Patent ID: 7650149

Claim:
A method, comprising: detecting that a user equipment has requested a registration to a second serving controller using at least one of a plurality of identities in association with a first serving controller, the plurality of the identities being associated with respective registration statuses selected from a registered status and an unregistered status; issuing a registration termination request identifying the at least one of the plurality of identities, which has been newly assigned to the second serving controller as a result of the requested registration; and responsive to the registration termination request, issuing a re-registration notification to the user equipment including the at least one of the plurality of identities which has a registered status and which was not assigned to the second serving controller as a result of the requested registration, and disassociating all identities of the said user from the first serving controller, wherein at least two user equipments have a shared identity and a non-shared identity and checking, when the non-shared identity has been newly assigned to the second serving controller, whether the user eguipment has the shared identity and, if so, issuing a re-registration notification to other user equipments sharing the shared identity.