Thèses sur le sujet « Communication multicast »
Pour voir les autres types de publications sur ce sujet consultez le lien suivant : Communication multicast.
Créez une référence correcte selon les styles APA, MLA, Chicago, Harvard et plusieurs autres
Consultez les 50 meilleures thèses pour votre recherche sur le sujet « Communication multicast ».
À côté de chaque source dans la liste de références il y a un bouton « Ajouter à la bibliographie ». Cliquez sur ce bouton, et nous générerons automatiquement la référence bibliographique pour la source choisie selon votre style de citation préféré : APA, MLA, Harvard, Vancouver, Chicago, etc.
Vous pouvez aussi télécharger le texte intégral de la publication scolaire au format pdf et consulter son résumé en ligne lorsque ces informations sont inclues dans les métadonnées.
Parcourez les thèses sur diverses disciplines et organisez correctement votre bibliographie.
1
Asfour, Taghrid. « Protocoles de communication multicast fiables ». Paris : École nationale supérieure des télécommunications, 2001. http://catalogue.bnf.fr/ark:/12148/cb388211552.
Texte intégral
2
Akkor, Gün. « Multicast communication support over satellite networks ». College Park, Md. : University of Maryland, 2005. http://hdl.handle.net/1903/2452.
Texte intégralRésumé :
Thesis (Ph. D.) -- University of Maryland, College Park, 2005.Thesis research directed by: Electrical Engineering. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
3
ABELEM, ANTONIO JORGE GOMES. « MULTICAST COMMUNICATION IN OPTICAL IP INTERNETWORKS ». PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2003. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=3898@1.
Texte intégralRésumé :
COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIORA difusão seletiva e os recentes avanços na tecnologia de transmissão óptica, mais especificamente na multiplexação por comprimento de onda (Wavelength Division Multiplexing- WDM), aliados à consolidação do IP como protocolo dominante das redes convergentes, vêm oferecendo novas perspectivas para as futuras gerações de inter-redes. Este trabalho faz uso da evolução dessas tecnologias para propor um conjunto de adaptações à difusão seletiva, em especial ao IP Multicast, denominado MIRROR (Multicast IP para Redes baseadas em Rajadas Ópticas Rotuladas). A proposta MIRROR sugere modificações e adequações para tornar o IP Multicast menos complexo, mais escalável em relação ao número de grupos ativos simultaneamente e mais adequado às redes baseadas em comutação óptica. Basicamente, MIRROR revê a necessidade de todos os roteadores ao longo da árvore de distribuição multiponto manterem informações de estado relacionadas a esta, bem como sugere adequações na forma como os caminhos multiponto são estabelecidos quando se emprega comutação baseada em rótulos na difusão seletiva. Para avaliar a proposta MIRROR, investiu-se em duas frentes distintas, uma baseada na análise comparativa entre a MIRROR e algumas alternativas ao IP Multicast apresentadas na literatura, e outra baseada no desenvolvimento de um protótipo da proposta no simulador NS (Network Simulator), com o intuito de referendar os resultados da análise comparativa. Na análise comparativa, confronta-se parâmetros como: requisitos de informações de estado, custo com informações de controle, custo de encaminhamento dos pacotes e custo da árvore de multiponto. O desenvolvimento do protótipo envolveu a criação de uma nova estrutura de nó e a alteração de módulos já existentes no NS, para tornar possível a simulação de redes comutadas por rajadas ópticas rotuladas no contexto da difusão seletiva.
Multicast communication and recent advances in optical technology, most specifically in Wavelength Division Multiplexing (WDM), allied with the consolidation of IP as the dominant protocol of convergent networks, offer new perspectives for the next generation Internet. This thesis utilises these technologies to propose a set of adaptations, called MIRROR, to multicast communication, specifically IP Multicast, in labelled burst-switched optical networks. MIRROR proposes modifications to traditional IP Multicast in order to improve its scalability as a function of the number of simultaneously active groups, as well as making it more appropriate for use in optically switched networks. Basically, MIRROR includes new proposals for handling state information about the multicast distribution tree, as well as for the establishment of label-based multicast paths. In order to evaluate this proposal, two approaches are followed, one based on a comparative analysis between MIRROR and a number of other alternatives to IP Multicast proposed in the literature, and the other based on the implementation of a prototype in the simulation environment provided by NS (Network Simulator). The comparative analysis evaluates such parameters as: state requirement information, control overhead, packet processing efficiency and tree cost. The prototype implementation implements a new node structure and alters existing NS modules (OBS e MPLS), to make possible the simulation of labelled burst-switched optical networks in the multicast context.
4
Cogdon, Stephen. « Application-level multicast for group communication ». Thesis, University of Sussex, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.413333.
Texte intégral
5
Boyer, Eric B. « Multicast communication with guaranteed quality of service ». Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 1993. http://handle.dtic.mil/100.2/ADA277650.
Texte intégralRésumé :
Thesis (M.S. in Electrical Engineering and Electrical Engineer) Naval Postgraduate School, December 1993.Thesis advisor(s): Shridhar B. Shukla. "December 1993." Includes bibliographical references. Also available online.
6
Ben, Jemaa Inès. « Communication multicast pour les systèmes véhiculaires coopératifs ». Thesis, Paris, ENMP, 2014. http://www.theses.fr/2014ENMP0065/document.
Texte intégralRésumé :
La communication véhiculaire permet le développement de nouvelles applications multicast émergentes telles que la gestion de la flotte et la distribution des Points d'Intérêt (POI). Ces deux catégories d'applications nécessitent une communication multicast de l'Internet vers les réseaux véhiculaires (VANET). Afin de mettre en place une communication multicast adaptée au contexte de la communication Internet-vers-réseaux véhiculaires, notre travail traite de deux aspects différents. Tout d'abord, l'accessibilité des véhicules en mouvement au service Internet et en deuxième lieu, la dissémination du message dans les VANET. Nous introduisons un schéma d'adressage multicast basé sur les coordonnées géographiques des véhicules qui leur permet de s'auto-configurer d'une façon dynamique sans aucun besoin d'échanger des messages de signalisation avec Internet. Nous proposons aussi une approche simplifiée de gestion de la mobilité des véhicules dans le cadre des architectures Mobile IP et Proxy Mobile IP. Le but de cette approche est d'optimiser l'échange des messages avec les entités responsables de la gestion de la mobilité dans Internet. Afin d'étudier les mécanismes de dissémination appropriés aux applications de gestion de flottes, nous nous proposons de revisiter les techniques de routage multicast traditionnelles basées sur une structure de diffusion en arbre. Pour cela, nous étudions leur application aux réseaux véhiculaires. Nous présentons une étude théorique portant sur la durée de vie des liens entre les véhicules en milieux urbains. Ensuite, en utilisant la simulation, nous étudions l'application de Multicast Adhoc On Demand Vector, MAODV et proposons Motion-MAODV, une version adaptée de MAODV qui a pour objectif d'établir des routes plus robustes Enfin, concernat la dissémination multicast géolocalisée dans les applications POI, nous proposons le protocole de routage Melody qui permet une diffusion geocast en milieu urbain. A partir de simulations, nous constatons que, comparé aux protocoles de géo-brodcasting dans les milieux urbain très denses, Melody assure plus de fiabilité et d'efficacité lors de l'acheminement des données vers les zones géographiques de destinationVehicular communications allow emerging new multicast applications such as fleet management and point of interest (POI). Both applications require Internet-to-vehicle multicasting. These approaches could not be applied to vehicular networks (VANET) due to their dynamic and distributed nature. In order to enable such multicasting, our work deals with two aspects. First, reachability of the moving vehicles to the multicast service and second, multicast message dissemination in VANET. We introduce first a self-configuring multicast addressing scheme that allows the vehicles to auto-configure a dynamic multicast address without a need to exchange signalling messages with the Internet. Second, we propose a simplified approach that extends Mobile IP and Proxy Mobile IP. This approach aims at optimizing message exchange between vehicles and entities responsible for managing their mobility in Internet. To study the dissemination mechanisms that are suitable for fleet management applications, we propose to revisit traditional multicast routing techniques that rely on a tree structure. For this purpose, we study their application to vehicular networks. In particular, as vehicular networks are known to have changing topology, we present a theoretical study of the link lifetime between vehicles in urban environments. Then, using simulations, we study the application of Multicast Adhoc On Demand Vector, MAODV. We propose then Motion-MAODV, an improved version of MAODV that aims at enhancing routes built by MAODV in vehicular networks and guarantee longer route lifetime. Finally, to enable geographic dissemination as required by POI applications, we propose a routing protocol Melody that provides a geocast dissemination in urban environments. Through simulations, Melody ensures more reliable and efficient packet delivery to a given geographic area compared to traditional geo-brodcasting schemes in highly dense scenarios
7
Jiang, Tianji. « Accommodating heterogeneity and scalability for multicast communication ». Diss., Georgia Institute of Technology, 2000. http://hdl.handle.net/1853/8190.
