Re: [MMUSIC] Trickle ICE for SIP Questions

[Christer Holmberg <[e-mail]>]

Hi,

As I've been on vacation, I tried to go through this thread in one sweep. I may have missed/misunderstood some parts, and my apologies if my comments below have already been dealt with.

First, regarding 180, no matter if we use PRACK or not, SIP requires the SDP to be identical in all 180 responses. That means you can't add new candidates in subsequent 180 responses (eventhough vanilla ICE uses 180s without PRACK, the SDP is identical in all 180s, AFAIR).

Second, I get a little confused when we talk about the UAS sending INFO before it knows that the dialog is established, and that we would define some new handling rules when an error response is received. Now, IF we want the UAC to inform the UAS that the dialog has been established, we don't need PRACK for that. The UAC could send an INFO when it receives the 180, and when the UAS receives the INFO it knows the dialog has been established. I haven't thought so much about it, so I am not suggesting such mechanism at this point, I am only saying that it would be a possible solution from a SIP protocol perspective :)

Regards,

Christer