Abstract

Currently, there is a significant change in data traffic on networks, both local and Internet, across the spectrum of possible customers, whether fixed or mobile. The consumption of video traffic increases day by day in all its formats. Service providers are required more bandwidth, quality and performance, for all products, but mainly those based on video. This article presents an improved version of our laboratory tests for generic networks with four sub-scenarios, which allow injecting multicast video traffic, represented in different codecs. The topology of network used includes a streaming server and up to 20 desktop computers as clients. The most important metrics to be analyzed have been defined, based on performance and quality of service (QoS) measurements under limited bandwidth conditions. Experimental numerical results can be useful for administrators, simulation analysts, designers, and data network planners. But, also, this document aims to serve as a guide for the management of similar networks and the efficiently use available resources, without compromising performance and QoS.

Abstract

ISBN 978-1-61520-791-1; The Internet is an interconnection of multiple networks called domains. Inter-domain routing is ensured by BGP which preserves each domain's independence and announces routes arbitrarily chosen by domains. BGP messages carry no information concerning quality parameters of announced routes. The authors' goal is to provide domains with information regarding the congestion state of other domains without any changes in BGP. A domain, which is aware of heavily congested domains, can choose a bypass instead of a route exhibiting possible problems with QoS satisfaction. They propose a mechanism which sends alert messages in order to notify domains about the congestion state of other domains. The major difficulty consists in avoiding flooding the Internet with signaling messages. The authors' solution limits the number of alerts by taking advantage of the hierarchical structure of the Internet set by P2C and P2P relationships. Their algorithm is distributed and heuristic because it is a solution to an NP-complete and inapproximable problem. They prove these properties by reducing the Steiner problem in directed acyclic graphs to our problem of alert diffusion. The simulations show that our mechanism significantly diminishes the number of unavailable domains and routes compared to those obtained with BGP routing and with a theoretical centralized mechanism.

Abstract

International audience; In this contribution, we consider a novel approach for efficiently supporting IP packets directly into a slotted optical wavelength- division-multiplexing (WDM) layer with several quality of service (QoS) requirements. The approach is based on aggregating IP packets, regardless of their final destinations, at fixed time intervals before the optical conversion phase. A QoS support access mechanism based on the strict priority discipline is evaluated by means of an analytical model. In this case, IP packet aggregation is performed in a loop manner by always beginning the aggregation cycle with the highest priority class. The aggregation cycle ends if the aggregate packet cannot accommodate more IP packets, or if the lowest priority class is reached. In order to overcome the drawbacks of the strict priority discipline, an algorithm depicting a probabilistic priority discipline is presented. The aggregation technique leads to increasing the filling ratio of an optical packet, and consequently, the bandwidth efficiency of an optical network, due to the multicast nature of the aggregation technique. In this context, the support of multicast in metropolitan area networks (MANs), with ring architectures, is presented. Furthermore, a new architecture is proposed in order to support the multicast aggregation technique in wide area networks (WANs)

Abstract

The expectations of every user of today’s internet is becoming relatively high more especially as the internet applications are becoming steadily sensitive to time and delays. The critical nature of some of these applications is more apparent now that they are real-time. These pose a whole lot of challenges to network operators and service providers because they will not only need to provide these services to users but also ensure that these services rendered meet up to quality expectations and standards. It is therefore very necessary and important for them to provide good quality of service with appreciable good performance at no incurable costs- that is while maximizing revenue- to them. A need therefore arises for the adoption of a scalable method or tool for meeting up to these challenges. Multi-Protocol Label Switching (MPLS) stands out to be the choicest tool and key for providing these requirements because of its traffic engineering (TE) capability in IP network and as such the internet needs to be equipped with this all-embracing technology. This report presents the performance analysis of this technology (MPLS TE) vis-à-vis the traditional IP with respect to the average throughput, Quality of service rendered, delay suffered and minimization of congestions or traffic overflow in a bid to seeing how and why MPLS is more capable in optimizing traffic applications when adopted by service providers and network operators. And from the conclusion of the analysis and results it would have been established that MPLS appeared to be more capable in the optimization of traffic applications with respect to the above characteristics when compared with the traditional IP.

