Question: In an MCPTT (Mission Critical Push To Talk) call setup, under what condition can the IWF (Interworking Function) floor control server optionally give an early indication to send RTP media packets to the inviting MCPTT media endpoint?
Option 1: When the "mc_queueing" feature is supported and negotiated.
Option 2: Upon receiving the first confirmed indication from the invited participating MCPTT function.
Option 3: When the first unconfirmed indication is received from the invited participating MCPTT function.
Option 4: After the IWF floor control server assigns itself an SSRC identifier.
Explanation: This question requires understanding of the initial procedures in MCPTT call setup, specifically the handling of indications and permissions for sending media. The correct answer, Option 3, highlights a nuanced aspect of MCPTT protocol where an early indication to send RTP media packets can be given based on receiving the first unconfirmed indication, showcasing the protocol's flexibility in managing real-time communications. This scenario is particularly relevant in mission-critical contexts where timely communication is paramount.