Planificación de Redes Troncales de Conmutación Óptica Transparente

El continuo crecimiento de Internet está obligando a buscar nuevos medios para proporcionar mayores capacidades de transmisión en las redes de comunicaciones. Las redes troncales de conmutación óptica transparente representan una respuesta factible a corto y medio plazo para lograr este fin. Por tanto, la planificación de estas redes, buscando un diseño que minimice los costes de la red, tanto OPEX como CAPEX, adquiere una especial relevancia. Este articulo pretende hacer una breve exposición de los conceptos básicos de este tipo de planificación. Para concluir se muestra un caso de estudio, donde se compararan las principales metodologías de planificación de redes ópticas transparentes

Designing of multichannel optical communication systems topologies criteria optimization

This paper presents the issues necessary to solve in the designing process of multichannel optical communication systems topologies. The main design assumption is the acceptance of mul-tichanneling in communication system realization. In particular, the basics of designing physical and logical topologies are shown. Also cost aspects of physical and logical topologies realization are shown

Optimal Algorithms for Near-Hitless Network Restoration via Diversity Coding

Diversity coding is a network restoration technique which offers near-hitless restoration, while other state-of-the art techniques are significantly slower. Furthermore, the extra spare capacity requirement of diversity coding is competitive with the others. Previously, we developed heuristic algorithms to employ diversity coding structures in networks with arbitrary topology. This paper presents two algorithms to solve the network design problems using diversity coding in an optimal manner. The first technique pre-provisions static traffic whereas the second technique carries out the dynamic provisioning of the traffic on-demand. In both cases, diversity coding results in smaller restoration time, simpler synchronization, and much reduced signaling complexity than the existing techniques in the literature. A Mixed Integer Programming (MIP) formulation and an algorithm based on Integer Linear Programming (ILP) are developed for pre-provisioning and dynamic provisioning, respectively. Simulation results indicate that diversity coding has significantly higher restoration speed than Shared Path Protection (SPP) and p-cycle techniques. It requires more extra capacity than the p-cycle technique and SPP. However, the increase in the total capacity is negligible compared to the increase in the restoration speed.Comment: An old version of this paper is submitted to IEEE Globecom 2012 conferenc

Considering Transmission Impairments in Wavelength Routed Networks

Abstract — We consider dynamically reconfigurable wavelength routed networks in which lightpaths carrying IP traffic are on demand established. We face the Routing and Wavelength Assignment problem considering as constraints the physical impairments that arise in all-optical wavelength routed networks. In particular, we study the impact of the physical layer when establishing a lightpath in transparent optical network. Because no signal transformation and regeneration at intermediate nodes occurs, noise and signal distortions due to non-ideal transmission devices are accumulated along the physical path, and they degrade the quality of the received signal. We propose a simple yet accurate model for the physical layer which consider both static and dynamic impairments, i.e., nonlinear effects depending on the actual wavelength/lightpath allocation. We then propose a novel algorithm to solve the RWA problem that explicitly considers the physical impairments. Simulation results show the effectiveness of our approach. Indeed, when the transmission impairments come into play, an accurate selection of paths and wavelengths which is driven by physical consideration is mandatory. I

An application of a genetic algorithm for throughput optimization in non-broadcast WDM optical networks with regular topologies

We apply a genetic algorithm from Podnar and Skorin-Kapov [5] to a virtual topology design of a Wide-Area WDM Optical Network with regular topologies. Based on a given physical topology a virtual topology consisting of optical lightpaths is constructed. The objective is to minimize the maximal throughput, which implies balancing link loads and accommodating on-growing traffic requirements in a timely fashion. The genetic algorithm is applied to benchmark instances of regular topologies

On Delay versus Congestion in Designing Rearrangeable Multihop Lightwave Networks

We investigate design issues of optical networks in light of two conflicting criteria: throughput maximization (or, equivalently, congestion minimization) versus delay minimization. We assume the network has an arbitrary topology, the flow can be split and sent via different routes, and it can be transferred via intermediate nodes. Tabu search heuristic is used to compare solutions with different weights assigned to each of the two criteria. The approach is tested on a benchmark data set, the 14-dimensional NSFNET T1 network with traffic from 1993. The results suggest that (1) some connectivity matrices are quite robust and desirable regarding both criteria simultaneously; (2) forcing minimization of total delay unconditionally can result with significantly inferior throughput. Some decisions strategies are outlined

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).

WDM Network Design with Node Protection : An approach based on MOACO

This work studies the survivable optical network design prob- lem subject to simple node failure where disruption by network recon g- uration degrades the Quality of Service. The impact of the number of recon gurations when a node fails over other objective functions is crit- ical. Therefore, a Multi-Objective Ant Colony Optimization (MOACO) Algorithm is proposed, which tries to nd the best network design as well as the primary and back-up multicast trees considering a multicast re- quest set. The MOACO algorithm simultaneously minimizes the network design cost, the maximum end-to-end optical delay, the total number of recon gurations and the maximum number of recon gurations. The ex- perimental results over di erent instances show the bene ts of the pro- posed approach front to two state-of-the-art protection approaches based on total or partial recon guration.IX Workshop de Arquitecturas, Redes y Sistemas OperativosRed de Universidades con Carreras en Informática (RedUNCI

WDM Network Design with Node Protection : An approach based on MOACO

This work studies the survivable optical network design prob- lem subject to simple node failure where disruption by network recon g- uration degrades the Quality of Service. The impact of the number of recon gurations when a node fails over other objective functions is crit- ical. Therefore, a Multi-Objective Ant Colony Optimization (MOACO) Algorithm is proposed, which tries to nd the best network design as well as the primary and back-up multicast trees considering a multicast re- quest set. The MOACO algorithm simultaneously minimizes the network design cost, the maximum end-to-end optical delay, the total number of recon gurations and the maximum number of recon gurations. The ex- perimental results over di erent instances show the bene ts of the pro- posed approach front to two state-of-the-art protection approaches based on total or partial recon guration.IX Workshop de Arquitecturas, Redes y Sistemas OperativosRed de Universidades con Carreras en Informática (RedUNCI