Experimental Evaluation of RSA Algorithms for SDN- programmable VCSEL-based S-BVT in High-Capacity and Cost-Efficient Optical Metro Networks R. Martínez 1 , R. Casellas 1 , M. Svaluto Moreolo 1 , J. M. Fabrega 1 , R. Vilalta 1 , R. Muñoz 1 , L. Nadal 1 , J. P. Fernández Palacios 2 , V. López 2 , D. Larrabeiti 3 and G. Otero 3 1 Centre Tecnològic de Telecomunicacions de Catalunya (CERCA/CTTC), Castelldefels, Spain 2 Telefónica I+D, GTCO, Madrid, Spain 3 Universidad Carlos III, Madrid, Spain ricardo.martinez@cttc.es Abstract. Future metro networks need to increase the transport capacity and im- prove the cost- and power-efficiency. These challenges are tackled by the EU- H2020 PASSION project exploiting dense photonic integration and cost-efficient optical technologies. Specifically, PASSION investigates a) modular sliceable bandwidth variable transceivers (S-BVTs) built upòn a set of both vertical cavity surface emitting lasers (VCSEL) and Coherent Receivers (CO-Rx); and b) hier- archical switching nodes in a flexigrid network. An SDN controller handles the network programmability where a key functionality is the path computation and resource selection to fulfil the connection requirements. This is conducted by the Routing and Spectrum Assignment (RSA) algorithms. The considered S-BVT transmitter imposes that each S-BVT VCSEL reaches up to 50 Gb/s. Thus, con- nections requesting higher bandwidth (e.g., 200 Gb/s) are accommodated over several optical flows. In this context, two RSA algorithms called co-routed (RSA-CR) and inversed multiplexed (RSA-IM) optical flows are proposed and compared. The RSA-CR enforces that all the connection’s optical flows are routed over the same spatial path; the RSA-IM relaxes this allowing the optical flows being set up over different spatial routes. The experimental evaluation, made upon dynamic traffic, aims at comparing both RSA algorithms performance according to the blocked bandwidth ratio, the average used of S-BVT devices, and the average setup time. Keywords: SDN, Flexi-Grid Metro Networks, S-BVT. 1 Introduction The design of the metro networks is becoming crucial to deal with the requirements bound to the 5G services with respect to both huge transport capacity and very high dynamicity. In this context, as discussed in [1], 33% of the total transport capacity of- fered by the telecom operators will strictly remain within the metro networks. Thereby,