Impairment-Aware RWA Algorithms for Elastic- Data-Rate Optical Networks

Novel technologies to improve spectral efficiency and lower power consumption in optical transport networks (OTNs) have been recently studied and developed.. These new technologies allow transmission at multiple data-rates from a single opto-electronic (OE) interface. Networks with such tunable data-rate interfaces are called "elastic". The introduction of such interfaces in the optical network will require improvement in both the control and the management layer, in particular the implementation of new routing algorithms. In fact the routing of a request is no longer limited to the search of a path aimed at minimizing the resource utilization (e.g. wavelength and transponders), but it also has to identify an appropriate data-rate for the request, considering that different data rates suffer different physical impairments and require a different amount of regeneration. . In this paper we propose and compare two planning tools for data-rate elastic networks, whose goal is the minimization of required data-rate tunable interfaces. The first approach is based on Integer Linear Programming (ILP) formulation and the other is a heuristic algorithm. We demonstrate that the proposed heuristic provides solutions close to the ILP for a wide range of traffic characteristics and used physical estimators, while largely outperforming the ILP in terms of computation time.