El Miércoles, 4 de Febrero de 2009, Daniel-Constantin Mierla escribió:
REFER initial-dialog is much cleaner than INVITE of 3PCC, but it's usually not allowed by common phones. So a PBX or SIP server implementing click2dial could try first a REFER initial-request, and in case it receives a negative response (i.e. "403 Forbidden" or "501 Not Implemented") the the server could use the 3PCC INVITE.
You can do it with kamailio/openser - uac module first, then dialog module.
The admin can even build a list of devices supporting first or second option.
Great :)