Etude d'une architecture IP intégrant un lien satellite géostationnaire

Cette thèse aborde les problèmes relatifs à l'intégration des satellites géostationnaires dans les réseaux IP. Une première étape de ce travail consiste en une analyse critique des systèmes utilisant le Digital Video Broadcating pour véhiculer des flux IP. Cette étude souligne les faiblesses des solutions actuelles : tandis que les solutions classiques souffrent de limites inhérentes à la technologie et aux protocoles utilisées, les propositions reposant sur les satellites de nouvelles génération impliquent un système spécifique et à fortes contraintes financières. Ces limites engendrent des difficultés d'interopérabilité, témoignant de la nécessité d'une démarche plus globale qui viserait à dessiner une architecture plus large qui ne reposerait pas sur des contraintes techniques. La thèse propose alors de suivre cette démarche, et de concevoir une architecture pour intégrer ces différentes solutions dans un seul système et pouvoir supporter des services porteurs comme l'accès Internet, la vidéo à la demande et l'interconnexion de réseaux privés. Au coeur de cette architecture se trouve la notion de charge utile hybride, c'est-à-dire intégrant une partie transparente traditionnelle et une partie régénérative utilisant une intelligence embarquée plus ou moins évoluée. Ses objectifs sont alors d'assurer l'intégration de services porteurs sur satellite, d'offrir une transition entre les systèmes transparents et les satellites de nouvelle génération, et enfin de s'adapter aux évolutions protocolaires. Dans ce contexte, cette proposition est décrite à plusieurs niveaux, en insistant sur le lien entre le niveau réseau et la couche liaison. Cette description implique des choix technologiques témoignant des solutions actuelles, mais reste ouverte aux technologies à venir par son intégration d'IP comme un élément fédérateur. Enfin l'analyse du système hybride permet de légitimer les services choisis, et de souligner sa flexibilité offerte par la coexistence de ces deux modes et la possibilité de choisir pour chaque type de trafic celui qui permet les meilleurs performances. ABSTRACT : This thesis studies issues related to the integration of geostationary satellites in IP networks. A first part of this work presents an analysis of today and future DVB systems for IP support. The limits of standard solutions are underlined. However new technologies and protocols adaptations allow satellite systems to be more compliant to IP services, but at several costs: high complexity and specificity. As there is a real need of a global solution, an architecture based on two different payloads (a transparent one and an on-board-processing) in a same system is proposed for service integration. This solution, called a hybrid system, is defined according to different service needs. It proposes to undertake the transition between today systems and next generation satellites, as to integrate different services and protocols. The study describes such a solution, underlining that the technologic choices have been made according to today solutions, and may be changed in future days. Eventually this architecture is evaluated. The analysis of the system overhead for IP support shows that the architecture proposes a light way to manage IP streams and hybrid mode. The study of service integration concludes on the flexibility of managing two modes for different traffic streams, allowing the best performances for each one

Handover management for hybrid satellite/terrestrial networks

9 pagesInternational audienceInitially envisaged to support handover between different wireless 802.x network technologies, the IEEE 802.21 standard also appears as the good candidate for handover management in future integrated satellite / terrestrial systems. This paper presents an analysis of how this standard could be implemented in the frame of a realistic scenario and taking into account the current trends in wireless network and mobility architectures. Our solution is then evaluated by means of emulation over a DVB-RCS representative testbed, and based on an experimental MIH implementation. We finally show that seamless handover can nearly be achieved with very short service outages

Convergence architecture for home service communities

Nowadays, home networks have integrated day to day life through the classical internet access and deliver numerous services to end users. This home entrance is a real opportunity for operators to deploy services directly between homes. However, one major issue is the interconnection between Home Networks (HN) which requires suitable architectures and efficient authentication mechanisms. In this paper, two network architectures were proposed to interconnect HNs in order to support home service delivery and then compared with the IMS as reference architecture. The first architecture was based on a centralized SIP solution and used HTTP digest for authentication purpose; while the second proposition consisted in a distributed architecture based on pure P2P and Identity based cryptography. The study of these two solutions has been undergone through the simulation of a simple photo sharing scenario. As a result, the centralized SIP solution can be relevant for an average number of users and the easiest way to deploy new services. The decentralized solution (pure P2P) can be deployed for small service communities and may be compliant to larger system with improved algorithms

