Temporary Public User Identities and Multi-SIM Scenarios

The Oracle Communications Unified Session Manager’s SIP interface supports multiple registered users for the same P-Asserted-Uri (PAU), a useful ability for multi-SIM scenarios. The call flow for this type of scenario differs depending on whether or not you configure the SIP interface facing the UE with the reg-via-key and reg-via-match options.

In a multi-SIM scenario, the UE derives a temporary IMS public identity (IMPU); that UE then registers with the Oracle Communications Unified Session Manager using the IMPU as the address of record (AoR) from a unique IP. The S-CSCF returns a PAU in the 200 OK, which the Oracle Communications Unified Session Manager caches. The UE then derives another IMPU; it registers with the Oracle Communications Unified Session Manager using that IMPU as the AoR from another unique IP. The S-CSCF again returns the same PAU in the 200OK.