Dissertations / Theses on the topic 'Virtual networks and slicing'
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1
Luu, Quang Trung. "Dynamic Control and Optimization of Wireless Virtual Networks." Electronic Thesis or Diss., université Paris-Saclay, 2021. http://www.theses.fr/2021UPASG039.
Abstract:
Le découpage du réseau est une technologie clé des réseaux 5G, grâce à laquelle les opérateurs de réseaux mobiles peuvent créer des tranches de réseau indépendantes. Chaque tranche permet à des fournisseurs d'offrir des services personnalisés. Comme les tranches sont opérées sur une infrastructure de réseau commune gérée par un fournisseur d'infrastructure, il est essentiel de développer des méthodes de partage efficace des ressources. Cette thèse adopte le point de vue du fournisseur d'infrastructure et propose plusieurs méthodes de réservation de ressources pour les tranches de réseau. Actuellement, les chaines de fonctions appartenant à une tranche sont déployées séquentiellement sur l'infrastructure, sans avoir de garantie quant à la disponibilité des ressources. Afin d'aller au-delà de cette approche, nous considérons dans cette thèse des approches de réservation des ressources pour les tranches en considérant les besoins agrégés des chaines de fonctions avant le déploiement effectif des chaines de fonctions. Lorsque la réservation a abouti, les chaines de fonctions ont l'assurance de disposer de suffisamment de ressources lors de leur déploiement et de leur mise en service afin de satisfaire les exigences de qualité de service de la tranche. La réservation de ressources permet également d'accélérer la phase d'allocation de ressources des chaines de fonctionsNetwork slicing is a key enabler for 5G networks. With network slicing, Mobile Network Operators (MNO) create various slices for Service Providers (SP) to accommodate customized services. As network slices are operated on a common network infrastructure owned by some Infrastructure Provider (InP), efficiently sharing the resources across various slices is very important. In this thesis, taking the InP perspective, we propose several methods for provisioning resources for network slices. Previous best-effort approaches deploy the various Service Function Chains (SFCs) of a given slice sequentially in the infrastructure network. In this thesis, we provision aggregate resources to accommodate slice demands. Once provisioning is successful, the SFCs of the slice are ensured to get enough resources to be properly operated. This facilitates the satisfaction of the slice quality of service requirements. The proposed provisioning solutions also yield a reduction of the computational resources needed to deploy the SFCs
2
Elkael, Maxime. "Reinforcement learning and optimization for energy efficient 5G slicing with Quality of Service guarantees." Electronic Thesis or Diss., Institut polytechnique de Paris, 2023. http://www.theses.fr/2023IPPAS015.
Abstract:
Cette thèse traite des problèmes d'allocation des ressources dans les réseaux 5G. Notre objectif est d'exploiter le slicing du réseau (c'est-à-dire un corpus de techniques basées sur la virtualisation et la softwarisation du réseau qui permettent à l'opérateur de fournir différentes quantités de ressources à différents clients) afin d'améliorer l'efficacité énergétique et la consommation de ressources des réseaux 5G, tout en respectant des contraintes de Qualité de Service. Pour ce faire, nous formulons et résolvons des problèmes d'optimisation dans les différents domaines du réseau : nous nous intéressons tout d'abord au placement des slices dans le réseau coeur. Pour résoudre le problème, une nouvelle approche combinant la recherche Monte Carlo et la recherche par voisinage est formulée. Nous montrons qu'elle permet d'accepter plus de slices que les techniques de l'état de l'art pour le problème de placement du réseau coeur. Ensuite, nous mettons l'accent sur l'efficacité énergétique en proposant un framework pour l'allocation de ressources dans les réseaux 5G partagés entre les opérateurs de réseaux physiques (PNO) et les opérateurs de réseaux mobiles virtuels (MVNO). Ce framework tient compte à la fois du placement des composants logiciels, du routage des demandes des utilisateurs et du dimensionnement des ressources, tout en respectant les accords de niveau de service (SLA) basés sur des contraintes de latence et de fiabilité. Grâce à la génération de colonnes, nous obtenons des solutions exactes, démontrant des économies d'énergie allant jusqu'à 50% dans des réseaux réels, par rapport aux algorithmes de placement ou de minimisation des ressources existants. Enfin, nous abordons le problème de l'optimisation de l'énergie dans les réseaux Integrated Access and Backhaul (IAB), un élément clé des déploiements denses de la 5G. S'appuyant sur le framework du réseau d'accès ouvert Open RAN (O-RAN), notre modèle minimise les noeuds IAB actifs tout en garantissant une capacité minimale pour l'équipement de l'utilisateur (UE). Formulée comme un programme non linéaire binaire, cette approche réduit la consommation d'énergie du RAN de 47%, tout en maintenant la qualité de service pour les UEs. Dans l'ensemble, cette thèse propose de nouveaux algorithmes pour améliorer la l'efficacité en ressources et en énergie du réseau 5G slicé. Ces améliorations sont étudiées dans différentes parties du réseau, du coeur au réseau d'accèsThis thesis addresses resource allocation problems in 5G networks. Our objective is to leverage network slicing (e.g. the set of techniques based on virtualization and network softwarization which allows the network operator to provide different amounts of resources to different tenants) in order to to improve the energy-efficiency and resource consumption of 5G networks, while guaranteeing Quality of Service constraints. To do so, we formulate and solve optimization problems at the different domains of the network: We are first concerned with the placement of slices in the core network. To solve the problem, a new approach combining Monte Carlo Search and Neighborhood Search is formulated. We show it accepts more core slices than state-of-the-art approaches for the core network placement problem. Then we shift the focus to energy efficiency in resource allocation in 5G networks shared between Physical Network Operators (PNOs) and Mobile Virtual Network Operators (MVNOs). This framework jointly considers software component placement, user request routing, and resource dimensioning while meeting Service Level Agreements (SLAs) based on latency and reliability constraints. Through Column Generation, we obtain exact solutions, demonstrating energy savings of up to 50% in real networks compared to existing placement or resource minimization algorithms. Finally, we delve into the realm of energy optimization in Integrated Access and Backhaul (IAB) networks, a key component of dense 5G deployments. Leveraging the Open Radio Access Network (O-RAN) framework, our model minimizes active IAB nodes while ensuring a minimum capacity for User Equipment (UE). Formulated as a binary nonlinear program, this approach reduces RAN energy consumption by 47%, while maintaining Quality-Of-Service for UEs. Overall, this thesis provides novel algorithms for improving resource and energy efficiency of 5G network slicing. Such improvement is studied in different parts of the network, from the core up to the access network
3
Dawaliby, Samir. "Machine-to-Machine (M2M) Communications in Next Generation Networks : Spectrum management and energy efficiency." Thesis, Poitiers, 2019. http://www.theses.fr/2019POIT2280.
Abstract:
Cette thèse traite le problème de garantir la qualité de service (QoS) dans l'internet des objets (IoT) en termes d’urgence et de fiabilité. Pour atteindre cet objectif, nous avons proposé différentes solutions adaptées aux réseaux étendus LoRa (LoRaWAN). Premièrement, nous mettons en œuvre un découpage virtuel du réseau LoRa en plusieurs tranches et nous évaluons son impact en utilisant plusieurs stratégies statiques et dynamiques. Les résultats des simulations exécutés sur NS3 ont prouvé l'efficacité de l'isolation virtuelle des ressources physiques pour une tranche d'un réseau ayant des communications urgentes en réduisant l'impact venant des autres communications IoT. Motivés par ces résultats, une méthode d'optimisation est ensuite proposée pour chercher une meilleure configuration des nœuds LoRa en regardant plus en détail leur paramètres au niveau de la couche physique permettant d’améliorer ses performances en termes de QoS, de fiabilité et d’efficacité énergétique. Par contre, même avec le découpage du réseau en tranches virtuels, l’évolutivité de LoRa reste un défi en raison du manque de flexibilité lors de la gestion des réseaux sans fil actuels. Par conséquent, pour atteindre l'objectif global de garantir une bonne QoS dans un réseau IoT à grande échelle, les technologies SDN et le découpage virtuel du réseau sont adoptés simultanément pour proposer une architecture virtualisée et distribuée. Cette dernière proposition est basée sur la théorie des jeux et s'adapte plus rapidement aux changements dans un environnement IoT encombré en exploitant la prise de décision du découpage du réseau et la configuration des nœuds LoRa à la périphérie du réseauThis thesis deals with the problem of guaranteeing heterogeneous quality of service (QoS) requirements for Internet of Things (IoT) communications in terms of urgency and reliability. Various solutions are proposed towards achieving this goal in LoRa Wide Area Networks (LoRaWAN). First, we implement network slicing over LoRa standard architecture and evaluate its impact using various static and dynamic strategies. Simulation Results performed over NS3 proved the efficiency of network slicing in isolating physical resources for each slice and serving delay critical communications. Motivated by these results, a slice-based optimization is proposed next to improve the dynamic slicing strategy by investigating more LoRa parameters at the physical layer. The proposed method finds for each device the best parameters configuration that potentially improves the performance of its slice in terms of QoS, reliability and energy efficiency. Moreover, we also looked towards meeting upcoming challenges in future IoT networks that comes from the increasing number of IoT devices. Even with network slicing, LoRa scalability remained as a big challenge that should be carefully considered especially due to the lack of flexibility in managing current wireless networks. Therefore, to meet the global objective in guaranteeing QoS in large scale IoT deployments, software defined networking (SDN) and network slicing are adopted as backbone technologies for a distributed virtualized architecture and slicing strategy. The latter proposition is based on game theory and adapts faster to the changes in a congested IoT environment by leveraging slicing decision making closer to the edge
4
Nerini, Matteo. "Network Slicing for IEEE 802.11 Wireless Networks." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amslaurea.unibo.it/21149/.
Abstract:
Future networks will pave the way for a myriad of applications with different requirements. In such a context, the today’s one-size-fits-all approach will not be able to efficiently address the different demands that verticals impose in terms of QoS and involved data volumes. To this end, network slicing is a new network paradigm which may provide the needed flexibility. It allows to offer multiple logical networks over a common infrastructure, tailored to the services which run on the network.
In today’s Wi-Fi networks, all the users are connected to the same wireless channel, which allows service differentiation only at the traffic level. Thus, in this study, we propose a standard-compliant network slicing approach for the radio access segment of Wi-Fi, often neglected by the literature on network slicing.
We present two algorithms to realize network slicing at the access level. The first assigns resources according to the requirements of the slices in a static way. On the other hand, the second, more advanced, dynamically configures the slices according to the network conditions and relevant KPIs. These techniques can be applied to the IEEE 802.11 standard and, in general, to all the protocols that use Carrier Sensing Multiple Access (CSMA) as channel access technique.
The proposed algorithms were validated through extensive simulations, conducted with ns-3 network simulator and accompanied by theoretical calculations. Particular attention, often neglected in similar simulation-based works, has been paid to the electromagnetic properties of the spectrum, which play a fundamental role in radio communications.
From the conducted simulations, we found that our slicing approaches largely outperform the today’s Wi-Fi access technique. They allow to reach higher goodput (i.e. a lower error probability) and lower latency, when needed. At the same time, tailored slicing saves energy to low-power devices and increases the spectrum efficiency.
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Bakri, Sihem. "Towards enforcing network slicing in 5G networks." Electronic Thesis or Diss., Sorbonne université, 2021. http://www.theses.fr/2021SORUS067.
Abstract:
Les architectures de réseaux sans fil actuelles, de type « une taille pour tous », ne peuvent pas prendre en charge ces critères de services hétérogènes de nouvelle génération 5G. Par conséquent, la recherche autour de la 5G vise à fournir des architectures et des mécanismes plus adéquats pour répondre à ce besoin. L'architecture 5G est conçue pour répondre aux exigences variées et contradictoires des services, en termes de latence, de bande passante et de fiabilité, qui ne peuvent être assurées par la même infrastructure du réseau. Dans ce contexte, le découpage du réseau fourni par la virtualisation du réseau permet de diviser l'infrastructure en différentes tranches, chaque tranche est adaptée aux besoins spécifiques des services, où elle permet à différents services (comme l'automobile, l'Internet des objets...) d'être fournis par différentes instances de la tranche du réseau. Les chercheurs ont défini trois grandes classes de services de découpage en réseau, qui sont: enhanced Mobile BroadBand (eMBB), massive Machine Type Communication (mMTC), and ultra-Reliable and Low-Latency Communication (uRLLC). L'un des principaux défis du déploiement des tranches de réseau est le découpage du réseau d'accès radio (RAN). En effet, la gestion des ressources RAN et leur partage entre les tranches de réseau est une tâche particulièrement difficile. Cette thèse propose des solutions qui visent à améliorer les performances du réseau et d'introduire de la flexibilité et une plus grande utilisation des ressources du réseau, en fournissant de manière précise et dynamique aux tranches de réseau activées les quantités de ressources appropriées pour répondre à leurs divers besoinsThe current architecture “one size fits all” of 4G network cannot support the next-generation 5G heterogeneous services criteria. Therefore, research around 5G aims to provide more adequate architectures and mechanisms to deal with this purpose. The 5G architecture is envisioned to accommodate the diverse and conflicting demands of services in terms of latency, bandwidth, and reliability, which cannot be sustained by the same network infrastructure. In this context, network slicing provided by network virtualization allows the infrastructure to be divided into different slices. Each slice is tailored to meet specific service requirements allowing different services (such as automotive, Internet of Things, etc.) to be provided by different network slice instances. Each of these instances consists of a set of virtual network functions that run on the same infrastructure with specially adapted orchestration. Three main service classes of network slicing have been defined by the researchers as follows: Enhanced Mobile Broadband (eMBB), massive Machine Type Communication (mMTC), and ultra-Reliable and Low-Latency Communication (uRLLC). One of the main challenges when it comes to deploying Network Slices is slicing the Radio Access Network (RAN). Indeed, managing RAN resources and sharing them among Network Slices is an increasingly difficult task, which needs to be properly designed. This thesis proposes solutions that aim to improve network performance, and introduce flexibility and greater utilization of network resources by accurately and dynamically provisioning the activated network slices with the appropriate amounts of resources to meet their diverse requirements
6
Biallach, Hanane. "Optimization of VNF reconfiguration problem for 5G network slicing." Electronic Thesis or Diss., Compiègne, 2022. http://www.theses.fr/2022COMP2707.
