En routage next-hop, paradigme de routage utilisé dans l'Internet Global, chaque routeur choisit le next-hop de chaque paquet en fonction de son adresse destination. Le routage sensible à la source est une extension compatible du routage next-hop où le choix du next-hop dépend de l'adresse source du paquet en plus de son adresse destination. Nous montrons dans cette thèse que le routage sensible à la source est adapté au routage des réseaux multihomés avec plusieurs adresses, qu'il est possible d'étendre de manière compatible les protocoles de routage à vecteur de distance existants et que ce paradigme de routage offre avantageusement plus de flexibilité aux hôtes. Nous montrons d'abord que certains systèmes n'ordonnent pas correctement les entrées sensibles à la source dans leurs tables de routage et nous définissons un algorithme adapté aux protocoles de routage pour y remédier. Nous montrons comment étendre les protocoles à vecteur de distances au routage sensible à la source de manière compatible. Nous validons notre approche en concevant une extension d'un protocole existant (Babel), en réalisant la première implémentation complète d'un protocole sensible à la source et en utilisant ce protocole pour router un réseau multihomé. Enfin, nous montrons que le routage sensible à la source offre des possibilités de multichemin aux couches supérieures des hôtes. Nous vérifions qu'il s'intègre aux technologies existantes (MPTCP) et nous concevons des techniques d'optimisation pour les applications légères. Nous évaluons ces techniques après les avoir implémentées dans le cadre d'une application existante (mosh). / With next-hop routing, the routing paradigm used on the Global Internet, each router chooses the next-hop of each packet depending on its destination address. Source-specific routing is a compatible extension of next-hop routing in which the choice of the next-hop depends on the source address of the packet in addition to its destination address. In this thesis, we show that source-specific routing is well adapted to multihomed networks with multiple addresses, that extending a distance vector routing protocol and ensuring compatibility with the base protocol is possible and that source-specific routing gives more flexibility and thus new possibilities to hosts. First, we show that on some systems, source-specific routing tables are not correctly interpreted and we define an algorithm designed for a routing protocol to fix it. We show how to extend distance vector routing protocols to source specific routing while ensuring compatibility. We validate our approach with the conception of an extension to an existing protocol (Babel), with the realization of the first complete implementation of a source-specific routing protocol and with the use of this protocol to route a multihomed network. Lastly, we show that source-specific routing gives multipath possibilities to host's highest layers. We check that it works well with existing technology (MPTCP) and we design optimization techniques for lightweight applications. We evaluate these techniques after their implementation in an existing application (mosh).

To provide mobile hosts with seamless and broadband wireless Internet access, two fundamental problems that need to be tackled in wireless networking are transparently supporting host mobility and effectively utilizing wireless bandwidth. The increasing heterogeneity of wireless networks and the proliferation of wireless devices, however, severely expose the limitations of the paradigms adopted by existing solutions. In this work, we explore new research directions for addressing network heterogeneity and bandwidth scarcity in future wireless data networks. In addressing network heterogeneity, we motivate a transport layer solution for transparent mobility support across heterogeneous wireless networks. We establish parallelism and transpositionality as two fundamental principles to be incorporated in designing such a transport layer solution. In addressing bandwidth scarcity, we motivate a cooperative wireless network model for scalable bandwidth utilization with wireless user population. We establish base station assistance and multi-homed peer relay as two fundamental principles to be incorporated in designing such a cooperative wireless network model. We present instantiations based on the established principles respectively, and demonstrate their performance and functionality gains through theoretic analysis, packet simulation, and testbed emulation.

Overlay networks have been the subject of significant research and practical interest recently in addressing the inefficiency and ossification of the current Internet. In this thesis, we cover various aspects of overlay network design, including overlay routing algorithms, overlay network assignment and multihomed overlay networks. We also examine the behavior of overlay networks under a wide range of network settings and identify several key factors that affect the performance of overlay networks. Based on these findings, practical design guidelines are also given. Specifically, this thesis addresses the following problems: 1) Dynamic overlay routing: We perform an extensive simulation study to investigate the performance of available bandwidth-based dynamic overlay routing from three important aspects: efficiency, stability, and safety margin. Based on the findings, we propose a hybrid routing scheme that achieves good performance in all three aspects. We also examine the effects of several factors on overlay routing performance, including network load, traffic variability, link-state staleness, number of overlay hops, measurement errors, and native sharing effects. 2) Virtual network assignment: We investigate the virtual network (VN) assignment problem in the scenario of network virtualization. Specifically, we develop a basic VN assignment scheme without reconfiguration and use it as the building block for all other advanced algorithms. Subdividing heuristics and adaptive optimization strategies are presented to further improve the performance. We also develop a selective VN reconfiguration scheme that prioritizes the reconfiguration for the most critical VNs. 3) Overlay network configuration tool for PlanetLab: We develop NetFinder, an automatic overlay network configuration tool to efficiently allocate PlanetLab resources to individual overlays. NetFinder continuously monitors the resource utilization of PlanetLab and accepts a user-defined overlay topology as input and selects the set of PlanetLab nodes and their interconnection for the user overlay. 4) Multihomed overlay network: We examine the effectiveness of combining multihoming and overlay routing from the perspective of an overlay service provider (OSP). We focus on the corresponding design problem and examine, with realistic network performance and pricing data, whether the OSP can provide a network service that is profitable, better (in terms of round-trip time), and less expensive than the competing native ISPs.