Question: In MBMS (Multimedia Broadcast/Multicast Service) using SDP (Session Description Protocol), how is the presence of an FEC (Forward Error Correction) layer between IP/UDP and RTP/RTCP indicated?
Option 1: Using a new payload type in the RTP/AVP protocol identifier
Option 2: With specific protocol identifiers ‘UDP/MBMS-FEC/RTP/AVP’ and ‘UDP/MBMS-FEC/RTP/SAVP’
Option 3: By adding an FEC parameter to the Security Description for MIKEY messages only
Option 4: Through a separate SDP attribute for each media component's FEC parameters
Explanation: The correct answer highlights that specific protocol identifiers ‘UDP/MBMS-FEC/RTP/AVP’ and ‘UDP/MBMS-FEC/RTP/SAVP’ are defined to indicate the presence of an FEC layer between IP/UDP and RTP or SRTP in MBMS, signaling how devices interpret and handle error correction in multicast streams.