ADMP: an adaptive multicast routing protocol for mobile ad hoc networks

We present ADMP, the adaptive mesh-based multicast routing protocol, in which nodes are able to independently tune the amount of redundancy used to transmit data packets with the goal of improving the overall packet delivery ratio while keeping the retransmission overhead as low as possible. ADMP is based on a novel distributed algorithm for computing connected dominating sets. ADMP uses a single type of control packet, called multicast announcement, which is used to build the meshes of multicast groups, elect the core of each mesh and obtain two-hop neighborhood information. Using detailed simulations for different scenarios, we show that ADMP achieves similar or better reliability than two mesh-based multicast protocols that are very resilient (ODMRP and PUMA) while inducing low packet retransmission overhead.1st IFIP International Conference on Ad-Hoc NetWorkingRed de Universidades con Carreras en Informática (RedUNCI

ADMP: an adaptive multicast routing protocol for mobile ad hoc networks

We present ADMP, the adaptive mesh-based multicast routing protocol, in which nodes are able to independently tune the amount of redundancy used to transmit data packets with the goal of improving the overall packet delivery ratio while keeping the retransmission overhead as low as possible. ADMP is based on a novel distributed algorithm for computing connected dominating sets. ADMP uses a single type of control packet, called multicast announcement, which is used to build the meshes of multicast groups, elect the core of each mesh and obtain two-hop neighborhood information. Using detailed simulations for different scenarios, we show that ADMP achieves similar or better reliability than two mesh-based multicast protocols that are very resilient (ODMRP and PUMA) while inducing low packet retransmission overhead.1st IFIP International Conference on Ad-Hoc NetWorkingRed de Universidades con Carreras en Informática (RedUNCI

Opportunistic Mobile Sensing in the Fog

The increasing adoption of mobile personal devices and Internet of Things devices is leveraging the emergence of a wide variety of opportunistic sensing applications. However, the designers of this type of applications face a set of technical challenges related to the limitations and heterogeneity of the hardware and software platforms and to the dynamics of the scenarios where they are deployed. In this paper, we introduce a Semantic-Centric Fog-based framework aimed at effectively and efficiently supporting this type of applications. The proposed framework is composed of local and distributed algorithms that support the establishment and coordination of sensing tasks in the Fog. First, it performs ontology-driven in-network processing to locate the most adequate devices to carry out a given sensing task and then, it establishes efficient multihop routes that are used to coordinate relevant devices and to transport the collected sensory data to Fog sinks. We present a set of theorems that prove that the proposed algorithms are correct and the results of a series of detailed simulation-based experiments in NS3 that characterize the performance of the proposed platform. The results show that the proposed framework outperforms traditional sensing platforms that are based on centralized services

Java RMI

ArtículosEn el presente artículo se describe la arquitectura de una de las principales alternativas para el desarrollo de aplicaciones basadas en objetos distribuidos, Java RMI. Además se presenta de manera detallada un ejemplo donde se muestra una de las adiciones más significativas al modelo de objetos distribuidos de Java en su versión 1.2 con respecto a la 1.1, la capacidad de activar "sobre demanda" a los objetos remotosThis paper describes the architecture of Java RMI that is one of the main alternatives for the developing of applications based on distributed objects. Also we develop a detailed example of activation on demand of distributed objects that is one of the most significant improvements introduced in the JDK 1.

Arquitectura de la Máquina Virtual Java

ArtículosEn el presente artículo se describe la Arquitectura de la Máquina Virtual Java, que es parte medular de toda la tecnología Java. Se hace énfasis en sus componentes principales, como el procesador virtual Java, que se encarga de ejecutar los códigos de operación (bytecodes) generados por los compiladores Java, el verificador de código, que junto con el cargador de clases y el administrador de seguridad, se encargan de implementar los mecanismos empleados para proporcionar seguridad a los usuarios de Java. Además, a lo largo de la discusión, se hace un análisis de las principales características que han hecho posible el éxito de Java en nuestros díasThe present article describes the architecture of the Java virtual machine that is one of main components of the Java technology. We focus in its main components such as the Java virtual processor that executes the operation codes (bytecodes) generated by the Java compilers, the code verifier that along with the class loader and the security manager implement the Java security mechanisms. We analyze the main characteristics that have made possible the Java success in our day

A Window-Based, Server-Assisted P2P Network for VoD Services with QoE Guarantees

We describe a Peer-to-Peer (P2P) network that is designed to support Video on Demand (VoD) services. This network is based on a video-file sharing mechanism that classifies peers according to the window (segment of the file) that they are downloading. This classification easily allows identifying peers that are able to share windows among them, so one of our major contributions is the definition of a mechanism that could be implemented to efficiently distribute video content in future 5G networks. Considering that cooperation among peers can be insufficient to guarantee an appropriate system performance, we also propose that this network must be assisted by upload bandwidth from servers; since these resources represent an extra cost to the service provider, especially in mobile networks, we complement our work by defining a scheme that efficiently allocates them only to those peers that are in windows with resources scarcity (we called it prioritized windows distribution scheme). On the basis of a fluid model and a Markov chain, we also developed a methodology that allows us to select the system parameters values (e.g., windows sizes or minimum servers upload bandwidth) that satisfy a set of Quality of Experience (QoE) parameters

A comprehensive analytical framework for VoD services in hybrid CDN-P2P systems

International audienceVideo on Demand services generate the largest amount of traffic in networks nowadays. Previous works have proposed integrating Content Delivery Networks (CDN) and Peer-to-Peer (P2P) networks to satisfy this demand. However, their analytical methods do not consider all the factors that affect the performance of these systems. Hence, we present a novel comprehensive framework, based on a fluid model, to evaluate VoD services over hybrid CDN-P2P systems. The proposed framework considers features of the service (e.g., size, coding-rate and popularity of the video), network attributes (e.g., upload data-rate capacity of servers and peers) and characteristics of the behavior of the users (e.g., sojourn time, cooperativeness and frequency of random-seeks). Our framework allows a system to be evaluated under a wide variety of scenarios in terms of network-cost and Quality-of-Service (QoS) parameters and is flexible enough to model different resource allocation schemes, including a novel scheme to distribute the upload network capacity. Despite the wide variety of considered factors, our framework is tractable and as accurate as discrete-models based on Markov chains