Estudo de caso de técnicas de utilização de transponders em redes ópticas elásticas

Abstract

The growth in data traffic is mainly caused due to both the increasing number of subscriber and new applications that require high transmission rates. Optical networks have been the most suitable way to support this demand. One of the biggest challenges faced by these networks is optimizing the use of the available spectrum. The technologies that may lead to better use of the available optical spectrum is the one that allows to the divide the spectrum narrow slices. This approach is known as Elastic Optical Networks (EON), EONS are an evolution of WDM (Wavelength Division Multiplexing) networks. Moreover translucent elastic optical network may be designed from a transparent network by the addition of certain amount of regenerators 3R distributed in a strategically way in the network. In a translucent network, some nodes are transparent and other ones are opaque or translucent. Therefore, in such networks the question of deciding which nodes are translucent or transparent arises. This problem is known as Regenerator Placement (RP). The RP consists of to decide at which of EONs will be deployed 3R regenerators and as well as the number of 3R should be placed at each node. After the RP problem is solved, the regenerator allocation algorithm (RA) is responsible to determine whether to use, or not, the 3R regenerators deployed in each intermediate node of a given route. In EONs, the use of regenerators can be done by lack of quality in the transmission, by spectrum conversion or to improve modulation format. In this thesis, three algorithms to perform regenerator assignment for EONs are proposed. EONs with sparse regeneration and dynamic traffic are considered. The proposed algorithms are: The FLR-RA (First Longest Reach Regenerator Assignment), which tries to use as less as possible regenerators along a route, the FNS-RA (First Narrowest Spectrum Regenerator Assignment), which tries to use as less as possible spectrum along a route, and the exhaustive, that returns either the solution that uses the fewest possible number of regenerators or occupy fewest possible number of slots along a given route. The algorithms a simulated in two network topologies. The results show, in the simulated scenarios, that the FLR-RA reaches smaller blocking probabilities when the number of regenerators deployed in network is small, while the FNS-RA reaches smaller blocking probabilities in the cases in which many regenerators are placed in network. The FLR-RA and FNS-RA heuristics show similar results to the exhaustive, meaning that the heuristics present a good performance.