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Ces dernières années, en raison de la croissance sans précédent du nombre d'appareils connectés et de données mobiles, et des développements continus des technologies pour répondre à cette énorme demande de données, le réseau de cinquième génération (5G) a émergé. La future architecture 5G sera essentiellement basée sur le Network Slicing (NS), qui permet de fournir une approche flexible pour réaliser la vision 5G. Grâce au concept émergent de virtualisation des fonctions réseau (NFV), les fonctions réseau sont découplées des matériels physiques dédiés et réalisées sous forme de logiciel. Cela offre plus de flexibilité et d'agilité dans les opérations commerciales. Malgré les avantages qu'il apporte, NFV soulève quelques défis techniques, le problème de reconfiguration étant l'un d'entre eux. Ce problème, qui est NP-difficile, consiste à réaffecter les fonctions de réseau virtuel (VNFs) pour s'adapter aux changements du réseau, en transformant l'état courant des services déployés, on peut illustrer cela par la migration des machines virtuelles (VM) qui hébergent les VNF, à un autre état qui répond aux objectives des opérateurs. Cette thèse de doctorat étudie comment reconfigurer les VNFs en les migrant vers un état optimal qui pourrait être calculé en avance ou inconnu. Dans cette thèse, nous avons étudié les deux cas en minimisant la durée d'interruption de service et la durée de migration des VNFs. Nous avons proposé des méthodes exactes et approchées. Parmi les méthodes exactes, nous citons deux modèles PLNE. Nous avons également proposé deux approches heuristiques, l'une basée sur la génération de colonnes et la deuxième utilisant la notion de “feedback arc set". L'objectif global de ce travail est donc de définir et d'étudier le problème de reconfiguration des VNFs dans le contexte du 5G network slicing, et de proposer des modèles mathématiques et des algorithmes efficaces pour résoudre les problèmes d'optimisation sous-jacentsIn recent years, because of the unprecedented growth in the number of connected devices and mobile data, and the ongoing developments in technologies to address this enormous data demand, the fifth generation (5G) network has emerged. The forthcoming 5G architecture will be essentially based on Network Slicing (NS), which enables provide a flexible approach to realize the 5G vision. Thanks to the emerging Network Function Virtualization (NFV) concept, the network functions are decoupled from dedicated hardware devices and realized in the form of software. This offers more flexibility and agility in business operations. Despite the advantages it brings, NFV raises some technical challenges, the reconfiguration problem is one of them. This problem, which is NP-Hard, consists in reallocating the Virtual Network Functions (VNFs) to fit the network changes, by transforming the current state of deployed services, e.g., the current placement of Virtual Machines (VM) that host VNFs, to another state that updates providers’ objectives. This PhD thesis investigates how to reconfigure the VNFs by migrating them to an optimal state that could be computed in advance or free placement. In this thesis, we studied both cases while minimizing the service interruption duration and the VNF migration duration. We have proposed exact and approximate methods. Among the exact methods, we cite two ILP models. We also proposed two heuristic approaches, one based on column generation and the second using the concept of “arc set feedback”. The overall objective of this work is therefore to define and study the problem of VNF reconfiguration problem in the context of 5G network slicing, and propose mathematical models and efficient algorithms to solve the underlying optimization problems
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Sun, Shaobo. "Applications of spectrum slicing in optical access networks." Thesis, University of Warwick, 2010. http://wrap.warwick.ac.uk/34617/.
Abstract:
Spectrum-slicing (SS) is a novel attractive technique for the implementation of optical access network. Its main advantage compared to the conventional optical network is utilizing spectral slices of a broadband source for different data channels. Since the light sources employed are quite cost effective, this technology is economically attractive to the modern communication system. The major objective of this dissertation is to investigate the performance of systems employing spectrum-slicing, for implementing wavelength division multiplexing (WDM) and optical code division multiple access (OCDMA) in optical access systems. The analysis is conducted mainly through the theoretical model based on the statistics, derived from fundamental chi-square and Gaussian distribution. Firstly, the analysis of an SS-WDM system performance when employing an optical preamplifier receiver is carried out to improve understanding of the SS in a realistic situation where dispersion significantly impacts the signal in transmission. It is shown that there exists an optimum optical bandwidth which minimizes the detection sensitivity for a given error probability caused by two competing effects of inherent signal fluctuation and dispersion. The optically preamplified receiver delivers increased transmission capacity and a substantially improved power budget compared to a pin receiver. The results are obtained using the saddle point approximation and compared to the customary Gaussian approximation, which is found to be reasonably accurate in predicting the optimum bandwidth but conservative in sensitivity predictions. The second part of the work investigates the performance of an SS-OCDMA employing and proposes a supporting adaptive coding scheme developed from prime-hop codes. The concomitant higher-order dispersion, beat noise and multiple access interference in incoherent OCDMA systems become limiting factors to the bit error rate. The major thrusts of the new schemes are to alleviate the performance degradation from these impacts especially to reduce the power loss and the bit error rate (BER) degradation due to higher-order dispersion. Performance comparisons between the adaptive PHC and original PHC schemes indicate that the former is more suitable for use in the considered incoherent system in terms of accommodating more users for a given BER. The proposed adaptive method can be universally applied to mitigate dispersion effects in the similar 2-D OCDMA systems. Within the last part of the work, regular low-density parity-check (LDPC) codes are applied for the first time to a SS-WDM system. An adaptive decoding algorithm of low density parity check (LDPC) codes based on the precise SSWDM noise statistics is developed, which outperforms the decoding with conventional Gaussian model. The simulation results for various code rates show that such a forward error correction scheme provides significant coding gain for a dedicated system in terms of improving the overall transmission capacity and available power budget. The adaptive algorithm of LDPC codes can be generically applied to all the asymmetric channels.
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Schmidt, Robert. "Slicing in heterogeneous software-defined radio access networks." Electronic Thesis or Diss., Sorbonne université, 2021. http://www.theses.fr/2021SORUS525.
Abstract:
Les réseaux 5G sont envisagés comme un changement de paradigme vers des réseaux orientés services. Dans cette thèse, nous étudions comment combiner efficacement le découpage en tranches et le SD-RAN afin de fournir le niveau requis de flexibilité et de programmabilité dans l'infrastructure RAN pour réaliser des réseaux multi-locataires orientés services. Premièrement, nous concevons une abstraction d'une station de base pour représenter les stations de base logiques et décrire un service de réseau virtualisé. Deuxièmement, nous proposons une nouvelle plateforme SD-RAN conforme aux normes, appelée FlexRIC, sous la forme d'un kit de développement logiciel (SDK). Troisièmement, nous fournissons une conception modulaire pour un cadre d'ordonnancement MAC tenant compte des tranches afin de gérer et de contrôler efficacement les ressources radio dans un environnement multiservice avec un support de qualité de service (QoS). Enfin, nous présentons une couche de virtualisation SD-RAN dynamique basée sur le SDK FlexRIC et le cadre d'ordonnancement MAC pour composer de manière flexible une infrastructure SD-RAN multiservice et fournir une programmabilité pour de multiples contrôleurs SD-RAN5G networks are envisioned to be a paradigm shift towards service-oriented networks. In this thesis, we investigate how to efficiently combine slicing and SD-RAN to provide the required level of flexibility and programmability in the RAN infrastructure to realize service-oriented multi-tenant networks. First, we devise an abstraction of a base station to represent logical base stations and describe a virtualized network service. Second, we propose a novel standard-compliant SD-RAN platform, named FlexRIC, in the form of a software development kit (SDK). Third, we provide a modular design for a slice-aware MAC scheduling framework to efficiently manage and control the radio resources in a multi-service environment with quality-of-service (QoS) support. Finally, we present a dynamic SD-RAN virtualization layer based on the FlexRIC SDK and MAC scheduling framework to flexibly compose a multi-service SD-RAN infrastructure and provide programmability for multiple SD-RAN controllers
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MOREIRA, André Luis Cavalcanti. "An adaptable storage slicing algorithm for content delivery networks." Universidade Federal de Pernambuco, 2015. https://repositorio.ufpe.br/handle/123456789/17331.
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Thesis - André Luis Cavalcanti Moreira.pdf: 3666881 bytes, checksum: 956e0e6be2bd9f076c0d30eea9d3ea25 (MD5)Made available in DSpace on 2016-07-12T12:20:38Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Thesis - André Luis Cavalcanti Moreira.pdf: 3666881 bytes, checksum: 956e0e6be2bd9f076c0d30eea9d3ea25 (MD5) Previous issue date: 2015-08-28
Several works study the performance of Content Delivery Networks (CDNs) under various network infrastructure and demand conditions. Many strategies have been proposed to deal with aspects inherent to the CDN distribution model. Though mostly very effective, a traditional CDN approach of statically positioned elements often fails to meet quality of experience (QoE) requirements when network conditions suddenly change. CDN adaptation is a key feature in this process and some studies go even further and try to also deal with demand elasticity by providing an elastic infrastructure (cloud computing) to such CDNs. Each Content Provider (CP) gets served only the amount of storage space and network throughput that it needs and pays only for what has been used. Some IaaS providers offer simple CDN services on top of their infrastructure. However, in general, there is a lack of PaaS tools to create rapidly a CDN. There is no standard or open source software able to deliver CDN as a service for each tenant through well-known managers. A PaaS CDN should be able to implement content delivery service in a cloud environment, provision and orchestrate each tenant, monitor usage and make decisions on planning and dimensioning of resources. This work introduces a framework for the allocation of resources of a CDN in a multi-tenant environment. The framework is able to provision and orchestrate multi-tenant virtual CDNs and can be seen as a step towards a PaaS CDN. A simple dot product based module for network change detection is presented and a more elaborate multi-tenant resource manager model is defined. We solve the resulting ILP problem using both branch and bound as well as an efficient cache slicing algorithm that employs a three phase heuristic for orchestration of multi-tenant virtual CDNs. We finally show that a distributed algorithm with limited local information may be also offer reasonable resource allocation while using limited coordination among the different nodes. A self-organization behavior emerges when some of the nodes reach consensus.
Vários trabalhos estudam o desempenho de Redes de Distribuição de Conteúdo (CDN) em diferentes condições e demanda e de infraestrutura. Muitas estratégias têm sido propostas para lidar com aspectos inerentes ao modelo de distribuição de CDN. Embora essas técnicas sejam bastante eficazes, uma abordagem tradicional de elementos estaticamente posicionados numa CDN muitas vezes não consegue atender os requisitos de qualidade de experiência (QoE) quando as condições da rede mudam repentinamente. Adaptação CDN é uma característica fundamental neste processo e alguns estudos vão ainda mais longe e tentam lidar com a elasticidade da demanda, proporcionando uma infraestrutura elástica (computação em nuvem) para a CDN. Cada provedor de conteúdo obtém apenas a quantidade de armazenamento e de rede necessários, pagando apenas pelo efetivo uso. Alguns provedores IaaS oferecem serviços de CDN sobre suas estruturas. No entanto, em geral, não existe padrão ou softwares de código aberto capazes de entregar serviços de CDN por meio de gerenciadores. Uma CDN PaaS deve ser capaz de fornecer um serviço de entrega de conteúdo em um ambiente de nuvem, provisionar e orquestrar cada tenant, monitorar uso e tomar decisões de planejamento e dimensionamento de recursos. Este trabalho apresenta um framework para alocação de recursos de uma CDN em ambiente multi-tenant. O framework é capaz de provisionar e orquestrar CDNs virtuais e pode ser visto como um passo em direção a uma PaaS CDN. Um módulo baseado em simples produto escalar para detecção de mudanças na rede é apresentado, bem como um modelo mais elaborado de gerenciamento de recursos. Resolvemos o problema ILP resultante dessa abordagem por meio de um algoritmo de divisão de cache que emprega uma heurística em três fases para a orquestração de CDN virtuais. Por fim, mostramos uma outra abordagem com algoritmo distribuído que usa informação local e que também oferece uma alocação razoável usando coordenação limitada entre os diferentes nós. Um comportamento de auto-organização surge quando alguns desses nós chegam a um consenso.
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Suárez, Trujillo Luis Carlos. "Securing network slices in 5th generation mobile networks." Thesis, Brest, 2020. http://www.theses.fr/2020BRES0050.
