On 04/12/2020 13.10, Andrew Chen wrote:
So from a SIP point of view, the 200 OK should of sent the final negotiation of SDP once the client ACK's it right?
The requirement to send an updated offer once ICE has completed with the final negotiated candidates existed in the original ICE RFC, but I believe it has been removed in the newer ICE RFC (I'm not 100% sure about that though). For rtpengine that requirement certainly doesn't exist and it's happy to negotiate and conclude ICE without a final updated offer. Also rtpengine itself cannot trigger such an updated offer since it's not directly in the SIP path, so that would have to be left up to the clients. So in short, a single offer/answer exchange is enough to get ICE started and it can complete negotiation out of band without further signalling.
Cheers