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

QoS multicast tree construction in IP/DWDM optical internet by bio-inspired algorithms

Copyright @ Elsevier Ltd. All rights reserved.In this paper, two bio-inspired Quality of Service (QoS) multicast algorithms are proposed in IP over dense wavelength division multiplexing (DWDM) optical Internet. Given a QoS multicast request and the delay interval required by the application, both algorithms are able to find a flexible QoS-based cost suboptimal routing tree. They first construct the multicast trees based on ant colony optimization and artificial immune algorithm, respectively. Then a dedicated wavelength assignment algorithm is proposed to assign wavelengths to the trees aiming to minimize the delay of the wavelength conversion. In both algorithms, multicast routing and wavelength assignment are integrated into a single process. Therefore, they can find the multicast trees on which the least wavelength conversion delay is achieved. Load balance is also considered in both algorithms. Simulation results show that these two bio-inspired algorithms can construct high performance QoS routing trees for multicast applications in IP/DWDM optical Internet.This work was supported in part ny the Program for New Century Excellent Talents in University, the Engineering and Physical Sciences Research Council (EPSRC) of UK under Grant EP/E060722/1, the National Natural Science Foundation of China under Grant no. 60673159 and 70671020, the National High-Tech Reasearch and Development Plan of China under Grant no. 2007AA041201, and the Specialized Research Fund for the Doctoral Program of Higher Education under Grant no. 20070145017

Survivable multicasting in WDM optical networks

Opportunities abound in the global content delivery service market and it is here that multicasting is proving to be a powerful feature. In WDM networks, optical splitting is widely used to achieve multicasting. It removes the complications of optical-electronic-optical conversions [1]. Several multicasting algorithms have been proposed in the literature for building light trees. As the amount of fiber deployment increases in networks, the risk of losing large volumes of data traffic due to a fiber span cut or due to node failure also increases. In this thesis we propose heuristic schemes to make the primary multicast trees resilient to network impairments. We consider single link failures only, as they are the most common cause of service disruptions. Thus our heuristics make the primary multicast session survivable against single link failures by offering alternate multicast trees. We propose three algorithms for recovering from the failures with proactive methodologies and two algorithms for recovering from failures by reactive methodologies. We introduce the new and novel concept of critical subtree. Through our new approach the proactive and reactive approaches can be amalgamated together using a criticality threshold to provide recovery to the primary multicast tree. By varying the criticality threshold we can control the amount of protection and reaction that will be used for recovery. The performance of these five algorithms is studied in combinations and in standalone modes. The input multicast trees to all of these recovery heuristics come from a previous work on designing power efficient multicast algorithms for WDM optical networks [1]. Measurement of the power levels at receiving nodes is indeed indicative of the power efficiency of these recovery algorithms. Other parameters that are considered for the evaluation of the algorithms are network usage efficiency, (number of links used by the backup paths) and the computation time for calculating these backup paths. This work is the first to propose metrics for evaluating recovery algorithms for multicasting in WDM optical networks. It is also the first to introduce the concept of hybrid proactive and reactive approach and to propose a simple technique for achieving the proper mix

A New Kind of Dynamic RWA Algorithm with QoS and Link Protection Under the Constraint of Wavelength Continuity

AbstractA new kind of dynamic RWA algorithm with QoS and link protection mechanism under the constraint of wavelength continuity is presented. Using a peculiar link protection method, a protection routing is established with unique links and working routing for every service request. Additionally, the wavelength information is taken into account to make the entire network load balanced with respect to routing choice. It is known that when the network is trouble-free, load balance is needed, and when there are some links destroyed in the network, a protection mechanism is needed. This new algorithm includes these two mechanisms while also adopting a kind of QoS guaranteed mechanism. This allows for a better network performance even under the situation that some links were destroyed and includes a higher quality of service guarantee and a lower rate of service blocking. The simulation results show that this algorithm can significantly improve the rate of service blocking and guarantee the quality of service to meet expectations

