[SR-Users] Asterisk re-INVITE race condition, error 500.

[Ovidiu Sas]

Maybe adding a "Retry-After" header to the 500 might help.

Regards,
Ovidiu Sas

On Mon, Jun 3, 2013 at 8:20 PM, Klaus Darilion
<klaus.mailinglists at pernau.at> wrote:
> This is a known problem without simple solution. It can also happen if the
> ACK gets lost somewhere.
>
> The proper solution is to fix Freeswitch. The reINVITE is an implicit ACK
> (as there wouldn't be a reINVITE if there wouldn't have been an ACK). Thus,
> FS should accept the reINVITE and implicitly behaves like the ACK was
> received. Later, when the ACK arrives, it should be ignored by FS.
>
> Actually Asterisk should also handle the 500 correctly and try the reINVITE
> again (or works although the reINVITE failed).
>
> regards
> Klaus
>
>
> On 03.06.2013 21:23, David K wrote:
>>
>> Hello all,
>>
>> So I have three machines, we don't care about audio for this problem, so
>> everything I mention here is SIP related.
>>
>> Freeswitch <--> Kamailio 3.3.2 <--> Asterisk
>>
>> 1. Asterisk sends an INVITE to Freeswitch through the Kamailio proxy.
>> 2. Kamailio replies 100 Trying and forwards to Freeswitch
>> 3. Freeswitch replies 100 Trying
>> 4. Freeswitch replies 180 Ringing to Kamailio
>> 5. Kamailio routes the answer to Asterisk
>> 6. Freeswitch replies 200 OK to Kamailio
>> 7. Kamailio replies 200 OK to Asterisk
>> 8. Asterisk replies ACK to Kamailio
>> 9. Asterisk sends a re-INVITE to Freeswitch through Kamailio
>> 10. Kamailio routes the re-INVITE to freeswitch
>> 11. Kamailio routes the ACK to freeswitch.
>> 12. Freeswitch replies 500 Server error because it got a re-INVITE
>> before the ACK.
>>
>> So, my problem is that Kamailio seems to process my re-INVITE more
>> quickly than the ACK. So Freeswitch replies an error because it got the
>> re-INVITE before the ACK.
>>
>> So my "solution" is to add a usleep(20); for re-INVITEs on Kamailio, but
>> I think this is a lousy solution.
>>
>> Has anyone here had to deal with problems where Kamailio routes a
>> re-INVITE faster than an ACK causing endpoints to return error
>> messages?  Has anyone had to deal with a similar issue?
>>
>> Thanks,
>>
>> David
>>
>>
>>
>> _______________________________________________
>> SIP Express Router (SER) and Kamailio (OpenSER) - sr-users mailing list
>> sr-users at lists.sip-router.org
>> http://lists.sip-router.org/cgi-bin/mailman/listinfo/sr-users
>
>
> _______________________________________________
> SIP Express Router (SER) and Kamailio (OpenSER) - sr-users mailing list
> sr-users at lists.sip-router.org
> http://lists.sip-router.org/cgi-bin/mailman/listinfo/sr-users



-- 
VoIP Embedded, Inc.
http://www.voipembedded.com