# Engine Editor > Routing > Link Usage

Use this branch to select a Link Usage Profile for an Security Engine and to define link usage exceptions for the Security Engine.

Option | Definition
--- | ---
Link Usage Profile | To enable dynamic link selection for the Security Engine, select a Link Usage Profile element.
Link Usage Profile Properties (read only) (Not editable) | Shows the properties of the selected Link Usage Profile element.
Exceptions to Link Usage Profile table (When a Link Usage Profile element has been selected) Click Add to add a row to the table, or Remove to remove the selected row. Click Up or Down to move the selected item up or down.
Source | The source IP addresses or users that the rule matches. Double-click the cell to select an element. You can also use type-ahead search to select an element.
Destination | The destination IP addresses or users that the rule matches. Double-click the cell to select an element. You can also use type-ahead search to select an element.
Service | The service or Network Application that the rule matches. Double-click the cell to select an element. You can also use type-ahead search to select an element.
ISP Link | The NetLink that traffic that matches the rule uses. Double-click the cell to select an element.
Comment (Optional) | A comment for your own reference.