The Home Subscriber Server (HSS) combines the HLR and the Authentication Center (AuC) functions. The HLR stores and updates the database containing all the user subscription information, including the following:
- User identification and addressing, similar to the International Mobile Subscriber Identity (IMSI) and Mobile Subscriber ISDN Number (MSISDN) or mobile telephone number.
- User profile information, includes service subscription states and user-subscribed Quality of Service information (such as maximum allowed bit rate or allowed traffic class).
The generates security information from user identity keys and provides this information to the HLR and to other entities in the network. Security information is used for:
- Mutual network-terminal authentication.
- Radio path ciphering and integrity protection, to ensure data and control information transmitted between the network and the terminal is not eavesdropped or altered.