Concurrent Multipath Transfer: Scheduling, Modelling, and Congestion Window Management

Known as smartphones, multihomed devices like the iPhone and BlackBerry can simultaneously connect to Wi-Fi and 4G LTE networks. Unfortunately, due to the architectural constraints of standard transport layer protocols like the transmission control protocol (TCP), an Internet application (e.g., a file transfer) can use only one access network at a time. Due to recent developments, however, concurrent multipath transfer (CMT) using the stream control transmission protocol (SCTP) can enable multihomed devices to exploit additional network resources for transport layer communications. In this thesis we explore a variety of techniques aimed at CMT and multihomed devices, such as: packet scheduling, transport layer modelling, and resource management. Some of our accomplishments include, but are not limited to: enhanced performance of CMT under delay-based disparity, a tractable framework for modelling the throughput of CMT, a comparison of modelling techniques for SCTP, a new congestion window update policy for CMT, and efficient use of system resources through optimization. Since the demand for a better communications system is always on the horizon, it is our goal to further the research and inspire others to embrace CMT as a viable network architecture; in hopes that someday CMT will become a standard part of smartphone technology

LTE Optimization and Resource Management in Wireless Heterogeneous Networks

Mobile communication technology is evolving with a great pace. The development of the Long Term Evolution (LTE) mobile system by 3GPP is one of the milestones in this direction. This work highlights a few areas in the LTE radio access network where the proposed innovative mechanisms can substantially improve overall LTE system performance. In order to further extend the capacity of LTE networks, an integration with the non-3GPP networks (e.g., WLAN, WiMAX etc.) is also proposed in this work. Moreover, it is discussed how bandwidth resources should be managed in such heterogeneous networks. The work has purposed a comprehensive system architecture as an overlay of the 3GPP defined SAE architecture, effective resource management mechanisms as well as a Linear Programming based analytical solution for the optimal network resource allocation problem. In addition, alternative computationally efficient heuristic based algorithms have also been designed to achieve near-optimal performance

SIGMA: A mobility architecture for terrestrial and space networks.

Internet Protocol (IP) mobility can be handled at different layers of the protocol stack. Mobile IP has been developed to handle mobility of Internet hosts at the network layer. Mobile IP suffers from a number of drawbacks such as the requirement for infrastructure change, high handover latency, high packet loss rate, and conflict with network security solutions. As an alternative solution, a few transport layer mobility protocols have been proposed in the context of Transmission Control Protocol (TCP), for example, MSOCKS and TCP connection migration. In this dissertation, a S&barbelow; eamless I&barbelow; P-diversity-based G&barbelow; eneralized M&barbelow; obility Architecture (SIGMA) is described. SIGMA works at the transport layer and utilizes IP diversity to achieve seamless handover, and is designed to solve many of the drawbacks of Mobile IP. It can also cooperate with normal IPv4 or IPv6 infrastructure without the support of Mobile IP. The handover performance, signaling cost, and survivability issues of SIGMA are evaluated and compared with those of Mobile IP. A hierarchical location management scheme for SIGMA is developed to reduce the signaling cost of SIGMA, which is also useful to other transport layer mobility solutions. SIGMA is shown to be also applicable to managing satellite handovers in space. Finally, the interoperability between SIGMA and existing Internet security mechanisms is discussed

