I've had a request from a user wanting to be able to initiate a 3 way call from my B2BUA. I don't do any media handling on my B2BUA so employing a server side audio mixer or such is not an option.
The desired call flow is: 1. User calls the B2BUA, 2. B2BUA initiates two outgoing calls to the two remote 3 way call participants, 3. As the remote participants answer they automagically join the 3 way call. Of course the problem is when the second remote participant answers the origin call is already answered. The first solution that springs to mind is a call flow like: 1. User calls the B2BUA, 2. B2BUA initiates single outgoing call to the first of the remote 3-way call participants, 3. After leg 2 is answered the B2BUA initiates a new call to the original caller from step 1 (who is already on the phone) who will answer and place the current call on hold, 4. After leg 3 is answered the B2BUA initiates a new call to the second of the remote 3-way call participants and when they answer the call originator will be able to bridge the two calls together on their device. That's a very clunky solution and is probably worse than the call originator just initiating the two calls himself. Are there likely to be any widely supported mechanisms that would allow something like a re-INVITE to be sent to a SIP device that's in the middle of an existing call that causes it to add an RTP stream to an existing call and create a 3-way call that way? Or is there some other way to do it noting that the call originator is likely to be using a fairly standard ATA like a PAP2 or such? Regards, Aaron _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
