NOVO ALGORITMO BASEADO NO USO DOS SLOTS PARA DEFINIÇÃO DE ROTEAMENTO NAS REDES ÓPTICAS ELÁSTICAS

Neste artigo é proposto um novo algoritmo para melhorar o desempenho do roteamento nas redes ópticas elásticas. O algoritmo busca a rota que utiliza uma métrica para a escolha das rotas de menores caminhos, utilizando a quantidade de slots ocupados e o total de slots nos enlaces para a escolha da rota. O algoritmo aqui proposto é comparado com o algoritmo Melhor entre as Menores Rotas com Decisão por Similaridade (MMRDS) que escolhe a rota com mais enlaces em comum e ao algoritmo que utiliza o Sistema Fuzzy que infere um grau de pertinência na qualidade da rota. O algoritmo proposto apresentou uma taxa de bloqueio de circuito inferior de 4.02% e 8.2% e, 73.40% e 39.42%, comparados aos algoritmos MMRDS e ao sistema fuzzy [9] para as topologias NSFNET e USA, respectivamente. Além disso, foram analisadas outras métricas como a probabilidade de bloqueio por banda e utilização do espectro

Optimized traffic profile for FlexGrid optical networks

This work is focused on studying the connections’ bandwidth distribution effects on the FlexGrid network performance. An accurate study of spectrum occupancy in heavy loaded FlexGrid optical networks is carried out. This analysis is useful to figure out which traffic profiles are more suitable for this kind of networks. Two different cases are considered with respect to the offered connections. In the elastic case, connections sizes can take any value from 1 to a maximum number of spectrum slots. In the multi-rate case, only three connections sizes are allowed. It is demonstrated that by generating the connections with some specific statistical properties, the network performance is improved. These properties are derived from the theoretical study of spectrum occupation in ideal conditions. The main contribution of this work is therefore the proposal of an Optimum traffic profile which allows to efficiently use the spectrum in FlexGrid optical networks. The gain obtained by generating the proposed traffic profile is evaluated by means of simulations at the link as well as at the whole network level.Peer ReviewedPostprint (author's final draft

Spectrum management strategies for performance improvement in Elastic and Multi-Rate Optical Networks

Evaluation of different allocation algorytmes for dinamic resource allocation, and spectrum efficiency in Elastic Optical NetworksPerformance comparison between elastic optical networks and multi-rate optical networks, using different spectrum allocation algorithms to prevent fragmentation

Quantifying bypass traffic in partially meshed transparent optical networks

This work investigates the transparent bypassing capacity requirements of elastic backbone optical networks to determine the all-optical cross-connection capacity needed at network nodes. Topological parameters have been used to develop a random network generator, and the generated topologies are evaluated. Reference values are obtained and applied to well-known topologies, and extensive simulations are conducted to obtain network nodes' bypassing traffic under realistic traffic profiles. The study reveals that although bypassing traffic varies by topology, it never exceeds 9% of total network traffic per node degree. These findings can help properly dimension network nodes by determining the necessary quantity of transceivers and cross-connection capacity based on the network topology and expected traffic.Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature. This work has been partially funded by Spanish AEI IBON (PID2020-114135RB-I00).Peer ReviewedPostprint (published version

FlexGrid optical network simulator implementation

A study about EON has been realized. Firstly, the capacity and fragmentation of EON network has been studied; study published in (Jaume, Xavier y Gabriel, Efficient spectrum assignment in Elastic Optical Networks 2016). Then, a study about the measurement of transceivers of EON was done. Also, different configurations have been compared to establish the connections in the network in order to improve the spectral efficiency. Finally, how the connections are adapted better in the network when the bandwidth of each connection increases has been studied

On spectrum assignment in elastic optical tree-networks

International audienceTo face the explosion of the Internet trac, a new generation of optical networks is being developed; the Elastic Optical Networks (EONs). EONs use the optical spectrum eciently and flexibly, but that gives rise to more diculty in the resource allocation problems. In this article, we study the problem of Spectrum Assignment (SA) in Elastic Optical Tree-Networks. Given a set of trac requests with their routing paths (unique in the case of trees) and their spectrum demand, a spectrum assignment consists in allocating to each request an interval of consecutive slots (spectrum units) such that a slot on a given link can be used by at most one request. The objective of the SA problem is to find an assignment minimizing the total number of spectrum slots to be used. We prove that SA is NP-hard in undirected stars of 3 links and in directed stars of 4 links, and show that it can be approximated within a factor of 4 in general stars. Afterwards, we use the equivalence of SA with a graph coloring problem (interval coloring) to find constant-factor approximation algorithms for SA on binary trees with special demand profiles

On Spectrum Assignment in Elastic Optical Tree-Networks

To face the explosion of the Internet traffic, a new generation of optical networks is being developed; the Elastic optical Networks (EONs). The aim with EONs is to use the optical spectrum efficiently and flexibly. The benefit of the flexibility is, however, accompanied by more difficulty in the resource allocation problems. In this report, we study the problem of Spectrum Allocation in Elastic Optical Tree-Networks. In trees, even though the routing is fixed, the spectrum allocation is NP-hard. We survey the complexity and approximability results that have been established for the SA in trees and prove new results for stars and binary trees