The TMSI is a 32-bit temporary mobile subscriber identity that can be used to avoid sending the IMSI in the clear on Um.

Note that the subscriber identity must be established before authentication or encryption, so the first transaction in a new network must be initiated by transmitting the IMSI in the clear.

The Bridgewater Home Subscriber Server (HSS) is a master repository that contains subscriber and device information, and manages subscriber identities, service profiles, authentication, authorization, and quality of service for LTE and IP Multimedia Subsystems (IMS) networks.

In public land mobile networks, the E.212 numbering plan is used for subscriber identities (e.g., stored in the GSM SIM) while E.214 is used for routing database queries across PSTN networks.

The Tru SIM allows more than one mobile subscriber identity (IMSI) to be added onto the SIM, so a user can have a number for every country Truphone has a local partnership with.

These errors are caused by the spoofed subscriber identities.

At that point, the global "international mobile subscriber identity" (IMSI) must be sent to the network.

This is the reason a mobile phone is, in fact, a combination of phone and the subscriber identity (SIM).

This can be done by using a communication terminal or else just by using the subscriber identity in the visited network.

Beyond that is the subscriber number or mobile subscriber identity number, though even that may be divided into sections.