Qualité de service et calcul de chemins dans les réseaux inter-domaine et multicouches

Quality of Service (QoS) is a guarantee of network parameters (high bandwidth, short delay, etc.). In an inter-domaine network, it can be provided by contracts between domains, called Service Level Agreements (SLAs). In this thesis, we first focus on the SLA negotiation step, i.e., the selection of SLAs proposed by a domain. We provide exact and approximate methods that allow the domains to propose the SLAs that maximize their revenues. We also study the impact of the domain reputation on the negotiation process. Regarding the SLA instantiation step, we focus on path computation processes that take into account the encapsulation of protocols (in order to overcome the domain technological heterogeneity). Using tools from Language Theory, we provide the first polynomial solution to the path computation problem in this context.La Qualité de Service (Quality of Service - QoS) est une garantie de paramètres réseau (bande passante élevée, délai court, etc.). Dans un réseaux inter-domaine, elle peut être assurée par des contrats entre domaines appelés Service Level Agreements (SLA). Dans cette thèse, nous nous intéressons d’abord à l’étape de négociation de SLA : la sélection des SLA proposés par un domaine. Nous proposons des méthodes exactes et approchées permettant aux domaines de proposer les SLA qui maximisent leurs revenus. Nous étudions également l'impact de la réputation des domaines sur cette négociation. Au niveau de l’instanciation des SLA, nous nous intéressons au calcul de chemins qui prennent en compte les encapsulations de protocoles (afin de pallier l’hétérogénéité technologique des domaines). En utilisant des outils de théorie des langages, nous proposons la première solution polynomiale au calcul de chemins dans un tel context

Path computation in multi-layer networks: Complexity and algorithms

Carrier-grade networks comprise several layers where different protocols coexist. Nowadays, most of these networks have different control planes to manage routing on different layers, leading to a suboptimal use of the network resources and additional operational costs. However, some routers are able to encapsulate, decapsulate and convert protocols and act as a liaison between these layers. A unified control plane would be useful to optimize the use of the network resources and automate the routing configurations. Software-Defined Networking (SDN) based architectures, such as OpenFlow, offer a chance to design such a control plane. One of the most important problems to deal with in this design is the path computation process. Classical path computation algorithms cannot resolve the problem as they do not take into account encapsulations and conversions of protocols. In this paper, we propose algorithms to solve this problem and study several cases: Path computation without bandwidth constraint, under bandwidth constraint and under other Quality of Service constraints. We study the complexity and the scalability of our algorithms and evaluate their performances on real topologies. The results show that they outperform the previous ones proposed in the literature.Comment: IEEE INFOCOM 2016, Apr 2016, San Francisco, United States. To be published in IEEE INFOCOM 2016, \<http://infocom2016.ieee-infocom.org/\&g

You, the Web and Your Device: Longitudinal Characterization of Browsing Habits

Understanding how people interact with the web is key for a variety of applications, e.g., from the design of effective web pages to the definition of successful online marketing campaigns. Browsing behavior has been traditionally represented and studied by means of clickstreams, i.e., graphs whose vertices are web pages, and edges are the paths followed by users. Obtaining large and representative data to extract clickstreams is however challenging. The evolution of the web questions whether browsing behavior is changing and, by consequence, whether properties of clickstreams are changing. This paper presents a longitudinal study of clickstreams in from 2013 to 2016. We evaluate an anonymized dataset of HTTP traces captured in a large ISP, where thousands of households are connected. We first propose a methodology to identify actual URLs requested by users from the massive set of requests automatically fired by browsers when rendering web pages. Then, we characterize web usage patterns and clickstreams, taking into account both the temporal evolution and the impact of the device used to explore the web. Our analyses precisely quantify various aspects of clickstreams and uncover interesting patterns, such as the typical short paths followed by people while navigating the web, the fast increasing trend in browsing from mobile devices and the different roles of search engines and social networks in promoting content. Finally, we contribute a dataset of anonymized clickstreams to the community to foster new studies (anonymized clickstreams are available to the public at http://bigdata.polito.it/clickstream).Comment: 30 page

Quality of service and path computation in inter-domain and multi-layer networks

La Qualité de Service (Quality of Service - QoS) est une garantie de paramètres réseau (bande passante élevée, délai court, etc.). Dans un réseaux inter-domaine, elle peut être assurée par des contrats entre domaines appelés Service Level Agreements (SLA). Dans cette thèse, nous nous intéressons d’abord à l’étape de négociation de SLA : la sélection des SLA proposés par un domaine. Nous proposons des méthodes exactes et approchées permettant aux domaines de proposer les SLA qui maximisent leurs revenus. Nous étudions également l'impact de la réputation des domaines sur cette négociation. Au niveau de l’instanciation des SLA, nous nous intéressons au calcul de chemins qui prennent en compte les encapsulations de protocoles (afin de pallier l’hétérogénéité technologique des domaines). En utilisant des outils de théorie des langages, nous proposons la première solution polynomiale au calcul de chemins dans un tel contexteQuality of Service (QoS) is a guarantee of network parameters (high bandwidth, short delay, etc.). In an inter-domaine network, it can be provided by contracts between domains, called Service Level Agreements (SLAs). In this thesis, we first focus on the SLA negotiation step, i.e., the selection of SLAs proposed by a domain. We provide exact and approximate methods that allow the domains to propose the SLAs that maximize their revenues. We also study the impact of the domain reputation on the negotiation process. Regarding the SLA instantiation step, we focus on path computation processes that take into account the encapsulation of protocols (in order to overcome the domain technological heterogeneity). Using tools from Language Theory, we provide the first polynomial solution to the path computation problem in this context

Path computation in multi-layer multi-domain networks: A language theoretic approach

International audienceMulti-layer networks are networks in which several protocols may coexist at different layers. The Pseudo-Wire architecture provides encapsulation and de-capsulation functions of protocols over Packet-Switched Networks. In a multi-domain context, computing a path to support end-to-end services requires the consideration of encapsulation and decapsulation capabilities. It appears that graph models are not expressive enough to tackle this problem. In this paper, we propose a new model of heterogeneous networks using Automata Theory. A network is modeled as a Push-Down Automaton (PDA) which is able to capture the encapsulation and decapsulation capabilities, the PDA stack corresponding to the stack of encapsulated protocols. We provide polynomial algorithms that compute the shortest path either in hops or in the number of encapsulations and decapsulations along the inter-domain path, the latter reducing manual configurations and possible loops in the path

Algorithmic and complexity aspects of path computation in multi-layer networks

International audienceCarrier-grade networks comprise several layers where different protocols coexist. Nowadays, most of these networks have different control planes to manage routing on different layers, leading to a suboptimal use of the network resources and to additional operational costs. However, some routers are able to encapsulate, decapsulate, and convert protocols, and act as a liaison between these layers. A unified control plane would be useful to optimize the use of the network resources and to automate the routing configurations. Software-Defined Networking based architectures, offer an opportunity to design such a control plane. One of the most important problems to deal with in this design is the path computation process. Classical path computation algorithms cannot resolve the problem as they do not take into account encapsulations and conversions of protocols. In this paper, we propose algorithms to solve this problem, and we study several cases. If there is no bandwidth constraint, we propose a polynomial algorithm that compute the optimal path. We also give lower and upper bounds on the optimal path length. On the other hand, we show that the problem is NP-hard if there is a bandwidth constraint (or other Quality of Service parameters), even if there is only two protocols and in a symmetric graph. We study the complexity and the scalability of our algorithms and evaluate their performances on real and random topologies. The results show that they are faster than the previous ones proposed in the literature. These algorithms can also have important applications in automatic tunneling