Question: In 3GPP IP-based services security, when a User Equipment (UE) receives a challenge with the stale parameter set to TRUE in the WWW-Authenticate header during a REGISTER request, what action must the UE take regarding the existing TLS session for the retry?
Option 1: Establish a new Transport Layer Security (TLS) session for the retry.
Option 2: Abort the current TLS session and wait for a new challenge before retrying.
Option 3: Utilize the existing TLS session for the REGISTER request retry.
Option 4: Send an error response to the network indicating stale parameter receipt.
Explanation: When the UE encounters a stale parameter set to TRUE, it indicates that the server wants the UE to retry with updated credentials but sees no need to re-establish security context. Thus, the UE should retry the REGISTER request with a new encrypted response while leveraging the existing TLS session for efficiency and maintaining the already established secure connection. This approach ensures continuity of security without unnecessary overhead.