An apparatus in an IP network, the apparatus comprises: a receiver configured to: obtain an identity of a first entity, the identity is a unique identification of the first entity at a given time, obtain a first identifier of the identity, and obtain a second identifier of the identity, the first identifier and the second identifier are identifications of the identity; and a processor coupled to the receiver and configured to: create an association of the first identifier and the second identifier with the identity, and instruct storage of the association in a database.