What happens when SIP Early Offer is enabled?

• A. SDP sent in INVITE
• B. RTP streams renegotiated automatically
• C. Media streams are opaque to signaling
• D. No SDP is exchanged in INVITE

Answer: (A)

SIP Early Offer means the initial INVITE carries an SDP offer describing the media the caller wants to use. By including the SDP in the INVITE, the caller tells the callee in advance about codecs, media types, ports, and other session parameters. The callee then chooses compatible settings and answers with an SDP in the 200 OK to finalize the negotiation. This lets the media path be established sooner and with clearly negotiated parameters.

Renegotiating RTP streams isn’t automatic just from enabling Early Offer; any changes to the media setup after the call starts typically require additional signaling (like a re-INVITE or UPDATE). Also, signaling isn’t opaque here—SDP is the mechanism signaling uses to describe and negotiate media. And there is SDP exchanged in the INVITE with Early Offer, so saying there’s no SDP in INVITE isn’t correct.