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

[Olle E. Johansson]

On 30 Jan 2014, at 23:23, dotnetdub <dotnetdub at gmail.com> wrote:

> Hi David,
> 
> Sorry to drag up a very old thread - we are seeing this also with
> asterisk kamailio and FS and I have tried lots of different
> combinations on both asterisk and FS to make it go away without
> success.. Did you ever come up with something better than the usleep ?
> 
If freeswitch believes it already has an open INVITE transaction it should
not respond with 500, it should respond with 491 request pending. In that 
case Asterisk will back off and retry.

Please check with the FreeSwitch people and file a bug report so that they
can fix this issue. That's the long term solution, all the rest is just quick and
dirty fixes. Seems like if this problem is still around, no one filed a bug report.

/O
> Many Thanks
> 
> 
> 
> 
> On 3 June 2013 20:23, David K <kamailio.org at spam.lublink.net> 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
>> 
>> 
>> 
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