Traffic grooming and power level tuning for physical impairment constrained routing

In both, metropolitan optical networks (MON) and long haul optical networks (LHON) the signal quality is often influenced by the physical impairments, therefore proper impairment constrained routing decisions are needed. In this paper we propose two new approaches that jointly perform, on the one hand, routing and wavelength assignment (RWA) and, on the other hand, either tuning the signal power of certain wavelength division multiplexed (WDM) channels or grooming the traffic of some WDM channels in nodes that are grooming capable. We evaluate the proposed optimization methods for both, single and multilayer networks. In the first case we assume that no signal regeneration is allowed along the path, only re-amplification, while in the more complex two-layer case we assume grooming in the electronic layer that implicitly performs 3R signal regeneration and wavelength conversion as well.