In mobile cloud computing (MCC), rich mobile application data is processed at the cloud infrastructure by reliving resource limited mobile devices from computationally complex tasks. However, due to the ubiquitous and mobility nature, providing time critical rich applications over remote cloud infrastructure is a challenging task for mobile application service providers. Therefore, according to the literature, close proximity placement of cloud services has been identified as a way to achieve lower end-to-end access delay and thereby provide a higher quality of experience (QoE) for rich mobile application users. However, providing a higher Quality of Service (QoS) with mobility is still a challenge within close proximity clouds. Access delay to a closely placed cloud tends to be increased over time when users move away from the cloud. However, reactive resource relocation mechanism proposed in literature does not provide a comprehensive mechanism to guarantee the QoS and as well as to minimize service provisioning cost for mobile cloud service providers. As a result, using the benefits of SDN and the data plane programmability with logically centralized controllers, a resource allocation framework was proposed for IaaS mobile clouds with regional datacenters. The user mobility problem was analyzed within SDN-enabled wireless networks and addressed the possible service level agreement violations that could occur with inter-regional mobility. The proposed framework is composed of an optimization algorithm to provide seamless cloud service during user mobility. Further a service provisioning cost minimization criteria was considered during an event of resource allocation and inter-regional user mobility.

L’émergence du Cloud Computing change le paysage des infrastructures qui soutiennent les systèmes informatiques. L’originalité du Cloud Computing réside avant tout dans l’offre d’un nouveau mode de consommation proposé aux clients: les ressources informatiques en tant que service à la demande. Les fournisseurs de "hardware" et de "software" qui ont historiquement fondé leurs revenus sur la vente de produits matériels et de licences logiciels ont fait face à un changement de leurs modèles de revenus, et donc à considérer de nouveau Business Models. Ce travail révèle que les fournisseurs de services d’infrastructure Cloud Computing se définissent comme étant des opérateurs Cloud. Ils ont un rôle d’agrégateur de service et proposent des services d’infrastructures fonctionnelles, disponible à la demande et accessible à distance. Ces fournisseurs construisent un écosystème de partenaires-fournisseurs et un écosystème de partenaires-produits pour accroitre la valeur ajoutée globale. La garantie de niveau de service (SLA) devient l’objet de la transaction entre le fournisseur et le client. Ce dernier se décharge de toutes les problématiques techniques, et les transfère au fournisseur lors de la signature du contrat. Lors de la fixation des prix, une hypothèse de taux d’usage est prise en compte et sera à la base des calculs des coûts. Nous proposons alors trois leviers d’actions aux fournisseurs d’infrastructure Cloud Computing pour accroître leur part de valeur ajoutée : (1) la baisse des coûts par l’innovation technologique, (2) la capacité d’attirer et de garder les clients pour avoir un taux d’usage élevé, et (3) le développement d’un écosystème de services. / The emergence of cloud computing is changing the landscape of the infrastructure supporting IT systems. The originality of cloud computing lies primarily in the offer of a new consumption mode available to consumers: IT resources as a service provided on demand. IT providers that have based their income from products sales (hardware and software licenses) faced a change in their revenue models, and thus have to consider new business models. This research reveals that IaaS provider is defined as cloud operators. They are service aggregator and offer functional infrastructure available on demand available over the network. IaaS providers are building a supplier-partners and product-partners ecosystems to increase the overall value. When consumers sign contract, they declaim all technical issues by transferring them to providers. Service Level Agreement (SLA) becomes the object of transaction between providers and consumers. For the pricing process, rate of use is the basis of cost assessment. We suggest three leverage to IaaS providers in order to increase their share of value added: (1) lower costs through technological innovation, (2) ability to attract and retain customers to have high rate of use, and (3) development of services ecosystem.

Cloud Computing has become a serious participant in ICT in past few years. Technical and economic attributes of Cloud Computing can change a forecast in an organization. These benefits are investigated and putted into large picture of teleworking. In critical moment there is flexibility, which is crucial either for the organization or for the individual. How much is flexibility important is illustrated on the example of organization, that is considering whether the cloud computing and teleworking is the right way for the their future.