Texte intégral
8
Belkeir, Nasr Eddine. « Multicast communication in distributed systems with dynamic groups ». Diss., Georgia Institute of Technology, 1991. http://hdl.handle.net/1853/8134.
Texte intégral
9
Martina, Jean Everson. « Verification of security protocols based on multicast communication ». Thesis, University of Cambridge, 2011. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.609650.
Texte intégral
10
Macedo, Raimundo Jose de Araujo. « Fault-tolerant group communication protocols for asynchronous systems ». Thesis, University of Newcastle Upon Tyne, 1994. http://hdl.handle.net/10443/2021.
Texte intégralRésumé :
It is widely accepted that group communication (multicast) is a powerful abstraction that can be used whenever a collection of distributed processes cooperate to achieve a common goal such as load-sharing or fault-tolerance. Due to the uncertainties inherent to distributed systems (emerging from communication and/or process failures), group communication protocols have to face situations where, for instance, a sender process fails when a multicast is underway or where messages from different senders arrive in an inconsistent order at different destination processes. Further complications arise if processes belong to multiple groups. In this thesis, we make use of logical clocks [Lamport78] to develop the concept of Causal Blocks. We show that Causal Blocks provide a concise method for deducing ordering relationships between messages exchanged by processes of a group, resulting in simple methods for dealing with multiple groups. Based on the Causal Blocks representation, we present a protocol for total order message delivery which has constant and low message space overhead (Le. the protocol related information contained in a multicast message is small). We also present causal order protocols with different trade-offs between message space overhead and speed of message delivery. Furthermore, we show how the Causal Blocks representation can be used to easily deduce and maintain reliability information. Our protocols are faulttolerant: ordering and liveness are preserved even if group membership changes occur (due to failures such as process crashes or network partitions). The total order protocol, together with a novel flow control mechanism, has been implemented over a set of networked Unix workstations, and experiments carried out to analyse its performance in varied group configurations.
11
Huang, Luan. « Multicast resource management for next generation mobile communication systems ». Thesis, University of Surrey, 2006. http://epubs.surrey.ac.uk/804477/.
Texte intégral
12
Doar, John Matthew Simon. « Multicast in the asynchronous transfer mode environment ». Thesis, University of Cambridge, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.241604.
Texte intégral
13
Wang, Yanhua. « Minimizing Overlap in Tree-Based Multipoint Communication ». University of Cincinnati / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1109346846.
Texte intégral
14
Costa, Luís Henrique Maciel Kosmalski. « Routage dans l'Internet : qualité de service et communication de groupe ». Paris 6, 2001. http://www.theses.fr/2001PA066454.
Texte intégral
15
Ballardie, Anthony Joseph. « A new approach to multicast communication in a datagram internetwork ». Thesis, University College London (University of London), 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.281760.
Texte intégral
16
Khan, Gul Zameen. « Reliable and Efficient Multicast Communication in WiFi Direct (P2P) 802.11Wireless Networks ». Thesis, Griffith University, 2017. http://hdl.handle.net/10072/370913.
Texte intégralRésumé :
This thesis focuses on exploring a multicast communication protocol forWiFi Direct (WD) 802.11
networks. The aim is to improve reliability and efficiency of multicast communication in WD networks.
Multicast inWDhas numerous potential applications such as local content sharing, sharing
network services, playing multi-player games, and a number of other proximity based services in
various fields, viz. health, sports, agriculture, transportation, and gaming. The two major issues
with multicast, reliability and efficiency, have been extensively studied in literature for standard
WiFi 802.11 networks. However, multicast protocols used in standard WiFi 802.11 networks cannot
be straightforwardly used in WD networks because the two technologies are different. Some
of these differences include multicast group formation, group architecture, network topology, role
and capacity of multicast transmitter. As a result, a multicast protocol cannot achieve reliability
and efficiency without taking into account the specifications of the MAC and PHY layers of WD
802.11 networks.
Motivated from the leader based approaches of standard WiFi, an Enhanced Leader Based
Multicast (ELBM) protocol is proposed to achieve reliability in multicast communication in WD
networks. It reduces collision and interference in multicast data transmission by improving the
channel access mechanism and selecting an optimal representative multicast receiver. In order to
assess the performance improvement which results from early detection of packet collision, Early
Packet Loss Detection (EPLD) analytical model is proposed, which surpasses the standard protocol
in terms of system throughput. Similarly, a theoretical model is formulated to investigate the
new features of the MAC and PHY layers of 802.11ac, such as different Multiple In Multiple Out
(MIMO) configurations, Modulation and Coding Schemes (MCS), and wider channel bandwidths
under TGn channel models. Because hidden nodes can largely affect the throughput of WD networks,
therefore an improved analytical model known as Vidden is developed to analyse the Very
High Throughput (VHT) of 802.11ac in the presence of hidden stations. Vidden carefully calculates
the collision probability by taking into account both the contending, as well as, the hidden
stations
A novel adaptive algorithm is proposed to maximize the efficiency of WD 802.11 networks
under a TGn channel model by choosing optimal PHY parameters in accordance with targeted
Quality of Experience (QoE) for a particular application. The simulation results show that the
proposed method outperforms the standard method, thereby achieving an optimal performance in an adaptive manner. Thereafter, an efficient methodology is proposed to reduce the overall Packet
Error Rate (PER) based on the simulation results.
Finally, the problem of selecting the most favourable transmission channel and rate is investigated
for a multicast communication system in the context of WD 802.11 networks. To this end, a
novel Multi-rate Multi-channel Multicast (M3-Cast) protocol is proposed, which not only chooses
the most favourable communication channel and transmission rate but also takes into account the
implementation details of the underlying WD technology, thereby optimizing the overall system
performance. M3-Cast is formulated analytically and evaluated by a complete system level simulation.
The detailed results and analysis consider a number of performance metrics, such as bit
error rate (BER), multicast capacity, and system throughput under different MIMO configurations,
channel bandwidths, and various network radii. Consequently, the simulation and analytical results
show that M3-Cast protocol outperforms the standard multicast protocol of WD by almost two-fold in terms of system throughput.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Info & Comm Tech
Science, Environment, Engineering and Technology
Full Text
17
Nikitin, Kirill. « DTLS Adaptation for Efficient Secure Group Communication ». Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-172355.
Texte intégralRésumé :
The Internet has been growing rapidly during the past threedecades, evolving into a new paradigm called the Internet ofThings where all electronic devices are to be connected tothe global network. One of the most crucial needs forcommunication in this future global network is assuring its security.Datagram Transport Layer Security is a de facto standard protocolto secure end-to-end communication in the IoT. However, there isalso an increasing need for secure and efficient groupcommunication due to the frequently resource-constrained IoTenvironment. A DTLS adaptation for multicast communication hasbeen already proposed but protection of responses to multicastrequests has not been fully addressed yet. Furthermore, there is nopublicly available implementation of this adaptation. This thesis work is conducted in collaboration with SICS SwedishICT which is a research organization with a focus on appliedComputer Science. We have implemented the existing DTLS-basedapproach for multicast communication for the Contiki OS. We havealso implemented an approach for efficient response protectionthat was initially proposed at SICS and that we analyse andenhance in this thesis. Finally, we have experimentally evaluatedour and other approaches on a constrained hardware platform interms of memory requirements, communication performance andenergy consumption. We demonstrate advantages of our approachbased upon obtained results.Internet har vuxit snabbt under de tre senaste decennierna, ochutvecklas till ett nytt paradigm kallat Internet of Things där allaelektroniska enheter kopplas till det globala nätverket. Ett av deviktigaste behoven för kommunikation i detta framtida globalanätverk är att garantera säkerhet. Datagram Transport LayerSecurity protokollet är en de facto-standard för säker end-to-endkommunikation i IoT. Det finns emellertid också ett ökande behovav säker och effektiv gruppkommunikation på grund av att IoTmiljöni regel är resursbegränsad. En anpassning av DTLS förmulticast-kommunikation har föreslagits men skydd av svar påmulticast-förfrågningar har ännu inte till fullo behandlats.Dessutom finns ingen offentligt tillgänglig implementation av dennaanpassning. Detta examensarbete utförs i samarbete med SICS Swedish ICTsom är en forskningsorganisation med fokus på tillämpaddatavetenskap. Vi har implementerat den existerande DTLSbaseradelösningen för multicast-kommunikation föroperativsystemet Contiki. Vi har också implementerat en lösningför effektivt skydd av svar på förfrågningar som ursprungligenföreslogs hos SICS och som vi analyserar och förbättrar i dettaexamensarbete. Slutligen har vi experimentellt utvärderat vår ochandra metoder på en begränsad hårdvaruplattform när det gällerminnesbehov, kommunikationsprestanda och energiförbrukning. Vivisar fördelar med vår metod baserat på de erhållna resultaten.
18
Boinpalli, Vamshi Krishna. « A Robust Wireless Multicast Protocol ». Ohio University / OhioLINK, 2005. http://www.ohiolink.edu/etd/view.cgi?ohiou1121356426.
