In Sentinel VoLTE, subscriber data is stored either as transparent user data in the HSS or in the HLR.
When using HSS, it is accessed through:
the XCAP Server
the REST Provisioning API
and various screens in REM.
When using HLR, it is accessed through:
Session processing uses the Sh Cache RA via the SubscriberDataLookupFromHSS feature or CGIN RA via SubscriberDataLookupFromHLR.
For more information, see Sh Cache RA configuration and Supplementary Service Data Access.