My question is when will MME initiate detach request with detach type as IMSI detach. I know that IMSI detach will happen when MME wants the subscriber to move out of non-eps service and move the association with the MSC to GS-NULL state .
In the network to UE direction:
Bits
3 2 1
0 0 1 re-attach required
0 1 0 re-attach not required
0 1 1 IMSI detach
1 1 0 reserved
1 1 1 reserved
I searched through all the spec but couldn't find a spec ref when will MME initiate detach request with detach type as IMSI detach.