Texte intégral
19
Shahnaz, Ambreen. « Approximating node-weighted Steiner subgraphs for multicast communication in wireless networks ». Thesis, University of Leicester, 2012. http://hdl.handle.net/2381/10837.
Texte intégralRésumé :
We are motivated by the problem of computing multicast routing structures in wireless ad-hoc networks modelled by special classes of graphs including unit disk graphs, quasi-unit disk graphs and (λ + 1)-claw-free graphs. Multicast communication can be established by a tree known as Steiner tree. Wireless ad-hoc networks must operate using limited resources, therefore, the suitability of nodes for inclusion in a Steiner tree can vary widely between different nodes. We model this by assuming that each node of the network is assigned a weight that represents the cost of including it in the Steiner tree. Our goal is to compute a Steiner tree with minimum total node weight. However, in scenarios where nodes and links are not reliable, a tree has the drawback that it can be disconnected by the failure of even a single link or node in the network. Therefore, we also consider various fault-tolerant routing structures called 2-edge-connected Steiner subgraphs, k-edge-connected Steiner subgraphs, 2-vertex-connected Steiner subgraphs, and 2-edge-connected group Steiner subgraphs. The problems we consider are NP-hard, so we are interested in algorithms that compute provably good approximate solutions in polynomial time. We present a generalization of Steiner subgraph problems referred to as the node-weighted δ-Steiner subgraph problem, where δ represents connectivity requirements. We present an algorithm with approximation ratio 0.5dρ for the node-weighted δ-Steiner subgraph problem, where d is the bounded maximum degree of the solution subgraph, and ρ is the approximation ratio of the edge-weighted version of the δ-Steiner subgraph problem. We then shown how to construct solution subgraphs of bounded maximum degree d in several graph classes for our problem variants. As a result, we obtain algorithms for the problems we consider, on graph classes that admit subgraphs of small degree, whose approximation ratios are better than the best known ratios for the same problems on general graphs.
20
Schnell, Felicia. « Multicast Communication for Increased Data Exchange in Data- Intensive Distributed Systems ». Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-232132.
Texte intégralRésumé :
Modern applications are required to handle and communicate an increasing amount of data. Meanwhile, distributed systems containing multiple computationally weak components becomes more common, resulting in a problematic situation. Choosing among communication strategies, used for delivering message between entities, therefore becomes crucial in order to efficiently utilize available resources. Systems where identical data is delivered to many recipients are common nowadays, but may apply an underlying communication strategy based on direct interaction between sender and receiver which is insufficient. Multicasting refers to a technique for group communication where messages can be distributed to participating nodes in a single transmission. This technique is developed to circumvent the problem of high workload on sender side and redundant traffic in the network, and constitutes the focus for this thesis. Within the area of Electronic Warfare and self-protection systems, time constitutes a critical aspect in order to provide relevant information for decision making. Self-protection systems developed by Saab, used in military aircrafts, must provide situational awareness to guarantee that correct decisions can be made at the right time. With more advanced systems, where the amount of data needed to be transmitted increases, the need of fast communication is essential to achieve quality of service. This thesis investigates how the deployment of multicast, in a distributed data-intensive system, could prepare a system for increased data exchange. The result is a communication design which allows for the system to distribute messages to a group of receivers with less effort from the sender and with reduced redundant traffic transferred over the same link. Comparative measurements are conducted between the new implementation and the old system. The result of the evaluation shows that the multicast solution both can decrease the time for message handling as well as the workload on endpoints significantly.Nutidens applikationer måste kunna hantera och kommunicera en ökad datamängd. Samtidigt har distribuerade system bestående av många beräkningsmässigt svaga enheter blivit allt mer vanligt, vilket är problematiskt. Valet av kommunikationsstrategi, för att leverera data mellan enheter i ett system, är därför av stor betydelse för att uppnå effektivt utnyttjande av tillgängliga resurser. System där identisk information ska distribueras till flertalet mottagare är vanligt förekommande idag. Den underliggande kommunikationsstrategin som används kan dock baseras på direkt interaktion mellan sändare och mottagare vilket är ineffektivt. Multicast (Flersändning) syftar till ett samlingsbegrepp inom datorkommunikation baserat på gruppsändning av information. Denna teknik är utvecklad för att kringgå problematiken med hög belastning på sändarsidan och dessutom minska belastningen på nätverket, och utgör fokus för detta arbete. Inom telekrigföring och självskyddssystem utgör tiden en betydande faktor för att kunna tillhandahålla relevant information som kan stödja beslutsfattning. För självskyddssystem utvecklade av Saab, vilka används i militärflygplan, är situationsmedvetenhet av stor betydelse då det möjliggör för att korrekta beslut kan tas vid rätt tidpunkt. Genom utvecklingen av mer avancerade system, där mängden meddelanden som måste passera genom nätverket ökar, tillkommer höga krav på snabb kommunikation för att kunna åstadkomma kvalité. Denna uppsatsrapport undersöker hur införandet av multicast, i ett dataintensivt distribuerat system, kan förbereda ett system för ökat datautbyte. Arbetet har resulterat i en kommunikationsdesign som gör det möjligt för systemet att distribuera meddelanden till grupp av mottagare med minskad belastning på sändarsidan och mindre redundant trafik på de utgående länkarna. Jämförandet mätningar har gjorts mellan den nya implementationen och det gamla systemet. Resultaten visar att multicast-lösningen både kan reducera tiden för meddelande hantering samt belastningen på ändnoder avsevärt.
21
Reeve, Jonathan Mark. « Learning algorithms for the control of routing in integrated service communication networks ». Thesis, Durham University, 1998. http://etheses.dur.ac.uk/4687/.
Texte intégralRésumé :
There is a high degree of uncertainty regarding the nature of traffic on future integrated service networks. This uncertainty motivates the use of adaptive resource allocation policies that can take advantage of the statistical fluctuations in the traffic demands. The adaptive control mechanisms must be 'lightweight', in terms of their overheads, and scale to potentially large networks with many traffic flows. Adaptive routing is one form of adaptive resource allocation, and this thesis considers the application of Stochastic Learning Automata (SLA) for distributed, lightweight adaptive routing in future integrated service communication networks. The thesis begins with a broad critical review of the use of Artificial Intelligence (AI) techniques applied to the control of communication networks. Detailed simulation models of integrated service networks are then constructed, and learning automata based routing is compared with traditional techniques on large scale networks. Learning automata are examined for the 'Quality-of-Service' (QoS) routing problem in realistic network topologies, where flows may be routed in the network subject to multiple QoS metrics, such as bandwidth and delay. It is found that learning automata based routing gives considerable blocking probability improvements over shortest path routing, despite only using local connectivity information and a simple probabilistic updating strategy. Furthermore, automata are considered for routing in more complex environments spanning issues such as multi-rate traffic, trunk reservation, routing over multiple domains, routing in high bandwidth-delay product networks and the use of learning automata as a background learning process. Automata are also examined for routing of both 'real-time' and 'non-real-time' traffics in an integrated traffic environment, where the non-real-time traffic has access to the bandwidth 'left over' by the real-time traffic. It is found that adopting learning automata for the routing of the real-time traffic may improve the performance to both real and non-real-time traffics under certain conditions. In addition, it is found that one set of learning automata may route both traffic types satisfactorily. Automata are considered for the routing of multicast connections in receiver-oriented, dynamic environments, where receivers may join and leave the multicast sessions dynamically. Automata are shown to be able to minimise the average delay or the total cost of the resulting trees using the appropriate feedback from the environment. Automata provide a distributed solution to the dynamic multicast problem, requiring purely local connectivity information and a simple updating strategy. Finally, automata are considered for the routing of multicast connections that require QoS guarantees, again in receiver-oriented dynamic environments. It is found that the distributed application of learning automata leads to considerably lower blocking probabilities than a shortest path tree approach, due to a combination of load balancing and minimum cost behaviour.
22
Parnes, Peter. « The mStar environment : scalable distributed teamwork using IP multicast ». Licentiate thesis, Luleå tekniska universitet, Datavetenskap, 1997. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-18409.
