Nodes have a BrowseName Attribute that is used as a non-localised human-readable name when browsing the AddressSpace to create paths out of BrowseNames. The TranslateBrowsePathsToNodeIds Service defined in OPC 10000-4 can be used to follow a path constructed of BrowseNames.
Subclause 8.3 defines the structure of the BrowseName. It contains a namespace and a string. The namespace is provided to make the BrowseName unique in some cases in the context of a Node (e.g. Properties of a Node) although not unique in the context of the Server. If different organizations define BrowseNames for Properties, the namespace of the BrowseName provided by the organization makes the BrowseName unique, although different organizations may use the same string having a slightly different meaning.
Servers may often choose to use the same namespace for the NodeId and the BrowseName. However, if they want to provide a standard Property, its BrowseName shall have the namespace of the standards body although the namespace of the NodeId reflects something else, for example the local Server.
Standards bodies defining standard type definitions shall use their namespace(s) for the NodeId of the TypeDefinitionNode as well as for the BrowseName of the TypeDefinitionNode. BrowseNames of TypeDefinitionNodes, ReferenceTypes, and DataTypes shall be unique. A ny well-known instances used as entry points shall also be unique. For example, the Root Node defined in OPC 10000-5.
The string-part of the BrowseName is case sensitive. That is, Clients shall consider them case sensitive. Servers are allowed to handle BrowseNames passed in Service requests as case insensitive. Examples are the TranslateBrowsePathsToNodeIds Service or Event filter. If a Server accepts a case insensitive BrowseName it needs to ensure that the uniqueness of the BrowseName does not depend on case.