Session Modification
SDP Response Example
① Alice invite’s Bob to a session with the parameters in sdp1 ② Bob’s modified this in his response sdp2. |
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They communicate ③ Bob proposes a change in the session (sdp2¢), Alice does not accept this change ④ Bob tries with a new proposal (sdp2¢¢) ⑤ Alice accepts with the session description sdp1¢
They communication with the new spec. |
Transcript
[slide197] We said, initiate, modify, and terminate. In this case, in the middle of the media session, Bob proposes a change in the session. So while Alice and Bob are continuing, Bob sends the change in another SDP INVITE message. So he and Alice in the background, while they're talking and looking at each other, can be negotiating for a new set of parameters, for a new set of CODECs, and even a new set of IP addresses to send that media to. For instance, sending the video to the video projector instead of my laptop. Because it might have its own SIP server associated with it.