programmability in Software-Defined Networking (SDN) environments, namely P4 and XDP. At the same time, the Internet of Things (IoT) represents a pillar of future 6G networks, which will be also sustained by SDN. In this regard, there is a need to analyze the suitability of P4 and XDP for IoT. In this article, we aim to compare both technologies to help future research efforts in the field. To this purpose, we evaluate both technologies by implementing diverse use cases, assessing their performance and providing a quick qualitative overview. All tests and designed scenarios are publicly available in GitHub to guarantee replication and serve as initial steps for researchers that want to initiate in the field. Results illustrate that currently XDP is the best option for constrained IoT devices, showing lower latency times, half of CPU usage, and reduced memory in comparison with P4. However, development of P4 programs is more straightforward and the amount of code lines is more similar regardless of the scenario. Additionally, P4 has a lot of potential in IoT if a special effort is made to improve the most common software target, BMv2.Comunidad de MadridJunta de Comunidades de Castilla-La ManchaUniversidad de Alcal

The disjoint multipath challenge: multiple disjoint paths guaranteeing scalability

The multipath challenge is a research line in continuous development because of its multiple benefits, however, these benefits are overshadowed by scalability, which goes down considerably when the paths are multiple and disjoint. The disjointness aggregates an extra value to the multiple paths, but it also implies more complex mathematical operations that increase the computational cost. In fact, diverse proposals exist that try to increase scalability by limiting the number of paths obtained to the minimum possible (two-disjoint paths), which is enough for backup applications but not for other purposes. This paper presents an algorithm that solves these drawbacks by discovering multiple disjoint paths among multiple nodes in an efficient way, while keeping bounded the computational cost and ensuring scalability. The proposed algorithm has been validated thoroughly by performing a theoretical analysis, bolstered afterwards by an exhaustive experimental evaluation. The collected results are promising, our algorithm reduces the time spent to obtain the disjoint paths regarding its competitors between one and three orders of magnitude, at the cost of a slight decrease in the number of paths discovered.Comunidad de MadridJunta de Comunidades de Castilla-La Manch

One-Shot Multiple Disjoint Path Discovery Protocol (1S-MDP)

Multipath routing over disjoint paths is a classic solution to allow better resource allocation, resilience, and security. Current proposals rely on centralised computation or iterative distributed algorithms and exhibit large convergence times. We propose 1S-MDP, a distributed mechanism based on a single network exploration with concurrent path selection to discover multiple available paths among the target node and the remaining nodes in the network. The paper evaluates 1S-MDP in two different scenarios against previous solutions. We show how it reduces the convergence time by several orders of magnitude with a small decrease in the number of disjoint paths discovered.Comunidad de Madri

ARP-P4: deep analysis of a hybrid SDN ARP-Path/P4-Runtime switch

The Software-Defined Networking (SDN) architecture decouples the control plane from the data plane, but it does not explicitly state where the control should be located. This article analyses the benefits of maintaining the control as close as possible to the data plane, instead of the more traditional centralised control plane approach. To this purpose, it delves into the study of ARP-P4, a hybrid software switch defined by using the P4 language to facilitate its future use and deployment in P4 targets. Its hybrid properties come from supporting two complementary different ways of establishing paths: a centralised SDN approach based on P4-Runtime and a traditional distributed approach based on the ARP-Path protocol that obtains a similar performance to centralised solutions based on Equal Cost Multi-Path (ECMP) and Dijkstra. The results show the feasibility of hybrid devices that combine different forwarding paradigms without losing performance with respect to well-known solutions such as ECMP, and how their combined use can lead to enhance and scale communication networks.Comunidad de MadridUniversidad de Alcal

