CONTROL PLANE SHARED RISK (CPSR) FACTOR IN A CONVERGED PACKET-OPTICAL NETWORK

Presented herein is a control plane type along with numbers in the calculation of diverse paths for Label Switch Path (LSP) diversity. The control plane type is published along with the Shared Risk Link Group (SRLG) value at the termination endpoint. This helps in determining the source control plane of the SRLG value. The control plane type publication is local to the node/endpoint and does not need any additional signaling

Two heuristics for calculating a shared risk link group disjoint set of paths of min-sum cost

A shared risk link group (SRLG) is a set of links which share a common risk of failure. Routing protocols in Generalized MultiProtocol Label Switching, using distributed SRLG information, can calculate paths avoiding certain SRLGs. For single SRLG failure an end-to-end SRLG-disjoint path pair can be calculated, but to ensure connection in the event of multiple SRLG failures a set with more than two end-to-end SRLG-disjoint paths should be used. Two heuristic, the Conflicting SRLG-Exclusion Min Sum (CoSE-MS) and the Iterative Modified Suurballes’s Heuristic (IMSH), for calculating node and SRLG-disjoint path pairs, which use the Modified Suurballes’s Heuristic, are reviewed and new versions (CoSE-MScd and IMSHd) are proposed, which may improve the number of obtained optimal solutions. Moreover two new heuristics are proposed: kCoSE-MScd and kIMSHd, to calculate a set of k node and SRLG-disjoint paths, seeking to minimize its total cost. To the best of our knowledge these heuristics are a first proposal for seeking a set of k ðk[2Þ node and SRLG-disjoint paths of minimal additive cost. The performance of the proposed heuristics is evaluated using a real network structure, where SRLGs were randomly defined. The number of solutions found, the percentage of optimal solutions and the relative error of the sub-optimal solutions are presented. Also the CPU time for solving the problem in a path computation element is reported

Mécanismes d'allocation de ressources et fiabilité dans les réseaux coeur de prochaines générations

Définitions et concepts de bases -- Éléments de problématique -- Objectifs de recherche -- Principales contributions -- Revue de littérature -- Modèles de services -- Routage avec Qualité de Service -- Ingénierie de traffic -- Contrôle d'admission avec Qualité de Service -- Fiabilité des réseaux -- A novel admission control mechanism in GMPLS- BASED IP over optical networks -- Problem statement -- Numerical results -- Joint routing and admission control problem under statistical delay and jitter constraints in MPLS networks -- Simulation results -- A survivable multicast routing mechanism in WDM optical networks -- Survivable routing under SRLG constraints -- GR-SMRS : Greedy heuristic for survivable multicast routing under SRLG constraints -- simulation results

A Survey on the Path Computation Element (PCE) Architecture

Quality of Service-enabled applications and services rely on Traffic Engineering-based (TE) Label Switched Paths (LSP) established in core networks and controlled by the GMPLS control plane. Path computation process is crucial to achieve the desired TE objective. Its actual effectiveness depends on a number of factors. Mechanisms utilized to update topology and TE information, as well as the latency between path computation and resource reservation, which is typically distributed, may affect path computation efficiency. Moreover, TE visibility is limited in many network scenarios, such as multi-layer, multi-domain and multi-carrier networks, and it may negatively impact resource utilization. The Internet Engineering Task Force (IETF) has promoted the Path Computation Element (PCE) architecture, proposing a dedicated network entity devoted to path computation process. The PCE represents a flexible instrument to overcome visibility and distributed provisioning inefficiencies. Communications between path computation clients (PCC) and PCEs, realized through the PCE Protocol (PCEP), also enable inter-PCE communications offering an attractive way to perform TE-based path computation among cooperating PCEs in multi-layer/domain scenarios, while preserving scalability and confidentiality. This survey presents the state-of-the-art on the PCE architecture for GMPLS-controlled networks carried out by research and standardization community. In this work, packet (i.e., MPLS-TE and MPLS-TP) and wavelength/spectrum (i.e., WSON and SSON) switching capabilities are the considered technological platforms, in which the PCE is shown to achieve a number of evident benefits

