It may also be related to the timer accuracy of OpenSER 1.1 If the T1 interval is 500ms but OpenSER 1.1 doesn't support sub-second timer accuracy it is probable to see it retransmitting in situations where T1 hasn't been reached yet It shouldn't cause any problems though, just a few erroneous retransmits from time to time tavis Ovidiu Sas wrote: Hi Douglas, You posted this questionawhileago and by checkingthe archives Irealised that my answer was truncated somehow ... Here's the full answer: This is the way that is supposed to work. If nothing is received from upstream, the request is resent. 17.1.1.1 Overview of INVITE Transaction The INVITE transaction consists of a three-way handshake. The client transaction sends an INVITE, the server transaction sends responses, and the client transaction sends an ACK. For unreliable transports (such as UDP), the client transaction retransmits requests at an interval that starts at T1 seconds and doubles after every retransmission. T1 is an estimate of the round-trip time (RTT), and it defaults to 500 ms. It seems that your upstream UAS is slowin sending out the 100 Trying and therefor openSER is resending out the INVITE. Regards, Ovidiu Sas On Dec 3, 2007 12:35 PM, Douglas Garstang &lt;dougmig33(a)yahoo.com&gt; wrote: I have an OpenSER 1.1 install here, and for some reason, OpenSER is sending the INVITE message twice to the upstream host. Asterisk OpenSER Provider ----------------------------------------------- | ---INVITE---> | | | | ---INVITE---> | | | ---INVITE---> | | | <---TRYING--- | | | <---TRYING--- | The time difference between them is about 1/5 of a second. Nothing is received between the first and second INVITE's. Why is OpenSER doing this? I have xlog() statements everywhere in openser.cfg, and OpenSER is only logging ONE outgoing INVITE message, eventhough it's sending two. It is logging the multiple TRYING messages that come back however. OpenSER is not calling failure_route because nothing is logged in there. What could be going wrong? Why is it doing this? Doug. ________________________________ Be a better friend, newshound, and know-it-all with Yahoo! Mobile. Try it now. _______________________________________________ Users mailing list Users(a)lists.openser.org http://lists.openser.org/cgi-bin/mailman/listinfo/users _______________________________________________ Users mailing list Users(a)lists.openser.org http://lists.openser.org/cgi-bin/mailman/listinfo/users _______________________________________________ Users mailing list Users(a)lists.openser.org http://lists.openser.org/cgi-bin/mailman/listinfo/users