Artificial intelligence (AI) methods in optical networks: A comprehensive survey

Producción CientíficaArtificial intelligence (AI) is an extensive scientific discipline which enables computer systems to solve problems by emulating complex biological processes such as learning, reasoning and self-correction. This paper presents a comprehensive review of the application of AI techniques for improving performance of optical communication systems and networks. The use of AI-based techniques is first studied in applications related to optical transmission, ranging from the characterization and operation of network components to performance monitoring, mitigation of nonlinearities, and quality of transmission estimation. Then, applications related to optical network control and management are also reviewed, including topics like optical network planning and operation in both transport and access networks. Finally, the paper also presents a summary of opportunities and challenges in optical networking where AI is expected to play a key role in the near future.Ministerio de Economía, Industria y Competitividad (Project EC2014-53071-C3-2-P, TEC2015-71932-REDT

An Optical Multicast Routing with Minimal Network Coding Operations in WDM Networks

Network coding can improve the optical multicast routing performance in terms of network throughput, bandwidth utilization, and traffic load balance. But network coding needs high encoding operations costs in all-optical WDM networks due to shortage of optical RAM. In the paper, the network coding operation is defined to evaluate the number of network coding operation cost in the paper. An optical multicast routing algorithm based on minimal number of network coding operations is proposed to improve the multicast capacity. Two heuristic criteria are designed to establish the multicast routing with low network coding cost and high multicast capacity. One is to select one path from the former K shortest paths with the least probability of dropping the multicast maximal capacity. The other is to select the path with lowest potential coding operations with the highest link shared degree among the multiple wavelength disjoint paths cluster from source to each destination. Comparing with the other multicast routing based on network coding, simulation results show that the proposed multicast routing algorithm can effectively reduce the times of network coding operations, can improve the probability of reaching multicast maximal capacity, and can keep the less multicast routing link cost for optical WDM networks

A survey on OFDM-based elastic core optical networking

Orthogonal frequency-division multiplexing (OFDM) is a modulation technology that has been widely adopted in many new and emerging broadband wireless and wireline communication systems. Due to its capability to transmit a high-speed data stream using multiple spectral-overlapped lower-speed subcarriers, OFDM technology offers superior advantages of high spectrum efficiency, robustness against inter-carrier and inter-symbol interference, adaptability to server channel conditions, etc. In recent years, there have been intensive studies on optical OFDM (O-OFDM) transmission technologies, and it is considered a promising technology for future ultra-high-speed optical transmission. Based on O-OFDM technology, a novel elastic optical network architecture with immense flexibility and scalability in spectrum allocation and data rate accommodation could be built to support diverse services and the rapid growth of Internet traffic in the future. In this paper, we present a comprehensive survey on OFDM-based elastic optical network technologies, including basic principles of OFDM, O-OFDM technologies, the architectures of OFDM-based elastic core optical networks, and related key enabling technologies. The main advantages and issues of OFDM-based elastic core optical networks that are under research are also discussed

Computation of Dispersion Penalty for the Analysis of WDM Link Quality

The provisioning of light path over WDM/DWDM network is a challenging factor, which depends on various physical layer impairments such as dispersion in fiber. We proposed a light path provisioning mechanism by considering the effect of dispersion in fiber termed as dispersion penalty, which is the prominent effect at high speed WDM network. In the case of non-ideal filter, light path provisioning without considering the physical layer impairments does not satisfy the signal quality guaranteed transmission. In this algorithm, Quality of Service is described in terms of dispersion penalty values with an assumption that the entire client has a requirement of penalty less than 2 Db. Here we have analyzed the degradation in bit rate due to the effect of dispersion. The maximum possible length of fiber is also reduced due to high dispersion in fiber. Dispersion penalty is the increment in the received power to eliminate the effect of some undesirable distortion in optical fiber. Dispersion penalty is calculated in terms of bit rate and band width for each data path. The proposal of dispersion penalty budgeting is to ensure that the optical power reaching the receiver is adequate under all circumstances. The proposed algorithm defines a mechanism for effective light path provisioning by comparing the requirement of client and the available resources of the network