No / There are several merits of mobile communication devices having multiple network interfaces as compared to traditional devices with just one interface. Smart phones these days are a true example of a mobile multi-homed communication device with heterogeneous network interfaces. Several solutions are available for unicast applications to provide seamless handover using the multiple interfaces of a multi-homed device in terrestrial networks. However, very little has been done on similar support for IP multicast mobility support for mobile satellite terminals in a ubiquitous multi-beam satellite network. Most of the schemes proposed for handovers in multi-homed devices place a lot of emphasis on maintaining the multi-homed device identity especially when the second interface joins the communication session. This increases complexity in the whole system. The issue of maintaining the multi-homed device identity plus the additional signalling messages involve are neither necessary nor desired in an IP multicast communication handover in a multi-beam satellite scenario. This paper seeks to exploit the group communication features of IP multicast (i.e., the fact that anyone can join or leave a multicast group at any time and from any location) and the multiple interfaces of a mobile Return Channel Satellite Terminal (RCST) to support IP multicast communication during handover when a mobile multi-homed RCST changes its point of attachment to the network from one satellite gateway to another.

No / Random packet errors and erasures are common in satellite communications. These types of packet losses could become significant in mobile satellite scenarios like satellite-based aeronautical communications where mobility at very high speeds is a routine. The current adaptive coding and modulation (ACM) schemes used in new satellite systems like the DVBRCS2 might offer some solutions to the problems posed by random packet errors but very little or no solution to the problems of packet erasures where packets are completely lost in transmission. The use of the current ACM schemes to combat packet losses in a high random packet errors and erasures environment like the satellite-based aeronautical communications will result in very low throughput. Network coding (NC) has proved to significantly improve throughput and thus saves bandwidth resources in such an environment. This paper focuses on establishing how in random linear network coding (RLNC) the satellite bandwidth utilization is affected by changing values of the generation size, rate of packet loss and number of receivers in a satellite-based aeronautical reliable IP multicast communication. From the simulation results, it shows that the bandwidth utilization generally increases with increasing generation size, rate of packet loss and number of receivers.

ITC/USA 2006 Conference Proceedings / The Forty-Second Annual International Telemetering Conference and Technical Exhibition / October 23-26, 2006 / Town and Country Resort & Convention Center, San Diego, California / Traditional data acquisition systems have relied on physical connections between data sources and data receivers to handle the routing of acquired data streams. However, these systems grow exponentially in complexity as the number of data sources and receivers increases. New techniques are needed to address the ever increasing complexity of data acquisition. Furthermore, more advanced mechanisms are needed that move past the limitations of traditional data models that connect each data source to exactly one data receiver. This paper presents a software framework for the playback of multiplexed data acquired from a network acquisition system. This framework uses multicast technologies to connect data sources with multiple data receivers. The network acquisition system is briefly introduced before the software framework is discussed. Both the challenges and advantages involved with creating such a system are presented. Finally, this framework is applied to an aviation telemetry example.

Le travail effectué aborde la problématique des services de communication multipoints fiables à grande échelle. Dans ce contexte, la possibilité de déployer un tel service au moyen d'un satellite géostationnaire émettant en bande Ka est étudiée. L'emploi de la bande $Ka$ introduit cependant une grande variabilité de la qualité de réception au niveau des utilisateurs finals, rendant nécessaire l'utilisation d'un protocole de transport mettant en oeuvre des mécanismes spécifiques. Selon une fonction de coût définie, la comparaison des solutions basées sur IP Multicast classiquement utilisées montre que l'utilisation d'une approche hybride couplant l'utilisation des réseaux satellites et terrestres est avantageuse. Le principe de la proposition, nommée Hybrid Satellite Terrestrial Reliable Multicast, consiste ainsi à choisir, en fonction de la taille du groupe, le moyen de diffusion le plus rentable --- au vu d'une fonction de coût définie. Une description détaillée de la position inclut le comportement de la source et des récepteurs, et le format des messages échangés. Bien que le principe de cette approche soit simple, plusieurs points durs sont liés à la conception des mécanismes adéquats. Ces problèmes concernent notamment la gestion de la fiabilité (utilisation de code correcteur d'erreur ou FEC), l'estimation de taille de très grands groupes, et la reprise des erreurs par voie terrestre (utilisation de réseaux de pair-à-pairs). Ces mécanismes sont étudiés de manière unitaire afin de déterminer des configurations satisfaisantes, et pour détecter des problèmes de performances. Ces mécanismes étant définis, la proposition de transport a été globalement modélisée, de manière à obtenir une vérification fonctionnelle du service proposé. Le protocole a été décrit au moyen du profil UML temps réel TURTLE. Les résultats de validation ont été obtenus grâce à la chaîne d'outils TTool-RTL, et à CADP.

