Bootstrap IMSI is used as the default IMSI. When arriving at the destination, the optimal IMSI is switched according to tariffs and network quality, and the IMSI is delivered via binary SMS or data channel.

The mainstream form in the IoT era, integrating SIM into the device communication module, achieving flexible IMSI switching and low tariffs while ensuring data security.

A traditional SIM card form containing only one IMSI, generally used for local networks and roaming agreements in advantageous regions.

Multiple IMSIs are written into one physical SIM card to achieve low tariffs in multiple regions. However, the cost of multi-IMSI makes this form suitable for frequent cross-border scenarios.