The Home Subscriber Server, HSS is the master database for a given user. It is called Home, as this server contains all the information of the subscriber of that service area.It contains the subscription-related information to support the network entities actually handling calls/sessions.
A Home Network may contain one or several HSSs (depends on the number of Mobile subscriber, capacity and organisation of n/w)
The HSS is responsible for holding the following user related information:
- User Identification, Numbering and addressing information;
- User Security information: Network access control information for authentication and authorization;
- User Location information at inter-system level: the HSS supports the user registration, and stores inter-system location information, etc.;
- User profile information.
The HSS also generates User Security information for mutual authentication, communication integrity check and ciphering.
The HSS consists of the following functionalities:
- IP multimedia functionality to provide support to control functions of the IM subsystem such as the CSCF (Call Session Control Function).
- The subset of the HLR/AUC functionality required by the PS Domain (GPRS and EPC).
- The subset of the HLR/AUC functionality required by the CS Domain, if it is desired to enable subscribe access to the CS Domain or to support roaming to legacy GSM/UMTS CS Domain networks.