EMs (EM-NOs). A model that shows dependencies between objects (MOs or other types) is called (abstract) object structure in AMLs, see Appendix D. NE-MOs are static in the sense that they exist (in NEs) whether or not a man- agement action is performed. This is, however, not SO for EM-MOs and NM-MOs, which becomes revealed if we consider how such MOs are used. Figure 5.19 depicts an MO in an NM. This MO supports management of either the layer struc- ture of NL1 or of its logical-network structure. NM-MO Management operations Management Operator method EM-MO Management method NE-MO Management method Compiled Fig. 5.19 The components of a network MO The NM-MO is created by compiling the actual NL1 fragment into a data struc- ture for the object (for a software object it is the equivalence to its attributes). An 5 Management and Traffic Systems interface to the object user (which in this case would be an operator), consisting of a number of management operations, is defined and corresponding methods are implemented for the object. Let's look at a simple scenario of how network MOs can be used (see Fig. 5.20). MOid-removeRouteReq(n22 REi) AF in n11 removeNodeReq(n13N NN) WSF/OPF NW-MO removeNode AF in n12 Compiled model Compile MOid-removeAddressReq(n13 NA) / model Fig. 5.20 A scenario, showing the removal of a logical node from a traffic network via an NW- MO. NA=network address; NN=node name; REi=route endpoint identifier The model shows the LSM of a management layer with an OSF that, e.g., main- tains tables in network elements of a traffic system. Two network elements are indicated by the AFs. These AFs include MOs that are used to update T-RE and T- RO tables in the two network elements. The network elements are defined as logi- cal nodes in an AMLn logical-network structure of two logical networks: a hosting network nw1 that hosts nw2, as depicted. This model is available as a data structure in the OSF. This structure is used to create network MOs on operators' requests. The model shows a scenario where an opera