Some embodiments provide a method for updating registration information of a user equipment (UE) in a communication system that includes several evolved Universal Mobile Telecommunication System (UMTS) Terrestrial Radio Access Network (E-UTRANs) that communicatively couple the UE to a Voice over long term evolution (LTE) via Generic Access (VoLGA) network controller (VANC). The method receives a message at the UE from the VANC including a list of E-UTRAN tracking areas (TAs) served by the VANC, each tracking area identified by a tracking area identifier (TAI). The method stores the list of E-UTRAN tracking areas at the UE. The method sends a register update message that includes a TAI of a particular E-UTRAN tracking area from the UE to the VANC when the UE moves into the particular E-UTRAN tracking area and the particular E-UTRAN TAI is not in the list of E-UTRAN tracking areas (TAs) served by the VANC.