Abstract:
Le « network slicing » est la pierre angulaire pour la conception et le déploiement de services de communication à forte valeur ajoutée qui seront supportés par les nouveaux cas d’usage introduits par la nouvelle architecture 5G. Ce document souligne le défi que représente l’isolation des « network slices », et la gestion de sa sécurité en fonction des politiques retenues.Tout d’abord, un nouveau modèle de contrôle d’accès a été créé. Il permet de sécuriser les interactions entre les fonctions réseaux supportées par les systèmes 5G. Ensuite, la gestion des interactions entre les «network slices » a été abordée. On utilise le concept de chaînes de « network slices », qui seront mises en oeuvre après validation des contraintes de sécurité selon la politique choisie. Enfin, une méthode de quantification de l’isolation a été mise au point, permettant de connaître le degré d’isolation d’un service de communication offert via des « network slices». Cela permet aux opérateurs de réseau et aux clients de mesurer le degré d’isolation, puis d’améliorer la configuration des « network slices » afin de le renforcer. Ces éléments établissent un cadre solide contribuant à sécuriser, verticalement, les services de communication d’un réseau 5G et à évaluer le degré de sécurité en ce qui concerne leurs interactions et leur isolationNetwork slicing is a cornerstone in the conception and deployment of enriched communication services for the new use cases envisioned and supported by the new 5G architecture.This document makes emphasis on the challenge of the network slicing isolation and security management according to policy. First, a novel access control model was created, that secures the interactions between network functions that reside inside the 5G system. Then, the management of the interactions between network slices was addressed. We coin the concept of network slice chains, which are conceived after security constraint validation according to policy. Lastly, a method to quantify isolation was developed, permitting to find out how well isolated a communication service is, which is offered via network slices. This enables network operators and customers to measure the isolation level and improve the configuration of the network slices so the isolation level can be enhanced. These components establish a solid framework that contributes to secure, vertically, the communication services of a 5G network and assess how secure they are with respect to their interactions and isolation
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Richart, Matías. "Resource allocation and management techniques for network slicing in WiFi networks." Doctoral thesis, Universitat Politècnica de Catalunya, 2019. http://hdl.handle.net/10803/668043.
Abstract:
Network slicing has recently been proposed as one of the main enablers for 5G networks; it is bound to cope with the increasing and heterogeneous performance requirements of these systems. To "slice'' a network is to partition a shared physical network into several self-contained logical pieces (slices) that can be tailored to offer different functional or performance requirements.
Moreover, a key characteristic of the slicing paradigm is to provide resource isolation as well as an efficient use of resources. In this context, a slice is envisioned as an end-to-end virtual network which permits that the infrastructure operators lease their resources to service providers (tenants) through the dynamic, and on-demand, deployment of slices. Tenants may have complete control over the slice functions and resources, and employ them to satisfy their client’s demands.
Recent works on slicing for Radio Access Networks (RANs) just focus on general architectures and frameworks for the management and instantiation of network slices avoiding details on how the slices are implemented and enforced in the wireless devices.
Even more, while some techniques for slice enforcement already exist, most of them concentrate on cellular technologies, ignoring WiFi networks. Despite of their growing relevance and ubiquity, there are not many works addressing the challenges that appear when trying to apply slicing techniques over WiFi networks.
In this scenario, this thesis contributes to the problem of slicing WiFi networks by proposing a solution to enforce and control slices in WiFi Access Points. The focus of this work is on a particular and complex variant of network slicing called QoS Slicing, in which slices have specific performance requirements.
The main thesis contributions are divided in three: (1) a detailed analysis of the network slicing problem in RANs in general and in WiFi in particular, as well as a study and definition of the QoS Slicing problem, (2) a resource allocation model and mechanism for Wifi devices, and (3) a QoS Slicing solution to enforce and control slices with performance requirements in WiFi Access Points.
Given the novelty of the slicing concept and the complexity of the problem, a detailed study of the slicing problem was performed providing a comprehensive definition of the slicing concept, as well as a classification of the slicing variants. It is also introduced the two main problems of slicing wireless resources: resource allocation and isolation. In the scope of those problems, this thesis contributes with a novel approach where the resource allocation problem is divided on two sub-tasks: Dynamic Resource Allocation, and Enforcement and Control.
As a previous step to the construction of a QoS Slicing solution, it is proposed a novel method of proportionally distributing resources in WiFi networks, by means of the airtime. The proposed mechanism (called ATERR) is based on considering the airtime as the wireless resource to be shared and allocated. An analytical model of the ATERR algorithm is also developed, which shed light on how such resources could be split and on the capacities and limitations of the proposal.
The validity of the proposed model is assessed by means of a simulation-based evaluation on the NS-3 framework.
Finally, regarding the QoS Slicing problem, it is considered two different performance requirements: a guaranteed minimum bit rate and a maximum allowable delay.
The resource allocation problem to the different slices is formulated as a stochastic optimization problem, where each slice's requirement of bit rate and delay is modeled as a constraint.
A solution to the aforementioned problem is devised using the Lyapunov drift optimization theory to obtain an approximate deterministic problem. With this solution, it is developed a novel queuing and scheduling algorithm which allows implementing the obtained solution in WiFi devices.Network slicing ha estat recentment proposat com un dels aspectes claus de les xarxes 5G i s'espera que permeti afrontar les creixents demandes de rendiment que tindran aquests sistemes. Fer slicing consisteix en fer particions d'una xarxa física compartida en diverses parts (slices) lògiques autocontenidas que poden ser adaptades per oferir diferents requeriments funcionals o de rendiment. Més encara, una característica clau del paradigma de slicing és el de proveir aïllament dels recursos així com permetre un ús eficient dels mateixos. En aquest context, una slice es pot considerar com una xarxa virtual d'extrem a extrem que permet als operadors d'infraestructura arrendar els seus recursos a proveïdors de servei (arrendatari) mitjançant el desplegament dinàmic i sota demanda de slices. Els arrendataris poden tenir control complet sobre els recursos i funcions de la slice i utilitzar-los per satisfer les demandes dels seus clients. Treballs recents sobre slicing en xarxes d'accés sense fil s'han enfocat en arquitectures generals i esquemes de gestió per al desplegament de slicing. En aquest sentit, no s'ha aprofundit en detalls de com s'implementen i controlen les slices en els dispositius sense fils. A més, encara hi ha algunes tècniques per al control de slices, la majoria es concentren en tecnologies per a xarxes mòbils i no tenen en compte les xarxes WiFi malgrat la seva creixent rellevància i omnipresència. En aquest escenari, aquesta tesi contribueix al problema de slicing en xarxes WiFi proposant una solució per implementar i controlar slices en punts d'accés WiFi. El treball es concentra en slicing amb qualitat de servei (QoS Slicing), una variant complexa del problema on les slices tenen requeriments de rendiment específics. Les principals contribucions de la tesi es divideixen en tres: (1) una detallada anàlisi del problema de network slicing en xarxes d'accés sense fil i en particular en WiFi, així com un estudi i definició dels problemes de QoS Slicing, (2) un model i mecanisme per a l'assignació de recursos en dispositius WiFi, i (3) una solució per QoS Slicing que implementa i controla slices amb requeriments de rendiment en punts d'accés WiFi. Donada la novetat del concepte de slicing i la complexitat del problema, es va realitzar un estudi detallat del problema de slicing on es proveeix una definició completa del concepte de slicing. A més, s'introdueixen els dos principals problemes del slicing: l'assignació de recursos i l'aïllament. En aquest sentit, aquesta tesi contribueix amb una estratègia original on el problema d'assignació de recursos es divideix en dues tasques: l'assignació dinàmica de recursos i el control de l'assignació. Com un pas previ a la construcció d'una solució per QoS Slicing, es proposa un mètode original per a la distribució proporcional de recursos en xarxes WiFi mitjançant el control del temps de transmissió. El mecanisme proposat (anomenat ATERR) es basa en considerar el temps de transmissió com el recurs a ser compartit i assignat. També es va desenvolupar un model analític de l'algoritme ATERR del qual es poden obtenir les capacitats i limitacions del mecanisme. La validesa del model proposat és estudiada mitjançant una avaluació basada en simulacions sobre l'entorn NS-3. Finalment, pel que fa al problema de QoS Slicing, es van considerar dos requeriments diferents: una garantia de taxa de transmissió mínima i un màxim de latència permès. El problema d'assignació de recursos per a les diferents slices es va formular com un problema d'optimització estocàstica on els requeriments de cada slice es modelen com una restricció. Es va elaborar una solució al problema anterior utilitzant la teoria d'optimització de Lyapunov per obtenir un problema determinista aproximat. Amb aquesta solució, es va desenvolupar un algoritme d'assignació del temps de transmissió per a dispositius WiFi.
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Alfoudi, A. S. D. "Slicing-based resource allocation and mobility management for emerging wireless networks." Thesis, Liverpool John Moores University, 2018. http://researchonline.ljmu.ac.uk/9587/.
Abstract:
The proliferation of smart mobile devices and user applications has continued to contribute to the tremendous volume of data traffic in cellular networks. Moreover, with the feature of heterogeneous connectivity interfaces of these smart devices, it becomes more complex for managing the traffic volume in the context of mobility. To surmount this challenge, service and resource providers are looking for alternative mechanisms that can successfully facilitate managing network resources and mobility in a more dynamic, predictive and distributed manner. New concepts of network architectures such as Software-Defined Network (SDN) and Network Function Virtualization (NFV) have paved the way to move from static to flexible networks. They make networks more flexible (i.e., network providers capable of on-demand provisioning), easily customizable and cost effective. In this regard, network slicing is emerging as a new technology built on the concepts of SDN and NFV. It splits a network infrastructure into isolated virtual networks and allows them to manage network resources based on their requirements and characteristics. Most of the existing solutions for network slicing are facing challenges in terms of resource and mobility management. Regarding resource management, it creates challenges in terms of provisioning network throughput, end-to-end delay, and fairness resources allocation for each slice, whereas, in the case of mobility management, due to the rapid change of user mobility the network slice operator would like to hold the mobility controlling over its clients across different access networks, rather than the network operator, to ensure better services and user experience. In this thesis, we propose two novel architectural solutions to solve the challenges identified above. The first proposed solution introduces a Network Slicing Resource Management (NSRM) mechanism that assigns the required resources for each slice, taking into consideration resource isolation between different slices. The second proposed v solution provides a Mobility Management architecture-based Network Slicing (MMNS) where each slice manages its users across heterogeneous radio access technologies such as WiFi, LTE and 5G networks. In MMNS architecture, each slice has different mobility demands (e.g,. latency, speed and interference) and these demands are governed by a network slice configuration and service characteristics. In addition, NSRM ensures isolating, customizing and fair sharing of distributed bandwidths between various network slices and users belonging to the same slice depending on different requirements of each one. Whereas, MMNS is a logical platform that unifies different Radio Access Technologies (RATs) and allows all slices to share them in order to satisfy different slice mobility demands. We considered two software simulations, namely OPNET Modeler and OMNET++, to validate the performance evaluation of the thesis contributions. The simulation results for both proposed architectures show that, in case of NSRM, the resource blocking is approximately 35% less compared to the legacy LTE network, which it allows to accommodate more users. The NSRM also successfully maintains the isolation for both the inter and intra network slices. Moreover, the results show that the NSRM is able to run different scheduling mechanisms where each network slice guarantee perform its own scheduling mechanism and simultaneously with other slices. Regarding the MMNS, the results show the advantages of the proposed architecture that are the reduction of the tunnelling overhead and the minimization of the handover latency. The MMNS results show the packets delivery cost is optimal by reducing the number of hops that the packets transit between a source node and destination. Additionally, seamless session continues of a user IP-flow between different access networks interfaces has been successfully achieved.
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Boutiba, Karim. "On enforcing Network Slicing in the new generation of Radio Access Networks." Electronic Thesis or Diss., Sorbonne université, 2024. https://accesdistant.sorbonne-universite.fr/login?url=https://theses-intra.sorbonne-universite.fr/2024SORUS003.pdf.
