An aggregating Servermay also collect all of the AliasNamesdefined in underlying Serversand just build a composite list of these AliasNames. Since all of the AliasNamesare required to exist under the mandatory Aliases Object, it is simple for a Serverto browse the AddressSpaceand build a list. The aggregating Serverwould be required to merge all AliasNameslisted under the well-known Objects. Some information models might define their own well known AliasCategoryType Objects, which would then also need to be merged. An aggregating Servermay easily have the same AliasNameswith multiple NodeIds. For example, if a temperature sensor were to be connected to two Serversfor redundancy, the same AliasNameTI101 might exist in both Servers. The aggregating Serverwould simple report two ExpandedNodeIdsto any Clientthat requested TI101.


Figure A-6– Aggregating Server example 2

In the above example, if the Temperatures AliasNameCategoryTypeinstance were defined locally in the Serverand not defined in a standard namespace then two instances of the Temperatures AliasNameCategoryTypewill exist in the aggregating Serverwith different namespaces.