there is known issue with the first retransmission interval. As openser use unique timer with cadence of 1 second. So if the retransmission is set (added into timer) at second n+500 ms, that the timer will hit at n+1 seconds, resulting in a 500 ms period instead of 1 sec. It's about time quantification of the timer and the time linearity of the insertion in the timer.

check this: http://www.openser.org/pipermail/users/2005-November/001579.html Regards, -ovi On 9/13/06, Stefan Römer &lt;mail(a)roemer.se&gt; wrote: > Hi !!! > > I'm using OpenSER 1.0.1 and realized some strange behaviour > when SIP UA sends ReInvite Messages. > > Initial INVITE shown below (this is OK) > > UA A OpenSER UA B > _____________________________________________________________ > > --------INVITE------------> -----------INVITE------------> > > <--------200 OK----------- <---------200 OK---------------- > > ---------ACK-------------> -------------ACK---------------> > > > > > But when an UA sends a ReINVITE message I realized following behaviour. > This happens approximatly every 3rd or 4th ReInvite. > > UA A OpenSER UA B > _____________________________________________________________ > --------INVITE------------> > -----------INVITE------------> > -----------INVITE------------> > > <--------200 OK----------- <---------200 OK---------------- > <--------200 OK----------- <---------200 OK---------------- > . > . > . > . > > > Is there any reason for OpenSER sending ReINVTE twice? > Any chance to avoid this? > > > Sincerly > > Stefan > > > _______________________________________________ > Users mailing list > Users(a)openser.org > http://openser.org/cgi-bin/mailman/listinfo/users >