GDS that supports AliasNames,provides AliasNames functionality, but the target Nodesreferenced are in other Servers.The AliasNames are aggregated from the Serversthat have registered with the GDS that expose the “Alias" capability (for information on capabilities see OPC 10000-12). Additional examples on aggregating AliasNamescan be found in the aggregating Serverexample - A.3. A GDS implementation also requires additional behaviour. This section describes automatic behaviour that is required by all implementations of a GDS that supports AliasNames.

Figure B-8– Example GDS aggregating AliasNames

The following sections describe this required behaviour:

• When a Serverregisters with the GDS, the GDS shall merge the AliasNamesof the registering Serverinto a master AliasNameslist on the GDS.
• Pull all AliasNameCategoryinstances, merge any that have identical BrowseNames.
• The GDS will provide the ExpandedNodeIdof all of the referenced NodeIdsand the ServerURIof the Servercontaining the NodeId.

The details of the expected behaviour of a GDS that supports AliasNamesis described in the following sections.