Question: In a 3GPP IP-based service architecture, who decides which TLS CipherSuites are utilized for confidentiality protection between the User Equipment (UE) and the P-CSCF (Proxy-Call Session Control Function)?
Option 1: The UE initiates a fixed set of TLS CipherSuites as mandated by regulatory requirements.
Option 2: Both the UE and P-CSCF mutually agree on the TLS CipherSuites through a higher-layer signaling protocol.
Option 3: Network Domain Security (NDS) protocols dictate the selection of TLS CipherSuites.
Option 4: The P-CSCF determines which TLS CipherSuites are used from those offered by the UE.
Explanation: This reflects the protocol where the UE offers TLS CipherSuites, but the final decision rests with the P-CSCF, highlighting its role in ensuring secure communication sessions between the UE and the network for confidentiality protection.