AliasNamesallow a Clientto find TagVariablesor Topicseasily. Many industrial systems assign tags to specific measurement or sensors. These tags follow established nomenclatures. An example might be TI101, which would be a temperature indicator at a specific location in a plant. The example nomenclature is defined in ANSI/ISA-S5.1-1984 (R 1992), but this specification does not provide or even suggest any nomenclature. A Clientcould be configured to display or use the information provided by the sensor TI101, but the actual address/location of this sensor might not be known when the Clientis configured. AliasNamescan be used to resolve this tag to the actual sensor in the system.

The Client,on start-up or when it needs to access the tag, would call FindAliason a local Server, aggregating Serveror GDS depending on how a system is configured. A Clientmight select which AliasName source to call via a configuration setting. The FindAlias Methodcall would return a list of all ExpandedNodeIdsthat the AliasName References. It is important to note that there might be more than one Node referenced by an AliasNameand that the Clientmust be prepared for this. The first Nodein the list of referenced Nodesreturned by FindAlias Methodis the Nodethat the Serverfeels is the best match for the requested tag. The returned list might also return more than one instance of AliasNameTypeand each could have their own list of referenced Nodes. If the Methodcall was on a GDS or aggregating Server, the Clientwould need to read the ServerArrayto resolve which Serverthe ExpandedNodeIdwas referencing. This would be the last piece of information that a Clientwould need to be able to follow a normal connection pattern to obtain values from the Node.

AliasNamemight also be configured to provide other information, such as Pub/Sub information, but again it would only be the information that is needed to initially subscribe to an item.