The HSS configuration enables the following main features:
- identity and authentication management
- support for 3GPP LTE and IMS interfaces
- support for Voice over LTE (VoLTE/ViLTE) profile according to GSMA IR.92/94
- WLAN/3G interoperability
- HLR functionalities for 2G/3G users integration with 2G/3G external HLR for authentication functionality
- UPSF functionality for NGN users
i-TDS is deployable in High Availability (in the same site) and in Geographical Redundancy (in case of one site unavailability) activating two-way asynchronous replica between the two databases. In this configuration, it is possible to configure both active-standby and active-active scenarios. The latter allows turning on a load sharing access between the two different databases.