The GDS could include additional optional behaviour which this example illustrates. What is required is the availability of all AliasNames in the mandatory TagVariables folder and Topics folder, but a GDS could also choose to replicate or even merge the additional AliasNameCategoryType instances from the Servers that have registered. Figure B.2 provides an illustration of a GDS that merged the AliasNameCategory instance into a tree. A GDS shall aggregate AliasNameCategories, but the structure of these categories is not defined.

Figure B.2 – GDS with merged AliasNames example

For additional information about a GDS and AliasNames see Annex C.