Potentialities and criticalities of flexible-rate transponders in DWDM networks: A statistical approach

We propose a novel method to assess physical layer potentialities of core optical networks aimed at finding solutions that better exploit the installed equipment. We focus on the use of flexible-rate transponders for the implementation of the elastic paradigm on the state-of-the-art dense wavelength-division-multiplexed fixed-grid network scenarios. We make use of the waveplane-based routing and wavelength assignment algorithm presented in Dai et al. [J. Lightwave Technol., vol. 33, p. 3815, 2015] to implement a progressive statistical loading of the analyzed network topology, and perform a Monte Carlo analysis delivering a statistical characterization of the average bit rate per lightpath together with the assessment of network blocking. The proposed method allows for the identification of criticalities in terms of link congestion and lightpath quality of transmission, addressing solutions by identifying network bottlenecks. We apply the proposed method to a large pan-European network topology comparing two different transmission techniques for the implementations of flexible-rate transponders: pure PM-m-QAM versus hybrid modulation formats. Over this realistic network example, besides displaying the overall statistics for the average bit rate per lightpath, we show statistics for critical lightpaths and congested fiber links.