Abstract

Traffic engineering encompasses a set of techniques that can be used to control the flow of traffic in data networks. We discuss several of those techniques that have been developed during the last few years. Some techniques are focused on pure IP networks while others have been designed with emerging technologies for scalable Quality of Service (QoS) such as Differentiated Services and MPLS in mind. We first discuss traffic engineering techniques inside a single domain. We show that by using a non-linear programming formulation of the traffic engineering problem it is possible to meet the requirements of demanding customer traffic, while optimising the use of network resources, through the means of an automated provisioning system. We also extend the functionality of the traffic engineering system through policies. In the following, we discuss the techniques that can be used to control the flow of packets between domains. First, we briefly describe interdomain routing and the Border Gateway Protocol (BGP). Second, we summarise the characteristics of interdomain traffic based on measurements with two different Internet Service Providers. We show by simulations the limitations of several BGP-based traffic engineering techniques that are currently used on the Internet. Then, we discuss the utilisation of BGP to exchange QoS information between domains by using the QOS_NLRI attribute to allow BGP to select more optimum paths. Finally, we consider the multi-homing problem and analyse the current proposed IPv6 multi-homing solutions are analysed along with their impact on communication quality. Document type: Part of book or chapter of book

Abstract

The P-SHIM6 architecture provides ISP independence to IPv6 sites without compromising scalability. This architecture is based on a middle-box, the P-SHIM6, which manages the SHIM6 protocol exchange on behalf of the nodes of a site, which are configured with provider independent addresses. Incoming and outgoing packets are processed by the P-SHIM6 box, which can assign different locators to a given communication, either when it is started, or dynamically after the communication has been established. As a consequence, changes required for provider portability are minimized, and fine-grained Traffic Engineering can be enforced at the P-SHIM6 box, in addition to the fault tolerance support provided by SHIM6. This project has been supported by the RiNG project IST-2005-035167 and by the IMPROVISA project TSI2005-07384-C03-02. Publicado Document type: Part of book or chapter of book

Abstract

International audience; The experimental evaluation of wireless and mobile networks is a challenge that rarely substitutes simulation in research works. This statement is even more evident in vehicular communications, due to the equipment and effort needed to obtain significant and realistic results. In this paper, key issues in vehicular experimental evaluation are analyzed by an evaluation tool called AnaVANET, especially designed for assessing the performance of vehicular networks. This software processes the output of well-known testing tools such as ping or iperf, together with navigation information, to generate geo-aware performance figures of merit both in numeric and graphical forms. Its main analysis capabilities are used to validate the good performance in terms of delay, packet delivery ratio and throughput of NEMO, when using a road-side segment based on IPv6 GeoNetworking. Document type: Part of book or chapter of book

Abstract

Internet connectivity takes a strategic importance for a growing number of companies. Therefore, for reliability and performance reasons, many Internet service providers and corporate networks connect to at least two providers, a practice called multihoming. However, the current multihoming mechanism contributes to the explosive growth of the Internet routing tables. This growth has major implications for routers on storage requirements, protocol overhead and stability, and forwarding performance. As a consequence, the traditional way to be multihomed in IPv4 is prevented in the next generation IPv6 Internet. Many approaches for IPv6 multihoming were proposed, with little consideration for traffic engineering aspects. The aim of the thesis is to bridge this gap. The thesis investigates the way to best provide traffic engineering for IPv6 multihomed sites. It first demonstrates that Host-Centric multihoming, the foreseen approach for IPv6 multihoming, is the most promising in terms of fault-tolerance and traffic engineering capabilities. Compared to traditional multihoming approaches, our simulation results show that Host-Centric IPv6 multihomed sites are able to obtain lower delays by leveraging the path diversity that underlies the Internet. Unfortunately, no traffic engineering mechanism is available for this multihoming approach. Therefore, this thesis next presents a technique to effectively use the multiple interdomain paths that exist between multihomed sites. The proposed mechanism allows the multihomed sites to control how their flows are distributed over the links with their providers. The mechanism is able to take into account complex and very dynamic routing policies. Finally, the thesis proposes the use of synthetic coordinates as a scalable and efficient way to help hosts in selecting the interdomain paths with the lowest delays. Experimental results with real measurements show that this mechanism allows sites to avoid all paths with really bad delays, and to most often select the lowest delay path. (FSA 3)--UCL, 2005

