You can configure the router to support the AAA logical line identification feature. This feature enables service providers to track subscribers on the basis of a virtual port known as the logical line ID (LLID).
The LLID is an alphanumeric string that logically identifies a subscriber line. The service provider maps each subscriber to an LLID based on the user name and circuit ID from which the customer’s calls originate. When a subscriber moves to a new physical line, the service provider’s customer profile database is updated to map to the same LLID.
Because a subscriber’s LLID remains the same regardless of the subscriber’s physical location, using the LLID gives service providers a more secure mechanism for tracking subscribers and maintaining the customer database.