inFlexgridOpticalNetworks.PDFVIP

ICTON 2016 Tu.A3.4 Modulation Format-Aware Restoration and Re-Optimization in Flexgrid Optical Networks Ll. Gifre, M. Ruiz, and L. Velasco* Universitat Politecnica de Catalunya (UPC), Barcelona, Spain *e-mail: lvelasco@ac.upc.edu ABSTRACT Sliceable Bandwidth-variable Transponders (SBVTs) enhance the configurability and flexibility of Flexgrid optical networks. A single SBVT can be used to transmit and receive several optical signals each modulated with a specific format. A SBVT can be seen as a set of sub-transponders that can be specifically configured to end a specific lightpath, by defining, among other parameters, the modulation format and the central frequency to be used. Modulation formats are characterized by its spectrum efficiency and reachability. In this paper, we propose modulation format-aware algorithms to restore connections affected by a link failure, as well as to re-optimize resource utilization after a link repair. Keywords: flexgrid optical networks, in-operation planning. 1. INTRODUCTION When a new lightpath needs to be set up, not only the route and spectrum allocation (RSA) [1] needs to be computed, but also a modulation format must be chosen for the requested bitrate and the distance between source and destination nodes, thus defining the RSMA problem [2]. When a failure occurs, a restoration algorithm computes a global solution for all the affected LSPs. However, as a result of the combined effect of longer routes and lack of resources, the bitrate of the restored LSPs could become squeezed. Consequently, when the failure is repaired, an in-operation planning algorithm [3] can be run to compute shortest routes that allow, not only to save resources as proposed in [4], but also increase the bitrate of those LSPs which bi