Abstract:
Les réseaux 5G émergents et au-delà promettent de prendre en charge de nouveaux cas d'utilisation tels que la communication holographique immersive, l'internet des compétences et la cartographie interactive 4D [1]. Ces cas d'usage ont des exigences strictes en termes de Quality de Service (Quality of Service), telles qu'une faible latence, un débit descendant et ascendant (Downlink (DL)/Uplink (UL)) élevé, ainsi qu'une faible consommation d'énergie. Les spécifications du groupe de normalisation 3GPP ont introduit de nombreuses fonctionnalités aux système radio 5G (5G NR), dans le but d'améliorer l'efficacité spectrale de la 5G et de répondre aux exigences strictes et hétérogènes des services de la 5G et au-delà. Parmi les principales fonctionnalités de la 5G NR, on peut citer l'introduction du concept de numérologie et BandWidth Part (BWP), le multiplexage temporel (TDD) dynamique et Connected-mode Discontinuous Reception (C-DRX). Toutefois, les spécifications 3GPP n'indiquent pas comment configurer la next gNode B (gNB)/User Equipment (UE) pour optimiser l'utilisation des fonctionnalités 5G NR. Afin de combler ce manque, nous proposons de nouvelles solutions qui mettent en œuvre des fonctionnalités 5G NR en appliquant les techniques de l'apprentissage automatique ou Machine Learning (ML), en particulier l'apprentissage profond par renforcement ou Deep Reinforcement Learning (DRL). En effet, les outils de l'intelligence artificielle jouent un rôle essentiel dans l'optimisation des systèmes de communication et des réseaux [2] grâce à leurs capacités à rendre le réseau capable de s'auto-configurer et s'auto-optimiser.Dans cette thèse, nous proposons plusieurs solutions pour permettre une configuration intelligente du réseau d'accès radio (RAN). Nous avons divisé les solutions en trois parties distinctes.Dans la première partie, nous proposons deux contributions. Tout d'abord, nous présentons NRflex, une solution de découpage du RAN en tranches (ou slicing), aligné sur l'architecture Open RAN (O-RAN). Par la suite, nous modélisons le problème de découpage du RAN en tranches comme un problème Mixed-Integer Linear Programming (MILP). Après avoir montré que la résolution du problème prend un temps exponentiel, nous avons introduit une nouvelle approche pour le résoudre en un temps polynomial, ce qui est très important pour la fonction de l'ordonnancement (scheduling) des ressources radio. La nouvelle approche consiste à formaliser et résoudre ce problème par le biais l'apprentissage par renforcement profond (DRL).Dans la deuxième partie de la thèse, nous proposons une solution basée sur le DRL pour permettre un TDD dynamique dans une seule cellule 5G NR. La solution a été implémentée dans la plateforme OpenAirInterface (OAI) et testée avec UEs réels. Nous avons ensuite étendu la solution, en tirant parti de Multi-Agent Deep Reinforcement Learning (MADRL), pour prendre en charge plusieurs cellules en tenant compte de l'interférence radio entre les liaisons transversales entre les cellules.Dans la dernière partie de la thèse, nous avons proposé trois solutions pour optimiser le RAN afin de prendre en charge les services URLLC. Tout d'abord, nous avons proposé une solution en deux étapes basées sur l'apprentissage automatique pour prédire les coupures du lien radio ou Radio Link Failure (RLF). Le modèle de prédiction RLF a été entraîné avec des données réelles obtenues à partir d'un banc d'essai 5G. Dans la deuxième contribution, nous avons proposé une solution basée sur le DRL pour réduire la latence UL. Notre solution alloue (prédit) dynamiquement les futurs besoins en ressource radio du UL en apprenant du modèle de trafic. Dans la dernière contribution, nous introduisons une solution basée sur le DRL afin d'équilibrer la latence et la consommation d'énergie en calculant conjointement les paramètres C-DRX et la configuration BWPThe emerging 5G networks and beyond promise to support novel use cases such as immersive holographic communication, Internet of Skills, and 4D Interactive mapping [usecases]. These use cases require stringent requirements in terms of Quality of Service (QoS), such as low latency, high Downlink (DL)/Uplink (UL) throughput and low energy consumption. The 3rd Generation Partnership Project (3GPP) specifications introduced many features in 5G New Radio (NR) to improve the physical efficiency of 5G to meet the stringent and heterogeneous requirements of beyond 5G services. Among the key 5G NR features, we can mention the numerology, BandWidth Part (BWP), dynamic Time Duplex Division (TDD) and Connected-mode Discontinuous Reception (C-DRX). However, the specifications do not provide how to configure the next Generation Node B (gNB)/User Equipment (UE) in order to optimize the usage of the 5G NR features. We enforce the 5G NR features by applying Machine Learning (ML), particularly Deep Reinforcement Learning (DRL), to fill this gap. Indeed, Artificial Intelligence (AI)/ML is playing a vital role in communications and networking [1] thanks to its ability to provide a self-configuring and self-optimizing network.In this thesis, different solutions are proposed to enable intelligent configuration of the Radio Access Network (RAN). We divided the solutions into three different parts. The first part concerns RAN slicing leveraging numerology and BWPs. In contrast, the second part tackles dynamic TDD, and the last part goes through different RAN optimizations to support Ultra-Reliable and Low-Latency Communication (URLLC) services.In the first part, we propose two contributions. First, we introduce NRflex, a RAN slicing framework aligned with Open RAN (O-RAN) architecture. NRflex dynamically assigns BWPs to the running slices and their associated User Equipment (UE) to fulfill the slices' required QoS. Then, we model the RAN slicing problem as a Mixed-Integer Linear Programming (MILP) problem. To our best knowledge, this is the first MILP modeling of the radio resource management featuring network slicing, taking into account (i) Mixed-numerology, (ii) both latency and throughput requirements (iii) multiple slices attach per UE (iv) Inter-Numerology Interference (INI). After showing that solving the problem takes an exponential time, we consider a new approach in a polynomial time, which is highly required when scheduling radio resources. The new approach consists of formalizing this problem using a DRL-based solver.In the second part of this thesis, we propose a DRL-based solution to enable dynamic TDD in a single 5G NR cell. The solution is implemented in OAI and tested using real UEs. Then, we extend the solution by leveraging Multi-Agent Deep Reinforcement Learning (MADRL) to support multiple cells, considering cross-link interference between cells.In the last part, we propose three solutions to optimize the RAN to support URLLC services. First, we propose a two-step ML-based solution to predict Radio Link Failure (RLF). We combine Long Short-Term Memory (LSTM) and Support Vector Machine (SVM) to find the correlation between radio measurements and RLF. The RLF prediction model was trained with real data obtained from a 5G testbed. In the second contribution, we propose a DRL-based solution to reduce UL latency. Our solution dynamically allocates the future UL grant by learning from the dynamic traffic pattern. In the last contribution, we introduce a DRL-based solution to balance latency and energy consumption by jointly deriving the C-DRX parameters and the BWP configuration
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Hasan, Rasha. "Hybrid synchrony virtual networks." Pontif?cia Universidade Cat?lica do Rio Grande do Sul, 2017. http://tede2.pucrs.br/tede2/handle/tede/7344.
Abstract:
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Nas ?ltimas tr?s d?cadas de pesquisa em Sistemas Distribu?dos (SDs), um aspecto central discutido ? o de sincronia. Com um sistema ass?ncrono, n?o fazemos suposi??es sobre velocidades de execu??o de processos e / ou atrasos de entrega de mensagens; Com um sistema s?ncrono, fazemos suposi??es sobre esses par?metros [Sch93b]. Sincronismo em SDs impacta diretamente a complexidade e funcionalidade de algoritmos tolerantes a falhas. Uma infra-estrutura s?ncrona contribui para o desenvolvimento de sistemas mais simples e fi?veis, mas tal infra-estrutura ? muito cara e ?s vezes nem sequer vi?vel de implementar. Uma infra-estrutura totalmente ass?ncrona ? mais realista, mas alguns problemas foram mostrados como insol?veis em tal ambiente atrav?s do resultado de impossibilidade por Fischer, Lynch e Paterson [FLP85]. As limita?es tanto em ambientes totalmente s?ncronos como totalmente ass?ncronos levaram ao desenvolvimento de sistemas distribu?dos como s?ncronia parcial [CF99, Ver06]. Em um estudo de funcionalidade de sistemas distribu?dos s?ncronos parciais e de propriedades de Redes Virtuais (RVs), descobrimos que existem v?rios desafios para este tipo de sistemas que podem ser resolvidos com RVs devido ?s propriedades que a virtualiza??o traz. Por exemplo a) partilha de recursos fornecida por RVs permite diminuir o custo ao partilhar a parte s?ncrona da infra-estrutura f?sica, b) isolamento fornecido por a natureza da RVs, isso pode beneficiar os SDs coexistentes na mesma infra-estrutura f?sica que exigem certo n?vel de isolamento,c) resili?ncia garantido atrav?s do processo de aloca??o de recursos de Redes Virtuais, isso permite alocar recursos de reposi??o ao lado dos prim?rios para redes virtuais que exigem garantias de disponibilidade, por exemplo, SDs tolerantes a falhas. Em nosso trabalho, argumentamos que as RVs e um adequado processo de aloca??o de recursos das RVs oferecem um ambiente adequado para executar aplicativos distribu?dos com sincronia parcial. Isto levou ? abstra??o de um novo tipo de RVs: As Redes Virtuais com sincronia h?brida (RVSHs). Nesta tese, apresentamos a id?ia geral das Redes Virtuais com sincronia h?brida motivado pelos SDs com s?ncronia h?brida, e dividimos nosso trabalho em duas partes: a) Espa?oRVSHs propostos pelo SDs com sincronia h?brida em espa?o, e b) Tempo-RVSHs propostos pelo SDs com sincronia h?brida em tempo. No SDs com s?ncronia h?brida em espa?o, a infraestrutura ? composta de subconjuntos de componentes s?ncronos e ass?ncronos, e cada um desses subconjuntos mant?m seu status de sincronia atrav?s do tempo (i.e., os subconjuntos s?ncronos permanecem s?ncronos e os ass?ncronos permanecem ass?ncronos). No SDs com s?ncronia h?brida em tempo, a infra-estrutura ? composta de subconjuntos de n?s e la?os que podem alternar seu status de sincronia atrav?s do tempo (i.e., os componentes se comportam de forma s?ncrona durante os intervalos de tempo e de forma ass?ncrona durante outros intervalos de tempo). As principais contribui??es desta tese s?o: a) caracterizam os RVSHs em seus dois tipos Espa?o-RVSHs e Tempo-RVSHs para refletir tanto a natureza de sincronia em espa?o e em tempo; b) propor uma estrutura adequada para o processo de aloca??o de recursos para ambos Espa?o-RVSHs e Tempo-RVSHs, e c) fornecer uma avalia??o dos modelos propostos para RVSHs.
In the last three decades of research in Distributed Systems (DSs), one core aspect discussed is the one of synchrony. \Vith an asynchronous system, we make no assumptions about process execution speeds andj or message delivery delays; with a synchronous system, we do make assumptions about these parameters [Sch93b]. Synchrony in DSs impacts directly the complexity and functionality of fault-tolerant algorithms. Although a synchronous infrastructure contributes towards the development of simpler and reliable systems, yet such an infrastructure is too expensive and sometimes even not feasible to implemento On the other hand, a fully asynchronous infrastructure is more realistic, but some problems were shown to be unsolvable in such an environment through the impossibility result by Fischer, Lynch and Paterson [FLP85]. The limitations in both fully synchronous or fully asynchronous environments have led to the development of partial synchronous distributed systems [CF99, Ver06]. In a study of partial synchronous distributed systems functionality, and of Virtual Networks (VNs) properties, we found that there are several challenges for this kind of systems that can be solved with VNs due to the properties that virtualization brings. For example a) resources sharing provided by VNs allows decreasing the cost when sharing the synchronous portion of the physical infrastructure, b) isolation provided by the VNs nature can benefit the coexistent DSs on same physical infrastructure that demand certain leveI of isolation, c) resilience guaranteed through the Virtual Networks Embedding (VNE) process that allows allocating spare resources beside the primary ones for virtual networks that require availability guarantees, for example fault tolerant DSs. In our work, we argue that VNs and a suitable VN embedding process offer suitable environment for running distributed applications with partial synchrony. This has led to the abstraction of new type of VNs: The Hybrid Synchrony Virtual Networks (HSVNs). In this thesis, we introduce the general idea of Hybrid Synchrony Virtual Networks (HSVNs) motivated by the hybrid synchronous DSs, and we branch our work into two branches: a) Space-HSVNs addressed to spatial hybrid synchronous DSs, and b) TimeHSVNs addressed to the time hybrid synchronous DSs. In spatial hybrid synchronous DSs, the hybrid synchronous physical infrastructure is composed of subsets of synchronous and asynchronous components, and each of these subsets maintains its synchrony status through time (i.e., synchronous subsets remain synchronous and asynchronous ones remain asynchronous). In time hybrid synchronous DSs, the hybrid synchronous physical infrastructure is composed of subsets of nodes and links that can alternate their synchrony status through time (i.e., the components behave synchronously during time intervals, and asynchronously during other time intervals). The main contributions of this thesis are: a) characterize the HSVNs in its two types Space-HSVNs and Time-HSVNs to reflect both the synchrony space-variant and time-variant nature ofDSs; b) propose a suitable embedding framework for both Space-HSVNs and TimeHSVNs, and c) provide an evaluation of the embedding mo deIs addressed to the HSVNs.
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謝啓良 and Kai-leung Tse. "Actual business networks behind the virtual networks." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1998. http://hub.hku.hk/bib/B31269357.
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Tse, Kai-leung. "Actual business networks behind the virtual networks /." Hong Kong : University of Hong Kong, 1998. http://sunzi.lib.hku.hk/hkuto/record.jsp?B19878382.
17
Teague, Kory Alan. "Approaches to Joint Base Station Selection and Adaptive Slicing in Virtualized Wireless Networks." Thesis, Virginia Tech, 2018. http://hdl.handle.net/10919/85966.
