OsmoHLR, the Osmocom HLR is a minimal implementation of the Home Location Register, the subscriber database of a 2G/3G cellular network. It stores parameters such as the IMSI and MSISDN of each subscriber, together with the secret key material (Ki, K/OP/OPc) in order to generate authentication vectors.

OsmoHLR does not support the classic TCAP/MAP protocol but rather implements the more light-weight GSUP protocol.

Software / Logical specification

SGSN connection Osmocom GSUP
MSC connection Osmocom GSUP
Operating System Linux

More technical information can be found on Osmocom.