Tesis doctoral de Marc Ruiz Ramírez
The explosion of ip traffic due to the increase of ip-based multimedia services such as hdtv or video conferencing poses new challenges to network operators to provide a cost-effective data transmission. Although dense wavelength division multiplexing (dwdm) meshed transport networks support high-speed optical connections, these networks lack the flexibility to support sub-wavelength traffic leading to poor bandwidth usage. To cope with the transport of that huge and heterogeneous amount of traffic, multilayer networks represent the most accepted architectural solution. Multilayer optical networks allow optimizing network capacity by means of packing several low-speed traffic streams into higher-speed optical connections (lightpaths). During this operation, a dynamic virtual topology is created and modified the whole time thanks to a control plane responsible for the establishment, maintenance, and release of connections. Because of this dynamicity, a suboptimal allocation of resources may exist at any time. In this context, a periodically resource reallocation could be deployed in the network, thus improving network resource utilization. This thesis is devoted to the characterization, planning, and re-optimization of next-generation multilayer networks from an integral perspective including physical layer, optical layer, virtual layer, and control plane optimization. To this aim, statistical models, mathematical programming models and meta-heuristics are developed. More specifically, this main objective has been attained by developing five goals covering different open issues. First, we provide a statistical methodology to improve the computation of the q-factor for impairment-aware routing and wavelength assignment problems (ia-rwa). To this aim we propose two statistical models to compute the cross-phase modulation variance (which represents the bottleneck in terms of computation time and complexity) in off-line and on-line ia-rwa problems, proving the accuracy of both models when computing q-factor values in real traffic scenarios. Second and moving to the optical layer, we present a new wavelength partitioning scheme that allows maximizing the amount of extra traffic provided in shared path protected environments compared with current solutions. Specifically, we define several statistical models to estimate the traffic intensity given a target grade of service, and different network planning problems for maximizing the expected revenues and net present value. After solving these problems for real networks, we conclude that our proposed scheme maximizes both revenues and npv. Third, we tackle the design of survivable multilayer networks against single failures at the ip/mpls layer and wson links. To efficiently solve this problem, we propose a new approach based on over-dimensioning ip/mpls devices and lightpath connectivity and recovery and we compare it against the conventional solution based on duplicating backbone ip/mpls nodes. After evaluating both approaches by means of ilp models and heuristic algorithms, we conclude that our proposed approach leads to significant capex savings. Fourth, we introduce an adaptive mechanism to reduce the usage of opto-electronic (o/e) ports of ip/mpls-over-wson multilayer networks in dynamic scenarios. A ilp formulation and several heuristics are developed to solve this problem, which allows significantly reducing the usage of o/e ports in very short running times. Finally, we address the design of resilient control plane topologies in gmpls-enabled transport networks. After proposing a novel analytical model to quantify the resilience in mesh control plane topologies, we use this model to propose a problem to design the control plane topology. An iterative model and a heuristic are proposed and used to solve real instances, concluding that a significant reduction in the number of control plane links can be performed without affecting the quality of service of the network.
Datos académicos de la tesis doctoral «Characterization, design and re-optimization on multi-layer optical networks«
- Título de la tesis: Characterization, design and re-optimization on multi-layer optical networks
- Autor: Marc Ruiz Ramírez
- Universidad: Politécnica de catalunya
- Fecha de lectura de la tesis: 21/12/2012
Dirección y tribunal
- Director de la tesis
- Luis Domingo Velasco Esteban
- Tribunal
- Presidente del tribunal: raul Muñoz gonzalez
- michal Pióro (vocal)
- (vocal)
- (vocal)