Texte intégralRésumé :
This thesis addresses the question of how a scalable, distributed teamwork environment should be designed and realized. Central design criteria includes that the system should be scalable and robust, allow for easy access and be symmetric. The system should allow for project team members to collaborate even though they are not located at the same physical location. The resulting system presented in this thesis, called the mStar environment have been created to address exactly these questions. mStar is scalable and robust through the usage of standard networks and IP-multicast, it allows for easy access as it is desktop based and finally it is symmetric allowing for easy peer-communication. mStar includes support for desktop conferencing, including mAudio for audio, reuse of the MBone Vic tool for video, mWB for whiteboard, mChat for text based chat and mVote for voting. It also supports distributed synchronized presentations using the WWW and the mWeb application. As all traffic is network and IP-multicast based it allows for easy recording and playback of teamwork sessions using the mMOD application. To allow for easy access to users behind non-multicast capable network segments (primarily modem and ISDN), mTunnel was created. It allows for tunneling and transformation of the traffic. Another member of the mStar environment is Director for remote control of video equipment. mStar also includes support for easy creation of new teamwork tools and applications using the Tunable Multicast Platform - /TMP and the Generic Agent Architecture. The mStar environment can be used and is being used on a daily basis for electronic meetings, distance education and lectures, and daily teamwork. The usage mStar creates group awareness between project members and helps users from not becoming isolated from their department and project team. mStar allows for usage 24 hours a day and have resulted in, among other things, a new usage patterns, which resembles electronic corridors more than specific meetings, where users can and do meet spontaneously to talk about anything they want, but also overhear other interesting and important conversations just as in a physical office corridor.Godkänd; 1997; 20061004 (ysko)
23
Fang, Ke. « Optical multicast radio-over-fibre distributed antenna system ». Thesis, University of Cambridge, 2012. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.610095.
Texte intégral
24
Mekhitarian, Araxi. « Reducing Software Complexity in a Distributed Publish-Subscribe system using Multicast communication ». Thesis, KTH, Skolan för elektroteknik och datavetenskap (EECS), 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-232120.
Texte intégralRésumé :
Systems of distributed character are increasing in size and becoming more complex. Managing and adapting to constant changes of requirements is a challenge during the entire system development life cycle. While new functionalities are implemented, the software may change in design and may lead to poor software quality and increased system complexity. This thesis focuses on tackling the complexity issue in a distributed Electronic Warfare system used in military aircraft. The system consists of a server and several clients which acts as publishers or subscribers for different events sent in the system. The communication is based on unicast and uses a publish/subscribe pattern for the client nodes to register as publishers or subscribers to the server. The system is created to handle message passing in high rate and is sensitive for message delays. Due to this, the system is dependent on a reliable network structure with a continuous necessity for development. An implementation of a multicast prototype will be replacing the topic-specific unicast communication and the publish/subscribe registration process to the server. The system will be evaluated by a comparison of the old communication version with the new multicast implementation using software metrics. The result is to evaluate if the behavior and functionality of the distributed Electronic Warfare system change.System av distribuerad karaktär ökar i storlek och blir alltmer komplex. Att hantera och anpassa sig till ständiga kravändringar är emellertid en utmaning under hela systemets utvecklingsprocess. Medan nya funktioner implementeras kan mjukvaran ändras i design vilket kan leda till dålig programkvalitet och ökad systemkomplexitet. Denna rapport fokuserar på att hantera komplexiteten i ett distribuerat telekrigföringssystem som används i militära flygplan. Systemet består av en server och flera klienter som publicerar och prenumererar för olika typer av meddelanden som skickas i systemet. Kommunikationen baseras på enkelsändning och använder ett publish/subscribe meddelandemönster där klienterna registrerar sig som publicerare eller prenumeranter till servern. Systemet är skapat för att kunna hantera höga meddelandehastigheter och har låg tolerans för meddelandeförseningar. På grund av detta är tillförlitlighet i nätverksstrukturen ett essentiellt kvalitetsattribut då nätverket är i behov av en ständig utveckling. En prototyp av multisändning kommer att implementeras och ersätta kommunikationen baserad på enkelsändning och publish/subscribe registreringsprocessen till servern. Systemet kommer att utvärderas genom en jämförelse av den gamla kommunikationsversionen av systemet med den nya multicast-implementeringen med hjälp av mjukvarukomplexitetsmätningar. Resultatet är att utvärdera om beteendet och funktionaliteten hos det distribuerade telekrigföringssystemet ändras.
25
Talpade, Rajesh R. « Towards ubiquitous internet multicast : convergence mechanisms and data transfer reliability ». Diss., Georgia Institute of Technology, 1997. http://hdl.handle.net/1853/8297.
Texte intégral
26
HELMICK, MICHAEL T. « EFFICIENT GROUP COMMUNICATION AND THE DEGREE-BOUNDED SHORTEST PATH PROBLEM ». University of Cincinnati / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1178810750.
Texte intégral
27
Hoerdt, Mickaël. « Source Specific Multicast (SSM) : Vers un service de communication de groupe inter-domaine extensible ». Université Louis Pasteur (Strasbourg) (1971-2008), 2005. http://www.theses.fr/2005STR13086.
Texte intégral
28
Chaddoud, Ghassan. « Sécurisation de communication de groupes dynamiques ». Nancy 1, 2002. http://www.theses.fr/2002NAN10046.
Texte intégralRésumé :
Un déploiement commercial des communications de groupes dynamiques sur Internet i. E, les deux modèles ASM (Any Source Multicast) et SSM (Source-Specific Multicast), ne pourra être effectif que s'il offre des services de sécurité plus conséquents comme la confidentialité, l'intégrité, l'authentification et le contrôle d'accès. Dans le but d'assurer ces services de sécurité aux ASM et SSM, nous avons proposé deux nouvelles architectures de sécurité Baal et S-SSM. Baal : Sécurisation des communications de groupes dynamiques. Baal est une solution extensible pour la gestion des clés de groupes dynamiques. Il permet au Contrôleur Global, CG, de configurer et gérer un group sécurisé sur Internet. Une clé, la clé de groupe, est utilisée à chaque moment pour chiffrer le trafic du groupe. La gestion de la sécurité de groupe est assurée en utilisant des entités partiellement déléguées à la gestion de la clé de groupe au niveau des domaines où il a y des membres du groupe. S-SSM : A Secure SSM Architecture. S-SSM offre deux mécanismes de sécurité : le contrôle d'accès et la protection du contenu. Le mécanisme de contrôle d'accès est une extension de Baal qui utilise un token signé pour contrôler l'accès aux groupes. Le but d'une telle solution est d'authentifier des membres avec leurs routeurs locaux et de protéger les demandes d'appartenance aux groupes contre les attaques diverses. Le second mécanisme est réalisé via l'authentification de l'émetteur et le chiffrement des données. Ce mécanisme nécessite la gestion d'une clé unique appelée la clé de canal, k_ch, partagée entre l'émetteur et les abonnés. Il est une variante de BaalAn effective commercial multicast deployments of ASM (Any Source Multicast) and SSM (Source-Specific Multicast) should involve some security services such as confidentiality, integrity, authentication and access control. Having in mind the idea of ensuring these services, we have proposed two secuirty architectures Baal and S-SSM for ASM and SSM respectively. Baal : Securing Dynamic Group Communications. Baal is a scalable solution for the management of dynamic group keys. It allows a Global Controller, GC, to configure and manage a secured group on Internet. A single group key is used at any time to encrypt the group traffic. The group security management is ensured by using entities partially delegated to the management of the group key at the level of the domains where there are group members. S-SSM : A Secure SSM Architecture. S-SSM is composed of two security mechanisms: the access control and content protection. The access control mechanism is an extension of a solution proposed in Baal which uses a signed token to control access to group communication. The aim of such solution is to authenticate members by their local routers and to protect membership demands against attacks. As for the second one, it is achieved via sender authentication and data ciphering. This last one requires the management of a unique key, called the channel key, k_ch, shared among the sender and subscribers. This scheme is a variant of Baal
29
Alwadani, Dhaifallah. « Hybrid multicasting using Automatic Multicast Tunnels (AMT) ». Thesis, University of Stirling, 2017. http://hdl.handle.net/1893/26026.
Texte intégralRésumé :
Native Multicast plays an important role in distributing and managing delivery of some of the most popular Internet applications, such as IPTV and media delivery. However, due to patchy support and the existence of multiple approaches for Native Multicast, the support for Native Multicast is fragmented into isolated areas termed Multicast Islands. This renders Native Multicast unfit to be used as an Internet wide application. Instead, Application Layer Multicast, which does not have such network requirements but is more expensive in terms of bandwidth and overhead, can be used to connect the native multicast islands. This thesis proposes Opportunistic Native Multicast (ONM) which employs Application LayerMulticast (ALM), on top of a DHT-based P2P overlay network, and Automatic Multicast Tunnelling (AMT) to connect these islands. ALM will be used for discovery and initiating the AMT tunnels. The tunnels will encapsulate the traffic going between islands' Primary Nodes (PNs). AMT was used for its added benefits such as security and being better at traffic shaping and Quality Of Service (QoS). While different approaches for connecting multicast islands exists, the system proposed in the thesis was designed with the following characteristics in mind: scalability, availability, interoperability, self-adaptation and efficiency. Importantly, by utilising AMT tunnels, this approach has unique properties that improve network security and management.
30
Duma, Claudiu. « Security and Efficiency Tradeoffs in Multicast Group Key Management ». Licentiate thesis, Linköping : Univ, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-5695.
Texte intégral
31
Koyabe, Martin W. « Appropriate and robust reliable multicast transport techniques for satellite networks experiencing persistent link fades ». Thesis, University of Aberdeen, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.274816.
