Brett, This can probably be handled by timer C. The problem is that very few clients actually resend the last provisional response every minute to keep the transaction from expiring on timer C. In practice, application call timeouts are set to be much less then 3 minutes so that the entire cal gets hanged up and the whole transaction gets cancelled before timer C ever fires. My point is, there is a gap in SIP transaction state definition with INVITE transactions never expiring when in proceeding state, but in practice this is not a major problem since application call level timers typically terminate the whole call if it is not answered within reasonable time. So, this can be fixed but there is very little incentive for real world implementation to worry or care about this specification change.
_____________ Roman Shpount On Mon, Jun 23, 2014 at 7:14 AM, Brett Tate <[email protected]> wrote: > Hi Roman, > > Transaction state and call state are separate things. However since I'm > not > sure what timer (proprietary or RFC defined) sipcore was expecting to be > used while stuck within Proceeding because of the RFC 6026 requirement, I > posted the question to sipcore. > > It will eventually show up in the archive. > > http://www.ietf.org/mail-archive/web/sipcore/current/maillist.html > > > ----- > > From: Roman Shpount [mailto:[email protected]] > Sent: Monday, June 23, 2014 6:06 AM > To: Caixia Liu > Cc: Brett Tate; [email protected] > Subject: Re: [Sip-implementors] A Question about INVITE Server Transaction > in RFC 6026 > > Caixia, > > I do not think specification missed anything. This is quite intentional. > There is no limit of how long the caller can be dialing the number (as > there > is no limit on how long the caller can stay connected on a SIP call). If > you > need to put a limit on this duration, this will have to be application > specific and does not need to be defined in the SIP spec. For instance you > can define that dial timeout when placing the call is 1 minute and that > will > limit the duration of the proceeding state. Or you can set the dial timeout > at 10 minutes. Or you can set this to be unlimited and let the caller hang > up when they are done waiting for the call to connect. This is really up to > you. The same way you can put maximum call duration at 24 hours and limit > calls this way or you can let the caller hang up when they are done > talking. > _____________ > Roman Shpount > _______________________________________________ Sip-implementors mailing list [email protected] https://lists.cs.columbia.edu/mailman/listinfo/sip-implementors
