A user-defined link (UDL) is a logical link between two objects in Address Manager. In Address Manager 9.4.0 or greater, UDLs can be created
using the GUI, in addition to the API.
Setting up UDLs is a two step process. First, the user must create a UDL type, configured
with a name, description, and entity types to be linked. Once that is created, the user
can link eligible entities using the UDL type to create UDLs.
UDLs can be created between objects in the same configuration, or between objects in
different configurations. For information on use-cases and eligible objects, refer to
User-defined links in the API guide.