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

In recent years, IP based end-to-end services have grown in popularity. Efficiently meeting the user demand for such services, different techniques for traffic engineering transport networks have been developed. One such technique, currently being developed for multilayered networks, is Generalized Multi-Protocol Label Switching (GMPLS). GMPLS is a necessary networking technique because provisioning end-to-end services will today, and in the foreseeable future, very likely require the co-operation of multiple network layers. Here, the readiness of GMPLS for optical networks is investigated by reviewing the current support for optical networking components in the GMPLS standard documents. Based on this investigation, a candidate solution for routing and constraint-based path computation in optical network segments has been derived. This candidate solution is shown to efficiently handle the additional attributes and constraints inherent in optical networking components. De senaste åren har IP-baserade tjänster ökat i popularitet. För att effektivt möta de användarkrav som ställs på sådana tjänster har olika tekniker för att styra transportnätverk utvecklats. En sådan teknik, nu under utveckling för multi-lagrade nätverk, är GMPLS. GMPLS är en nödvändig nätverksteknik eftersom tillhandahållandet av sluttjänster mellan olika användare idag, och inom en överskådlig framtid, mycket sannolikt kommer att kräva samarbete mellan flera nätverkslager. Här undersöks GMPLS färdighet i optiska nätverk genom att se över det nuvarande stödet för optiska nätverkskomponenter i GMPLS standarddokument. Baserat på denna undersökning har en kandidatlösning för routing och begränsad vägberäkning i optiska nätverkssegment tagits fram. Denna kandidatlösning visas effektivt hantera de ytterligare attribut och restriktioner som existerar i optiska nätverkskomponenter.

Abstract

GMPLS is a still developing protocol family which is indented to assume the role of a control plane in transport networks. GMPLS is designed to provide traffic engineering in transport networks composed of different network technologies such as wavelength switched optical networks, Ethernet networks, point-to-point microwave links, etc. Integrating the different network technologies while using label switched paths to provide traffic engineering poses a challenge. The purpose of integrating multiple technologies under a single GMPLS control plane is to enable rapid service provisioning and efficient traffic engineering. Traffic engineering in networks provides two primary advantages, network resource utilization optimization and the ability to provide Quality of Service. Utilizing network resources more efficiently translates to lower expenditures for the network provider. Quality of Service can be used to provide the customer with for example guaranteed minimum bandwidth packet services. Specifically this thesis focused on the problems of signaling and establishing Forward Adjacency Label Switched Paths (FA-LSPs), and on a experimental method of connecting different network technologies. A testbed integrating an Ethernet network and a wave length division multiplexing network was used to show that the proposed solutions can work in practice. GMPLS består av en samling protokoll under utveckling, de är tänkta att anta rollen som kontrollplan i transportnätverk. GMPLS är designat för att tillhandahålla trafikplanering i transportnätverk bestående av flera olika nätverksteknologier såsom Ethernet, våglängds switchande nätverk m.fl. Integration av dessa olika nätverksteknologier under ett gemensamt kontrollplan och uppsättning av ”label switched paths” i dataplanet är en utmaning. Syftet med att integrera multipla teknologier under ett ensamt GMPLS kontroll plan är att snabbt kunna tillhandahålla tjänster över nätverket samt möjliggöra advancerad trafikplanering. Trafikplanering i nätverk ger två stora fördelar, optimering av utnyttjandet av nätverksresurser samt ökade möjligheter att erbjuda ”Quality of Service” till kunder. Bättre utnyttjande av nätverksresurser innebär lägre kostnader för nätverksleverantören medans ”Quality of Service” kan ge kunden t.ex. en garanterad bandbredd. Specifikt fokuserar denna avhandling på problemen med att signalera och etablera ”Forwarding Adjaceny Label Switched Paths” samt en experimentell metod som båda sammankopplar olika typer av nätverk. En testbed bestående av ett Ethernet nätverk samt ett optiskt våglängdsswitchande nätverk användes för att visa att lösningarna kan fungera i praktiken.