Abstract

The Internet is a wide network of computers in constant evolution. Each year, more and more organizations are connected to this worldwide network. Each of them has its own structure and administration that are not publicly revealed for economical, political, and security reasons. Consequently, our perception of the Internet structure, and more specifically, its topology, is incomplete. In order to balance this lack of knowledge, the research community relies on network measurements. Most of the time, they are performed based on the well-known tool traceroute. However, in practice, an operator may privilege other technologies than IP to forward packets inside its network. MultiProtocol Label Switching (MPLS) is one them. Even if it is heavily deployed by operators, it has not been really investigated by researchers. Prior to this thesis, only two studies focused on the identification of MPLS tunnels in traceroute data. Moreover, while one of them does not take all possible scenarios into account, the other lack of precision in some of its models. In addition, MPLS tunnels may hide their content to traceroute. Topologies inferred from such data may thus contain false links or nodes with an artificially high degree, leading so to biases in standard graph metrics used to model the network. Even if some researchers already tried to tackle this issue, the revelation of hidden MPLS devices in traceroute data is still an open question. This thesis aims at characterizing MPLS in two different ways. On the one hand, at an architectural level, we will analyze in detail its deployment and use in both IPv4 and IPv6 networks in order to improve its state-of-the-art view. We will show that, in practice, more than one IPv4 trace out of two crosses at least one MPLS tunnel. We will also see that, even if this protocol can simplify the internal architecture of transit networks, it also allows some operators to perform traffic engineering in their domain. On the other hand, MPLS will be studied from a measurement point of view. We will see that routers from different manufacturers may have distinct default behaviors regarding to MPLS, and that these specific behaviors can be exploited to identify MPLS tunnels during traceroute measurements. More precisely, we will focus on new methods able to infer the presence of tunnels that are invisible in traceroute outputs, as well as on mechanisms to reveal their content. We will also show that they can be used in order to improve the inference of Internet graph properties, such as path lengths and node degrees. Finally, these techniques will be integrated into Trace the Naughty Tunnels (TNT), a traceroute extension able to identify all types of MPLS tunnels along a path towards a destination. We will prove that this tool can be used in order to get a detailed quantification of MPLS tunnels in the worldwide network. TNT is publicly available, and can therefore be part of many future studies conducted by the research community. Internet est un immense réseau informatique en constante évolution. Chaque année, de plus en plus d’organisations s’y connectent. Chacune d’elles est gérée et administrée indépendamment des autres. En pratique, l’architecture interne de leur réseau n’est pas rendue publique pour des raisons politiques, économiques, ou de sécurité. Par conséquent, notre perception de la structure d’Internet, et plus particulièrement de sa topologie, est incomplète. Afin de pallier ce manque de connaissance, la communauté de la recherche s’appuie sur des mesures de réseau. La plupart du temps, elles sont réalisées avec l’outil traceroute. Cependant, des technologies autres que IP peuvent être privilégiées pour transférer les paquets dans un réseau. MultiProtocol Label Switching (MPLS) est l’une d’entre elles. Même si cette technologie est largement déployée dans Internet, elle n’est pas bien étudiée par les chercheurs. Avant cette thèse, seulement deux travaux se sont intéressés à l’identification d’MPLS dans les données collectées avec traceroute. Alors que le premier ne prend pas en compte tous les scénarios possibles, le second propose des modèles qui manquent de précision. De plus, les tunnels MPLS peuvent dissimuler leur contenu à traceroute. Les topologies inférées sur base de ces données peuvent donc contenir de faux liens, ou des noeuds avec un degré anormalement élevé. Les différentes modélisations d’Internet qui en résultent peuvent alors être biaisées. Aujourd’hui, la question de la révélation des routeurs MPLS qui sont invisibles dans les données de mesure n’est toujours pas résolue, même si certains chercheurs ont déjà proposé quelques méthodes pour y parvenir. Cette thèse a pour but de caractériser MPLS de deux manières différentes. Dans un premier temps, au niveau architectural, nous analyserons en détail son déploiement et son utilisation dans les réseaux IPv4 et IPv6 afin d’améliorer l’état de l’art. Nous montrerons qu’en pratique, plus d’une trace IPv4 sur deux traverse au moins un tunnel MPLS. Nous découvrirons également que bien que ce protocole peut être utilisé pour simplifier l’architecture interne des réseaux de transit, il peut aussi être déployé pour la mise en place de solutions d’ingénierie de trafic. Dans un second temps, MPLS sera étudié d’un point de vue mesure. Nous verrons que les comportements par défaut liés au protocole varient d’un fabricant de routeur à l’autre, et qu’ils peuvent être exploités afin d’identifier les tunnels MPLS dans les données traceroute. Plus précisément, nous découvrirons de nouvelles méthodes capables d’inférer la présence de tunnels invisibles avec traceroute, ainsi que de nouvelles techniques pour révéler leur contenu. Nous montrerons également qu’elles peuvent être utilisées afin d’améliorer la modélisation d’Internet. Pour terminer, ces techniques seront intégrées à Trace the Naughty Tunnels (TNT), une extension de traceroute qui permet d’identifier tous les types de tunnels MPLS le long du chemin vers une destination. Nous prouverons que cet outil peut être utilisé pour obtenir des statistiques détaillées sur le déploiement d’MPLS sur Internet. TNT est disponible publiquement, et peut donc être librement exploité par la communauté de la recherche pour de multiples futures études.