Gemeinsamer Workshop von Universitaetsrechenzentrum und Professur Rechnernetze und verteilte Systeme (Fakultaet fuer Informatik) der TU Chemnitz. Workshop-Thema: Infrastruktur der ¨Digitalen Universitaet¨ Der Vortrag gibt einen Überblick über den aktuellen Stand (April 2000) von IP-Multicast im Campusnetz und die MBONE-Anbindung der TU Chemnitz.

The inherent broadcast nature of satellites, their global coverage and direct access to a large number of subscribers give satellites unrivalled advantages in supporting IP multicast applications. A new generation of satellite systems that support regenerative on-board processors and multiple spot beam technology have opened new possibilities of implementing IP multicast communication over satellites. These new features enable satellites to make efficient use of their allocated bandwidth resources and provide cost effective network services but equally, create new challenges for mobile satellite terminals. IP mobility support in general and IP mobile multicast support in particular on mobile satellite terminals like the ones mounted on continental flights, maritime vessels, etc., still remain big challenges that have received very little attention from the research community. Up till now, there are no proposed mechanisms to support IP multicast for mobile receivers/sources in multi-beam satellite networks in open literature. This study explores the suitability of IP multicast mobility support schemes defined for terrestrial networks in a satellite environment and proposes novel schemes based on the concepts of Home and Remote subscription-based approaches, multiple interface and PMIPv6 protocol. Detailed analysis and comparison of results obtained from the proposed schemes, Mobile IP (MIP) Home and Remote subscription-based approaches (for terrestrial networks) when implemented on a reference multi-beam satellite network are presented. From these results, the proposed schemes outperform the MIP Home and Remote subscription-based approaches in terms of gateway handover latency, number of multicast packets lost and signalling cost over the satellite air interface.

The aim of this work is to become familiar with simulation environment Network Simulator 2, study the problems of sensor networks and their support in the simulator and implement the selected protocol and verify its funcitonality in a practical simulation.

The inherent broadcast nature of satellites, their global coverage and direct access to a large number of subscribers give satellites unrivalled advantages in supporting IP multicast applications. A new generation of satellite systems that support regenerative on-board processors and multiple spot beam technology have opened new possibilities of implementing IP multicast communication over satellites. These new features enable satellites to make efficient use of their allocated bandwidth resources and provide cost effective network services but equally, create new challenges for mobile satellite terminals. IP mobility support in general and IP mobile multicast support in particular on mobile satellite terminals like the ones mounted on continental flights, maritime vessels, etc., still remain big challenges that have received very little attention from the research community. Up till now, there are no proposed mechanisms to support IP multicast for mobile receivers/sources in multi-beam satellite networks in open literature. This study explores the suitability of IP multicast mobility support schemes defined for terrestrial networks in a satellite environment and proposes novel schemes based on the concepts of Home and Remote subscription-based approaches, multiple interface and PMIPv6 protocol. Detailed analysis and comparison of results obtained from the proposed schemes, Mobile IP (MIP) Home and Remote subscription-based approaches (for terrestrial networks) when implemented on a reference multi-beam satellite network are presented. From these results, the proposed schemes outperform the MIP Home and Remote subscription-based approaches in terms of gateway handover latency, number of multicast packets lost and signalling cost over the satellite air interface.