Descentralização da gestão da mobilidade IP nas redes do futuro

Doutoramento em Engenharia ElectrotécnicaThe massive adoption of sophisticated mobile devices and applications led to the increase of mobile data in the last decade, which it is expected to continue. This increase of mobile data negatively impacts the network planning and dimension, since core networks are heavy centralized. Mobile operators are investigating atten network architectures that distribute the responsibility of providing connectivity and mobility, in order to improve the network scalability and performance. Moreover, service providers are moving the content servers closer to the user, in order to ensure high availability and performance of content delivery. Besides the e orts to overcome the explosion of mobile data, current mobility management models are heavy centralized to ensure reachability and session continuity to the users connected to the network. Nowadays, deployed architectures have a small number of centralized mobility anchors managing the mobile data and the mobility context of millions of users, which introduces issues related to performance and scalability that require costly network mechanisms. The mobility management needs to be rethought out-of-the box to cope with atten network architectures and distributed content servers closer to the user, which is the purpose of the work developed in this Thesis. The Thesis starts with a characterization of mobility management into well-de ned functional blocks, their interaction and potential grouping. The decentralized mobility management is studied through analytical models and simulations, in which di erent mobility approaches distinctly distribute the mobility management functionalities through the network. The outcome of this study showed that decentralized mobility management brings advantages. Hence, it was proposed a novel distributed and dynamic mobility management approach, which is exhaustively evaluated through analytical models, simulations and testbed experiments. The proposed approach is also integrated with seamless horizontal handover mechanisms, as well as evaluated in vehicular environments. The mobility mechanisms are also speci ed for multihomed scenarios, in order to provide data o oading with IP mobility from cellular to other access networks. In the pursuing of the optimized mobile routing path, a novel network-based strategy for localized mobility is addressed, in which a replication binding system is deployed in the mobility anchors distributed through the access routers and gateways. Finally, we go further in the mobility anchoring subject, presenting a context-aware adaptive IP mobility anchoring model that dynamically assigns the mobility anchors that provide the optimized routing path to a session, based on the user and network context. The integration of dynamic and distributed concepts in the mobility management, such as context-aware adaptive mobility anchoring and dynamic mobility support, allow the optimization of network resources and the improvement of user experience. The overall outcome demonstrates that decentralized mobility management is a promising direction, hence, its ideas should be taken into account by mobile operators in the deployment of future networks.Na última década verificou-se uma massificação dos dispositivos móveis e das suas aplicações, o que tem vindo a aumentar o consumo de dados móveis. Este aumento dificulta o planeamento e dimensionamento das redes devido principalmente aos modelos extremamente centralizados adoptados por estas. Os operadores móveis têm vindo a estudar modelos mais até para as redes, os quais distribuem a responsabilidade de fornecer conectividade e mobilidade, no sentido de melhorar a escalabilidade e desempenho da rede. Além disso, de forma a garantir um desempenho elevado na entrega dos conteúdos, os fornecedores de serviço têm vindo a mover os servidores de conteúdos para locais mais próximos do utilizador. Apesar do esforço na procura de soluções para o crescente consumo de dados móveis, os modelos atuais de gestão de mobilidade são demasiado centralizados para conseguir assegurar a continuidade de sessão aos utilizadores conectados à rede. As arquiteturas implementadas têm um número muito reduzido de âncoras móveis centralizadas que gerem todos os dados móveis e a informação de contexto da mobilidade, o que leva a uma diminuição de desempenho e escalabilidade, solucionadas através de mecanismos de rede dispendiosos. A gestão da mobilidade precisa de ser repensada de forma a poder lidar com arquiteturas de rede até com a distribuição dos servidores de conteúdos para nós mais próximos dos utilizadores, que é o objectivo principal da Tese apresentada. Primeiro, é apresentada a caracterização da gestão de mobilidade em blocos funcionais, a interação entre eles e potenciais agrupamentos dos mesmos. A gestão da mobilidade descentralizada é estudada através de modelos analíticos e simulações, em que diferentes abordagens distribuem as funcionalidades da mobilidade pela rede. Como resultado deste estudo verificou-se que a descentralização da mobilidade traz vantagens claras. Com base nestes resultados foi proposta uma nova abordagem de gestão de mobilidade distribuída e dinâmica, que é exaustivamente avaliada através de modelos analíticos, simulações e experiências numa bancada de testes. A abordagem proposta é também integrada com mecanismos de handovers horizontais transparentes, assim como é avaliada em ambientes veiculares. Os mecanismos de mobilidade da abordagem proposta são também especificados para cenários de multihoming, de forma a proporcionar o offloading de dados com suporte de mobilidade das redes celulares para outras redes de acesso. Com o objectivo de optimizar o encaminhamento de dados móveis, foi criada uma nova estratégia para o suporte da mobilidade localizada, em que um sistema de replicação de bindings é integrado nas âncoras de mobilidade distribuídas através dos routers de acesso e dos gateways. Finalmente apresenta-se um modelo de ancoramento adaptativo para a mobilidade com base em contexto, o qual dinamicamente determina as âncoras de mobilidade que oferecem a melhor rota para uma dada sessão, baseado na informação do utilizador e da rede. A integração de conceitos de dinamismo e de distribuição na gestão da mobilidade, como o ancoramento adaptativo e o suporte dinâmico da mobilidade, permitem a optimização dos recursos da rede e uma melhor experiência por parte do utilizador. Os resultados demonstram, de uma forma geral, que a gestão descentralizada da mobilidade é um caminho promissor, logo este deve ser tomado em consideração pelas operadoras móveis aquando do desenvolvimento das redes do futuro

