Hello, I want just give a hit how we had solved it a long time ago.
a) the switch will send INVITE without SDP to BOB_ASIDE b) receive answer 200ok with SDP from BOB_ASIDE c) build the INVITE with sdp from BOB and send to ALICE_BSIDE d) ALICE will answer the INVITE with 200okSDP. e) sending RE-INVITE to BOB_ASIDE with SDP from ALICE. f) the call is complete , talk phase. g) BOB and ALICE release the call. Regards! Valdemar -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of ext Worley, Dale R (Dale) Sent: Wednesday, August 17, 2011 9:46 AM To: Aaron Clauson; [email protected] Subject: Re: [Sip-implementors] Initiate 3-Way Call > From: Aaron Clauson [[email protected]] > > 1. Alice places call to B2BUA which initiates a call to Bob, > > 2. Bob answers and a dialog 1 is established between Alive and Bob, > > 3. The B2BUA initiates a call to Alice and when she answers, putting Bob on > hold, the B2BUA initiates a call to Charlie, > > 4. Charlie answers and a dialog 2 is established between Alive and Charlie, > > 5. Alice hits the 3 way call button on her phone (on a Cisco 7960 the menu > option is Conf) and the media streams from the two dialogs are combined in > the audio mixer and the 3 way call proceeds. > > The problem with that approach is step 3 where Alice is waiting for Charlie > to answer when she would most likely prefer to be speaking to Bob. You're being rather sloppy here about "call", "dialog", and "B2BUA". If the device in the middle is a B2BUA, then Alice has a dialog to the B2BUA, which it connects to a dialog from the B2BUA to Bob -- there is no "dialog established between Alice and Bob", though in the logicl sense, there is a call between them. Until you use the terminology correctly, communication is going to be difficult. In regard to step 3, one alternative is: the B2BUA sends an INVITE to Charlie; when Charlie answers, the B2BUA sends a REFER to Charlie telling his UA to call Alice. That makes Charlie wait rather than Alice. Alternatively, in step 3, when Alice answers the call back from the B2BUA, she can flip back to the first call and let the second call complete on its own, though it's unlikely the UA will tell her clearly when Charlie answers. Dale _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