Mobile cloud computing, having embraced the ideas like computation ooading, mandates a low latency, high speed network to satisfy the quality of service and usability assurances for mobile applications. Networking performance of clouds based on Xen and Vmware virtualisation solutions has been extensively studied by researchers, although, they have mostly been focused on network throughput and bandwidth metrics. This work focuses on the measurement and analysis of networking performance of VMs in a small, KVM based data centre, emphasising the role of virtualisation overheads in the Host-VM latency and eventually to the overall latency experienced by remote clients. We also present some useful tools such as Driftanalyser, VirtoCalc and Trotter that we developed for carrying out specific measurements and analysis. Our work proves that an increase in a VM's CPU workload has direct implications on the network Round trip times. We also show that Virtualisation Overheads (VO) have significant bearing on the end to end latency and can contribute up to 70% of the round trip time between the Host and VM. Furthermore, we thoroughly study Latency due to Virtualisation Overheads as a networking performance metric and analyse the impact of CPU loads and networking workloads on it. We also analyse the resource sharing patterns and their effects amongst VMs of different sizes on the same Host. Finally, having observed a dependency between network performance of a VM and the Host CPU load, we suggest that in a KVM based cloud installation, workload profiling and optimum processor pinning mechanism can be e ectively utilised to regulate network performance of the VMs. The ndings from this research work are applicable to optimising latency oriented VM provisioning in the cloud data centres, which would benefit most latency sensitive mobile cloud applications. / Mobil cloud computing, har anammat ideerna som beräknings avlastning, att en låg latens, höghastighetsnät för att tillfredsställa tjänsternas kvalitet och användbarhet garantier för mobila applikationer. Nätverks prestanda moln baserade på Xen och VMware virtualiseringslösningar har studerats av forskare, även om de har mestadels fokuserat på nätverksgenomströmning och bandbredd statistik. Arbetet är inriktat på mätning och analys av nätverksprestanda i virtuella maskiner i en liten, KVM baserade datacenter, betonar betydelsen av virtualiserings omkostnader i värd-VM latens och så småningom till den totala fördröjningen upplevs av fjärrklienter. Wealso presentera några användbara verktyg som Driftanalyser, VirtoCalc och Trotter som vi utvecklat för att utföra specifika mätningar och analyser. Vårt arbete visar att en ökning av en VM processor arbetsbelastning har direkta konsekvenser för nätverket Round restider. Vi visar också att Virtualiserings omkostnader (VO) har stor betydelse för början till slut latens och kan bidra med upp till 70 % av rundtrippstid mellan värd och VM. Dessutom är vi noga studera Latency grund Virtualiserings Omkostnader som en nätverksprestanda och undersöka effekterna av CPU-belastning och nätverks arbetsbelastning på den. Vi analyserar också de resursdelningsmönster och deras effekter bland virtuella maskiner i olika storlekar på samma värd. Slutligen, efter att ha observerat ett beroende mellan nätverksprestanda i ett VM och värd CPU belastning, föreslar vi att i en KVM baserad moln installation, arbetsbelastning profilering och optimal processor pinning mekanism kan anvandas effektivt för att reglera VM nätverksprestanda. Resultaten från denna forskning gäller att optimera latens orienterade VM provisione i molnet datacenter, som skulle dra störst latency känsliga mobila molnapplikationer.

