I had a very funny and equally annoying experience today. I have a US-based DID number purchased from voip.ms. This number is forwarded to an extension of sipXecs system and from there a call forwarding rule via voip.ms sends the call to my cell phone. I received a call to the DID this morning and answered it on my cell phone. The caller had the wrong number so the call was over in a few seconds. After that I started getting strange calls from the same caller every half an hour. When answering the call I would hear dead silence on the line. This continued for hours. Loud noise from banging the phone on the desk and use of strong language would not stop the guy from calling over and over.
It turns out during call disconnect of the first call sipXbridge messed up the call termination, probably due to http://track.sipfoundry.org/browse/XX-6698. It was then left thinking that it had a call in progress and session timers audit would kick in every 30 minutes. Unfortunately the ITSP SIP UA (User-Agent: VoIPMS/SERAST) is not behaving properly and is treating the in-dialog session timers reINVITE as a new call. The ITSP is actually making a call to my cell phone each time. It is also OK with reusing the old "to" and "from" tags and callId for the new call. The other piece of the puzzle is that every time I would answer the call on my cell phone and hang up the BYE is generated by the ITSP, but sipXbridge would reject it with "500 out of order" response, and sipXbridge would keep the call alive. Clearly treatment of the reINVITE as a new call is an issue with the ITSP. But, I may have a hard time getting the ITSP to fix this problem on their end. Is there anything we can do at the sipXbridge end to help minimize the damage in this scenario? I see two opportunities: 1. During re-INVITE processing ITSP sends provisional 180 ringing response to sipXbridge. Could this be the hint that the UA is setting up a new call? 2. When ITSP sends a BYE to sipXbridge could this be a strong enough indication that this call is better be disconnected, even though sipXbridge sees that the sequence number is wrong. Thanks, Mark. _______________________________________________ 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/