Network simulation can be beneficial not only in solving problems while applying new standards or recommendations, but also primarily an aid in understanding and verifying knowledge of behaviour of communications protocols. The aim of the thesis is to create illustrative tasks in the simulation environment, Network Simulator 2 (NS-2), which are designed to verify the behavior of BGP and multicast. Created tasks are above all devoted to BGP, which is the cornerstone of routing information of all IP networks conglomerate, the Internet. The first two tasks designed for BGP use the implementation of ns-BGP and the remaining are based on the implementation of BGP++. The tasks verify both the function of basic attributes of the protocol, influencing the decision making process when routing information (AS_PATH, MED, LOCAL_PREF, WEIGHT), and furthermore the methods or parameters affecting the efficiency of the process of routing and a reduction of excessive network traffic (BGP confederation, routing, aggregation, MRAI). The last task regards multicast, more specifically the type of DM, which is a group of the so-called Dense Mode. The task illustrates how to join/leave groups and spread messages of types GRAFT and PRUNE under a constant data stream.

Made available in DSpace on 2014-12-17T14:55:32Z (GMT). No. of bitstreams: 1 WeldsonQL_capa_ate_pag12.pdf: 7162119 bytes, checksum: 5c9eb475de4851ecfa9f44218d55308a (MD5) Previous issue date: 2004-12-10 / In the two last decades of the past century, following the consolidation of the Internet as the world-wide computer network, applications generating more robust data flows started to appear. The increasing use of videoconferencing stimulated the creation of a new form of point-to-multipoint transmission called IP Multicast. All companies working in the area of software and the hardware development for network videoconferencing have adjusted their products as well as developed new solutionsfor the use of multicast. However the configuration of such different solutions is not easy done, moreover when changes in the operational system are also requirede. Besides, the existing free tools have limited functions, and the current comercial solutions are heavily dependent on specific platforms. Along with the maturity of IP Multicast technology and with its inclusion in all the current operational systems, the object-oriented programming languages had developed classes able to handle multicast traflic. So, with the help of Java APIs for network, data bases and hipertext, it became possible to the develop an Integrated Environment able to handle multicast traffic, which is the major objective of this work. This document describes the implementation of the above mentioned environment, which provides many functions to use and manage multicast traffic, functions which existed only in a limited way and just in few tools, normally the comercial ones. This environment is useful to different kinds of users, so that it can be used by common users, who want to join multimedia Internet sessions, as well as more advenced users such engineers and network administrators who may need to monitor and handle multicast traffic / Nas duas ?ltimas d?cadas do s?culo passado, com a consolida??o da Internet como rede mundial de computadores, aplica??es de fluxos mais robustos come?aram a surgir. A crescente uso de videoconfer?ncias impulsionou a cria??o de uma forma de transmiss?o ponto-multiponto chamada Multicast IP. Todas as empresas que desenvolviam software e hardware para videoconfer?ncia adequaram seus produtos e criaram novas solu??es para o uso do fluxo multicast. Entretanto, a configura??o das diversas solu??es n?o ? trivial e, normalmente, altera??es no sistema operacional precisam ser realizadas. Al?m disso, ferramentas gratuitas apresentam funcionalidades limitadas, e as solu??es propriet?rias encontradas na atualidade s?o muito dependentes de plataformas espec?ficas. Com o amadurecimento da tecnologia Multicast IP e com sua inclus?o em todos os sistemas operacionais atuais, as linguagens de programa??o desenvolveram classes capazes de manipular tr?fego multicast. Com as APIs Java para redes, banco de dados e p?ginas Web, tornou-se poss?vel a cria??o de um Ambiente Integrado capaz de manipular tr?fego multicast, que se constitui na proposta central deste trabalho. Esse documento descreve ent?o a implementa??o deste ambiente que agrega diversas funcionalidades para utiliza??o e ger?ncia de tr?fego multicast, funcionalidades at? ent?o presentes de forma limitada em poucas e distintas ferramentas comummente propriet?rias. O ambiente se adequa a diferentes perfis de usu?rio, no sentido de que pode ser usado por leigos em Engenharia de Redes, que desejem apenas participar de sess?es de multim?dia na Internet, como tamb?m por especialistas e administradores de rede que desejem monitorar e manipular o tr?fego multicast