Optimized Handover and Resource Management: An 802.21 Based Scheme to Optimize Handover and Resource Management in Hybrid Satellite-Terrestrial Networks

International audienceSatellite communications can provide fourth generation (4G) networks with large-scale coverage. However, their integration to 4G is challenging because satellite networks have not been designed with handover in mind. The setup of satellite links takes time, and so, handovers must be anticipated long before. This paper proposes a generic scheme based on the Institute of Electrical and Electronics Engineers 802.21 standard to optimize handover and resource management in hybrid satellite-terrestrial networks. Our solution, namely optimized handover and resource management (OHRM), uses the terrestrial interface to prepare handover, which greatly speeds up the establishment of the satellite link. We propose two mechanisms to minimize the waste of bandwidth due to wrong handover predictions. First, we leverage the support of 802.21 in the terrestrial access network to shorten the path of the signaling messages towards the satellite resource manager. Second, we cancel the restoration of the satellite resources when the terrestrial link rolls back. We use OHRM to interconnect a digital video broadcasting and a wireless 4G terrestrial network. However for the simulation tool, we use a WiMAX as the terrestrial technology to illustrate the schemes. The simulation results show that OHRM minimizes the handover delay and the signaling overhead in the terrestrial and satellite networks

Évaluation de l’impact de caches pour de la vidéo adaptative par satellite

International audienceAujourd’hui, le satellite géostationnaire propose à ses clients un accès Internet haut débit (de l’ordre de 20Mbit/s). Cependant le délai induit engendre une baisse de réactivité pour la plupart des applications. En particulier, le protocole de streaming vidéo adaptatif DASH ne parvient pas à s’y adapter. Au contraire, il sous-évalue les capacités du réseau et fournit le service minimal disponible. Pour réduire les délais, le CDN rapproche les données de l’utilisateur final grâce à la mise en place de caches. Ce service a fait ses preuves pour la navigation web et le téléchargement de fichiers dans Internet. Cet article propose d’analyser l’impact du CDN pour un service de streaming vidéo adaptatif et dans un contexte satcom, deux points qui, ensemble, divergent de l’utilisation habituelle du CDN. De cette première analyse, nous pouvons différentier trois situations. La première propose des performances optimales. Dans la deuxième, le CDN n’apporte rien. Enfin, dans la dernière situation, le CDN a un impact néfaste sur les performances. Ces deux derniers cas sont induits par une mauvaise politique de mise en cache qui leurre le client DASH sur les qualités à demander. Nous résolvons ce problème par le déploiement d’un proxy transparent indiquant les qualités disponibles dans les caches

Étude d'une architecture IP intégrant un lien satellite géostationnaire

TOULOUSE-ENSEEIHT (315552331) / SudocSudocFranceF

An analysis of NDN Congestion Control challenges

International audienceNamed Data Networking (NDN) proposes to change the core of the Internet. Based on mechanisms successfully used in P2P or CDN, it focuses on content and thus the Quality of Experience of users. Such an ambitious plan raises great challenges: caching, multipath, multi-producers, multi-consumers and security. This paper focuses on one of them: the control of congestion. Several studies have proposed congestion control solutions that fall into three kinds: the end-to-end solution, the hop-by-hop type and the hybrid one. However, the community lacks proper evaluations of such specific algorithms. In this work, we have implemented representative solutions on ndnSIM. In a first step, we have tested them on a small scale topology to ease their performance analysis and highlight their strengths and weaknesses. We complete this study with simulations on larger networks in order to confirm our conclusions. Furthermore, all results are reproducible. Eventually, the paper drives a discussion on how application needs could be considered in the design of a NDN congestion control