Abstract

This thesis aims to improve a satellite communication network which carries both data streams and Voice over IP (VoIP) communication sessions with resource reservation. The resource reservations are made using the standard protocols for Traffic Engineering: MPLS-TE and RSVP-TE. The goal of this thesis project is to optimize the number of concurrent VoIP calls that can be made, in order to use the available bandwidth while maintaining a guaranteed Quality of Service (QoS) level, which is not possible in the existing system. This thesis proposes and evaluates a solution to this optimization problem in the specific context of a satellite modem system that was developed by Thales Communications. This optimization improves the system's ability to carry VoIP communications through better use of the available transmission resources. A solution to this problem would also increase the  exibility in bandwidth allocation within the modem system, and could provide a framework for future development. The proposed solution allows all of the reservable bandwidth to be used.  The amount of reservable bandwidth must be at least a little lower than the channel's available bandwidth in order to avoid congestion. Some areas of future work are proposed. Detta projekt har försökt förbättra ett datornätverk bestående av satelliter som används till både data och Voice over IP (VoIP) kommunikation. VoIP använder sig av resursreservation som bestäms av standardprotokollen för Traffic Engineering, MPLS-TE och RSVP-TE.  Målet är att optimera antalet samtidiga VoIP samtal så att det mesta av den befintliga bandbredden kan utnyttjas samtidigt som Quality of Service (QoS) kan garanteras. Detta är omöjligt i det befintliga systemet. Projektet föreslår en lösning för problemet med modemet som utvecklas av Thales Communications och utvärderar därefter lösningen. Dessa optimeringar förbättrar systemets förmåga att driva VoIP kommunikationer genom att bättre använda de befintliga resurserna. En lösning för det här problemet skulle höja systemets flexibilitet och kunna användas som underlag för kommande utvecklingar. Tack vare lösningen kan hela utsedda bandbredden reserveras. Antalet bandbredd som kan reserveras måsta vara minst lite lågre än total befintling bandbredd för att undvika överbelastning. även några möjliga ideer för vidare undersökning föreslås. Ce projet a pour but d'améliorer un réseau de communication par satellite utilisé pour transporter des flux de données ainsi que des sessions de communication Voix sur IP (VoIP) avec réservation de ressources. Les réservations sont prises en charge par les protocoles standard de Traffic Engineering que sont MPLS-TE et RSVP-TE. L'objectif de ce projet est d'optimiser le nombre d'appels VoIP pouvant être passés en parallèle afin d'utiliser autant de bande passante que possible tout en offrant un niveau de Qualité de Service (QoS) garanti, chose impossible dans le système actuel. Ce rapport propose et évalue une solution à ce problème d'optimisation dans le contexte spécifique du modem satellite développé par Thales Communications. Ces optimisations amélioreraient la capacité du système à transporter des communications VoIP grâce à une meilleure utilisation des ressources disponibles pour la transmission. Une solution à ce problème rendrait aussi l'allocation de ressources plus flexible au sein du système, et pourrait fournir une base à de futurs développements. La solution proposée permet l'utilisation de toute la bande passante réservable. La quantité réservable doit être un peu inférieure à la bande passante totale disponible afin d'éviter la congestion. Les résultats de ces évaluations sont exposés. Enfin, ce rapport propose de futurs développements possibles.

Abstract

demanda de eficiência no gerenciamento das redes aumenta atualmente devido ao rápido desenvolvimento da computação em nuvem e a implantação em grande escala de centros de dados. O controle da infraestrutura deve ser capaz de classificar os diversos tipos de tráfego para aplicações diferentes, e prover o atendimento adequado no menor tempo possível. Porém, devido ao dinamismo da rede, nem sempre podem ser garantidos os requisitos mínimos necessários na Internet. Os mecanismos propostos para a engenharia de tráfego até hoje, são baseados em arquiteturas inflexíveis com a camada de controle e dados fortemente integrados. Isto dificulta um atendimento diferenciado adaptável aos diversos padrões de tráfego das aplicações modernas. Para enfrentar os problemas de flexibilidade das redes tradicionais, as Redes Definidas por Software, apresentam um paradigma inovador que separa as camadas de controle e encaminhamento de pacotes de forma a garantir a utilização eficiente dos recursos disponíveis, e ao mesmo tempo maior flexibilidade de implementação. Este paradigma permite conhecer o estado da rede e a sua topologia em tempo real, o que faz possível a reconfiguração de rotas e alocação de recursos de forma dinâmica. Esta dissertação apresenta um framework para engenharia de tráfego em SDN que utiliza a teoria matemática Network Calculus como ferramenta para subsidiar a caracterização e o policiamento de fluxos de pacotes. Através desta teoria, as decisões de encaminhamento e a distribuição do tráfego são baseadas não só por valores obtidos monitorando a rede, como também por projeções determinísticas que descrevem o comportamento do tráfego. Os resultados obtidos nos experimentos, comprovaram a eficiência no balanceamento de carga da rede em termos de atraso, demonstrando ganhos em termos de vazão do sistema e possibilitando a diminuição da porcentagem de perda de pacotes dos fluxos trafegados. O framework proposto visa contribuir na solução dos desafios relacionados a se estabelecer Engenharia de Tráfego para SDN com a especificação de mecanismos de gerenciamento adaptáveis as mudanças topológicas da rede, as diferentes características dos fluxos e que sejam capazes de distribuir de forma equilibrada o tráfego na rede. The demand for network management efficiency is currently boosted by the rapid development of cloud computing and the large-scale deployment of data centers. Infrastructure control should be able to classify the various types of traffic for different applications, and provide adequate service in the shortest time possible. However, due to the dynamism of the network, the necessary minimum requirements on the Internet can not always be guaranteed. The proposed mechanisms for traffic engineering to date are based on inflexible architectures with the control and data layer strongly integrated. This hinders a differentiated service adaptable to the different traffic patterns of modern applications. To address the flexibility problems of traditional networks, Software Defined Networks presents an innovative paradigm that separates packet control and datapath layers to ensure the ecient use of available resources while providing greater deployment flexibility. This paradigm allows to know the state of the network and its topology in real time, which makes it possible to reconfigure routes and allocate resources dynamically. This work presents a framework for SDN traffic engineering that uses the mathematical theory Network Calculus as a tool to subsidize the characterization and policing of packet flows. Through this theory, routing decisions and traffic distribution are based not only on values obtained by monitoring the network, but also on deterministic projections of traffic behavior. The results obtained in the experiments, proved the efficiency in the load balancing of the network based on flow delay, demonstrating gains in terms of total system throughput and enabling the reduction of the percentage of packet loss of the traffic flows. The framework proposed aims to contribute to the solution of the challenges related to establishing Traffic Engineering for SDN with specification of management mechanisms, adaptables to the topological changes of the network, the different characteristics of the flows and capable of distribute in a balanced way the traffic in the network.

