Sometimes, a high-level Reference might be refined by more fine granular References, including a more detailed path. For example, DeviceA controls DeviceB (see Figure 3, A)). This might be refined, exposing what network equipment is used for the communication (see Figure 3, B)), and further refined by exposing, which ports are used (see Figure 3, C)). Alternatively, it might directly be refined with ports and switches (see Figure 3, D)).
Figure 3 – Examples of Reference Refinements
Without providing Reference refinement, there may be multiple paths possible (e.g., several switches, see Figure 4), and thus it is not clear which path the high-level Reference is using at any given instance in time.
Figure 4 – Example of Reference Refinements with multiple path options
Therefore, the Property ReferenceRefinement is defined for the ReferenceDescriptionVariableType (see 5.3.1) allowing to make the refined References explicit. In Figure 5, an example is given. The ReferenceDescription Variable containing the refinement can be referenced by any Node in the refinement path using the HasReferenceDescription ReferenceType to expose the information (see Figure 5).
Figure 5 – Example of how to use Reference Refinements
When multiple levels are addressed, each ReferenceDescription Variable only contains one level, as shown in Figure 6. The “Controls” Variable only contains the first level, via the Switch. The “ConnectedTo1” and “ConnectedTo2” Variables further refine the References used in the first refinement level. Both contain multiple hops in one refinement. In the example, the Nodes used in the refinement of “ConnectsTo1” do reference the ReferenceDescription Variable, whereas for “ConnectsTo2” they do not. Both options are allowed.
Figure 6 – Example of how to use Reference Refinements with two Levels and Multiple Hops
Note that the ReferenceRefinement intentionally only defines one refinement path (of potentially many possible paths between the Nodes). If the path used changes, the ReferenceRefinement needs to change.