Question: In a non-3GPP access scenario, how is MIPv4 signaling security typically ensured between the User Equipment (UE) and the node acting as the Home Agent (HA), which in this context is the PDN Gateway?
Option 1: Using IPSec tunnels as defined by IETF for general mobility security.
Option 2: Through TLS encryption, standard for web security, adapted for MIPv4.
Option 3: Utilizing MIP Authentication extensions as outlined in RFC 3344.
Option 4: Relying on inherent non-3GPP access network security mechanisms.
Explanation: The correct answer is Option 3 because MIPv4 security employs MIP Authentication extensions, defined in RFC 3344, to protect signaling messages between the UE and the node acting as the HA (in this case, the PDN Gateway), tailored for Mobile IPv4's unique requirements.