Texte intégralRésumé :
Over the last decade, the Internet has been experiencing an exponential growth in multimedia (i.e. voice and video) and bulk data traffic mainly generated by IP multicast applications. This surge in IP multicast traffic has led to a growing belief among many network infrastructure experts, that the current Internet should widely support IP multicast as a core transport service for both multimedia and bulk data traffic. IP multicast enables efficient use of bandwidth and scales to large groups of receivers (i.e. overheads at the source, per transport stream, remains constant with increasing number of receivers); which makes it an ideal transport service for alleviating congestion and minimising bandwidth usage over the current Internet infrastructure. This work, considers the use of next generation broadband satellite networks as a future complementary solution, for large-scale deployment of reliable IP multicast services over the present Internet infrastructure. It examines how different classes of reliable multicast transport techniques (suited for deployment over satellite networks) perform over link channels experiencing fades/outages similar to next generation satellite links. It then demonstrates how reliable multicast transport protocol techniques; can be optimised over next generation satellite networks. Based on experience gained in conducting benchmark experiments and performance analysis of a set of reliable multicast protocol techniques over varying link conditions, such as high loss rate (significantly due to persistent link fades) and propagation delay. Design specification and implementation of an optimised reliable multicast transport protocol, Satellite Reliable Multicast Transport Protocol (SAT-RMTP), suited for hybrid terrestrial-satellite network, has been presented. Analysis of SAT-RMTP performance over both terrestrial and satellite networks has been conducted and compared with similar protocols currently being proposed for standardisation in the IETF.
32
Kellil, Mounir. « Sécurité Multicast dans les environnements IP Mobile ». Compiègne, 2005. http://www.theses.fr/2005COMP1579.
Texte intégralRésumé :
Ce travail de thèse traite les problèmes de sécurité des communications multipoint (ou Multicast) en environnement IP Mobile. Il a été motivé par l'accroissement des applications de groupes telles que la vidéoconférence, la formation électronique à distance, etc. Cependant, cet accroissement a été accompagné par l'émergence des technologies sans fil (ex. IEEE 802. 11 b, UMTS, etc. ) et les standards de mobilité sur Internet (Mobile IP). Par conséquent, les communications multipoint en environnement IP mobile représentent aujourd'hui une perspective attractive profitant à la fois de l'apport du multipoint (ex. Flexibilité) et de la mobilité. Néanmoins, sécuriser les communications multipoint dans les environnements mobiles est une tâche difficile. En effet, une solution sécurisée pour un tel scénario doit répondre à la fois aux exigences des communications multipoint (ex. Flexibilité) ainsi qu'aux diverses contraintes des environnements mobiles (ex. Faibles ressources et mobilité)The present work addresses the multicast security problem in mobile IP environments. The goal behind such an interest is to efficiently secure future generations of Internet group communications (e. G. Pay-per-view applications, videoconferences, etc), where users can securely communicate together using IP multicasting while seamlessly moving from a network to another. The multicast security problem is challenging and some related topics are still largely open. Moreover, the mobile environments complicate the multicast security problem. Specifically, the mobile environments inherit the security problems of the stationary case, and raise performance and interoperability issues that should be taken into account
33
Parnes, Peter. « An IP-multicast based framework for designing synchronous distributed multi-user applications on the Internet ». Doctoral thesis, Luleå tekniska universitet, Datavetenskap, 1999. http://urn.kb.se/resolve?urn=urn:nbn:se:ltu:diva-25971.
Texte intégralRésumé :
This thesis examines the problems of how to design scalable, robust, and distributed real-time media applications for the Internet. An agent based framework for solving this problem is presented. The framework promotes several important design requirements such as modularity and reusability of software modules, remote management of applications, adaptiveness, robustness, accessibility, symmetry and the most important scalability. The issue of scalability is examined on several levels including data-distribution, different end-user platforms, scalability of real-time media flows, bandwidth adaption and scalability of sessions. The design of the framework is based on the important concept of IP-multicast, which allows for scalable distribution of data on the Internet. How this decision has influenced the design of the framework is examined in the thesis. The design of the framework have been verified by building a reference implementation in Java and building a number of high-level end-user applications for real-time e-meetings, e-learning (net-based learning) and social awareness via the e-corridor.Godkänd; 1999; 20061004 (ysko)
34
Laouiti, Mohamed Anis. « Unicast et Multicast dans les réseaux ad hoc sans fil ». Versailles-St Quentin en Yvelines, 2002. http://www.theses.fr/2002VERS018V.
Texte intégralRésumé :
La présente thèse aborde 3 thèmes : -Le routage sans fil unicast OLSR;-Le routage sans fil multicast MOLSR;-Mise en oeuvre et test du protocole OLSR dans un environnement réel. Une brève description des trois thèmes de cette thèse : Le routage sans fil unicast OLSR : Le protocole de routage OLSR(Optimized Link State Routing), héritier du protocole HIPERLAN normalisé par l'ETSI, est un protocole de routage proactif niveau IP soumis au groupe MANET de l'IETF. Il présente une caractéristique très intéressante qui permet d'économiser les ressources radio lors des diffusions. Il utilise la technique de diffusion par des relais multipoint, qui permet avec un nombre réduit de répétitions d'atteindre tous les noeuds dans le réseau. Dans cette thèse, on étudie en particulier cette technique pour les grands réseaux, et on évalue les performances du protocole de routage OLSR par simulation. -Le routage sans fil multicast MOLSR : La transmission radio est par nature une transmission broadcast ; Et même si dans un premier temps les chercheurs se sont penchés sur la résolution et la mise au point des algorithmes de routage unicast, il est très important d'exploiter cette propriété naturelle de la diffusion radio. Dans cette perspective, nous avons défini un protocole de routage Multipoint (Multicast OLSR) qui se greffe naturellement sur le protocole de routage OLSR. Nous avons aussi, conçu un protocole de gestion d'abonnement aux groupes multicast (Wireless IGMP) qui tient compte des spécificités du monde sans fil. -Mise en oeuvre d'OLSR : Entre la théorie et la réalité il y a parfois d'énormes fossés. Pour démontrer la faisabilité et l'efficacité du protocole du routage OLSR, une implémentation est mise au point en intégrant un protocole de contrôle du routage OLSR, une implémentation est testée à échelle réelle avec des trafic de données TCP et UDP.
35
Romdhani, Imed. « Multicast Support for Mobile Receivers and Sources ». Compiègne, 2005. http://www.theses.fr/2005COMP1559.
Texte intégralRésumé :
Cette thèse traite de la communication de groupe ou multipoint (multicast) en environnement IP Mobile (récepteurs et sources mobiles). L'objectif est de proposer des algorithmes et des protocoles de routage assurant la continuité du service multipoint et optimisant les ressources globales du réseau et cela indépendamment de la mobilité des membres. D'une part, la mobilité des récepteurs multipoint introduit des nouveaux problèmes comme la latence d'adhésion, l'interruption de la session multipoint, la perte des paquets et la complexité du routage multipoint. D'autre part, la mobilité des sources multipoint induit divers challenges comme l'unicité de l'identité des sources multipoint au point de vue routage IP, la reconstruction de l'arbre de diffusion multipoint et l'interruption de la session. Nous étudions tout d'abord l'Etat de l'Art dans le domaine traditionnel du support du multipoint et de la mobilité IP et les problèmes lies à la combinaison des deux aspects. Cette étude nous permet de définir une taxonomie des problèmes spécifiques des récepteurs mobiles et des sources mobiles ainsi qu'une comparaison des solutions existantes. Dans un premier temps, nous proposons deux nouvelles solutions dédiées au support des récepteurs mobiles. La première solution améliore la signalisation du protocole IP mobile dans le contexte d'une communication multipoint. La seconde solution optimise le routage multipoint et évite un routage triangulaire dans le réseau mère des récepteurs mobiles. Par la suite, nous proposons une nouvelle solution pour le support des sources mobiles. Cette solution a pour objectif de garantir une transparence de la mobilité des sources et d'éviter le coût de reconstruction de l'arbre multipoint due à la mobilité IP. Les performances de ses diverses solutions sont évaluées par simulation. Nous concluons ce travail par la proposition de deux nouvelles architectures du protocole IP Mobile avec divers agents mère et les perspectives de nos travaux futursThis thesis is devoted to the study of the support of multicast communication with Mobile IP receivers and senders. The purpose is to provide continuous and optimal multicast delivery to multicast members that change regularly their point of attachment from one IP network to another. On one hand, the receiver mobility introduces new issues conceming the question of membership latency, multicast session interruption, packet loss and optimal routing. On the other hand, the source mobility must be considered because it raises a number of new challenges such as source identification, reconstruction of the multicast tree and session interruption due to the handover. Our first contribution is the definition of a taxonomy that is used to describe the main challenges of mobile multicast receivers and mobile multicast sources and the comparison of existing solutions. Our second contribution is the proposition of two solutions to enhance the support of mobile receivers. The first solution optimizes the Mobile IP signalling by avoiding unnecessary signalling traffic between mobile receiver and multicast source induced by binding update mechanism. The second solution introduces a new multicast proxy entity in Mobile IP home networks to optimize the multicast delivery path between mobile receivers and their correspondent home agents. Finally, we propose a new solution to handle transparently source mobility by reducing the multicast routing state change and avoiding the reconstruction of the multicast delivery tree. The performance of our solutions is evaluated by simulation. We conclude this dissertation with a prospective architecture for Mobile IP that uses multiple home agents and a number of future works identified during this study
36
Valouch, Jaromír. « Hromadná komunikace v bezdrátových senzorových sítích ». Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2009. http://www.nusl.cz/ntk/nusl-218088.
