This Recommendation provides an information model for the Synchronous Digital Hierarchy (SDH) Network. This model describes the managed object classes and their properties for the configuration of the protection switching function, as defined in Recommendations G.805 and G.774.3 and as related to SDH transmission resources. These objects are useful to describe information exchanged across interfaces defined in M.3010 Telecommunications Management Network (TMN) architecture for the configuration of the protection function. The protection switching scheme of an SDH network element is usually set up autonomously by the network element according to its make-up and mode of operation. When this is not possible, the information model defined by this Recommendation will be used. Post-configuration management of the protection function is described in Recommendation G.774.3.