The increasing number of reports on data leakage incidents increasingly erodes the already low consumer confidence in cloud services. Hence, some organisations are still hesitant to fully trust the cloud with their confidential data. Therefore, this study raises a critical and challenging research question: How can we restore the damaged consumer confidence and improve the uptake and security of cloud services? This study makes a plausible attempt at unpacking and answering the research question in order to holistically address the data leakage problem from three fronts, i.e. conflict-aware virtual machine (VM) placement, strong authentication and digital forensic readiness. Consequently, this study investigates, designs and develops an innovative conceptual architecture that integrates conflict-aware VM placement, cutting-edge authentication and digital forensic readiness to strengthen cloud security and address the data leakage problem in the hope of eventually restoring consumer confidence in cloud services. The study proposes and presents a conflict-aware VM placement model. This model uses varying degrees of conflict tolerance levels, the construct of sphere of conflict and sphere of non-conflict. These are used to provide the physical separation of VMs belonging to conflicting tenants that share the same cloud infrastructure. The model assists the cloud service provider to make informed VM placement decisions that factor in their tenants’ security profile and balance it against the relevant cost constraints and risk appetite. The study also proposes and presents a strong risk-based multi-factor authentication mechanism that scales up and down, based on threat levels or risks posed on the system. This ensures that users are authenticated using the right combination of access credentials according to the risk they pose. This also ensures end-to-end security of authentication data, both at rest and in transit, using an innovative cryptography system and steganography. Furthermore, the study proposes and presents a three-tier digital forensic process model that proactively collects and preserves digital evidence in anticipation of a legal lawsuit or policy breach investigation. This model aims to reduce the time it takes to conduct an investigation in the cloud. Moreover, the three-tier digital forensic readiness process model collects all user activity in a forensically sound manner and notifies investigators of potential security incidents before they occur. The current study also evaluates the effectiveness and efficiency of the proposed solution in addressing the data leakage problem. The results of the conflict-aware VM placement model are derived from simulated and real cloud environments. In both cases, the results show that the conflict-aware VM placement model is well suited to provide the necessary physical isolation of VM instances that belong to conflicting tenants in order to prevent data leakage threats. However, this comes with a performance cost in the sense that higher conflict tolerance levels on bigger VMs take more time to be placed, compared to smaller VM instances with low conflict tolerance levels. From the risk-based multifactor authentication point of view, the results reflect that the proposed solution is effective and to a certain extent also efficient in preventing unauthorised users, armed with legitimate credentials, from gaining access to systems that they are not authorised to access. The results also demonstrate the uniqueness of the approach in that even minor deviations from the norm are correctly classified as anomalies. Lastly, the results reflect that the proposed 3-tier digital forensic readiness process model is effective in the collection and storage of potential digital evidence. This is done in a forensically sound manner and stands to significantly improve the turnaround time of a digital forensic investigation process. Although the classification of incidents may not be perfect, this can be improved with time and is considered part of the future work suggested by the researcher. / Thesis (PhD)--University of Pretoria, 2020. / Computer Science / PhD / Unrestricted

Le Cloud Computing a évolué au cours de la dernière décennie, passant d’un simple service de stockage à des services plus complexes, en proposant le software comme service (SaaS), les plateformes comme service(PaaS) et très récemment la sécurité comme service (SECaaS).Dans notre travail, nous sommes partis de l'idée simple d'utiliser les ressources offertes par le Cloud avec un faible coût financier pour proposer des nouvelles architectures de service de sécurité. La sécurité des environnements virtuels est un sujet majeur pour le déploiement de l’usage du Cloud. Malheureusement, comme ces environnements sont composés d’un ensemble de technologies déjà existantes, utilisées d'une manière nouvelle, de nombreuses solutions sécuritaires ne sont que des solutions traditionnelles reconditionnées à la problématique Cloud et réseaux virtuels. Le travail effectué dans le cadre de cette thèse vient répondre à la limitation de ressources des équipements physiques de sécurité comme les Firewalls et a pour objectif de proposer de nouveaux services de sécurité composés d’architectures de gestion de la sécurité des réseaux dans le Cloud basé sur le modèle Security as a Service, ainsi que des architectures de management de ces services. Nous avons pris l’initiative de proposer une architecture totalement Cloud-Based. Cette dernière, permet à un Cloud provider de proposer un service de Firewalling à ses clients. Celui-ci leur demande de s’abonner à l’offre en leur garantissant le traitement (analyse) d’une capacité de bande-passante de trafic avec des règles de filtrages fonctionnelles et d’autres proposées par l’abonné. Les résultats obtenus ont démontré les aptitudes de nos architectures à gérer et à faire face à des attaques réseaux de type DDoS et à augmenter la capacité d’analyse en distribuant le trafic sur plusieurs pare-feu virtuels. / Cloud computing has evolved over the last decade from a simple storage service for more complex services, offering the software as a service (SaaS) platforms as a service (PaaS) and most recently the security as a service (SECaaS). In our work, we started with the simple idea to use the resources offered by the Cloud with a low financial cost to propose new architectures of security service. The security of virtual environments is a major issue for the deployment of the use of the Cloud. Unfortunately, these environments are composed of a set of already existing technologies used in a new way, many security solutions are only traditional reconditioned solutions to solve the Cloud and virtual networks security issues. The work done in this thesis is a response to the resource limitations of physical security devices such as firewalls and propose new security architectures consist of management of network security in the cloud-based services following Security as a Service model and propose novel architectures for managing these services. We took the initiative to propose a completely Cloud-Based architecture. The latter allows a cloud provider to provide firewalling service to its customers. It asks them to subscribe to the offer by guaranteeing treatment (analysis) with a capacity of bandwidth traffic with functional filtering rules and other proposed by the subscriber. The results demonstrated the ability of our architecture to manage and cope with network DDoS attacks and to increase analytical capacity by distributing traffic over multiple virtual

