Add attributes to the port structure using the Struture Viewer window.
In the Design window, right-click the port, and
select Edit Structure.
In the Structure Viewer window, select Actions > Add,
or right-click the attribute and select Add.
Enter a name for the attribute. The names for port attributes
must start with an alphabet character and can contain only alphanumeric
characters. You cannot have reserved JavaScript keywords as names.
Select Populate Attribute to add the attribute to multiple
port structures. The new attribute is added to all port structures
participating in the selected connections and is automatically mapped.
Click OK.