The present document defines the information model to be used at the interface between network elements and management systems, for the management of Radio Relays equipments which use the SDH. The present document defines: - the information model fragment for Radio Relay Network Elements using SDH multiplexing. The present document does not define: - the protocol stack to be used for message communication; - the network level management processes; - the application contexts; - the conformance requirements to be met by an implementation of this information model; - information models for other systems or equipment. The information model defined here (and the