Question: In a Network Operation Mode II, how does a GPRS-attached MS with simultaneous GPRS and IMSI attach capability perform CS operation while being GPRS-attached?
Option 1: By accessing non-GPRS common control channels for CS operation.
Option 2: By performing an explicit IMSI detach via PS domain NAS from the SGSN.
Option 3: By avoiding all CS signaling and relying on implicit IMSI detachment.
Option 4: By executing a Combined RA/LA Update procedure.
Explanation: In Network Operation Mode II, for an MS that is GPRS-attached and has the capability to be simultaneously GPRS-attached and IMSI-attached, CS operation can be performed in parallel with GPRS operation by accessing non-GPRS common control channels. This approach allows for simultaneous use of both services without conflicting procedures.