Texte intégralRésumé :
This master’s thesis describes energy consumption in wireless sensor networks. It is focused on energy consumption during communication and it provides rules to save energy during this operation. There are terms like wireless sensor networks, multicast, ad-hoc networks, routing protocols, multicast routing protocols, IGMP protocol, AODV routing protocol, MAODV routing protocol explained in this thesis. The main difference between multicast and unicast communication is analyzed as well. In the end of this thesis there are results of simulation small wireless sensor network from network simulator2. The simulations were focused on energy consumption during communication. The length of packet was changed during communication between two nodes in this simulation. In wireless sensors network nodes play a dual role as both data sender and data router therefore there were made research into energy consumption senders, routers, receivers in wireless sensor network during communication.
37
Khanfir, Hajer. « Contribution à l'étude des systèmes de communication en liaison descendante muti-antenne mutli-utilisateur avec voie de retour ». Paris, CNAM, 2009. http://www.theses.fr/2009CNAM0652.
Texte intégralRésumé :
The next generation of wireless networks will require more efficient use of the system resources to accommodate the demand for voice, video, and data transmission. In this thesis, we investigate methods to increase the transmission rate in three different downlink multi-antenna systems : the first and the second are respectively the single user and multi-user systems with partial channel state information (CSIT), the third one is the multicast multi-user system. For the first two systems, we studied and compared two feedback methods : the limited feedback, where a quantized version of the CSI is transmitted to the scheduler and the analog feedback method. For the multi-antenna multi-user systems,we proposed a technique to reduce the feedback load for multi-antenna multi-user system,this technique can at the same time preserve the multi-user diversity while reducing the complexity of the user selection algorithm. A part of the proposed user-selection algorithm is implemented on the users’ sides. The feedback load on the uplink channels is controlled by thresholds which are determined by the base station according to the number of users in the cell. We showed that in this case the system performances are more affected by the size quantization of the channel direction than the size quantization of the channel magnitude. We also derived a lower bound on the ergodic sum rate for the proposed system. We also studied the single and multi-user system performance when the feedback channels are affected by the noise. In the case of the multi-user system, we proposed an algorithm to reduce this noise on the feedback channels. Finally, in the case of the multi-user muticast system, we proposed two user selection algorithms in order to maximize the total sumrate. We analyze the performance of these algorithms in multicast orthogonal frequency division multiplexing (OFDM) systems with single and multiple transmit antennas. We showed that the resource allocation that includes the subcarrier allocation, bit loading, and the precoding vector selection in the multiple-input single-output (MISO) case is a difficult optimization problem. Consequently, we propose suboptimal algorithms based on the maximization of the sum data rate and the maximization of the minimum user data rate criteriaLes futures générations de réseaux sans fil ont besoin d’une meilleure utilisation des ressources afin de satisfaire la demande croissante en services tels que la voix, le transfert de données et les applications multimédia. Les travaux de cette thèse ont porté sur la maximisation des débits de transmission dans trois différents systèmes multi-antenne en voie descendantes : le premier et le second sont respectivement les systèmes mono-utilisateur et multi-utilisateur avec une connaissance partielle du canal de transmission et le troisième est le système multi-diffusion multi-utilisateur. Pour les deux premiers systèmes, nous avons étudié et comparé deux méthodes de transmission des données sur voies de retour renvoyant respectivement des données quantifiées et non-quantifiées. Pour les systèmes multi-antenne multi-utilisateur, nous avons proposé une technique de réduction du flux sur les voies de retour qui permet à la fois de préserver la diversité multi-utilisateur tout en réduisant la complexité de l’algorithme de sélection des utilisateurs. Une partie de l’algorithme de sélection des utilisateurs proposé est implémenté au niveau des récepteurs. Le flux sur la voie de retour est contrôlé par des seuils fixés par la station de base en fonction du nombre d’utilisateurs dans la cellule. Nous avons montré que dans ce cas les performances du système sont bien plus affectées par la précision de la quantification de la direction que celle de la norme du canal. Nous avons aussi dérivé une borne inférieure sur la somme des capacités du système proposé. Nous avons également étudié les performances des deux systèmes multi-antenne multiutilisateur et mono-utilisateur quand les voies de retours sont altérées par du bruit. Dans le cas du système multi-utilisateur, nous avons proposé un algorithme de réduction de bruit cas du système multi-utilisateur, nous avons proposé un algorithme de réduction de bruit sur les voies de retour. Finalement, dans le cas du système multi-utilisateur multi-diffusion (multicast), nous avons proposé deux algorithmes de sélection des utilisateurs ayant pour objectif de maximiser le débit de l’ensemble des utilisateurs. Le premier algorithme est proposé dans un contexte mono-antenne, alors que le second algorithme est dans un contexte multi-antenne à l’émission. Ces algorithmes ont été étudiés pour une transmission par multiplexage fréquentiel de sous-porteuses orthogonales (OFDM) et permettent également des allocations de ressources optimisées par la sélection des utilisateurs
38
Chelius, Guillaume. « Architectures et communications dans les réseaux spontanés sans-fil ». Lyon, INSA, 2004. http://theses.insa-lyon.fr/publication/2004ISAL0024/these.pdf.
Texte intégralRésumé :
Cette thèse aborde différentes problématiques liées aux réseaux ad hoc ainsi qu'aux réseaux de senseurs. Nous définissons d'abord la notion d'architecture ad hoc avant de décrire nos deux propositions d'architecture, Ana4 et Ana6. Ces architectures sont utilisées pour l'évaluation et l'optimisation du routage dans les réseaux hybrides sans-fil, union d'un réseau d'accès sans-fil et d'une connectivité ad hoc. Nous nous intéressons ensuite au multicast où, après avoir présenté des résultats de NP-complétude pour les problèmes du broadcast et du multicast ad hoc, nous introduisons notre proposition de routage DMZ utilisant des structures mêlant arborescence et maillage et reposant sur la notion, de zones denses. Finalement nous abordons la problématique de consommation d'énergie dans les réseaux de senseurs. En se basant sur un nouveau modèle analytique, nous dérivons des bornes supérieures et inférieurs pour les problèmes de couverture et de broadcast en énergie minimumThis PhD addresses several issues bound to ad hoc and sensor networks. We first define the notion of ad hoc architecture before describing our two proposals, Ana4 and Ana6. These architectures are notably used to evaluate and optimize unicast routing in wireless hybrid networks, i. E. , the rnerging of a wireless infrastructure network and ad hoc connectivity. Then we study ad hoc multicast routing. After having presented NP-completeness results for both ad hoc multicast and broadcast problems, we describe our ad hoc multicast routing protocol DMZ (Dense Multicast Zone). DMZ uses tree and mesh structures to create robust diffusion structures and rely on the notion of dense zones. Fin ally, we address the issue of energy consumption in sensor networks. Using a new analytical model, we derive upper and lower bounds for the minimum energy broadcast and covering problems
39
Chelius, Guillaume Fleury Éric Ubéda Stéphane. « Architectures et communications dans les réseaux spontanés sans-fil ». Villeurbanne : Doc'INSA, 2005. http://docinsa.insa-lyon.fr/these/pont.php?id=chelius.
Texte intégral
40
Sesia, Stefania. « Techniques de codage avancées pour la communication sans fil dans un système point à multipoint ». Phd thesis, Télécom ParisTech, 2005. http://pastel.archives-ouvertes.fr/pastel-00001399.
