LMSI - Local Mobile Station Identity

The Local Mobile Station Identity (LMSI) is a temporarily identification that can be assigned to a mobile station that visits another network than its home network. This supplementary LMSI may be assigned in the case where the roaming telephone number (MSRN) is allocated on a call-by-call basis. In these cases a LMSI can be used to speed up the search for the subscriber data in the visitors location register (VLR).

The LMSI is allocated by the VLR if the location is updated and is sent to the home location register (HLR) together with the subscriber identity (IMSI). However, the HLR does not make use of the LMSI. It includes it together with the IMSI in all messages sent to the VLR concerning that mobile station.