Abstract:
Wireless network virtualization is a promising avenue of research for next-generation 5G cellular networks. This work investigates the problem of selecting base stations to construct virtual networks for a set of service providers, and adaptive slicing of the resources between the service providers to satisfy service provider demands. A two-stage stochastic optimization framework is introduced to solve this problem, and two methods are presented for approximating the stochastic model. The first method uses a sampling approach applied to the deterministic equivalent program of the stochastic model. The second method uses a genetic algorithm for base station selection and adaptively slicing via a single-stage linear optimization problem. A number of scenarios are simulated using a log-normal model designed to emulate demand from real world cellular networks. Simulations indicate that the first approach can provide a reasonably tight solution, but is constrained as the time expense grows exponentially with the number of parameters. The second approach provides a significant improvement in run time with the introduction of marginal error.Master of Science
5G, the next generation cellular network standard, promises to provide significant improvements over current generation standards. For 5G to be successful, this must be accompanied by similarly significant efficiency improvements. Wireless network virtualization is a promising technology that has been shown to improve the cost efficiency of current generation cellular networks. By abstracting the physical resource—such as cell tower base stations— from the use of the resource, virtual resources are formed. This work investigates the problem of selecting virtual resources (e.g., base stations) to construct virtual wireless networks with minimal cost and slicing the selected resources to individual networks to optimally satisfy individual network demands. This problem is framed in a stochastic optimization framework and two approaches are presented for approximation. The first approach converts the framework into a deterministic equivalent and reduces it to a tractable form. The second approach uses a genetic algorithm to approximate resource selection. Approaches are simulated and evaluated utilizing a demand model constructed to emulate the statistics of an observed real world urban network. Simulations indicate that the first approach can provide a reasonably tight solution with significant time expense, and that the second approach provides a solution in significantly less time with the introduction of marginal error.
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Harris, B. A. "Firewalls and virtual private networks." Thesis, University of Canterbury. Computer Science, 1998. http://hdl.handle.net/10092/8413.
Abstract:
The Internet has become a global computing phenomenon, and during the 1990's has had more influence on the computer - communications industry than any other development in its history. There are two major issues effecting the development of the Internet for the 21st century; performance and security. This thesis is concerned with the later; in particular the issues raised by the interconnection of TCP/IP based networks between trusted and untrusted network domains.
Four main topics are addressed: the common threats and vulnerabilities that effect the TCP/IP protocol suite at the Network, Transport, and Application layers; the application of firewall architectures to counter the risks posed by TCP/IP based connections between trusted and untrusted network domains; the issue of independent firewall architecture evaluation and certification; and the application of Virtual Private Network (VPN) technology to protect traffic over untrusted networks.
This thesis examines the common threats and vulnerabilities which effect the current TCP/IP protocol suite, and hence the Internet. A firewall architecture can be a powerful tool for preventing attacks based on TCP/IP vulnerabilities, however, it is only as effective as the security policy that it implements. Although firewalls can benefit computer and network security, they suffer from several significant limitations, including; the inability to protect network traffic; defending against insider abuse; and controlling the content of end-user access (e.g. virus infected files, Java applets, etc.)
Firewalls are generally considered impregnable, however they are certainly not immune to software and hardware vulnerabilities. Therefore, this thesis examines independent evaluation and certification of firewall architectures with particular focus on New Zealand and Australian efforts.
The final section of this thesis examines the use of VPNs for securing network traffic. The amalgamation of VPN and firewall technologies allows the security policy to be extended onto the network in the form of services, such as, confidentiality, integrity, non-repudiation, and strong authentication.
19
Randall, Keith H. (Keith Harold). "Virtual networks--implementation and analysis." Thesis, Massachusetts Institute of Technology, 1994. http://hdl.handle.net/1721.1/35969.
20
Ögren, Niklas. "Selecting/realization of Virtual Private Networks with Multiprotocol Label Switching or Virtual Local Area Networks." Thesis, KTH, Mikroelektronik och Informationsteknik, IMIT, 2002. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-93211.
Abstract:
Many reports have been written about the techniques behind Virtual Private Networks (VPN) and Multi Protocol Label Switching (MPLS). They usually deal with the low level design of the software implementing a specific technique. The initial products are usually not mature enough to run in a large network or have to be adjusted in some way to fit. This report investigates the different ways of implementing strict layer 2 Virtual Private Networks in an existing nation-wide Gigabit Ethernet. The infrastructure in use, as well as the hardware, has to be used without major changes. Since 1998/1999, when MPLS first started in the laboratories, development has continued. Today it is possible to introduce MPLS or tunneled national virtual local area network into an existing network. This requires high speed, fault tolerant, and stable hardware and software. Going beyond the separation of traffic at layer 3 using Virtual Private Networks, i.e., IPSec, we can tunnel layer 2 traffic through a network. Although the first layer 3 VPN products are already in use, layer 2 VPNs still need to be evaluated and brought into regular use. There are currently two ways of tunneling VLANs in a core network: tunneled VLANs (or as Extreme Networks calls them, VMANs) and MPLS. This project showed that it is possible to start with a VLAN-only solution, and then upgrade to MPLS to solve scalability issues. The VMAN solution can not be used at Arrowhead, since there are too many disadvantages in the way Extreme Networks has implemented it. However, a mix of tunneling VMAN in a VLAN core is possible, and enables customer tagging of VLANs in a Layer 2 VPN. Furthermore, the testing of EAPS and per-VLAN Spanning Tree Protocol turned out well, and showed that EAPS should not be used when there is more than one loop.
21
BALIEIRO, Andson Marreiros. "Cognitive radio virtual networks environment: definition, modeling and mapping of secondary virtual networks onto wireless substrate." Universidade Federal de Pernambuco, 2015. https://repositorio.ufpe.br/handle/123456789/16360.
Abstract:
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FACEPE
The wireless technologies are progressing at a rapid pace such that the future of digital communication will be dominated by a dense, ubiquitous and heterogeneous wireless network. Along with this, there is a growing demand for wireless services with different requirements. In this respect, the management of this complex wireless ecosystem becomes challenging, and the wireless virtualization is pointed as an efficient solution to perform it, where different virtual wireless networks can be created, sharing and running on the same wireless infrastructure, and providing differentiated services to users. However, to satisfy the high demand for mobile communications, it is necessary the availability of a natural and scarce resource, the electromagnetic spectrum. Although the insertion of virtualization in wireless networks provides better resources utilization, the current approaches to employ the wireless virtualization can cause resource underutilization. To overcome this underutilization and enable that new wireless virtual networks can be deployed, the wireless virtualization can be combined with the cognitive radio technology and dynamic spectrum access (DSA) techniques in order to achieve the deepest level of wireless virtualization and to improve the resource utilization through the deployment of opportunistic resource sharing. Thus, virtual wireless networks with different access priorities to the resources (e.g. primary and secondary) can be deployed in an overlay form, sharing the same substrate wireless network, where the secondary virtual network (SVN) accesses the resources only when the primary one (PVN) is not using them. However, this new scenario brings new challenges: from the mapping to operation of these networks. The SVN mapping is a NP-hard problem and presents some constraints and objectives related to both PVNs and SVNs. Achieving all objectives simultaneously is a challenging process. This thesis addresses the SVNs mapping problem onto substrate network considering the existence of the PVNs on the same substrate network. It discloses the environment composed by these networks, denoted as cognitive radio virtual network environment (CRVNE), models this environment by using a M/M/N/N queue with preemptive and priority service, and delineates a multi-objective problem formulation for the SVNs mapping. Moreover, a scheme based on Genetic Algorithms to solve the SVNs mapping problem is proposed and evaluated in terms of collision, secondary user (SU) dropping, and SU blocking probabilities, and joint utilization, achieving better results than other based on the First-Fit strategy.
Recentemente, as tecnologias sem fio estão progredindo rapidamente de modo que o futuro da comunicação digital será dominado por uma rede sem fio densa, ubíqua e heterogênea. Adicionado a isso, existe uma demanda crescente por serviços sem fio com diferentes requisitos. Neste aspecto, o gerenciamento deste ecossistema complexo se tona desafiador e a virtualização sem fio é apontada como uma solução eficiente para realizá-lo, onde redes virtuais sem fio diferentes podem ser criadas, compartilhando e executando sobre a mesma infraestrutura de rede sem fio e provendo serviços diferenciados aos usuários. Entretanto, para satisfazer à alta demanda por comunicação móvel é necessária a disponibilidade de um recurso natural e escasso, o espectro eletromagnético. Embora a inserção de virtualização em redes sem fio forneça maior utilização dos recursos, as abordagens atuais para empregar a virtualização sem fio podem causar subutilização de recursos. Para superar esta subutilização, a virtualização sem fio pode ser combinada com a tecnologia de rádio cognitivo e técnicas de acesso dinâmico ao espectro (DSA) para alcançar o mais profundo nível de virtualização sem fio e melhorar a utilização de recursos através do compartilhamento oportunista deles. Assim, redes virtuais sem fio com diferentes prioridades de acesso aos recursos (ex. primária e secundária) podem ser implantadas sobrepostas, compartilhando a mesma infraestrutura de rede sem fio, onde as redes virtuais secundárias (SVNs) acessam os recursos somente quando as redes virtuais primárias (PVNs) não os estiverem utilizando. Entretanto, este novo cenário traz novos desafios, desde o mapeamento até a operação destas redes. O mapeamento de SVNs é um problema NP-difícil e apresenta restrições e objetivos relacionados tanto às PVNs quanto às SVNs. Alcançar todos os objetivos simultaneamente é um processo desafiador. Esta tese aborda o problema de mapeamento de SVNs em redes de substrato considerando a existência de PVNs na mesma rede de substrato. Ela apresenta o ambiente de redes virtuais de rádio cognitivo (CRVNE), modela este ambiente utilizando uma fila M/M/N/N preemptiva e com prioridade e delineia uma formulação multiobjetivo para o mapeamento de SVNs. Além disso, um esquema baseado em Algoritmos Genéticos (GA) para resolver o problema de mapeamento de SVNs é proposto e avaliado em termos das probabilidades de colisão, descarte de usuário secundário (US), bloqueio de US e utilização conjunta, alcançando melhores resultados do que um esquema baseado na estratégia First-Fit.
22
Youssef, Mina Nabil. "Optimal topology design for virtual networks." Thesis, Manhattan, Kan. : Kansas State University, 2008. http://hdl.handle.net/2097/560.
23
Söderström, Gustav. "Virtual networks in the cellular domain." Thesis, KTH, Mikroelektronik och Informationsteknik, IMIT, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-93117.
Abstract:
Data connectivity between cellular devices can be achieved in different ways. It is possible to enable full IPconnectivity in the cellular networks. However this connectivity is combined with a lot of issues such as security problems and the IPv4 address space being depleted. As a result of this many operators use Network Address Translation in their packet data networks, preventing users in different networks from being able to contact each other. Even if a transition to IPv6 takes place and the potential problem of address space is solved, it is not likely that operators will leave their packet data networks open to the Internet. An alternative to solving the problem on the IP level is to use overlay networks. In an overlay network applications on the cellular devices identify themselves at the application level rather than on the IP level. While full IP connectivity always gives the most efficient routing, an overlay network can offer services that are difficult to implement on the IP level. This can enable an application to span Network Address Translating entities without having to share the entire device. They can also provide private dynamic virtual networks and groups for users that trust each other. These private networks can use permissions and group casting functions, without the problems associated with traditional IP multicast. The relatively limited bandwidths of the GSM and UMTS networks allow for application level routing of continuous data streams if the overlay network is distributed enough and mapped to the physical network in an efficient way. One of the advantages of using overlay networks is that although standard IP networks may be able to offer similar services in the future, overlay networks can be implemented in the existing IPv4 networks today at comparatively low costs. This may create the incentive needed in order for future larger investments to be justified. A distributed overlay network not only allows for real-time services such as instant messaging, which is already possible with a centralized server solution, but it also allows for higher bandwidth services such as video conferencing, Voice over IP, etc. that are not possible on a large scale with a centralized relaying server. An overlay network could be implemented by any third party without the support of an operator. This suggests that free networks may be created for what could be called reversed file sharing, i.e. networks where users upload files to each other rather than download as in most existing file sharing networks. These could become direct competitors to SMS, MMS and other operator-owned services. The thesis investigates the mentioned possibilities and potential threats. Along with this an implementation of an overlay network for cellular devices is created that is totally independent of the operator’s network.Datakonnektivitet mellan cellulära terminaler kan uppnås på olika sätt. Ett sätt är att utrusta de cellulära näten med full IP konnektivitet. Detta medför dock en del problem såsom säkerhetsfrågor och problem med att antalet IPv4 addresser kanske inte kan täcka framtidens behov. På grund av detta använder många operatörer såkallad nätverksadressöversättning i sina paketdatanät vilket hindrar användare i olika paketdatanät från att kunna kontakta varandra. Även om en framtida övergång till IPv6 löser problemen med för liten adressrymd så är det inte troligt att operatörerna kommer att lämna sina paketdatanät öppna mot resten av Internet. Ett alternativ till att lösa problemet på IP-nivån är att istället använda overlaynätverk. I ett sådant nätverk identifierar applikationer sig själva på applikationsnivån istället för på IP-nivån. Medans ren IP-konnektivitet innebär effektivast möjliga routing av data så erbjuder ett overlaynätverk möjlighet till tjänster som är svåra att implementera på IP-nivå. Bland annat kan applikationsnät som traverserar nätverksadressöversatta nätverk skapas utan att en mobil terminal behöver exponeras helt och hållet mot Internet. Dessa overlaynätverk kan också skapas dynamiskt och tillfälligt vilket ger användare möjlighet att skapa privata nätverk och grupper med med enheter de litar på, endast dessa får då tillgång till terminalen. Overlaynätverken kan också erbjuda multicast funktionalitet inom grupperna utan de problem som hör ihop med traditionell IP-multicast. De relativt begränsade bandbredderna i GSM och UMTS nätverken tillåter routing av data på applikationsnivån om overlaynätverket är tillräckligt väl distribuerat och effektivt mappat mot det underliggande nätverket. En av fördelarna med att använda overlaynätverk är att även om den eftersökta funktionaliteten kanske kan implementeras på IP-nivå i framtiden med hjälp av ny teknik så kan overlaynätverk implementeras i nuvarande IPv4-nätverk till relativt låga kostnader då de endast består av mjukvara som körs på existerande hårdvara. Ett distribuerat overlaynätverk erbjuder inte bara realtidstjänster såsom instant messaging vilket redan är möjligt och fungerar bra med en central serverlösning. Det distribuerade nätverket kan dessutom hantera routing av högre bandbredder mellan terminaler, såsom videokonferenser, Voice over IP etc. som inte är möjligt i stor skala med en centraliserad lösning. Overlaynätverk kan implementeras av en tredjepart utan operatörers samarbete. Detta kan innebära att gratisnätverk skapas för vad som skulle kunna kallas omvänd fildelning, dvs. nätverk där användare laddar upp information till varandra snarare än laddar ner vilket är fallet i de flesta existerande fildelningsnätverk. Dessa nätverk skulle kunna bli direkta konkurrenter till SMS, MMS och andra operatörsägda tjänster. Examensarbetet undersöker de nämnda möjligheterna och potentiella hoten i dessa nätverk. Utöver detta skapas även en implementation av ett overlaynätverk som är helt oberoende av operatörens nätverk.
