Effect of Impairment Modeling Errors on Reachability Graph Based Lightpath Setup in Translucent Optical Networks

GMPLS-based transparent optical networks suffer from accumulation of physical layer impairments (PLIs) and wavelength continuity constraint along the transparent optical path. To increase optical reach, resource utilization, and average call acceptance ratio (and hence the revenues), network operators resort to translucent optical networks. In these networks a limited number of regenerators are placed at a selected set of network nodes. Hence, it is important to develop GMPLS-based distributed optical control plane (OCP) for on-demand lightpath provisioning considering both PLIs and availability of regenerators. In this paper, we propose and study a novel three phase approach - reachability graph construction, route computation on reachability graph, and signaling, for routing lightpaths with multiple transparent segments. However, the reachability graph - which contains all network nodes and a set of new optically reachable links - is computed based on approximate PLIs models. Hence, in this paper we analyze the effect of PLIs modeling errors on the network performance in two scenarios - fixed additional OSNR penalty and adaptive cost penalty based on error feedback. The simulation results suggest that adaptive cost penalty is independent of network topological characteristics and provides a good trade-off between blocking probability and additional number of required regenerators.