The MS doesn’t know it, but the BSS does. So the BSS will handle an IMSI ATTACH from the MS as a “COMBINED GPRS/IMSI ATTACH” –> The MS will actually communicate with the SGSN, instead of the MSC directly.
I don’t know all the details, if anyone can elaborate …
Also the MS should check the NMO (=Network Mode of Operation) inside “GPRS Cell Options”/SysInfo3.
Based on this value and its MS Class, the mobile has to know if it has to perform a combined attach.
Yes, MS know NMO from system info (from SI13\GPRS Cell Options). When MS want to perform any mobility management procedures (e.g. Attach/Detach) and NMO=I, it should indicate to network what Type of Attach it doing in attach request (only GPRS attach, GPRS attach with already IMSI Attached or Combined GPRS / IMSI attach ).
Sorry Guys It was my first time on this forum. This clear code is not related to Gs interface. It is related to call Clearing. The desccription is
“This cause is used to report a resource unavailable event only when no other cause in the resource unavailable class applies.”