24
Bainbridge, Christopher James. "Digital control networks for virtual creatures." Thesis, University of Edinburgh, 2010. http://hdl.handle.net/1842/4812.
Abstract:
Robot control systems evolved with genetic algorithms traditionally take the form of floating-point neural network models. This thesis proposes that digital control systems, such as quantised neural networks and logical networks, may also be used for the task of robot control. The inspiration for this is the observation that the dynamics of discrete networks may contain cyclic attractors which generate rhythmic behaviour, and that rhythmic behaviour underlies the central pattern generators which drive lowlevel motor activity in the biological world. To investigate this a series of experiments were carried out in a simulated physically realistic 3D world. The performance of evolved controllers was evaluated on two well known control tasks—pole balancing, and locomotion of evolved morphologies. The performance of evolved digital controllers was compared to evolved floating-point neural networks. The results show that the digital implementations are competitive with floating-point designs on both of the benchmark problems. In addition, the first reported evolution from scratch of a biped walker is presented, demonstrating that when all parameters are left open to evolutionary optimisation complex behaviour can result from simple components.
25
Lukaszewski, Daniel. "Multipath transport for virtual private networks." Thesis, Monterey, California: Naval Postgraduate School, 2017. http://hdl.handle.net/10945/53013.
Abstract:
Approved for public release; distribution is unlimitedVirtual Private Networks (VPNs) are designed to use the Transmission Control Protocol (TCP) or User Datagram Protocol (UDP) to establish secure communication tunnels over public Internet. Multipath TCP (MPTCP) extends TCP to allow data to be delivered over multiple network paths simultaneously. This thesis first builds a testbed and investigates the potential of using MPTCP tunnels to increase the goodput of VPN communications and support seamless mobility. Based on the empirical results and an analysis of the MPTCP design in Linux kernels, we further introduce a full-multipath kernel, implementing a basic Multipath UDP (MPUDP) protocol into an existing Linux MPTCP kernel.We demonstrate the MPUDP protocol provides performance improvements over single path UDP tunnels and in some cases MPTCP tunnels. The MPUDP kernel should be further developed to include more efficient scheduling algorithms and path managers to allow better performance and mobility benefits seen with MPTCP.
Outstanding Thesis
Lieutenant, United States Navy
26
Evlogimenou, Anna. "Programmable accounting management for Virtual Private Networks." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp04/MQ62962.pdf.
27
Müller, Christoph H. P. "Similarity-based virtual screening using inference networks." Thesis, University of Sheffield, 2010. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.531182.
28
JUNIOR, ALEXANDRE SHEREMETIEFF. "VIRTUAL ORGANIZATIONAL NETWORKS: CHARACTERIZATION, FORMATION AND MANAGEMENT." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2003. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=4323@1.
Abstract:
Uma Rede Organizacional Virtual é uma organização de
cooperação interorganizacional, com uso intenso de
Tecnologia de Informação e Comunicação, típica do
ambiente
globalizado. Nesta dissertação, busca-se caracterizar esse
padrão de rede e propor instrumentos para seu
gerenciamento. O termo Redes Organizacionais Virtuais é
introduzido, a partir da caracterização e da
classificação
das Redes de Cooperação e das Organizações Virtuais.
Propõe-
se a Metodologia de Reticulação para o planejamento e
formação dessas redes e explicita-se a necessidade de
instrumentos de coordenação, controle e avaliação para
assegurar o seu melhor desempenho. Com essa
fundamentação,
analisa-se a Rede de Projeto e Desenvolvimento de
Turbinas
a Gás - RTG, determinando-se suas características e
propondo-se metodologias de planejamento, coordenação e
controle para sua administração. Recomenda-se, ainda, a
implementação de um sistema de informações como
instrumento
reticulador.A Virtual Organizational Network is an inter-organizational cooperation organization, based in Communication and Information Technology, typical of the global environment. The objective of this dissertation is to characterize this network and propose appropriate management tools for its adequate functioning. The term Virtual Organizational Network is introduced based on the characteristics and taxonomy of Cooperation Networks and Virtual Organizations. To form, consolidate and plan this network, the Reticulation Methodology is proposed. The necessity of coordination, governance and performance evaluation tools for these networks is made explicit. This constitutes the basis for the analysis of the Gas Turbine Development and Project Network- RTG. Its characteristics are identified and methodologies for its planning, coordination and governance are proposed, as well as an Information System, as instrument for reticulation.
29
Gilbert, Seth 1976. "Virtual infrastructure for wireless ad hoc networks." Thesis, Massachusetts Institute of Technology, 2007. http://hdl.handle.net/1721.1/42228.
Abstract:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2007.Includes bibliographical references (v. 2, p. 585-591) and index.
One of the most significant challenges introduced by ad hoc networks is coping with the unpredictable deployment, uncertain reliability, and erratic communication exhibited by emerging wireless networks and devices. The goal of this thesis is to develop a set of algorithms that address these challenges and simplify the design of algorithms for ad hoc networks. In the first part of this thesis, I introduce the idea of virtual infrastructure, an abstraction that provides reliable and predictable components in an unreliable and unpredictable environment. This part assumes reliable communication, focusing primarily on the problems created by unpredictable motion and fault-prone devices. I introduce several types of virtual infrastructure, and present new algorithms based on the replicated-state-machine paradigm to implement these infrastructural components. In the second part of this thesis, I focus on the problem of developing virtual infrastructure for more realistic networks, in particular coping with the problem of unreliable communication. I introduce a new framework for modeling wireless networks based on the ability to detect collisions. I then present a new algorithm for implementing replicated state machines in wireless networks, and show how to use replicated state machines to implement virtual infrastructure even in an environment with unreliable communication.
by Seth Gilbert.
Ph.D.
30
Nolte, Tina Ann 1979. "Virtual stationary timed automata for mobile networks." Thesis, Massachusetts Institute of Technology, 2009. http://hdl.handle.net/1721.1/47745.
Abstract:
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2009.Includes bibliographical references (p. 339-347).
In this thesis, we formally define a programming abstraction for mobile networks called the Virtual Stationary Automata programming layer, consisting of real mobile clients, virtual timed I/O automata called virtual stationary automata (VSAs), and a communication service connecting VSAs and client nodes. The VSAs are located at prespecified regions that tile the plane, defining a static virtual infrastructure. We present a theory of self-stabilizing emulation and use this theory to prove correct a self-stabilizing algorithm to emulate a timed VSA using the real mobile nodes that are currently residing in the VSA's region. We also specify two important services for mobile networks: motion coordination and end-to-end routing. We split the implementation of the end-to-end routing service into three smaller pieces, consisting of geographic routing and location management services with an end-to-end routing service built on top of them. We provide stabilizing implementations of each of these services using the VSA abstraction, and provide formal correctness analyses for each implementation.
by Tina Ann Nolte.
Ph.D.
31
Bays, Leonardo Richter. "Virtual network embedding in software-defined networks." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2017. http://hdl.handle.net/10183/178658.
Abstract:
Pesquisas acadêmicas em virtualização de redes vêm sendo realizadas durante diversos anos, nos quais diferentes abordagens de alocação de redes virtuais foram propostas. Tais abordagens, no entanto, negligenciam requisitos operacionais importantes impostos por plataformas de virtualização. No caso de virtualização baseada em SDN/OpenFlow, um exemplo fundamental de tais requisitos operacionais é a disponibilidade de espaço de memória para armazenar regras em dispositivos OpenFlow. Diante dessas circunstâncias, argumentamos que a alocação de redes virtuais deve ser realizada com certo grau de conhecimento sobre infraestruturas físicas; caso contrário, após instanciadas, tais redes podem sofrer instabilidade ou desempenho insatisfatório. Considerando redes físicas baseadas em SDN/OpenFlow como um cenário importante de virtualização, propõe-se um arcabouço baseado na coordenação entre a alocação de redes virtuais e redes OpenFlow para realizar a instanciação de redes virtuais de forma adequada. A abordagem proposta desdobra-se nas seguintes contribuições principais: uma abstração de infraestruturas virtuais que permite que um requisitante represente os detalhes de seus requerimentos de rede de maneira aprofundada; um compilador ciente de privacidade que é capaz de pré-processar requisições com tal grau de detalhamento, ofuscando informações sensíveis e derivando requisitos operacionais computáveis; um modelo para a alocação de redes virtuais que visa a maximizar a viabilidade no nível físico. Resultados obtidos por meio de uma avaliação da nossa abordagem evidenciam que considerar tais requisitos operacionais, bem como computá-los de forma precisa, é imprescindível para garantir a “saúde” das redes virtuais hospedadas na plataforma de virtualização considerada.Research on network virtualization has been active for a number of years, during which a number of virtual network embedding (VNE) approaches have been proposed. These approaches, however, neglect important operational requirements imposed by the underlying virtualization platforms. In the case of SDN/OpenFlow-based virtualization, a crucial example of an operational requirement is the availability of enough memory space for storing flow rules in OpenFlow devices. Due to these circumstances, we advocate that VNE must be performed with some degree of knowledge of the underlying physical networks, otherwise the deployment may suffer from unpredictable or even unsatisfactory performance. Considering SDN/OpenFlow-based physical networks as an important virtualization scenario, we propose a framework based on VNE and OpenFlow coordination for proper deployment of virtual networks (VNs). The proposed approach unfolds in the following main contributions a virtual infrastructure abstraction that allows a service provider to represent the details of his/her VN requirements in a comprehensive manner; a privacy-aware compiler that is able to preprocess this detailed VN request in order to obfuscate sensitive information and derive computable operational requirements; a model for embedding requested VNs that aims at maximizing their feasibility at the physical level. Results obtained through an evaluation of our framework demonstrate that taking such operational requirements into account, as well as accurately assessing them, is of paramount importance to ensure the “health” of VNs hosted on top of the virtualization platform.
32
Balasubramanian, Ashok. "Protected virtual private networks in the hose model." Thesis, University of Hawaii at Manoa, 2003. http://hdl.handle.net/10125/7018.
Abstract:
A Virtual Private Network (VPN) is a service by a Telecommunication (TSP) or Internet Service Provider (ISP) to emulate a private network for a customer. The hose model is for VPNs where the customer is not required to know the exact pair wise traffic pattern between VPN sites, but specifies the maximum traffic rate that can originate or terminate at each VPN site. Hose VPNs protected from single link failures are considered. Two strategies for protection - Path and Line are described, and mixed integer linear programming problems (MILP) are formulated to determine the bandwidth requirements of the protection schemes. Comparisons are performed for path and line protection using simulations on topologies like a 12-node ring, NSFNET16 and Euroring. Path protection is found to be the most bandwidth-efficient strategy and requires approximately 100% or more additional bandwidth than an unprotected optimal tree, whereas line protection requires approximately 200% or more additional bandwidth. To compute the bandwidth required for protected VPN trees, a naive strategy of first computing optimal unprotected VPN trees and then determining the protection bandwidth is used. We also investigate the efficiency of this naive approach, by formulating a simple heuristic that iteratively constructs different trees for a given set of VPN sites and determines the cost of path protection for each of the trees. This heuristic determines a VPN tree that requires the minimum total bandwidth. Experimental results on NSFNET16 and Euroring show that this heuristic results in average savings of about 5% of the total bandwidth from the naive strategy.vii, 52 leaves
33
Avellana, Pardina Albert. "Comparison of Virtual Networks Solutions for Community Clouds." Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-177017.
