2009/8/31 Stefan Sayer <stefan.sa...@iptego.de>: > > Hi Iñaki, > > o Iñaki Baz Castillo [08/31/09 13:23]: >> >> Hi, an existing and very extended privative and diabolic VoIP protocol >> has a cool feature about voice conference: >> >> 1) alice is speaking with bob. >> 2) alice decide to invite carol to the conference. >> 3) carol receives a call and shows the number of the participants >> (alice and bob). >> >> With the current SIP conference specifications (which I have not read >> yet): >> >> - Is point 2 possible? This is: creating a conference from a previous >> user2user normal call. > > alice can set up the conference call and transfer bob and possibly carol > into the conference.
Yes, but this is not so useful. In most of the cases the flow is: - alice is speaking with bob. - Later, both realize that carol has been connected (presente status). - alice wants to invite carol to the *existing* conference. This is what people expects instead of having to call first to the conference server, latter invite bob and carol in other phone line and transfer them to the conference. >> - Is point 3 possible? This is: the INVITE carol receives contains >> info about the current participants and also includes some header or > > I think the idea is to SUBSCRIBE to a conference notification service that > will give you the list of participants attending, and NOTIFY you in case of > changes. Sorry but I don't understand. How could it be useful? what about dynamically created conferences? Nobody can expect that carol is always subscribed to *any* conference. And anyway... does a "subscription to conference status" exist for SIP? >> attribute that indicates carol that the request comes from a >> conference system. > > grep the standards for "isfocus". > > A much much simpler method for a completely centralized conference: Have the > SDP contain an u= line (see RFC4566), or the INVITE a Call-Info header (see > 3261) with the url, and in the client display the conference status and > control with state of the art web app GUI (not very beautiful example, but > does have url in SDP: https://webconference.iptel.org ). REFER bob to the > conference. Thanks, but what you suggest seems more a "propietary" implementation rather than a real standard, so it would require "custom" clients understanding these parameters in the way you suggest. Also, I expect that the days in which all the "cool" SIP features are implemented as a web are close to dissapear :) The intelligence must be in the endpoints rather than in a web page :) -- Iñaki Baz Castillo <i...@aliax.net> _______________________________________________ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
