OPC UA uses Namespaces, and in a defined scope, all identifiers (NodeId, QualifiedName) use a NamespaceIndex instead of a NamespaceUri. The scope has a NamespaceArray with URIs where the NamespaceIndex is defined as an index into this array. For a Server, the scope is the complete Server. For a UANodeSet XML file, it is the file.

A ConnectionConfigurationSet (see 6.8.2) contains node identifiers related to different scopes, as illustrated in Figure F.2. In this illustration, the ConnectionConfigurationSet contains information for two different Servers. Node identifiers in the Information Model for the ConnectionManager (i.e., an instance of ConnectionConfigurationSetType) use PortableNodeIdentifier (see 10.32) to support the resolution for the dedicated scope (see also 13.3).

Figure F.2 – Scopes within a ConnectionConfigurationSet

To reduce the overall size of the DataTypes defined in this Clause (i.e. ConnectionConfigurationSetConfDataType), NodeId, AliasName and RelativePath are used instead of their portable version. The scope of those identifiers is defined by the related ServerAddressConfDataType structure containing a Namespace array. The NamespaceIndex of a node identifier is used as an index into the Namespace array of the related ServerAddressConfDataType.

A ConnectionManager can map NodeId and RelativePath  contained in the DataTypes to their portable versions using the NamespaceUri from the Namespace array when it loads the ConnectionConfigurationSet from the data structure.