Recommendation ITU-T G.672 provides a description of the relevant characteristics of multi-degree reconfigurable optical add/drop multiplexer (MD-ROADM) network elements. The MD-ROADM is intended to be used in optical networks based on dense wavelength division multiplexing (DWDM), to enhance network scalability and to support enhanced service provisioning and resilience features. This Recommendation also provides classification criteria and a list of optical transfer parameters (without values in the current version) for MD-ROADMs. In this version of this Recommendation, characteristics, classification criteria and optical transfer parameters are applied to MD-ROADMs appropriate for fixed DWDM grid applications.