The 3Gdb Home Subscriber Server(HSS)

This is an implementation of the HSS network element within an IP Multimedia Subsystem (IMS) Core Network (CN).
This project implements the (IMS) database schema described in 23.008 Subscriber Data, the procedures in 29.228 Signaling and the algorithms in 35.206 MILENAGE. It is based upon Release 7.
It is represented below (red background) inside an IMS Core Network.

Another well-known HSS: FOKUS Home Subscriber Server (FHoSS), used in OpenIMSCore.

Reference: http://code.google.com/p/hss/
For more information visit http://www.3gdb.org/doc/overview-summary.html