In order to speed up the search for subscriber data in the VLR a supplementary Local Mobile Station Identity (LMSI) is
The LMSI may be allocated by the VLR at location updating and is sent to the HLR together with the IMSI. The HLR
makes no use of it but includes it together with the IMSI in all messages sent to the VLR concerning that MS.
The LMSI consists of 4 octets and may be allocated by the VLR. The VLR shall not allocate the value zero. The value
zero is reserved to indicate that an LMSI parameter sent from the HLR to the VLR shall not be interpreted.