Showing papers by "Miroslaw Klinkowski published in 2012"

Modeling the routing and spectrum allocation problem for flexgrid optical networks

Abstract: Flexgrid optical networks are attracting huge interest due to their higher spectrum efficiency and flexibility in comparison with traditional wavelength switched optical networks based on the wavelength division multiplexing technology. To properly analyze, design, plan, and operate flexible and elastic networks, efficient methods are required for the routing and spectrum allocation (RSA) problem. Specifically, the allocated spectral resources must be, in absence of spectrum converters, the same along the links in the route (the continuity constraint) and contiguous in the spectrum (the contiguity constraint). In light of the fact that the contiguity constraint adds huge complexity to the RSA problem, we introduce the concept of channels for the representation of contiguous spectral resources. In this paper, we show that the use of a pre-computed set of channels allows considerably reducing the problem complexity. In our study, we address an off-line RSA problem in which enough spectrum needs to be allocated for each demand of a given traffic matrix. To this end, we present novel integer lineal programming (ILP) formulations of RSA that are based on the assignment of channels. The evaluation results reveal that the proposed approach allows solving the RSA problem much more efficiently than previously proposed ILP-based methods and it can be applied even for realistic problem instances, contrary to previous ILP formulations.

Offline RSA algorithms for elastic optical networks with dedicated path protection consideration

Abstract: In this article, we address the problem of static routing and spectrum allocation (RSA) in an elastic optical network (EON) with dedicated path protection (DPP) consideration. We formulate RSA-DPP as an Integer Linear Programming (ILP) problem. Since RSA is a difficult problem, we propose an Adaptive Frequency Assignment with Dedicated Path Protection (AFA-DPP) heuristic algorithm to provide near-optimal solutions to the problem. We investigate the efficiency of AFA-DPP for a set of network scenarios. Evaluation results show that the proposed algorithm outperforms other reference algorithms.

On the effect of regenerator placement on spectrum usage in translucent Elastic Optical Networks

Abstract: Translucent optical networks are considered as a promising solution for reducing the electronic processing overhead of opaque optical networks thanks to a cost-effective use of regenerator resources. In a translucent Elastic Optical Network (EON), in which each transparent segment of an optical path may have different spectrum requirements, the use of regenerators will have an impact on the spectrum occupancy in the network. In this work, we focus on the spectrum allocation and regenerator placement problem and we show that the use of regenerators reduces considerably the utilization of spectrum resources in a translucent EON.

Elastic spectrum allocation for variable traffic in flexible-grid optical networks

Abstract: We focus on lightpath adaptation under variable traffic demands in flexible-grid optical networks. Specifically, we study three different adaptation schemes for the variable spectrum allocation. Illustrative numerical results show the benefits of the schemes.

Optimized Burst LSP Design for Absolute QoS Guarantees in GMPLS-Controlled OBS Networks

Abstract: Over the past decade, the scientific community has thrown itself into assessing optical burst switching (OBS) as the switching technology for next-generation all-optical networks. In this regard, a significant amount of work has concentrated on providing OBS with the required carrier-class features. During this process, however, little attention has been paid to fundamental questions on the interoperability and interworking issues that OBS will have to face in a heterogeneous network scenario such as the future Internet. This article introduces a generalized multi-protocol label switching (GMPLS)-based control plane architecture for future OBS networks. This GMPLS/OBS control plane solution leverages on the GMPLS interoperability to enable seamless vertical and horizontal OBS integration with different switching layers under a common control plane. The burst label switched path (b-LSP) entity has been introduced to accomplish this purpose, as well as to guarantee end-users' quality of service (QoS) requirements to effectively support emerging data applications. The establishment of a b-LSP does not entail explicit resource reservation, but the addition of new entries in the OBS node forwarding tables with the resources available for that b-LSP. Hence, by making a resource available to multiple b-LSPs, the statistical multiplexing nature of OBS is preserved. A mixed integer linear programming formulation has been presented to get the most out of the available resources given the expected traffic demands and their QoS requirements. Moreover, in the network operation phase, GMPLS-driven b-LSP capacity reconfigurations are dynamically triggered whenever unfavorable network conditions are detected. An exhaustive simulation campaign assesses the performance of the proposed GMPLS/OBS network architecture on different network scenarios. Finally, future research lines on the topic are outlined.

On the performance of flexgrid-based optical networks

Abstract: The ever increasing IP traffic volume has finally brought to light the high inefficiency of current wavelength-routed rigid-grid networks in matching the client layer requirements. Such an issue results in the deployment of large-size, expensive and power-consuming IP/MPLS layers to perform the required grooming/aggregation functionality. To deal with this problem, the emerging flexgrid technology, allowing for reduced size frequency grids, usually referred to as frequency slot, has recently attracted great attention among network operators, component and equipment suppliers, and the research community. In this paper, we report the main contributions performed in the context of EU STRONGEST project regarding flexgrid optical networks.

Accurate calculation of FWM noise power for ultra-dense phase modulated optical systems

Abstract: Closed-form analytical expressions for nonlinear noise power FWM density Ifwm have been derived for WDM systems as a function of the optical fiber and system properties (i.e. fiber attenuation, dispersion, nonlinearity, power spectral density, and spectral efficiency).