[OpenSIPS-Users] Re-invite problem -> 491 Request Pending

[Bogdan-Andrei Iancu]

Hi Brett,

This is an ancient topic that needs to be solved once for all. The 
bottom problem is that OpenSIPS / TM does try o match the 200OK ACK 
against the INVITE transaction - and it should not do that as 200OK ACK 
forms a separate transaction and it matches at dialog level, not 
transaction level. Because of this, the 200OK ACK matching is not 
reliable (especially if you do spirals on opensips) and it is also time 
consuming.

Because of this, the 200OK ACK matching takes longer than processing of 
a re-INVITE and here comes the changing in order.

IMO, this artificial / forced matching of 200 OK should be dropped.

But there are 2 modules using this:
ACC - for accounting ACK for 200 OK - not sure how many people do enable 
this
OSP - no clue :D.....

Regards,
Bogdan

Brett Nemeroff wrote:
> Jeff,
> Thanks for your reply. Is this in the loose route? or.. ? Does it 
> break anything else? Bogdan, anyway you can explain what's going on 
> here? :)
> -Brett
>
>
> On Mon, Oct 5, 2009 at 12:30 PM, Jeff Kronlage <jeff at data102.com 
> <mailto:jeff at data102.com>> wrote:
>
>     Brett,
>
>     I had this same exact problem. The solution was a little clunky
>     but sending the ACK out statelessly solves the problem.
>
>     My code looks like:
>
>     t_check_trans();
>
>     if (is_method("ACK") && !t_check_trans()) {
>
>     if (!forward()) sl_reply_error();
>
>     exit;
>
>     }
>
>     if (!t_relay()) sl_reply_error();
>
>     I wish I could give a more techie explanation on why this works –
>     it was a hackjob answer for me. Bogdan posted an answer perhaps a
>     week ago that explained it a bit.
>
>     Cheers,
>
>     --
>
>     Jeff Kronlage
>
>     Senior IT Engineer, Data102
>
>     102 South Tejon, Suite #1250
>
>     Colorado Springs, CO 80903
>
>     (719) 387-0000 x 1335 direct
>
>     (719) 578-8844 fax
>
>     jeff at data102.com <mailto:jeff at data102.com> / http://www.data102.com
>
>     *From:* users-bounces at lists.opensips.org
>     <mailto:users-bounces at lists.opensips.org>
>     [mailto:users-bounces at lists.opensips.org
>     <mailto:users-bounces at lists.opensips.org>] *On Behalf Of *Brett
>     Nemeroff
>     *Sent:* Monday, October 05, 2009 9:51 AM
>     *To:* users at lists.opensips.org <mailto:users at lists.opensips.org>
>     *Subject:* [OpenSIPS-Users] Re-invite problem -> 491 Request Pending
>
>     Hello All,
>
>     I'm not sure where the problem is.. it's either my switch, or it's
>     the customer's box.
>
>     What's happening is the customer sends a call. As soon as the
>     200OK gets back to them, they re-invite.. very fast. The reinvite
>     occurs BEFORE the ACK for the 200OK makes it back to the provider.
>     Because of this, when the RE-INVITE hits the provider they respond
>     with "491 Request Pending", in other words, I can't process a
>     re-invite because the last INVITE hasn't send me an ACK back yet.
>     This happens over.. and over.. and over.
>
>     What I'm wondering is if there is a timer I can adjust for this.
>     Seems like OpenSIPs should know that the transaction is in a state
>     where there is a PENDING ACK and it shouldn't process the
>     RE-INVITE quite yet (Request Queued?). Perhaps that isn't a normal
>     function of a Proxy. So I guess I'm looking for either a timer
>     adjustment or a way to insert some sorta delay (sounds like a bad
>     idea) to allow the ACK to traverse.
>
>     The numbers are VERY close.. the ACK actually arrives at timestamp
>     12.757073, but the INVITE goes to the provider at 12.755913. So in
>     other words, if the RE-INVITE occured 0.001161 seconds later, this
>     wouldn't happen. Seems like there should be something to prevent
>     these events? (A properly working UAC perhaps?!)
>
>     Any ideas?
>
>     Thanks,
>
>     Brett
>
>
>     _______________________________________________
>     Users mailing list
>     Users at lists.opensips.org <mailto:Users at lists.opensips.org>
>     http://lists.opensips.org/cgi-bin/mailman/listinfo/users
>
>
> ------------------------------------------------------------------------
>
> _______________________________________________
> Users mailing list
> Users at lists.opensips.org
> http://lists.opensips.org/cgi-bin/mailman/listinfo/users
>