GDMO (Guidelines for Definition of Managed Objects) is a standard for defining objects in a network in a consistent way. With a consistent "language" for describing such objects as workstations, LAN servers, and switches, programs can be written to control or sense the status of network elements throughout a network. Basically, GDMO prescribes how a network product manufacturer must describe the product formally so that others can write programs that recognize and deal with the product. Using GDMO, you describe the class or classes of the object, how the object behaves, its attributes, and classes that it may inherit.
GDMO is part of the Open Systems Interconnection (OSI) Common Management Information Protocol (CMIP) and also the guideline for defining network objects under the Telecommunications Management Network (TMN), a comprehensive and strategic series of international standards for network management. The object definitions created using GDMO and related tools form a Management Information Base (MIB). GDMO uses Abstract Syntax Notation One (ASN.1) as the rules for syntax and attribute encoding when defining the objects.
GDMO is specified in ISO/IEC standard 10165/x.722.