Analysis, Design and Experimental Evaluation of Connectivity Management in Heterogeneous Wireless Environments
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The future of network communications is mobile as user's demand for ubiquitous connectivity increases. Wireless has become the primary access technology, leading to an explosion in traffic demand. This challenges network providers to manage and configure new requirements without incrementing costs in the same amount. In addition to the growth in the use of mobile devices, there is a need to operate simultaneously different access technologies. As well, the great diversity of applications and the capabilities of mobile terminals make possible for us to live in a hyper-connected world and offer new scenarios. This heterogeneity poses great challenges that need to be addressed to offer better performance and seamless experience to the final user. We need to orchestrate solutions to increase flexibility and empower interoperability. Connectivity management is handled from different angles. In the network stack, mobility can be conveniently handled by IP mobility protocols, since IP is the common layer between the different access technologies and the application diversity. From the end-user perspective, the connection manager in mobile devices is in charge of handling connectivity issues, but it is an unstandardized entity so its performance is heavily implementation-dependent. In this thesis, we explore connectivity management and handover by taking into account the previous challenges. We study and evaluate IP mobility protocols and their combination, including an experimental evaluation of handover latency performance, as they are part of our proposed solutions. We consider heterogeneous scenarios, with several access technologies where mobile devices have also several network interfaces. To increase our understanding of the impact of the mobile terminal behavior in the mobility management, we evaluate how connectivity is handled in the three most widely-used mobile operating systems, as well as its influence in a handover. We include an experimental evaluation of performance with 3G and IEEE 802.11 as the main technologies. Third, once the mobility protocols and the end terminal have been evaluated, we propose and confirm the suitability of more efficient mobility management, based on the analysis of real traces from a cellular network operator. Moreover, we propose and evaluate three diverse solutions for providing mobility support in different heterogeneous scenarios: vehicular networks, wireless optical broadband access networks and software-defined networks. We perform an experimental evaluation of a vehicular route optimization for network mobility, reporting on the challenges and lessons learned in the development process from the laboratory controlled environment to the working prototype on the road for such a complicated networking environment. We propose an architecture for supporting mobility and enhance handover in a passive optical network deployment, by leveraging the architecture of a passive optical network, collocated with mobility management entities to support Proxy Mobile IPv6 and IEEE 802.21 mechanisms for a more efficient handover. In addition, we design and deploy a mechanism for mobility management based on software-defined networking, leveraging SDN mechanisms for adding flexibility and including an experimental evaluation in an initial prototype.