Question: In HRPD to E-UTRAN Interworking for 3GPP System Architecture Evolution (SAE), what authentication protocol does the User Equipment (UE) utilize when interacting directly with the Mobility Management Entity (MME) to establish a security association?
Option 1: UMTS-AKA (Universal Mobile Telecommunications System Authentication and Key Agreement)
Option 2: EPS-AKA (Evolved Packet System Authentication and Key Agreement)
Option 3: EAP-SIM (Extensible Authentication Protocol for Subscriber Identity Module)
Option 4: IKEv2 (Internet Key Exchange version 2)
Explanation: In the context of HRPD to E-UTRAN Interworking, when a UE connects to the EPS via a non-3GPP access network like HRPD, it directly interacts with the MME for authentication and security association establishment. Given this scenario, the UE employs EPS-AKA, designed for authenticating subscribers in the Evolved Packet System, ensuring secure access to the EPS network even when tunneled over non-3GPP accesses like HRPD.