Texte intégralRésumé :
La thèse aborde quelques problèmes non résolus dans le secteur de la transmission efficace des données sensibles aux pertes et sensibles aux retards sur un canal sans fil. La thèse traite principalement des techniques de codage pour des systèmes de multicast. Le multicast diffère du canal broadcast normalement traité en théorie de l'information, puisque seule l'information commune est envoyée. Dans une transmission point à point, la fiabilité est réalisée au moyen de demandes automatiques de retransmission (ARQ). Le FEC et l'ARQ sont combinés ensemble afin d'optimiser la compensation entre la fiabilité et l'efficacité. Cette approche s'appelle Hybrid ARQ, (HARQ). Nous considérons l'utilisation de HARQ pour la transmission point à point avec des techniques modernes de codage (codes de contrôle de parité de faible densité, LDPC). L'analyse théorique prouve que ces codes atteignent les performances optimales. Cependant, pour des codes pratiques de longueur finie, il y a une perte dans les performances. Deux solutions différentes sont montrées pour récupérer la majeure partie de cette perte. Dans un cas de multicast, cependant, les protocoles de HARQ sont inefficaces. À proprement parler, ils ne sont pas entièrement scalable, c'est à dire le throughput va à zéro quand le nombre d'utilisateurs augmente. Ceci nous motive pour étudier le throughput par utilisateur de ces protocoles. En particulier, HARQ basé sur la répétition sélective (SR) ou redondance incrémentielle peut être défini pour être entièrement scalable si nous tenons compte d'une fraction x >0 des utilisateurs qui ne décodent pas avec succès. Tandis que dans la première partie de la thèse nous avons considéré les communications de données, pour lesquelles la mesure de performance appropriée est la probabilité d'erreur, dans la deuxième partie nous considérons la transmission d'une source analogue (par exemple une image). Les solutions pratiques existantes, principalement basées sur le théorème de la séparation de Shannon, sont fortement inefficaces et en particulier elles ne sont pas robustes aux erreurs de canal. Dans un cas de multicast, d'ailleurs, il est important de concevoir un système qui garantit la bonne exécution sur un éventail de rapport de signal-bruit. Les différents utilisateurs avec différents états de canal peuvent décoder la source avec la qualité acceptable de reconstruction. Le codage conjoint de source-canal est une solution viable pour la robustesse et l'efficacité dans ce contexte. Dans cet environnement de multicast nous analysons et optimisons deux stratégies digitales bien connues: la première est la transmission progressive; la seconde est basée sur un code d'émission de superposition. Ces deux techniques entièrement numériques sont comparées à un système hybride analogue/numérique (HDA). En conclusion, le problème de la construction de code pour le système de HDA est abordé dans la dernière partie de la thèse. On propose deux arrangements. Dans le premier cas toute la complexité se fonde sur le design de quantisateur. Nous considérons un quantisateur à plusieurs étages basé sur un treillis (MTQ). La seconde considère un quantisateur très simple. La compression de données et le codage de canal sont combinés et accomplis avec un code linéaire. Ici un arrangement à multi niveaux de compression basé sur des codes linéaires (codes Turbo) est considéré.
41
Yeo, Yong-Kee. « Dynamically Reconfigurable Optical Buffer and Multicast-Enabled Switch Fabric for Optical Packet Switching ». Diss., Georgia Institute of Technology, 2006. http://hdl.handle.net/1853/14615.
Texte intégralRésumé :
Optical packet switching (OPS) is one of the more promising solutions for meeting the diverse needs of broadband networking applications of the future. By virtue of its small data traffic granularity as well as its nanoseconds switching speed, OPS can be used to provide connection-oriented or connectionless services for different groups of users with very different networking requirements. The optical buffer and the switch fabric are two of the most important components in an OPS router. In this research, novel designs for the optical buffer and switch fabric are proposed and experimentally demonstrated. In particular, an optical buffer that is based on a folded-path delay-line tree architecture will be discussed. This buffer is the most compact non-recirculating optical delay line buffer to date, and it uses an array of high-speed ON-OFF optical reflectors to dynamically reconfigure its delay within several nanoseconds. A major part of this research is devoted to the design and performance optimization of these high-speed reflectors. Simulations and measurements are used to compare different reflector designs as well as to determine their optimal operating conditions. Another important component in the OPS router is the switch fabric, and it is used to perform space switching for the optical packets. Optical switch fabrics are used to overcome the limitations imposed by conventional electronic switch fabrics: high power consumption and dependency on the modulation format and bit-rate of the signals. Currently, only those fabrics that are based on the broadcast-and-select architecture can provide truly non-blocking multicast services to all input ports. However, a major drawback of these fabrics is that they are implemented using a large number of optical gates based on semiconductor optical amplifiers (SOA). This results in large component count and high energy consumption. In this research, a new multicast-capable switch fabric which does not require any SOA gates is proposed. This fabric relies on a passive all-optical gate that is based on the Four-wave mixing (FWM) wavelength conversion process in a highly-nonlinear fiber. By using this new switch architecture, a significant reduction in component count can be expected.
42
Rush, Andrew J. « Partial Destination Resolution in Multicast Elastic Optical Networks : A Mixed-Integer Linear Programming Approach ». Miami University / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=miami1470324185.
Texte intégral
43
Israel, Dave, Ron Parise, Keith Hogie et Ed Criscuolo. « SPACE COMMUNICATION DEMONSTRATION USING INTERNET TECHNOLOGY ». International Foundation for Telemetering, 2002. http://hdl.handle.net/10150/607486.
Texte intégralRésumé :
International Telemetering Conference Proceedings / October 21, 2002 / Town & Country Hotel and Conference Center, San Diego, CaliforniaThis paper presents work being done at NASA/GSFC by the Operating Missions as Nodes on the Internet (OMNI) project to demonstrate the application of Internet communication technologies to space communication. The goal is to provide global addressability and standard network protocols and applications for future space missions. It describes the communication architecture and operations concepts that will be deployed and tested on a Space Shuttle flight in July 2002. This is a NASA Hitchhiker mission called Communication and Navigation Demonstration On Shuttle (CANDOS). The mission will be using a small programmable transceiver mounted in the Shuttle bay that can communicate through NASA’s ground tracking stations as well as NASA’s space relay satellite system. The transceiver includes a processor running the Linux operating system and a standard synchronous serial interface that supports the High-level Data Link Control (HDLC) framing protocol. One of the main goals will be to test the operation of the Mobile IP protocol (RFC 2002) for automatic routing of data as the Shuttle passes from one contact to another. Other protocols to be utilized onboard CANDOS include secure login (SSH), UDP-based reliable file transfer (MDP), and blind commanding using UDP. The paper describes how each of these standard protocols available in the Linux operating system can be used to support communication with a space vehicle. It will discuss how each protocol is suited to support the range of special communication needs of space missions.
44
Muramoto, Eiichi, Tatsuya Jinmei, Takahiro Kurosawa, Odira Elisha Abade, Shuntaro Nishiura et Nobuo Kawaguchi. « NAT Free Open Source 3D Video Conferencing using SAMTK and Application Layer Router ». IEEE, 2009. http://hdl.handle.net/2237/15458.
Texte intégral
45
Penhoat, Joël. « Méthode hiérarchisée et distribuée de sélection d'un réseau radio et d'un mode de transmission ». Rennes 1, 2012. http://www.theses.fr/2012REN1S113.
Texte intégralRésumé :
Le déploiement généralisé des réseaux radio hétérogènes, le succès des smartphones, et la mise en œuvre des réseaux sociaux, créent des nouveaux comportements chez les Internautes. Chaque Internaute devient une source émettrice d'informations à destination de la communauté à laquelle il appartient. Les sources d'informations étant liées aux Internautes, elles deviennent mobiles et nombreuses. Les architectures IP Multicast ne sont pas adaptées à ces nouveaux comportements. Dans la première partie de notre thèse, nous analysons les travaux existants visant à adapter les architectures multicast à ces nouveaux comportements. Mais le déploiement des architectures capables de prendre en considération ces nouveaux comportements peut impacter la qualité du service reçu ou émis par un Internaute. En outre, comme les Internautes sont mobiles, la qualité du service qu'ils reçoivent ou émettent dépend aussi des réseaux radio auxquels ils se connectent. Dans la seconde partie de notre thèse, nous montrons, premièrement, que le processus mis en œuvre pour gérer la mobilité entre des réseaux radio hétérogènes dans les architectures définies par le Third Generation Partnership Project n'est pas complètement défini et ne permet pas aux Internautes et aux fournisseurs de services de participer au processus de sélection du réseau radio cible. Deuxièmement, nous montrons que, dans l'architecture Multimedia Broadcast Multicast Service et dans l'architecture définie par le projet Context Casting, les Internautes et les fournisseurs de services ne participent pas au processus de sélection du mode de transmission, unicast versus multicast. Après avoir montré que les Internautes et les fournisseurs de services ne participent pas au processus de sélection d'un réseau radio et d'un mode de transmission, nous proposons un processus dans lequel les Internautes, les opérateurs et les fournisseurs de services participent au choix d'un réseau radio et d'un mode de transmissionThe widespread deployment of heterogeneous wireless networks, the success of smartphones, and the implementation of social networks, create new behaviours among Internet users. Each user becomes a source of information to the community to which he belongs. The sources of information being linked to the users, they become mobile and numerous. The IP Multicast architectures are not suited to these new behaviours. In the first part of our thesis, we analyze the existing works aiming to adapt these new multicast architectures to these new behaviours. But the deployment of architectures capable of taking into account these new behaviours can degrade the quality of services received or emitted by a user. Besides, as the users are mobile, the quality of the services they receive or transmit also depends on the radio networks to which they connect. In the second part of our thesis, we show, in the first place, that the process implemented to manage the mobility between heterogeneous radio networks in the architectures defined by the Third Generation Partnership Project is not completely defined and does not allow the users and the service providers to participate in the process of selection of the target radio network. Secondly, we show that, in the Multimedia Broadcast Multicast Service architecture and in the architecture defined by the european project called Context Casting, the users and the service providers do not participate in the process of selection of the transmission mode, multicast versus unicast. After having shown that the users and the service providers do not participate in the process of selection of a radio network and a transmission mode, we propose a process in which the Internet users, the network operators and the service providers participate in the choice of a radio network and a transmission mode
46
Kaluvakuri, Swathi. « RESIDUE CLASS-BASED COMMON INTEREST NETWORK : A NOVEL APPROACH IN DESIGNING A LOW DIAMETER, TWO-LEVEL HIERARCHICAL, STRUCTURED P2P NETWORK ARCHITECTURE AND COMMUNICATION PROTOCOLS ». OpenSIUC, 2021. https://opensiuc.lib.siu.edu/dissertations/1933.
