This paper provides detailed information on the ITU (International Telecommunications Union) management model - TMN. It describes the TMN framework in terms of the managed object model in addition to describing the relationship between Manager and Agent.The module also explains the relationship between the TMN 5 layer model and standard network elements found with both fixed and wireless networks. This includes a description of the TMN functions; Operation System, Mediation Device, Q Adapter, Network Element, Work Station and Data Communication Network.The protocol CMIP (Common Management Information Protocol) is also discussed in addition to CORBA (Common Object Resource Broker Architecture) and the IP based protocol - SNMP (Simple Network Management Protocol).