Le cloud computing est un modèle informatique donnant accès à un grand nombre de ressources de calcul et de stockage. Trois types de cloud existent, le cloud public, le cloud privé et le cloud hybride. Afin de proposer une solution cloud hybride, nous utilisons le protocole TRILL qui permet d'optimiser l'utilisation des ressources réseau d'une infrastructure. Cependant, TRILL ne permet pas d'interconnecter des data centers sans perdre l'indépendance de leur plan de contrôle. Pour modifier ce comportement, lequel implique la création d'un unique domaine de broadcast s'étendant sur tout le réseau, nous proposons, comme première contribution, une solution (MLTP) qui permet d'interconnecter des réseaux TRILL tout en les maintenant indépendants. Un autre élément manquant de TRILL est l'isolation des flux réseau. Notre seconde contribution consiste donc à trouver et implémenter une solution d'isolation des flux au sein de MLTP. Ce nouveau protocole (MLTP+VNT), permet d'avoir une solution de cloud hybride, mais elle possède deux désavantages. Le premier est la gestion des pannes. Certains éléments de MLTP+VNT, les Border RBridges (BRB), contiennent des informations nécessaires au routage inter-data center et lorsqu'ils tombent en panne, ces informations sont perdues. Pour éviter cela, nous avons, dans notre troisième contribution, modifié MLTP+VNT pour synchroniser les BRBs. Le second est l'obligation de n'utiliser que des réseaux MLTP+VNT pour réaliser un cloud hybride. Pour lever cette restriction, nous avons, dans notre quatrième contribution, conçu une passerelle entre un réseau TRILL, pour le cloud public, et un réseau OpenFlow, pour le cloud privé. / Cloud computing uses infrastructure with a lot of computing and storage resources. There are three types of cloud: Public cloud, Private cloud, and Hybrid cloud. In order to provide a hybrid cloud solution, we used as a base the TRILL protocol which optimizes the use of the data center infrastructure. However, TRILL cannot interconnect data centers as doing so will merge the data centers networks and each data center will lose its independence. Our first contribution is to change this behavior and we develop MLTP which allows to interconnect TRILL or MLTP network without merging them. Another functionality missing from TRILL is network isolation. To fill this lack, in our second proposal we add to MLTP a solution called VNT and we then have a new protocol called MLTP+VNT. In this protocol, each user traffic is isolated from one another. Therefore, MLTP+VNT allows to have a hybrid cloud environment. Nevertheless, it has two shortcomings. The first one is its “single” point of failure. As a matter of fact, MLTP+VNT uses a new type of nodes called Border RBridges which contains inter-data centers routing information. If a Border RBridge fails, then the information it contained is lost. In order to prevent this loss, we implement a method to synchronize the Border RBridges in our third contribution. The second shortcoming is the obligation to use MLTP+VNT in each network to form the hybrid cloud. To lift this limitation, we design and develop, in our fourth contribution, a bridge between a MLTP+VNT network and an OpenFlow network. This way, our solution allows to create a hybrid cloud environment with the MLTP+VNT solution in the public cloud and OpenFlow in the public cloud.

Alors que le surcoût de la virtualisation reste marginal sur des machines peu puissantes, la situation change radicalement quand le nombre de cœur disponible augmente. Il existe aujourd’hui des machines de plusieurs dizaines de cœurs dans les data centers dédiés au cloud computing, un modèle de gestion de ressources qui utilise largement la virtualisation. Ces machines reposent sur une architecture Non Uniform Memory Access (NUMA) pour laquelle le placement des tâches sur les cœurs ainsi que celui des données en mémoire est déterminant pour les performances.Cette thèse montre d’une part comment la virtualisation affecte le comportement des applications en les empêchant notamment d’utiliser un placement efficace de leurs données en mémoire. Cette étude montre que les erreurs de placement ainsi provoquées engendrent une dégradation des performances allant jusqu’à 700%. D’autre part, cette thèse propose une méthode qui permet la virtualisation efficace d’architectures NUMA par la mise en œuvre dans l’hyperviseur Xen de politiques génériques de placement mémoire. Une évaluation sur un ensemble de 29 applications exécutées sur une machine NUMA de 48 cœurs montre que ces politiques multiplient les performances de 9 de ces applications par 2 ou plus et diminuent le surcoût de la virtualisation à moins de 50% pour 23 d’entre elles. / While virtualization only introduces a negligible overhead on machines with few cores, this is not the case when the number of cores increases. We can find such computers with tens of cores in todays data centers dedicated to the cloud computing, a resource management model which relies on virtualization. These large multicore machines have a complex architecture, called Non Uniform Memory Access (NUMA). Achieving high performance on a NUMA architecture requires to wisely place application threads on the appropriate cores and application data in the appropriate memory bank.In this thesis, we show how virtualization techniques modify the applications behavior by preventing them to efficiently place their data in memory. We show that the data misplacement leads to a serious performance degradation, up to 700%.Additionally, we suggest a method which allows the Xen hypervisor to efficiently virtualize NUMA architectures by implementing a set of generic memory placement policies. With an evaluation over a set of 29 applications on a 48-cores machine, we show that the NUMA policies can multiply the performance of 9 applications by more than 2 and decrease the virtualization overhead below 50% for 23 of them.