Prise de décision de handover vertical pour la gestion de mobilité dans les réseaux hétérogènes sans fil

L évolution des technologies réseaux sans fil, des terminaux mobiles ainsi que des contenus et des services créent des environnements hétérogènes de plus en plus complexes. Dans ce contexte, un compromis entre la mobilité, la transparence et la performance apparaît. Des utilisateurs mobiles, ayant différents profils et préférences, voudraient être toujours connectés au meilleur réseau à tout moment, sans avoir à se soucier des différentes transitions entre réseaux hétérogènes. Face à cette complexité, il parait nécessaire de proposer de nouvelles approches afin de rendre ces systèmes plus autonomes et de rendre les décisions de handover vertical plus efficaces. Cette thèse se concentre sur la gestion de mobilité verticale, plus précisément sur la prise de décision de handover vertical dans un environnement de réseaux hétérogènes sans fil. Après l identification des différents paramètres de prise de décision et l analyse de l état de l art relié à la gestion de la mobilité verticale, nous avons proposé un système de réputation qui permet de réduire les délais de prise de décision. La réputation d un réseau est introduite comme une nouvelle métrique de prise de décision qui peut être recueillie à partir des expériences précédentes des utilisateurs sur ce réseau. Nous montrons que la réputation est une métrique efficace qui permet l anticipation du handover et accélère la prise de décision. Bien que l objectif principal soit de garantir la meilleure qualité de service et l utilisation optimale des ressources radios, les aspects économiques doivent également être considérés, y compris la minimisation des coûts pour les utilisateurs et la maximisation des revenus pour les fournisseurs de services ou les opérateurs. Nous proposons alors, dans la deuxième partie de la thèse, un mécanisme de prise de décision basé sur la théorie des jeux. Ce dernier permet la maximisation des utilités des réseaux et des utilisateurs. Dans cette solution, chaque réseau disponible joue un jeu de Stackelberg avec un ensemble d utilisateurs, tandis que les utilisateurs jouent un jeu de Nash entre eux pour partager les ressources radios limitées. Un point d équilibre de Nash, qui maximise l utilité de l utilisateur et les revenus des fournisseurs de services, est trouvé et utilisé pour le contrôle d admission et la prise de décision de handover vertical. Dans la troisième partie de cette thèse, nous proposons et discutons deux différentes solutions architecturales sur lesquelles nos mécanismes de prise de décision proposés peuvent être intégrés. La première architecture proposée est basée sur la norme IEEE 802.21 à laquelle nous proposons certaines extensions. La seconde architecture proposée est basée sur un niveau de contrôle composé de deux couches de virtualisation. La virtualisation est assurée via des agents capables de faire un raisonnement et de prendre des décisions pour le compte d entités physiques qu ils représentent au sein du système. Cette architecture permet une plus grande flexibilitéMobility management over heterogeneous wireless networks is becoming a major interest area as new technologies and services continue to proliferate within the wireless networking market. In this context, seamless mobility is considered to be crucial for ubiquitous computing. Service providers aim to increase the revenue and to improve users satisfaction. However there are still many technical and architectural challenges to overcome before achieving the required interoperability and coexistence of heterogeneous wireless access networks. Indeed, the context of wireless networks is offering multiple and heterogeneous technologies (e.g. 2G to 4G, WiFi, Wimax, TETRA,...). On the one hand, this rich environment allows users to take profit from different capacities and coverage characteristics. Indeed, this diversity can provide users with high flexibility and allow them to seamlessly connect at any time and any where to the access technology that best fits their requirements. Additionally, cooperation between these different technologies can provide higher efficiency in the usage of the scarce wireless resources offering more economic systems for network providers. On the other hand, the heterogeneity of technologies and architectures and the multiplication of networks and service providers creates a complex environment where cooperation becomes challenging at different levels including and not limited to mobility management, radio resource provisioning, Quality of Service and security guarantees. This thesis is focusing on mobility management and mainly on decision making for Vertical handover within heterogeneous wireless network environments. After the analysis of the related state of the art, we first propose a reputation based approach that allows fast vertical handover decision making. A decision making scheme is then built on that approach. Network s reputation, is a new metric that can be gathered from previous users experiences in the networks. We show that it is an efficient construct to speed up the vertical handover decision making thanks to anticipation functionalities. While the main objective remains guaranteeing the best Quality of Service and optimal radio resource utilization, economical aspects have also to be considered including cost minimization for users and revenue maximization for network providers. For this aim, we propose, in the second part of the thesis, a game theoretic based scheme that allows maximizing benefits for both networks and users. In this solution, each available network plays a Stackelberg game with a finite set of users, while users are playing a Nash game among themselves to share the limited radio resources. A Nash equilibrium point, that maximizes the user s utility and the service provider revenue, is found and used for admission control and vertical handover decision making. The analyses of the optimal bandwidth/prices and the revenue at the equilibrium point show that there are some possible policies to use according to user s requirements in terms of QoS and to network capacities. For instance, we pointed out that networks having same capacities and different reputation values should charge users with different prices which makes reputation management very important to attract users and maximize networks revenue. In the third part of this thesis, we provide and discuss two different architectural and implementation solutions on which our proposed vertical handover decision mechanisms can be integrated. The first proposed architecture is a centralized one. It is based on the IEEE 802.21 standard to which some extensions are proposed. The second proposed architecture is distributed. It is based on an overlay control level composed of two virtualization layers able to make reasoning on behalf of physical entities within the system. This architecture allows higher flexibility especially for loosely coupled interconnected networksEVRY-INT (912282302) / SudocSudocFranceF