Abstract

International audience; Vehicular networks are one of the cornerstone of an Intelligent Transportation System (ITS). They are expected to provide ubiquitous network connectivity to moving vehicles while supporting various ITS services, some with very stringent requirements in terms of latency and reliability. Two vehicular networking technologies are envisioned to jointly support the full range of ITS services : DSRC (Dedicated Short Range Communication) for direct vehicle to vehicle/Road Side Units (RSU) communications and cellular technologies. To the best of our knowledge, approaches from the literature usually divide ITS services on each of these networks according to their requirements and one single network is in charge of supporting the each service. Those that consider both network technologies to offer multi-path routing, load balancing or path splitting for a better quality of experience of ITS services assume obviously separately controlled networks. Under the umbrella of SDN (Software Defined Networking), we propose in this paper a hybrid network architecture that enables the joint control of the networks providing connectivity to multi-homed vehicles and, also, explore the opportunities brought by such an architecture. We show through some use cases, that in addition to the flexibility and fine-grained programmability brought by SDN, it opens the way towards the development of effective network control algorithms that are the key towards the successful support of ITS services and especially those with stringent QoS. We also show how these algorithms could also benefit from information related to the environment or context in which vehicles evolve (traffic density, planned trajectory, ..), which could be easily collected by data providers and made available via the cloud.

Abstract

Optical Burst Switching (OBS) has been proposed as a future high-speed switching technology for Internet Protocol (IP) networks that may be able to efficiently utilize extremely high capacity links without the need for optical-electronic (O/E) conversions at intermediate nodes. Among its benefits of supporting statistical multiplexing at a rational granularity, OBS still gives poor performance in terms of burst drop probability. In an Optical Burst Switched network, the existence of highly congested links could lead to unacceptable performance for the entire network, causing Quality of Service (QoS) degradation to flows inserted into the network. In this paper we propose a Multi-Spanning Tree architecture that improves QoS management by increasing the efficiency in the wavelength assignment process. The new protocol uses wavelength spanning trees on demand depending on the QoS constraints demanded by inserted traffics. Moreover, the protocol avoids burst overlapping on each edge of the spanning trees, while at the same time, permitting the reutilization of lambda assignments between nodes contained in the same branch. Therefore, the protocol allows traffic aggregation from many nodes into a single branch, improving efficiency and link utilization. We take a traffic engineering approach to branch selection with the objective of balancing the traffic across the network links to reduce congestion and to improve overall performance. In this paper, the architecture, the design of the protocol and some simulation results are presented. Peer Reviewed

Abstract

International audience; Various Multi-Protocol Label Switching-Traffic Engineering (MPLS-TE) Routing Systems have been proposed in the literature to achieve optimization of resources utilization, Quality-of-Service (QoS) and Fast Recovery. This paper proposes a generic architecture for MPLS-TE Routing Systems, which aims to ease the classification and the analysis of these systems. Then this paper defines a set of MPLS-TE classification criteria. The combination of these criteria leads to the identification of main families of MPLS-TE Routing Systems which are finally compared and qualitatively evaluated according to a set of metrics.