Jährlich sterben weltweit 1,35 Millionen Menschen durch Verkehrsunfälle. Ob Cloud-Computing zu einer Reduzierung dieser Zahl beitragen wird, wird in der vorliegenden Arbeit untersucht. Zunächst werden Cloud-Anwendungen ermittelt, welche im Straßenverkehr verwendet werden und Einfluss auf die Straßenverkehrssicherheit haben. Anschließend wird deren genauer Einfluss auf die Straßenverkehrssicherheit durch die Betrachtung von Stu-dienergebnissen, Herstellerangaben sowie eigenen Kalkulationen untersucht. Zudem werden die Gefahren von Cyberangriffen und Netzausfällen für die ermittelten Anwendungen analysiert. Es folgt eine kritische Diskussion sowie die Zusammenfassung des Erarbeiteten: Cloud-Computing ermöglicht durch den einfachen, risikoarmen Zugang zu unlimitierten Rechenressourcen die Entwicklung und den Betrieb von Anwendungen, die Einfluss auf die Verkehrssicherheit nehmen. Es ist davon auszugehen, dass die Anwendungen bei einer weiter voranschreitenden Felddurchdringungsrate positiven Einfluss auf die Straßenverkehrssicherheit in Deutschland und anderen Industriestaaten nehmen und damit aktiv zur Reduzierung der Anzahl Verkehrstoter und -verletzter beitragen werden. Cloud-Computing wird somit ein indirekt positiver Einfluss auf die Straßenverkehrssicherheit zugeschrieben. / 1.35 million people die in traffic accidents worldwide every year. Whether cloud computing contributes to a reduction of this number is examined in the present work. First, cloud com-puting applications are identified, which are used in road traffic and have an impact on traffic safety. The exact influence on traffic safety is then examined by considering study results, manufacturer information and through own calculations. In addition, the dangers of cyber-attacks and network failures are examined in the context of the identified applications. This is followed by a critical discussion and a summary of what has been worked out: Cloud computing enables the development and operation of applications that affect traffic safety through simple, low-risk access to unlimited computing resources. It can be assumed that the applica-tions will have a positive influence on traffic safety in Germany and other industrialized countries and will thus actively contribute to reducing the number of deaths and injuries, given that the penetration rate is further increasing. Cloud computing is thus attributed an indirect positive influence on road safety.

Indiana University-Purdue University Indianapolis (IUPUI) / Growth of interest and need for many-core systems have steadily increased over the recent years. Industry trends lead many-core systems to become increasingly larger and more complex. Because of these realities it is important to researchers, academia, and industry that the design of these many-core systems be straightforward and comprehensive. There is a need for a many-core simulator that can be simple to use and learn from for students, dynamic and capable of emulating large systems for researchers, and flexible with fast turnover for industry designers. At the same time, as many-core systems have been becoming popular and complex, and hence their design, the long standing field of Cloud Computing has become more prevalent and feasible to use. Such cloud computing platforms as Windows Azure allow for the easy access and use of resources that in the past were simply not available to ordinary users. Large tasks can be performed in SaaS Cloud Computing models and be accessible from a small, lightweight device using nothing more than a web browser. As a solution to the needs for designing future many-core systems, we present a Many-Core Simulator on Azure Cloud Computing Platform called M3C Simulator. This is targeted at teaching, research, and industry and as such needs to be easy to use, flexible, and powerful. The Could Computing service model meets all these needs. This thesis discusses overall design of the M3C Simulator and how it leverages Cloud Computing resources, the simple-to-use and understand Interface layout, and the software design including program flow and dynamic compilation.