Aggregating the Bandwidth of Multiple Network Interfaces to Increase the Performance of Networked Applications

Devices capable of connecting to two or more different networks simultaneously, known as host multihoming, are becoming increasingly common. For example, most laptops are equipped with a least a Local Area Network (LAN) and a Wireless LAN (WLAN) interface, and smartphones can connect to both WLANs and 3G-networks (High-Speed Downlink Packet Access, HSDPA). Being connected to multiple networks simultaneously allows for desirable features like bandwidth aggregation and redundancy. Enabling and making efficient use of multiple network interfaces or links (network interface and link will be used interchangeably throughout this thesis) requires solving several challenges related to deployment, link heterogeneity and dynamic behavior. Even though multihoming has existed for a long time, for example routers must support connecting to different networks, most existing operating systems, network protocols and applications do not take host multihoming into consideration. The default behavior is still to use a single interface for all traffic. Using a single interface is, for example, often insufficient to meet the requirements of popular, bandwidth intensive services like video streaming. In this thesis, we have focused on bandwidth aggregation on host multihomed devices. Even though bandwidth aggregation has been a research field for several years, the related works have failed to consider the challenges present in real world networks properly, or does not apply to scenarios where a device is connected to different heterogeneous networks. In order to solve the deployment challenges and enable the use of multiple links in away that works in a real-world network environment, we have created a platform-independent framework, called MULTI. MULTI was used as the foundation for designing transparent (to the applications) and application-specific bandwidth aggregation techniques. MULTI works in the presence of Network Address Translation (NAT), automatically detects and configures the device based on changes in link state, and notifies the application(s) of any changes. The application-specific bandwidth aggregation technique presented in this thesis was optimised for and evaluated with quailty-adaptive video streaming. The technique was evaluated with different types of streaming in both a controlled network environment and real-world networks. Adding a second link gave a significant increase in both video and playback quality. However, the technique is not limited to video streaming and can be used to improve the performance of several, common application types. In many cases, it is not possible to extend applications directly with multilink support. Working on the network-layer allows for the creation of bandwidth aggregation techniques that are transparent to applications. Transparent, network-layer bandwidth aggregation techniques must support the behavior of the different transport protocol in order to achieve efficient bandwidth aggregation. The transparent bandwidth aggregation techniques introduced in this thesis are targeted at Universal Datagram Protocol (UDP) and Transmission Control Protocol (TCP), the two most common transport protocols in the Internet today