Amaru: plug&play resilient in-band control for SDN

Software-Defined Networking (SDN) is a pillar of next-generation networks. ImplementingSDN requires the establishment of a decoupled control communication, which might be installed either as anout-of-band or in-band network. While the benefits of in-band control networks seem apparent, no standardprotocol exists and most of setups are based on ad-hoc solutions. This article defines Amaru, a protocolthat provides plug&play resilient in-band control for SDN with low-complexity and high scalability. Amarufollows an exploration mechanism to find all possible paths between the controller and any node of thenetwork, which drastically reduces convergence time and exchanged messages, while increasing robustness.Routing is based on masked MAC addresses, which also simplifies routing tables, minimizing the numberof entries to one per path, independently of the network size. We evaluated Amaru with three differentimplementations and diverse types of networks and failures, and obtained excellent results, providing almoston-the-fly rerouting and low recovery time.Comunidad de MadridUniversidad de Alcal

The state of psychological treatments for social anxiety disorder in children and adolescents: An Umbrella Review

Estado de los tratamientos psicológicos para el Trastorno de Ansiedad Social en población infanto-juvenil: Revisión de revisiones. El Trastorno de Ansiedad Social (TAS) es un trastorno muy común en la infancia y adolescencia. Muchos estudios han analizado los diferentes tipos de Terapia Cognitivo-Conductual (TCC) para dicho trastorno, pero ello hace necesario estudiar la eficacia de TCC. El objetivo de esta revisión de revisiones es determinar que tratamientos y que factores son más eficaces para el TAS en población infanto-juvenil. Se realizó una revisión de revisiones sobre la efectividad de las intervenciones psicológicas para tratar el TAS en niños y adolescentes. Para ello, se realizó una búsqueda en nueve bases de datos utilizando una combinación de palabras clave. El riesgo de sesgo se evaluó mediante la herramienta AMSTAR-2. Se seleccionaron y analizaron seis revisiones sistemáticas y meta-análisis. Todos los estudios seleccionados evaluaron la eficacia de la TCC en niños y adolescentes con SAD, demostrando su efectividad a corto y largo plazo. Los componentes que parecen ser más efectivos son la exposición en cualquier modalidad y el entrenamiento en habilidades sociales. Otras consideraciones a tener en cuenta se abordan en la discusiónSocial Anxiety Disorder (SAD) is a very common disorder in childhood and adolescence. Many studies have examined various types of Cognitive Behavioral Therapy (CBT), meaning there is a need for a study exploring the efficacy of CBT. The objectives of this study are to determine what treatments and factors can improve treatment outcomes for SAD. We performed an umbrella review of the effectiveness of psychological interventions in treating SAD in children and adolescents. Nine databases were searched using a combination of keywords. Risk of bias was assessed using AMSTAR-2. Six systematic reviews and meta-analysis were selected and reported. All of those studies assessed the efficacy of CBT in children and adolescents with SAD, demonstrating its short- and long-term effectiveness. The components that seem to be most effective are exposure in any modality and social skills training. Other considerations to take into account are addressed in the discussio

Improving multipath routing of TCP flows by network exploration

Ethernet switched networks are widely used in enterprise and data center networks. However, they have some drawbacks, mainly that, to prevent loops, they cannot take advantage of multipath topologies to balance traffic. Several multipath routing proposals use link-state protocols and Equal Cost Multi-Path routing (ECMP) to distribute the load over multiple paths. But, these proposals are complex and prone to flow collisions that may degrade performance. This paper studies TCP-Path, a protocol that employs a different approach. It uses a distributed network exploration mechanism based on broadcasting the TCPSYN packet to identify and select the fastest available path to the destination host, on the fly. Our evaluation shows that it improves on ECMP by up to 70% in terms of throughput for elephant flows and by up to 60% in terms of flow completion time for mouse flows. Indeed, network exploration offers a better, yet simple alternative to ECMP-based solutions for multipath topologies. In addition, we also study TCP-Path for elephant flows (TFE), which restricts TCP-Path application to elephant flows to reduce the exploration broadcast overhead and the size of forwarding tables, thus improving its scalability. Although elephant flows represent a small fraction (about 5%) of total flows, they have a major impact on overall performance, as we show in our evaluation. TFE reduces both the overhead incurred during path setup and the size of the forwarding tables by a factor of almost 20. Moreover, it achieves results close to those obtained by TCPPath for elephant flows, especially when working with high loads, and yields significant improvements for all types of flow at medium and high load levels.Comunidad de MadridUniversidad de Alcal