Efficient Energy Routing with connections Rerouting in Elastic Optical Networks under static connections Nogbou Georges Anoh 1 , Michel Babri 2 and Tanon Lambert Kadjo 2 1 Sciences Fondamentales et Appliquées, Université Nangui Abrogoua, LARIT Abidjan, Côte d’Ivoire 2 Mathématiques et Informatique, INPHB, LARIT Yamoussoukro, Côte d’Ivoire Abstract The development of Internet traffic in recent years led telecommunication operators to increase networks bandwidth and motivate evolution of traditional WDM network towards SLICE networks (Spectrum-sLICed Elastic optical path network). The SLICE networks such as all-optical network inherit the problems of power consumption. Therefore, we present, in this paper, an efficient energy routing algorithm and spectrum allocation with connections rerouting under spectrum contiguity and spectrum continuity constraints. When a connection request must be established and there are no adequate and continuous spectrum resources between a source and a destination node, rerouting technique is used to move some existing connections to free resources. To meet such a connection request, and for power consumption management of a service requested, our proposition takes into account the path length, the number of links on optical paths and appropriate modulation format. Analysis of the results of our algorithm to the existing routing algorithm RMLSA in the literature shows that our approach has better performance in terms of the connections established in the network. Keywords: Efficient energy, routing algorithm, connection rerouting, elastic optical network, spectrum contiguity, spectrum continuity. 1. Introduction Transport networks are faced with the development of very different services, massively deployed and requiring relatively large network resources. A terminals extension supporting these types of services to the household and the requirements of current users are a major challenge for these transport networks. Wavelength multiplexing Technology (WDM: Wavelength Division Multiplexing) used in these networks can share the wide spectrum available in order to meet several requests for connections with interesting rates. Several studies have been conducted in order to improve optical spectrum management on the problem of routing and wavelength assignment [1-3], rerouting / optical reconfiguration problem [4-7] and problem of traffic grooming in such networks. However, fixed grid frequency at optical WDM networks generally lead to resources waste due to large sub-bands allocated to less demanding bandwidth applications. For better management of bandwidth offered by WDM networks, new studies have led to implementation of elastic optical networks called SLICE networks (Spectrum-sLICed Elastic optical path) [8-12]. SLICE networks are also faced with problem of routing, resources allocation and connections rerouting. The mechanism of routing and spectrum allocation consists in determining in the first instance a physical path between a source and a destination node. Thereafter, to this path, some number of frequency slots are allocated taking into account the length of the physical path, to rate desired for the connection and modulation format. This causes some heterogeneity of the frequency grids in the SLICE network unlike WDM networks where the grids are fixed [13-15]. When the optical routing fails due to lack of resources available to satisfy a connection request, in the literature the technique of connection rerouting is applied. This technique consists to modify the optical path of a connection. It therefore allows moving an existing connection in the network from an initial path to another final path that has free and sufficient resources to release resources for one connection that may be blocked. Rerouting problem has been extensively studied in WDM networks. The rerouting applying in SLICE networks in the interesting subject in this paper. As all-optical network, the elastic optical networks consist also to active components that have an impact on the overall energy consumption of the network. For example, for each service requested, an optical path between a source s and a destination d with a large number of nodes and with a long distance will consume more energy compared to another path from the same source and same destination however with fewer nodes and a shorter length. When there is no sufficient resource to establish a new connection request, connection rerouting technique is used to increase the number of connections established in the network. Our rerouting technique allows improving network performance by increasing the blocking probability of network. We consider static connections requests with the goal of finding efficient energy paths and low blocking probability to meet future demands. IJCSI International Journal of Computer Science Issues, Volume 11, Issue 6, No 2, November 2014 ISSN (Print): 1694-0814 | ISSN (Online): 1694-0784 www.IJCSI.org 89 2014 International Journal of Computer Science Issues