Entity links enable you to populate the drop-down list with the names of all entities created from the selected specification. For example, if you specify a Logical Device specification named Customer Edge Router, the drop-down list includes the names of all Logical Device instances created from the Customer Edge Router specification.

To populate a drop-down list with the names of entity instances created from a new specification:

1. From the Studio menu, select Show Design Perspective.

2. Click the Dictionary tab.

3. Select the data element that you want to tag as a characteristic.

   The Data Element tab appears in the Data Schema editor.

4. Click the Settings tab.

5. In the Control Type field, ensure that DropDown is selected.

   See “About Control Types" for more information.

6. Click the Characteristics tab.

   The fields on this tab are read-only if the data element is not tagged as a characteristic. See "Tagging Data Elements as Characteristics" for more information.

7. In the Drop Down Options field, select Entity Link.

8. In the Entity Link area, click the Entity link.

   The New Studio Entity dialog box appears.

9. Select an entity type, then click Next.

   The Entity Specification Wizard appears. See "Creating New Specifications" for more information.

10. Configure the properties of the new specification.

    See "Specification Editor" for more information.

11. When you finish configuring the new specification, return to the Data Schema editor.

    The new specification is displayed in the Entity Link area.

12. From the File menu, select Save.