Abstract

Traffic Engineering (TE) is one of the keys for improving packet forwarding in the Internet. It allows IP network operators to finely tune their forwarding paths according to various customer needs. One of the most popular tool available today for optimizing the use of networking resources is MPLS. On the one hand, operators may use MPLS and label distribution mechanisms such as RSVP-TE in conjunction with BGP to define multiple transit paths (for a given edge pair) verifying different constraints on their network. On the other hand, when operators simply enable LDP for distributing MPLS labels in order to improve the scalability of their network, another kind of path diversity may appear thanks to the ECMP feature of IGP routing. In this paper, using an MPLS labels analysis, we demonstrate that it is possible to better understand the transit path diversity deployed within a given ISP. More specifically, we introduce the Label Pattern Recognition (LPR) algorithm, a method for analyzing traceroute data including MPLS information. LPR reveals the actual usage of MPLS according to the inferred label distribution protocol and is able to make the distinction between ECMP and TE multi-path forwarding. Based on an extensive and longitudinal traceroute dataset obtained from CAIDA, we apply LPR and find that each ISP behavior is really specific in regard to its MPLS usage. In particular, we are able to observe independently for each ISP the MPLS path diversity and usage, and its evolution over time. Globally speaking, the main outcomes of our study are that (i) the usage of MPLS has been increasing over the the last five years with basic encapsulation being predominant, (ii) path diversity is mainly provided thanks to ECMP and LDP, and, (iii), TE using MPLS is as common as MPLS without path diversity. Peer reviewed

Abstract

Most major operators use MPLS technology to manage their network via signalling and label distribution protocols. However, these protocols are complex to deploy, maintain and troubleshooting is often very difficult. The IETF has initiated the standardization of a segment routing architecture based on a simple control plane, lightweight, easyto-manage and instantiated on MPLS or IPv6. This architecture is based on the concept of source routing, in which the packet header carries the indications of the path to follow to reach its destination. Suitable for simple use cases and natively resistant to failure, more complex use cases require the resolution of technological issues for which we offer several solutions.In this thesis carried out within Orange Labs, we were interested in the instantiation of the Segment Routing architecture on the MPLS transfer plan and more particularly in traffic engineering, particularly with resource reservation. We have proposed solutions to the problems related to the hardware limitation of current routers that do not allow the expression of all constrained paths. This work is divided into two parts : (i) the proposal of algorithms for computing and encoding segment routing paths in order to bypass hardware limitations. (ii) the definition of architectural requirements and the construction of a functional proof of concept. Finally, this thesis proposes new research issues to consolidate traffic engineering tools for segment routing.; La majorité des grands opérateurs utilise la technologie MPLS pour gérer leur réseau via des protocoles de signalisation et de distributions de labels. Or, ces protocoles sont complexes à déployer, à maintenir et la résolution des pannes est souvent très difficile. L'IETF a initié la standardisation d'une architecture de routage par segments (Segment Routing) s'appuyant sur un plan de contrôle simple, léger, facile à gérer et instanciée sur MPLS ou IPv6. Cette architecture repose sur le concept de routage à la source, dans lequel l'en-tête des paquets transporte les indications du chemin à suivre pour atteindre sa destination. Adapté aux cas d'usages simples et offrant nativement une résistance aux pannes, les cas d'usages plus complexes exigent de résoudre des verrous technologiques pour lesquels nous proposons plusieurs solutions. Dans cette thèse effectuée au sein d'Orange Labs, nous nous sommes intéressés à l'instanciation de l'architecture Segment Routing sur le plan de transfert MPLS et plus particulièrement à l'ingénierie de trafic, notamment avec réservation de ressources. Nous avons proposé des solutions aux problèmes liés à la limitation matérielle des routeurs actuels ne permettant pas l'expression de tous les chemins contraints. Ce travail est divisé en deux parties : (i) la proposition d'algorithmes de calcul et d'encodage de chemins de routage par segment afin de contourner les limitations matérielles. (ii) la définition des exigences architecturales et la construction d'une preuve de concept fonctionnelle. Enfin, cette thèse propose de nouvelles pistes d'études afin de consolider les outils d'ingénierie de trafic pour le routage par segment.