On Tue, 2010-04-27 at 14:57 -0400, Worley, Dale R (Dale) wrote: > That's an extremely ugly problem. > > On one hand, it's impossible to determine reliably whether a given > fork of a dialog has early media coming in. (That has caused a number > of headaches in SIP.) > > On the other hand, the fix you describe is about the only one that > allows such IVR systems to work reilably, but it also prevents a > no-answer condition at an external destination from falling over to > another destination. It also would be hard to implement, as you have > to prevent every passage of the INVITE through the proxy from applying > an expiration time, despite that the upstream passages may not know > that the call ultimately goes out a gateway. > > You might want to look into convincing the gateway to send a 200, to > treat the call as having connected.
We can't get gateways to send 200 - the early media IVR problem is well known. The mapping from ISDN signaling to SIP doesn't allow it. As Robert discovered, the existing forking logic would handle it correctly if that expires were not there. IVRs like this are _very_ common (American Airlines and the IRS both do this, for example). Why were those explicit expires parameters added? _______________________________________________ sipx-dev mailing list [email protected] List Archive: http://list.sipfoundry.org/archive/sipx-dev Unsubscribe: http://list.sipfoundry.org/mailman/listinfo/sipx-dev sipXecs IP PBX -- http://www.sipfoundry.org/
