Home Subscriber Server (HSS)
The Home Subscriber Server is a centralized database for IMS, Packet Switched (PS) and Circuit Switched (CS) entities. The Home Subscriber Server (HSS) is a core network entity that plays a very central role in user authentication, authorization and session management.
Home Subscriber Server based on 3GPP specifications. IMS HSS is built with a fully modular approach therefore is easily extensible. IMS HSS has been implemented using the high performance application development framework called AMPS (Asynchronous Middleware for Protocol Servers) that functions asynchronously so consequently HSS works in a smooth non blocking manner.
HSS Features
  • 3GPP IMS Cx/Dx and Sh applications (3GPP TS 28.229, 3GPP 28.228, 3GPP TS 29.328)
  • Diameter Base Protocol (RFC 3588)
  • Subscriber Profiles & Service Profiles
  • Extensibility Support for PS core and CS core Interfaces
  • High Performance and Scalability due to asynchronous development (AMPS)
HSS Architecture

HSS is implemented as an AMPS modules, which we can call the application's main module. The Sh and Cx/Dx interfaces which are part of HSS functionality are implemented as standalone AMPS modules. The functionality that accesses DBMS, is implemented as standalone AMPS module, and is known as Database Module. Any access to DBMS required by any constituent component of HSS will be serviced through the Database module and never through direct DBMS interaction. The following diagram represents the Home Subscriber Server Block Level Architecture.