A GPRS interworking and interoperability function (IIF) is interposed between
a
serving GSM/GPRS wireless system and a second wireless system of a different technology
family to allow a mobile station homed to the second wireless system to operate
in the GSM/GPRS system. The IIF executes or emulates the behavior of a GPRS HLR
when communicating with the GSM/GPRS system, and executes or emulates the behavior
of an MSC/VLR of the home system technology family when communicating with the
home system. When a mobile station registers in the serving system, the MSC/VLR
portion of the IIF transmits a registration notification message to the home system
HLR specifying the address of an associated SGSN as though it were an MSC.
