A generic Bootstrapping Server Function (BSF) and the UE shall mutually authenticate using the AKA protocol, and
agree on session keys that are afterwards applied between UE and a Network Application Function (NAF).
After the bootstrapping has been completed, the UE and a NAF can run some application specific protocol where the
authentication of messages will be based on those session keys generated during the mutual authentication between UE
The Number Portability Database (NPDB) is the central element of the IN based solution for Mobile Number
Portability (MNP). MNP is the ability for a mobile subscriber to change the GSM subscription network within a
portability cluster (e.g. a country) whilst retaining his/her original MSISDN or MSISDNs.
The NPDB stores the table of correspondence between MSISDNs and Subscription networks. Upon request of the
(gateway or visited) MSC, the NPDB retrieves from the MSISDN the Routing Number pointing out the Subscription