Ms are parts of, or known by the management system. OSF=operations system function; OPF=operator function; WSF=work station function This model is extremely simplified, considering what we know about the com- plexity of traffic systems: a system that may consist of many strata, layers, and a more or less complex structure of logical networks. In addition to maintaining this complex system in an optimal condition, the management system may also have to handle many functions that are not directly related to maintenance, such as traffic analysis and network dimensioning, subscribing and connecting new customers, charging, accounting, security and overall business aspects, which altogether can make a management system functionally much more complex than the traffic sys- tem itself. Managed objects (MOs) are developed and standardized for each type of traffic system. The number of MOs for a traffic system becomes very large, as already mentioned. Classification of management functions (i.e. MOs) is therefore needed. If a network system model exists for the traffic system, MOs should be classified and identified (using the OBJECT IDENTIFIER system) according to the structure of that model. If the model is an AMLn model, the basic classification structure will be defined by its layer structure and logical-network structure. The principle is shown in Fig. 5.11 for management functions that concern resources of a particular layer. In a similar way, configuration of layer elements to each other in traffic sys- tem nodes (described by the hosts relation of a logical network structure model) can be supported by logical node MOs. Note that the way the OBJECT IDENTIFIER system is used today indicates that traffic system models are not made up or used for classifying MOs. Only SNMP- MOs have identifications that are related to some extent to the Internet layer struc- ture. 5 Management and Traffic Systems TS node Layer X Layer X MOs Layer X resource management function Layer X Layer X MOs TS node Fig. 5.11 MOs should be classif