A Novel Attack and Throughput-Aware Routing and Wavelength Assignment Algorithm in Transparent Optical Networks

The transparency feature of All Optical Wavelength Division Multiplexing (WDM) Networks makes it an interesting topic of study. Although characterized by the high throughput, low bit error rate and low noise, Transparent Optical Networks are still considered prone to attacks. The transparency of the network and the lack of opto-electronic conversion allow malicious signals to propagate without being detected. This unnoticeable propagation results in performance degradation and damages the throughput of the network. While several approaches have been focusing on hardware based detective measures, this paper proposes a preventive throughput and attack aware algorithm based on secure topology design. This approach gives enough flexibility to the customer to choose the level of security and throughput that they want to achieve in the network. Namely, the algorithm aims at routing lightpaths in such a way as to minimize the worst case possible damage that can result from different physical-layer attacks. At the same time, the routes have to be selected in such a way as to ensure the desired throughput level. Consequently, two objective criteria for the Routing and Wavelength Assignment (RWA) problem are defined. The first one is referred to as the Maximum Lightpath Attack Radius (maxLAR), while the second is referred to as minimizing the blocking probability. Based on this, the routing sub-problem is formulated as mixed integer liner program (MILP). Tests are performed on small networks at the time being. When simulating attacks, results indicate that the formulation achieves significantly better results for the Maximum Lightpath Attack Radius and Minimum Blocking Probability

Scheduled virtual topology design under periodic traffic in transparent optical networks

This paper investigates offline planning and scheduling in transparent optical networks for a given periodic traffic demand. The main objective is to minimize the number of transceivers needed which make up for the main network cost. We call this problem ldquoScheduled Virtual Topology Designrdquo and consider two variants: non-reconfigurable and reconfigurable equipment. We formulate both problems as exact MILPs (Mixed Integer Linear Programs). Due to their high complexity, we propose a more scalable tabu search heuristic approach, in conjunction with smaller MILP formulations for the associated subproblems. The main motivation of our research efforts is to assess the benefits of using reconfigurable equipment, realized as a reduction in the number of required transceivers. Our results show that the achieved reductions are not very significant, except for cases with large network loads and high traffic variability.The work described in this paper was carried out with the support of the BONE-project ("Building the Future Optical Network in Europe”), a Network of Excellence funded by the European Commission through the 7th ICTFramework Programme, support of the MEC Spanish project TEC2007- 67966-01/TCM CONPARTE-1 and developed in the framework of "Programa de Ayudas a Grupos de Excelencia de la Región de Murcia, de la Fundación Séneca (Plan Regional de Ciencia y Tecnología 2007/2010).

Resource Allocation in Survivable WDM Networks Under a Sliding Scheduled Traffic Model

In recent years there has been an increasing number of applications that require periodic use of lightpaths at predefined time intervals, such as database backup and on-line classes. A new traffic model, referred to as the scheduled traffic model, has been proposed to handle such scheduled lightpath demands. In this thesis we present two new integer linear program ( ILP) formulations for the more general sliding scheduled traffic model, where the setup and teardown times may vary within a specified range. We consider both wavelength convertible networks and networks without wavelength conversion capability. Our ILP formulations jointly optimize the problem of scheduling the demands ( in time) and allocating resources for the scheduled lightpaths. Simulation results show that our formulations are able to generate optimal solutions for practical sized networks. For larger networks, we have proposed a fast two-step heuristic to solve the demand scheduling problem and the RWA problem separately

Resource Allocation for Periodic Traffic Demands in WDM Networks

Recent research has clearly established that holding-time-aware routing and wavelength assignment (RWA) schemes lead to significant improvements in resource utilization for scheduled traffic. By exploiting the knowledge of the demand holding times, this thesis proposes new traffic grooming techniques to achieve more efficient resource utilization with the goal of minimizing resources such as bandwidth, wavelength channels, transceivers, and energy consumption. This thesis also introduces a new model, the segmented sliding window model, where a demand may be decomposed into two or more components and each component can be sent separately. This technique is suitable for applications where continuous data transmission is not strictly required such as large file transfers for grid computing. Integer linear program (ILP) formulations and an efficient heuristic are put forward for resource allocation under the proposed segmented sliding window model. It is shown that the proposed model can lead to significantly higher throughput, even over existing holding-time-aware models