Abstract

This paper presents the tools that have been developed in the IST-Anemone project, a large European testbed deployed for testing and validating IPv6 mobility protocols and products. The testbed is available to third parties, which may include research projects and companies seeking to validate IPv6-ready products. "br/"This tested is particularly suitable for ITS experimentation as it includes several private roads and various network access technologies, IPv6 mobility support and a set of tools for testing IPv6 and performing demonstrations. "br/"Several ITS-related experiments have been performed by Anemone partners.

Abstract

Este documento contiene información pertinente sobre el estado del arte de la Ingeniería de Tráfico (TE) MPLS (Multiprotocol Label Switching) y RSVP (Resource Reservation Protocol); también es importante como caso de estudio y porque da a conocer las técnicas utilizadas bajo la nueva versión de IPV6, en comparación con la versión IPV4. El objetivo es que sirva como marco de referencia para el estudio de la TE basada en la nueva versión de IPV6, específicamente en redes MPLS y RSVP, teniendo en cuenta las consideraciones pertinentes a la hora de tomar decisiones con respecto a la estabilidad del backbone y siendo la clave para proveedores de servicios de Internet que recientemente han estabilizado su infraestructura con IPV4. This paper contains relevant information of the state of art of traffic engineering, MPLS (Multiprotocol Lable Switching) and RSVP (Resource Reservation Protocol), as a case study and the techniques used under the new version of IPV6, against IPV4 version. The paper is intended to serve as a framework for the study of Engineering Traffic Based on the new version of IPV6, specifically MPLS and RSVP, taking into account relevant considerations necessary when making decisions regarding the stability of the Backbone remains the key to Internet service providers that have recently stabilized its IPv4 infrastructure. Document type: Article

Abstract

This paper proposes to extend Mobile IP with adaptive individual paging. Paging reduces the signaling cost of Mobile IP making it more adapted to wireless cellular IP networks. By reducing the number of location updates to be sent per mobile host, paging also minimizes power consumption of the mobile devices. In the proposed extension, each mobile host computes dynamically its optimal location area size according to its traffic and mobility parameters. The optimal size is the size that provides the best paging versus location update cost tradeoff and, as a result, minimizes the signaling load in the network. We compare, by simulation, the performance of the proposed scheme with that of Mobile IP \\citeMIP, a paging scheme that uses fixed size location areas and Hierarchical Mobile IP \\citeCas98TR. We show that our extension provides a significant gain compared to Mobile IP and the fixed size paging scheme and performs as well and sometimes better than Hierarchical Mobile IP. We also show that the integration of adaptive individual paging within Hierarchical Mobile IP outperforms all scheme Document type: Report

Abstract

Once multihomed, an IPv6 site usually wants to engineer its interdomain traffic. We propose that IPv6 multihomed hosts inquire a so called "Name, Address and ROute System" (NAROS) to determine the source and destination addresses to use to contact a destination node. By selecting these addresses, the NAROS server roughly determines the routing. It thereby provides features like traffic engineering and fault tolerance, without transmitting any BGP advertisement and without impacting on the worldwide routing table size. The performance of the NAROS server is evaluated by using trace-driven simulations. We show that the the load on the NAROS server is reasonable and that we can obtain good load-balancing performances.