This Recommendation provides an information model for the Synchronous Digital Hierarchy (SDH) Radio-Relay Network Elements. This model describes the managed object classes and their properties for the Radio Synchronous Physical Interface and the protection function of sections having such a physical interface. These objects are useful to describe information exchanged across interfaces defined in ITU-T M.3010 Telecommunications Management Network (TMN) architecture for the management of the Radio-Relay Network Elements.