Temporary mobile station identities (TMSIs) are allocated within a VLR for enhancing the system security. A TMSI corresponds to an IMSI uniquely within a VLR.
The structure of TMSI can be codetermined by the carrier and the equipment provider.
The principles for TMSI allocation are as follows:
The structure of TMSI can be codetermined by the carrier and the equipment provider.
The principles for TMSI allocation are as follows:
- A TMSI is composed of four bytes, which can be eight hexadecimals.
- The 32 bits of a TMSI cannot be all ones, because an all-one TMSI in a SIM card indicates an invalid TMSI.