Texte intégralRésumé :
The main objective of this research is to build an interest based peer – to – peer network which is structured yet non-DHT. Maintaining DHTs is a complex task and needs substantial amount of effort to handle the problem of churn. So, the major challenge facing such architectures is how to reduce this amount of effort while still providing an efficient data query service. The rationale behind choosing non- DHT based interest based network is that users sharing common interests are likely to share similar contents, and therefore searches for a particular type of content is more efficient if peers likely to store that content type are neighbors. We have used a mathematical model based on modular arithmetic, specifically residue class (RC), to design a two-level structured architecture. To the best of my knowledge, there does not exist any such work that has used this mathematical model.
47
Pillai, Anju. « A Connection Admission Control Framework for UMTS based Satellite Systems.An Adaptive Admission Control algorithm with pre-emption control mechanism for unicast and multicast communications in satellite UMTS ». Thesis, University of Bradford, 2011. http://hdl.handle.net/10454/5487.
Texte intégralRésumé :
In recent years, there has been an exponential growth in the use of
multimedia applications. A satellite system offers great potential for
multimedia applications with its ability to broadcast and multicast a large
amount of data over a very large area as compared to a terrestrial system.
However, the limited transmission capacity along with the dynamically
varying channel conditions impedes the delivery of good quality multimedia
service in a satellite system which has resulted in research efforts for deriving
efficient radio resource management techniques. This issue is addressed in
this thesis, where the main emphasis is to design a CAC framework which
maximizes the utilization of the scarce radio resources available in the
satellite and at the same time increases the performance of the system for a
UMTS based satellite system supporting unicast and multicast traffic.
The design of the system architecture for a UMTS based satellite system is
presented. Based on this architecture, a CAC framework is designed
consisting of three different functionalities: the admission control procedure,
the retune procedure and the pre-emption procedure. The joint use of these
functionalities is proposed to allow the performance of the system to be
maintained under congestion. Different algorithms are proposed for different
functionalities; an adaptive admission control algorithm, a greedy retune
algorithm and three pre-emption algorithms (Greedy, SubSetSum, and
Fuzzy).
A MATLAB simulation model is developed to study the performance of the
proposed CAC framework. A GUI is created to provide the user with the
flexibility to configure the system settings before starting a simulation. The
configuration settings allow the system to be analysed under different
conditions.
The performance of the system is measured under different simulation
settings such as enabling and disabling of the two functionalities of the CAC
framework; retune procedure and the pre-emption procedure. The simulation
results indicate the CAC framework as a whole with all the functionalities
performs better than the other simulation settings.
48
Pillai, Anju. « A connection admission control framework for UMTS based satellite systems : an adaptive admission control algorithm with pre-emption control mechanism for unicast and multicast communications in satellite UMTS ». Thesis, University of Bradford, 2011. http://hdl.handle.net/10454/5487.
Texte intégralRésumé :
In recent years, there has been an exponential growth in the use of multimedia applications. A satellite system offers great potential for multimedia applications with its ability to broadcast and multicast a large amount of data over a very large area as compared to a terrestrial system. However, the limited transmission capacity along with the dynamically varying channel conditions impedes the delivery of good quality multimedia service in a satellite system which has resulted in research efforts for deriving efficient radio resource management techniques. This issue is addressed in this thesis, where the main emphasis is to design a CAC framework which maximizes the utilization of the scarce radio resources available in the satellite and at the same time increases the performance of the system for a UMTS based satellite system supporting unicast and multicast traffic. The design of the system architecture for a UMTS based satellite system is presented. Based on this architecture, a CAC framework is designed consisting of three different functionalities: the admission control procedure, the retune procedure and the pre-emption procedure. The joint use of these functionalities is proposed to allow the performance of the system to be maintained under congestion. Different algorithms are proposed for different functionalities; an adaptive admission control algorithm, a greedy retune algorithm and three pre-emption algorithms (Greedy, SubSetSum, and Fuzzy). A MATLAB simulation model is developed to study the performance of the proposed CAC framework. A GUI is created to provide the user with the flexibility to configure the system settings before starting a simulation. The configuration settings allow the system to be analysed under different conditions. The performance of the system is measured under different simulation settings such as enabling and disabling of the two functionalities of the CAC framework; retune procedure and the pre-emption procedure. The simulation results indicate the CAC framework as a whole with all the functionalities performs better than the other simulation settings.
49
Mapoka, Trust Tshepo. « Location based authenticated multi-services group key management for cyber security in high speed broadband wireless multicast communications : multi-service group key management scheme with location based handover authentication for multi-handoffs participating in multi-group service subscriptions, its performance evaluation and security correctness in high speed broadband wireless multicast communications ». Thesis, University of Bradford, 2015. http://hdl.handle.net/10454/14468.
Texte intégralRésumé :
Secure information exchanges over cyberspace is on the increase due to the convergence of wireless and mobile access technologies in all businesses. Accordingly, with the proliferation of diverse multicast group service subscriptions that are possible to co-exist within a single broadband network, there is also huge demand by the mobile subscribers to ubiquitously access these services over high speed broadband using their portable devices. Likewise, the Network Providers (NPs) invest hugely in infrastructure deployment to disseminate these services efficiently and concomitantly. Therefore, cyber security in any business is obligatory to restrict access of disseminated services to only authorised personnel. This becomes a vital requirement for a successful commercialisation of exchanged group services. The standard way to achieve cyber security in a wireless mobile multicast communication environment is through confidentiality using Group Key Management (GKM).The existing GKM schemes for secure wireless multicast from literature only target single group service confidentiality; however, the adoption of multiple group service confidentiality in them involve inefficient management of keys that induce huge performance overheads unbearable for real time computing. Therefore, a novel authenticated GKM scheme for multiple multicast group subscriptions known as slot based multiple group key management (SMGKM) is proposed. In the SMGKM, the handovers move across diverse decentralised clusters of homogeneous or heterogeneous wireless access network technologies while participating in multiple group service subscriptions. Unlike the conventional art, the SMGKM advances its security by integrating location based authentication and GKM functions. Both functions are securely offloaded from the Domain Key Distributor (DKD) to the intermediate cluster controllers, Area Key Distributors (AKDs), in a distributed fashion, using the proposed location based authenticated membership list (SKDL). A significant upgrade of fast handoff performance with reduced performance overheads of the SMGKM scheme is achieved. The developed numerical analysis and the simulation results display significant resource economy in terms of reduced rekeying transmission, communication bandwidth and storage overheads while providing enhanced security. The performance of the SMGKM in a high speed environment is also evaluated and has demonstrated that SMGKM outperforms the previous work. Finally, the SMGKM correctness against various attacks is verified using BAN logic, the eminent tool for analysing the widely deployed security protocols. The security analysis demonstrates that SMGKM can counteract the security flaws and redundancies identified in the chosen related art.
50
Moulierac, Joanna. « Agrégation des communications multicast ». Rennes 1, 2006. http://www.theses.fr/2006REN1S151.
Texte intégralRésumé :
L'agrégation d'arbres multicast est une proposition qui permet d'envisager le passage à l'échelle des communications de groupes sur l'Internet dites communications multicast. Cette proposition permet pour plusieurs groupes d'utiliser un seul arbre de communication, alors qu'en multicast traditionnel, pour chaque groupe, un arbre est maintenu. Ainsi, le nombre total d'arbres dans le réseau est réduit et avec lui le nombre d'entrées de routage multicast. Dans un premier temps, nous proposons un protocole d'agrégation STA qui réalise une agrégation très rapide en évaluant peu d'arbres pour chaque nouveau groupe. Ensuite, le protocole QSTA agrège des groupes sous contraintes de bande-passante. Le protocole DMTA est un protocole d'agrégation distribuée avec un nombre réduit de messages de contrôle entre les entités d'agrégation. Finalement, le protocole TALD réalise l'agrégation des groupes dans des domaines de très grande taille où les protocoles actuels d'agrégation ne sont pas efficaces.