Abstract:
Cloud computing has a huge importance and big impact nowadays on the IT world.The idea of community clouds has emerged recently in order to satisfy several user expectations. Clommunity is a European project that aims to provide a design and implementation of a self-congured, fully distributed, decentralized, scalable and robust cloud for a community of users across a commmunity network. One of the aspects to analyze in this design is which kind of Virtual Private Network (VPN) is going to beused to interconnect the nodes of the community members interested in access cloud services. In this thesis we will study, compare and analyze the possibility of using Tinc, IPOP or SDN-based solutions such as OpenFlow to establish such a VPN.
34
Ho, Ai Hua. "Virtual router approach for wireless ad hoc networks." Doctoral diss., University of Central Florida, 2011. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4781.
Abstract:
Wireless networks have become increasingly popular in recent years. There are two variations of mobile wireless networks: infrastructure mobile networks and infrastructureless mobile networks. The latter are also known as mobile ad hoc network (MANET). MANETs have no fixed routers. Instead, mobile nodes function as relay nodes or routers, which discover and maintain communication connections between source nodes and destination nodes for various data transmission sessions. In other words, an MANET is a self-organizing multi-hop wireless network in which all nodes within a given geographical area participate in the routing and data forwarding process. Such networks are scalable and self-healing. They support mobile applications where an infrastructure is either not available (e.g., rescue operations and underground networks) or not desirable (e.g., harsh industrial environments). In many ad hoc networks such as vehicular networks, links among nodes change constantly and rapidly due to high node speed. Maintaining communication links of an established communication path that extends between source and destination nodes is a significant challenge in mobile ad hoc networks due to movement of the mobile nodes. In particular, such communication links are often broken under a high mobility environment. Communication links can also be broken by obstacles such as buildings in a street environment that block radio signal. In a street environment, obstacles and fast moving nodes result in a very short window of communication between nodes on different streets. Although a new communication route can be established when a break in the communication path occurs, repeatedly reestablishing new routes incurs delay and substantial overhead. To address this limitation, we introduce the Virtual Router abstraction in this dissertation. A virtual router is a dynamically-created logical router that is associated with a particular geographical area. Its routing functionality is provided by the physical nodes (i.e., mobile devices) currently within the geographical region served by the virtual router. These physical nodes take turns in forwarding data packets for the virtual router. In this environment, data packets are transmitted from a source node to a destination node over a series of virtual routers. Since virtual routers do not move, this scheme is much less susceptible to node mobility. There can be two virtual router approaches: Static Virtual Router (SVR) and Dynamic Virtual Router (DVR). In SVR, the virtual routers are predetermined and shared by all communication sessions over time. This scheme requires each mobile node to have a map of the virtual routers, and use a global positioning system (GPS) to determine if the node is within the geographical region of a given router. DVR is different from SVR with the following distinctions: (1) virtual routers are dynamically created for each communication sessions as needed, and deprecated after their use; (2) mobile nodes do not need to have a GPS; and (3) mobile nodes do not need to know whereabouts of the virtual routers. In this dissertation, we apply Virtual Router approach to address mobility challenges in routing data. We first propose a data routing protocol that uses SVR to overcome the extreme fast topology change in a street environment. We then propose a routing protocol that does not require node locations by adapting a DVR approach. We also explore how the Virtual Router Approach can reduce the overhead associated with initial route or location requests used by many existing routing protocols to find a destination. An initial request for a destination is expensive because all the nodes need to be reached to locate the destination. We propose two broadcast protocols; one in an open terrain environment and the other in a street environment. Both broadcast protocols apply SVR. We provide simulation results to demonstrate the effectiveness of the proposed protocols in handling high mobility. They show Virtual Router approach can achieve several times better performance than traditional routing and broadcast approach based on physical routers (i.e., relay nodes).ID: 030646255; System requirements: World Wide Web browser and PDF reader.; Mode of access: World Wide Web.; Thesis (Ph.D.)--University of Central Florida, 2011.; Includes bibliographical references (p. 110-122).
Ph.D.
Doctorate
Computer Science
Engineering and Computer Science
Computer Science
35
PITASSI, CLAUDIO. "VIRTUAL STRATEGIC ALLIANCES AND NETWORKS: AN EXPLORATORY RESEARCH." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2004. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=5876@1.
Abstract:
PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIROEsta pesquisa procurou responder ao seguinte problema: Que fatores os executivos devem levar em conta nas suas decisões relativas à avaliação das implicações estratégicas pertinentes à virtualização das alianças e redes de relacionamento estabelecidas entre as empresas e seus parceiros de negócio? Como o fenômeno estava em formação no ambiente empresarial a pesquisa foi necessariamente exploratória. A metodologia aplicada foi pós-positivista, utilizando-se simultaneamente dos métodos hipotético- dedutivo e indutivo. A partir do referencial teórico estudado, desenvolveu-se um arcabouço de trabalho contendo os aspectos relativos à virtualização dos relacionamentos com parceiros de negócio, a saber, os direcionadores e atributos da virtualidade, e a tipologia de redes estratégicas virtuais - REVs. Este arcabouço foi aplicado previamente em dois estudos de caso pilotos nas empresas Neoris e GM-Fiat WWP e, após os ajustes nos instrumentos de coleta, em três outros estudos de caso: Construtora Norberto Odebrecht, Telemar e AmBev. Nas etapas subseqüentes da pesquisa, múltiplos métodos foram adotados para a captura de dados: investigação documental e telematizada, levantamento das percepções (survey) com os diretores das diferentes empresas. Os resultados obtidos por meio dos estudos de caso evidenciaram que, de fato, o arcabouço teórico proposto na pesquisa tinha o potencial de contribuir ao fornecimento de subsídios para a tomada de decisão estratégica de empresas que integram redes de relacionamentos, ao ajudá-las, não só a identificar, mas principalmente a influenciar as condições que permitam estabelecer uma participação mais efetiva nos diferentes tipos de REVs possíveis.
The research portrayed in this Doctoral Dissertation was designed to search an answer for the following problem: What factors and dimensions should the executives take into consideration on their decisions regarding the strategic implications related to the virtualization of strategic alliances and networks? Since the study`s object of analysis was a new phenomenon in the business environment that does not yet have an accepted theoretical tradition in the academic world, the research was, necessarily, an exploratory one. The methodology applied was post-positivist, using simultaneously the hypotheticdeductive and inductive methods. Based on the literature investigated, a working framework was developed containing the aspects regarding the virtualization of the relationships with business partners: the virtualization drivers and attributes, and a typology of virtual strategic networks (VSNs). This framework was previously tested in two pilot cases studies: Neoris and GM- Fiat WWP. After the necessary adjustments on the data collections instruments, the framework was applied on the other three research case studies: Construtora Norberto Odebrecht, Telemar e AmBev. On the subsequent research steps, multiple methods were adopted for the data collection. The results obtained by way of the case studies showed that, indeed, the working framework had the potential to contribute with subsidies for the strategic decisions involved, not only in the identification, but mainly in the creation of conditions that influence a more effective participation of firms on the different types of VSNs.
36
Hurley-Smith, Darren. "Virtual closed networks : optimised security for autonomous MANETs." Thesis, University of Greenwich, 2015. http://gala.gre.ac.uk/20953/.
Abstract:
Autonomous mobile platforms (such as Unmanned Aerial Vehicles, also known as UAVs) have become a popular tool in exploration, disaster management, civil-engineering, agricultural and military scenarios. Their endurance, low-cost, high mobility and ability to reduce human involvement in prolonged or hazardous activities have proven attractive to both commercial and military sectors. In such domains, security is required to protect the data, functionality and performance of the network, making it a vital consideration when developing such systems. Systems capable of independent action, following a human-defined mission without scripting or other forms of direction in the field, are adaptable and effective as a means of achieving individually simple tasks that due to their number and distribution represent complex objectives as a collective. However, such systems must communicate to achieve autonomous function. Efficient distribution of tasks requires significant communication between all members of the network to determine the nodes most fit to undertake a given task. Mobile ad hoc networks (MANETs) provide the foundation for such communication, providing a means by which nodes may communicate with other members of the network, even if they are not in range. Issues arise when considering the security of MANET communication, due to the ease observation, interception and manipulation of data broadcast over such networks. It is trivial for attackers to perform such actions, due to the open nature of the communication medium. This dissertation presents a novel security framework, which specifically targets autonomous MANET communication. Addressing the open-medium problem by providing a Virtual Closed Network (VCN) environment, Security Using Pre-Existing Routing for MANETs (SUPERMAN) also secures routing and control data, providing confidentiality, integrity and authentication services as a complete solution the network layer and above. Improvements to the efficiency of communication required by distributed task allocation are proposed (Cluster Form CBBA and Broadcast Enabled Cluster Form CBBA) based on this work, in the interests of optimising the use of network resources to facilitate the addition of robust security measures suitable for resource constrained MANETs.
37
Pandey, Shakti Raj, and Vijaya Praveen Prakash Tamadapalle. "AN ANALYSIS OF SECURITY PROBLEMS IN VIRTUAL NETWORKS." Thesis, Högskolan i Borås, Institutionen Handels- och IT-högskolan, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:hb:diva-20453.
Abstract:
Virtual networks have changed the face of the information technology in current world. Many organizations today cooperate in virtual networks in order to meet the competition and the increased demands on technological development. Our focus in this thesis is on the information interchange in inter-organizational virtual networks. In this case the problem is related to the efficiency of the virtual networks for information interchange. This paper aim is to identify and discuss the possible aspects in the virtual networks efficient information interchange. This paper provides the detail information about the security aspects and its improvement and use of the efficient information interchange in inter organizational virtual network. This paper also provides the information that is helpful for improving the security in the virtual network so that the work in virtual network or the work via virtual network is efficient.Program: Magisterutbildning i informatik
38
Cohen, Alain Jerome. "Simulating virtual circuits in mobile packet radio networks." Thesis, Massachusetts Institute of Technology, 1986. http://hdl.handle.net/1721.1/14904.
Abstract:
Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 1986.MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING
Bibliography: leaf 39.
by Alain Jerome Cohen.
B.S.
39
Flodin, Carl, and Pontus Lantz. "Studenters användning och syn på Virtual Private Networks." Thesis, Uppsala universitet, Institutionen för informatik och media, 2020. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-414714.
40
Ben, Houidi Zied. "Scalable routing in provider provisoned virtual private networks." Paris 6, 2010. http://www.theses.fr/2010PA066611.
Abstract:
Les entreprises ont souvent des sites dispersés dans des endroits éloignés et qui ont besoin de communiquer. Au lieu de construire leur propre infrastructure de communication, la plupart des entreprises aujourd'hui, préfèrent acheter un service de réseau privé virtuel (VPN) à un fournisseur de services. Le fournisseur de service VPN est responsable de réaliser le routage afin d'interconnecter les différents sites des entreprises. Dans cette thèse, on fait d'abord un effort pour unifier la vision du routage dans les réseaux privés virtuels fournis par un opérateur. En particulier, on s'intéresse de plus près à la technologie la plus répandue, BGP MPLS IP VPNs, pour réaliser ce besoin. On étudie les limites de cette technologie en se basant sur des données de routage récoltées sur le réseau d'un grand opérateur VPN. Ensuite, grâce à une étude expérimentale sur des routeurs de différents constructeurs, on explique et on aide à dépasser une de ces limites, à savoir la lenteur des transferts de table de routage BGP. Enfin, nous démontrons que le standard actuel n'est pas bien adapté pour servir les besoins du routage VPN tel qu'on l'a définit dans cette thèse et on propose un nouveau protocole pour le remplacer.
41
Kinniburgh, James B. "Who networks? The social psychology of virtual communities." Thesis, Monterey, Calif. : Springfield, Va. : Naval Postgraduate School ; Available from National Technical Information Service, 2004. http://library.nps.navy.mil/uhtbin/hyperion/04Jun%5FKinniburgh.pdf.
42
Celestino, Pedro. "Private virtual network." Universidade de Taubaté, 2005. http://www.bdtd.unitau.br/tedesimplificado/tde_busca/arquivo.php?codArquivo=264.
Abstract:
Along with the computers networks emerges the possibility of managing remotely the intelligent organizations although the safe change of information has become a problem to the institutions which transport structured data through nets of computers. One of the largest challenges is the search for safe and economically viable solutions. Protocols of safety, cryptographic algorithms, safe means of communication are essential items so that the information can travel in environmentals free of external interferences. One of the alternatives is the Virtual Private Networks. In this work, the main prominences of this technology will be presented using the protocol IPSec with the purpose of presenting a more atractive tool to the organizations due to its safety and
economical viability.Com as redes de computadores, surge também a possibilidade de administrar remotamente as organizações inteligentes, no entanto a troca de informações segura tornou-se um problema para as instituições que trafegam dados estruturados através das redes de computadores. Um dos maiores desafios é a busca de soluções economicamente viáveis e ao mesmo tempo seguras. Protocolos de segurança, algoritmos criptográficos meios de comunicação seguros, são itens essenciais para que a informação possa trafegar em ambientes livres de interferências externas. Uma das soluções é a Rede Virtual Privada. Neste trabalho, serão apresentados os principais destaques desta tecnologia, utilizando o protocolo IPSec, com o propósito de apresentar mais uma solução atrativa para as organizações, pois trata-se de uma solução economicamente viável e segura.
43
Chagdali, Abdellatif. "Multi-connectivity and resource allocation for slices in 5G networks." Electronic Thesis or Diss., université Paris-Saclay, 2022. http://www.theses.fr/2022UPAST052.
