Hi, On Jul 7, 2011, at 5:06 PM, Worley, Dale R (Dale) wrote:
> ________________________________________ > From: sip-implementors-boun...@lists.cs.columbia.edu > [sip-implementors-boun...@lists.cs.columbia.edu] On Behalf Of Saúl Ibarra > Corretgé [s...@ag-projects.com] > > When doing a call transfer, the party sending the REFER communicates the URI > the recipient is supposed to call by using the Refer-To header. This header > may also contain Replaces, in order to indicate that a dialog should be > "replaced". Is there a standard mechanism to communicate *what* streams > should the recipient use when sending the outbound INVITE? > _______________________________________________ > > The general advice is that whenever a UA is making an offer, it should offer > every capacity that it supports, consistent with any restrictions that the > user has indicated as to how they want to communicate. One or more versions > of this advice are in various RFCs. > > Situations where a UA makes a "less than complete" offer usually cause bad > performance because of situations with the following structure: > > 1. A can communicate using "facilities" P and Q. (A facility can be a media > type, a codec, or whatever.) B can communicate using facilities Q and R. C > can communicate using facilities P and R. > > 2. A is communicating with B, necessarily using facility Q. > > 3. A starts a consultative communication with C, necessarily using facility P. > > 4. A wants to cause B and C to communicate (e.g., consultative transfer). B > and C must necessarily communicate using facility R, but neither of A's > communications uses facility R, so any hint that A gives to B and C will fail > to mention R. > Good example. I didn't think about that case, thanks for the input! Regards, -- Saúl Ibarra Corretgé AG Projects _______________________________________________ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
