Question: What action does a User Equipment (UE) take when it fails to authenticate a network due to invalidation of the Proxy-Call Session Control Function (P-CSCF) certificate in an IP-based service scenario?
Option 1: The UE attempts to reconnect using a different access point.
Option 2: The UE sends a failure notification to the Serving Gateway (S-GW).
Option 3: The UE initiates a new TLS handshake with reduced security parameters.
Option 4: The UE sends an alert message to the P-CSCF, including failure information as specified in Transport Layer Security (TLS).
Explanation: In IP-based services, secure authentication between the User Equipment (UE) and the network is crucial. If the UE cannot validate the P-CSCF's certificate, it indicates a potential security risk. Sending an alert message to the P-CSCF with detailed failure information (as per TLS specifications) allows for swift identification and resolution of the issue, ensuring the integrity of the network and protecting against potential threats. This action prioritizes security and facilitates troubleshooting.