SUPI (Subscription Permanent Identifier) is a globally unique identifier for the UE in the 5G network. It is typically derived from the IMSI (International Mobile Subscriber Identity) of the UE, or a similar identifier.

SUPI can be IMSI-based, or Network Access Identifier (NAI) based.

• When the UE connects to the 5G Network through 3GPP access, its identifier will be the IMSI-based SUPI. And its format will be the same as the IMSI (MCC+MNC+MSIN).

• While, when the UE connects to the 5G Network through a non-3GPP access, such as Wifi, its identifier will be Network Access Identifier based, such as ([email protected]).