Abstract:
Les futurs réseaux mobiles promettent des opportunités sans précédent pour l'innovation et des cas d'utilisation disruptifs. L'engagement des réseaux 5G et au-delà à fournir des applications critiques nécessite un réseau polyvalent, évolutif, efficace et rentable, capable d'adapter son allocation de ressources pour répondre aux exigences de services hétérogènes. Pour relever ces défis, le découpage du réseau s'est imposé comme l'un des concepts fondamentaux proposés pour améliorer l'efficacité des réseaux mobiles 5G et leur conférer la plasticité requise. L'idée est de fournir des ressources à différentes industries verticales en construisant plusieurs réseaux logiques de bout en bout sur une infrastructure virtualisée partagée. Chaque "tranche de réseau" ainsi définie est personnalisée pour fournir un service spécifique en adaptant son architecture et ses technologies d'accès radio.Précisément, des applications telles que l'automatisation industrielle ou les communications entre véhicules imposent aux réseaux cellulaires des exigences strictes en matière de latence et de fiabilité. Étant donné que le réseau mobile actuel ne peut pas répondre à ces exigences, les communications ultra-fiables et à faible temps de latence constituent un sujet de recherche essentiel qui a suscité un élan considérable de la part du monde universitaire et des alliances industrielles. Pour répondre à ces exigences, l'utilisation de la multi-connectivité, c'est-à-dire l'exploitation simultanée de plusieurs liaisons radio comme voies de communication, est une approche prometteuse.L'objectif du présent manuscrit est d'étudier des techniques d'allocation de resources exploitant la couverture redondante des utilisateurs, garantie dans de nombreux scénarios 5G. Nous examinons d'abord l'évolution des réseaux mobiles et discutons des diverses considérations relatives à l'architecture de découpage du réseau et de son impact sur la conception des méthodes d'allocation des ressources. Nous utilisons ensuite les outils de la théorie des files d'attente pour modéliser un système dans lequel un ensemble d'utilisateurs URLLC sont connectés simultanément à deux stations de base ayant la même bande passante ; nous appelons ce scénario le cas homogène. Nous introduisons des politiques d'allocation appropriées et évaluons leurs performances respectives en évaluant leur fiabilité. Ensuite, nous étendons les résultats du cas homogène à un cadre plus général où les interfaces physiques gèrent des bandes passantes différentes, que nous appelons le cas hétérogène. Enfin, nous fusionnons les éléments ci-dessus pour valider le choix des schémas d'allocation des ressources en tenant compte de l'architecture déployéeFuture mobile networks envision unprecedented innovation opportunities and disruptive use cases. As a matter of fact, the 5G and beyond networks' pledge to deliver mission-critical applications mandates a versatile, scalable, efficient, and cost-effective network capable of accommodating its resource allocation to meet the services' heterogeneous requirements. To face these challenges, network slicing has emerged as one of the fundamental concepts proposed to raise the 5G mobile networks' efficiency and provide the required plasticity. The idea is to provide resources for different vertical industries by building multiple end-to-end logical networks over a shared virtualized infrastructure. Each network slice is customized to deliver a specific service and adapts its architecture and radio access technologies.Precisely, applications such as industrial automation or vehicular communications pose stringent latency and reliability requirements on cellular networks. Given that the current mobile network cannot meet these requirements, ultra-reliable low-latency communications (URLLC) embodies a vital research topic that has gathered substantial momentum from academia and industrial alliances. To reach URLLC requirements, employing multi-connectivity (MC), i.e., exploiting multiple radio links as communication paths at once, is a promising approach.Therefore, the objective of the present manuscript is to investigate dynamic scheduling techniques, exploiting redundant coverage of users, guaranteed in numerous 5G radio access network scenarios. We first review the evolution of mobile networks and discuss various considerations for network slicing architecture and its impact on resource allocation design. Then, we use tools from queuing theory to model a system in which a set of URLLC users are connected simultaneously to two base stations having the same bandwidth; we refer to this scenario as the homogenous case. We introduce suitable scheduling policies and evaluate their respective performances by assessing their reliability. Next, we extend the homogenous case's results to a more general setting where the physical interfaces manage different bandwidths, referred to as the heterogeneous case. Finally, we merge the above elements to validate the choice of resource allocation schemes considering the deployed architecture
44
Al-Amoudi, Ahmed. "Evaluation of virtual routing appliances as routers in a virtual environment /." Online version of thesis, 2008. http://hdl.handle.net/1850/7544.
45
Rodriguez, Brljevich Esteban 1984. "Energy-aware virtual network mapping." [s.n.], 2013. http://repositorio.unicamp.br/jspui/handle/REPOSIP/275512.
Abstract:
Orientador: Nelson Luis Saldanha da FonsecaDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Computação
Made available in DSpace on 2018-08-25T09:43:36Z (GMT). No. of bitstreams: 1 RodriguezBrljevich_Esteban_M.pdf: 2281259 bytes, checksum: 12557ac80a34c2bff2547f1f2aff1eaa (MD5) Previous issue date: 2013
Resumo: A virtualização de redes é uma tecnologia promissora para a Internet do futuro, já que facilita a implementação de novos protocolos e aplicações sem a necessidade de alterar o núcleo da rede. Um passo chave para instanciar redes virtuais é a alocação de recursos físicos para elementos virtuais (roteadores e enlaces). A fim de contribuir para o esforço global de poupança de energia, a escolha de recursos físicos para instanciar uma rede virtual deveria minimizar o consumo de energia rede. No entanto, esta não é uma tarefa trivial, já que requerimentos de QoS devem ser atingidos. A busca da solução ótima deste problema é NP-difícil. O mapeamento de redes virtuais em substratos de rede físicos em cenários de alocaç?o e desalocaç?o de redes virtuais pode não levar a um consumo mínimo de energia devido à dinâmica das atribuições dos elementos virtuais previamente alocados. Tal dinâmica pode levar à subutilização da rede substrato. Para reduzir os efeitos negativos desta dinâmica, técnicas tais como a migração de redes virtuais em tempo real podem ser empregadas para rearranjar as redes virtuais previamente mapeadas para poupar energia. Esta dissertação apresenta um conjunto de novos algoritmos para o mapeamento de redes virtuais em substratos de rede com o objetivo de reduzir o consumo de energia. Além disso, dois novos algoritmos são propostos para a migração dos roteadores e enlaces virtuais para reduzir o número de roteadores e amplificadores ópticos requeridos. Os resultados obtidos por simulação mostram a eficácia dos algoritmos propostos
Abstract: Network virtualization is a promising technology for the Internet of the Future since it facilitates the deployment of new protocols and applications without the need of changing the core of the network. A key step to instantiate virtual networks is the allocation of physical resources to virtual elements (routers and links). In order to contribute to the global effort of saving energy, choice of physical resources to instantiate a virtual network needs to minimize the network energy consumption. However, this is not a trivial task, since the QoS of the application requirements has to be supported. Indeed, the search for the optimal solution of this problem is NP-hard. The mapping of virtual networks on network substrates at the arrival time of requests to the establishment of virtual networks may not lead to a global minimum energy consumption of energy due to the dynamic allocations and deallocations of virtual networks. Actually, such dynamics can lead to the underutilization of the network substrate. To mitigate the negative effect of this dynamics, techniques such as live migration can be employed to rearrange already mapped virtual networks to achieve energy savings. This dissertation presents a set of new algorithms for the mapping of virtual networks on network substrates aiming to reduce energy consumption. Additionally, two new algorithms are proposed for the migration of virtual routers and links to reduce the number of powered routers and optical amplifiers. Results derived by simulation show the efficacy of the proposed algorithms
Mestrado
Ciência da Computação
Mestre em Ciência da Computação
46
Jia, Yuxiao. "Dynamic quality of service support in virtual private networks." Thesis, University of Ottawa (Canada), 2004. http://hdl.handle.net/10393/26667.
Abstract:
This thesis presents a framework for the provision of dynamic Quality of Service (QoS) support in Virtual Private Networks (VPNs). Specifically, we focus on MPLS based VPN, with the QoS components including use of MPLS Diffserv, MPLS Traffic Engineering, RSVP-TE signaling protocol etc. The framework consists of a Dynamic Bandwidth Allocation model that includes traffic estimators and the development of a resource reservation technique.
The Dynamic Bandwidth Allocation (DBA) uses traffic estimators whose outputs are used for the reservation of resource within some time duration in the future. Three traffic estimation algorithms are implemented and tested. The Dynamic Classed Based Queuing (CBQ) technique is applied in our systems to allocate resources. This model can automatically adjust to the bandwidth size of a VPN tunnel based on how much traffic is flowing through the tunnel. An Internet Service Provider (ISP) can simplify the task of managing its network and reduce costs by using our DBA mechanism, taking advantage of the available tunnel bandwidth while still providing guarantees for high-priority traffic.
We implemented and evaluated this model on our MPLS Diffserv enabled Linux test-bed. Performance evaluation shows a higher resource utilization can be achieved by using our model.
47
Dutta, Rudra. "VIRTUAL TOPOLOGY DESIGN FOR TRAFFIC GROOMING IN WDM NETWORKS." NCSU, 2001. http://www.lib.ncsu.edu/theses/available/etd-20010801-114312.
Abstract:
Wavelength division multiplexing (WDM) in optical fiber networks iswidely viewed as the technology with the potential to satisfy theever-increasing bandwidth needs of network users effectively and on asustained basis.In WDM networks, nodes are equipped with optical cross-connects(OXCs), devices which can optically switch a signal on any givenwavelength from any input port to any output port.This makes it possible to establish lightpaths between any pair of network nodes.A lightpath is a clear channel in which the signal remainsin optical form throughout the physical path between the two endnodes.The set of lightpaths established over the fiberlinks defines a .Consequently, the problem arises of designing virtual topologies tooptimize a performance measure of interest for a set of trafficdemands.
With the deployment of commercial WDM systems, it has become apparentthat the cost of network components, especially line terminatingequipment (LTE) is the dominant cost in building optical networks, andis a more meaningful metric to optimize than, say, the number ofwavelengths.Furthermore, since the data rates at which each individual wavelengthoperates continue to increase (to OC-192 and beyond), it becomes clearthat a number of independent traffic components must be multiplexed inorder to efficiently utilize the wavelength capacity.These observations give rise to the concept of ,which refers to the techniques used to combine lower speed componentsonto available wavelengths in order to meet network design goals suchas cost minimization. Traffic grooming is a hard problem in generalwhich remains computationally intractable even for simple networks.
We consider the problem of traffic grooming in ring, star andtree topologies. We provide theoretical results regarding achievabilitybounds for these networks as well as practical frameworks to obtainincreasingly better feasible solutions with the expenditure of morecomputational power.
48
Veitch, Paul A. "Virtual path restoration techniques for asyncronous transfer mode networks." Thesis, University of Strathclyde, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.336417.
49
Haddad, Don Derek. "Resynthesizing reality : driving vivid virtual environments from sensor networks." Thesis, Massachusetts Institute of Technology, 2018. http://hdl.handle.net/1721.1/115728.
Abstract:
Thesis: S.M., Massachusetts Institute of Technology, School of Architecture and Planning, Program in Media Arts and Sciences, 2018.Cataloged from PDF version of thesis.
Includes bibliographical references (pages 89-95).
The rise of ubiquitous sensing enables the harvesting of massive amounts of data from the physical world. This data is often used to drive the behavior of devices, but when presented to users, it is most commonly visualized quantitatively, as graphs and charts. Another approach for the representation of sensor network data presents the data within a rich, virtual environment. This thesis introduces the concept of Resynthesizing Reality through the construction of Doppelmarsh, the virtual counterpart of a real marsh located in Plymouth Massachusetts, where the Responsive Environments Group has deployed and maintained a network of environmental sensors. By freely exploring such environments, users gain a vivid, multi-modal, and experiential perspective into large, multi-dimensional datasets. We present a variety of approaches to manifesting data in "avatar landscape", including landscapes generated off live video, tinting frames in correspondence with temperature, or representing sensor history in the appearance and behavior of animals. The concept of virtual lenses is also introduced, which makes it easy to dynamically switch sensor-to-reality mapping from within virtual environments. In this thesis, we describe the implementation and design of Doppelmarsh, present techniques to visualize sensor data within virtual environments, and discuss potential applications for Resynthesizing Reality.
by Don Derek Haddad.
S.M.
50
Sherry, Zaida. "Governance of virtual private networks using COBIT as framework." Thesis, Stellenbosch : University of Stellenbosch, 2007. http://hdl.handle.net/10019.1/3389.
Abstract:
Thesis (MAcc (Accountancy))--University of Stellenbosch, 2007.The purpose of this assignment is to ascertain whether the COBIT framework is an adequate framework to assist in the governance of virtual private networks. The assignment focuses on whether the framework can ensure the identification of virtual private network-related risks and address IT compliance with policies and statutory regulations. A brief summary of the risks and issues pertaining to the pre-implementation, implementation and post-implementation phases of virtual private networks is included in the assignment. These risks and issues are then individually mapped onto a relevant COBIT control objective. The scope of the assignment does not include the intricacies of how these networks operate, the different types of network topologies or the different technologies used in virtual private networks. It was found that the COBIT framework can be implemented to manage and/or mitigate virtual private network risks.