Thanks, Castillo, Your advice is very useful.
> > A re-INVITE requires the dialog established prior to take place, while an > UPDATE could occur within the dialog establishment (between INVITE and 200 OK > I mean) to change SDP parameters and so. > This is an UPDATE usage for the early dialog in RFC3311 5.1., isn't it. > Also, an UPDATE is inmediately replied by the SIP core of the remote endpoint. ~~~~~~~~~~~~~~ Does 'immediate' (above) means 'befor the session is established'? > In the other hand, re-INVITE could require, in some cases, authorization of > the user (human user). May this be done, as same, by an UPDATE , too? > For example, alice is in an audio call with bob, and > after some minutes of conversation bob decides to add video to the session. > This is acomplished by sending a re-INVITE with audio&video SDP. Alice's phone > receives such re-INVITE and ask the human user to accept or reject the video > session. > I understood as follows: *A reINVITE MUST NOT be used until completion of the SESSION (NOT dialog). (For example, the session means a sequence from an INVITE to an ACK.) *An UPDATE MAY be used before completion of the SESSION. * Both of them(a reINVITE and UPDATE) MUST NOT be used until completion of dialog(that means an offer/answer exchange). *An UPDATE MUST NOT be used before an initial INVITE ( that start a session). I think the important point is the following: "The SESSION and DIALOG are different." Are my above thoughts right? Please let me know. I look forward to hearing from you(folks). Thanks, Tabt _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