Next generation control of transport networks

It is widely understood by telecom operators and industry analysts that bandwidth demand is increasing dramatically, year on year, with typical growth figures of 50% for Internet-based traffic [5]. This trend means that the consumers will have both a wide variety of devices attaching to their networks and a range of high bandwidth service requirements. The corresponding impact is the effect on the traffic engineered network (often referred to as the “transport network”) to ensure that the current rate of growth of network traffic is supported and meets predicted future demands. As traffic demands increase and newer services continuously arise, novel network elements are needed to provide more flexibility, scalability, resilience, and adaptability to today’s transport network. The transport network provides transparent traffic engineered communication of user, application, and device traffic between attached clients (software and hardware) and establishing and maintaining point-to-point or point-to-multipoint connections. The research documented in this thesis was based on three initial research questions posed while performing research at British Telecom research labs and investigating control of transport networks of future transport networks: 1. How can we meet Internet bandwidth growth yet minimise network costs? 2. Which enabling network technologies might be leveraged to control network layers and functions cooperatively, instead of separated network layer and technology control? 3. Is it possible to utilise both centralised and distributed control mechanisms for automation and traffic optimisation? This thesis aims to provide the classification, motivation, invention, and evolution of a next generation control framework for transport networks, and special consideration of delivering broadcast video traffic to UK subscribers. The document outlines pertinent telecoms technology and current art, how requirements I gathered, and research I conducted, and by which the transport control framework functional components are identified and selected, and by which method the architecture was implemented and applied to key research projects requiring next generation control capabilities, both at British Telecom and the wider research community. Finally, in the closing chapters, the thesis outlines the next steps for ongoing research and development of the transport network framework and key areas for further study

Définition d'un plan de contrôle pour les réseaux optiques sans filtre

Les réseaux optiques de prochaine génération sont destinés à faire face au succès croissant des applications Internet. Les architectures optiques doivent ainsi s’adapter au succès de l’Internet et de la donnée face à la voix, ce qui se traduit par des exigences en termes de reconfigurabilité et de simplicité d’opération, et ce pour accommoder des trafics de plus en plus imprédictibles et de types divers. Les réseaux tout optiques basés sur des commutateurs actifs, comme les « cross-connect » (OXC) ou les commutateurs sélectifs en longueur d’onde (WSS) sont à même de fournir ces aspects dans l’établissement dynamique et automatique des connexions optiques. L’agilité et la reconfigurabilité, dépendantes d’un plan de contrôle robuste et autonome déployant les derniers concepts de découverte du voisinage, de la gestion des connexions, et de routage intelligent en cas de maintenance ou de bris, viennent toutefois de pair avec un coût de déploiement plus élevé. Dans cette thèse, nous rappelons les principes des réseaux optiques sans filtre illustrés dans les travaux précédents. Un réseau optique sans filtre implémente les dernières avancées dans les lasers accordables, les récepteurs cohérents en fréquence, les formats de modulation avancés ou encore la compensation électronique de la dispersion, pour pouvoir remplacer les composants actifs de commutation par des diviseurs et des combineurs de puissance optiques passifs adaptés. De cette façon, l’agilité est déplacée aux noeuds émetteurs et aux destinataires associés. Nous présentons aussi les particularités intrinsèques à ces réseaux, comme les canaux non filtrés, les ports émetteurs en amont et en aval, ou encore les concepts de boucle laser et de réutilisation de longueurs d’onde, et nous montrons comment il est possible de développer d’autres façons d’opérer ces réseaux comme les bus de diffusion multipoint à multipoint, à la condition cependant de définir un plan de contrôle spécialisé sans lequel ces concepts pourraient nuire aux performances et aux connexions existantes. Finalement, un simulateur permet de reproduire ces concepts et de sélectionner les meilleures solutions issues des travaux antérieurs par le biais de métriques, telles le nombre de canaux par lien, incluant les canaux non filtrés, et d’une mesure de la quantité de requêtes bloquées. Nous montrons enfin, avec une étude finale des coûts et de la consommation électrique, comment il est possible de retenir des solutions prometteuses vis-à-vis des réseaux photoniques actifs