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 management of Connection Supervision Functionality (HCS/LCS), as defined in Recommendation G.783 [2] and as related to SDH network Elements. These objects are useful to describe information exchanged across interfaces defined in M.3010 [5] Telecommunications Management Network (TMN) architecture.