Question: When a UE supports both SIP Digest and other authentication methods, and is connected to an access network not defined in telecom standards, which authentication method should be used if both the UE and network support IMS AKA?
Option 1: SIP Digest
Option 2: IMS AKA
Option 3: IPsec
Option 4: HTTP Digest
Explanation: If the access network is non-standard and both the UE and network support IMS AKA, the authentication method shall be IMS AKA, prioritizing its stronger security through key agreement and authentication capabilities over SIP Digest.