Question: What indicates a successful incoming inter RAT (Radio Access Technology) handover from SGSN to MME in an EPC network, specifically for handovers from CDMA2000 to EPS?
Option 1: Transmission by SGSN of 'Relocation Request' message to MME
Option 2: Transmission by MME of 'Direct Transfer (S101 Session ID, Attach Accept, (and Bearer Setup Request))' to HRPD access network
Option 3: Receipt by SGSN of 'Forward Relocation Response' from MME
Option 4: Handover initiation by the UE: User Equipment
Explanation: The transmission by MME of a 'Direct Transfer' message, including S101 Session ID, Attach Accept, and potentially Bearer Setup Request, to an HRPD access network, signifies the completion of a handover from CDMA2000 to EPS. This ensures seamless transitions between different radio access technologies in heterogeneous network environments.