[OpenSIPS-Devel] Messages out of order?

[Chris Maciejewski]

Hi Bogdan,

Thanks for your comments.

2009/4/22 Bogdan-Andrei Iancu <bogdan at voice-system.ro>:
> Hi Chris,
>
> Chris Maciejewski wrote:
>>
>> Hi,
>>
>> Just noticed that sometimes OpenSIPs forwards SIP packets out of order.
>>
>> Please see example call flow at:
>> http://wima.co.uk/sip/2009-04-21_15-01-10-c2c-123_index.html
>>
>> Packets F11 and F12 from "Click2Call" are forwarded in the wrong order
>> to "UA1".
>>
>> Is it a bug?
>
> it is not a bug - packages may change order because:
>   1) UDP (there is no guarantee of the order)
>   2) processing - as opensips is a parallel processing proxy, some packages
> may be processed slower than others (depending of the nature of the request)
>>
>>  Or maybe it is some problem with my call flow?
>>
>> Please note: Packets from Click2Call are generated by
>> "PHP SIP library" I coded myself, so quite likely they are no good.
>>
>
> well, the REFER is sent at .0002 secs after the ACK - you should give more
> time to ACK before firing the REFER. This will eliminate the risk of order
> inversion .

This is exactly where the problem was. I have added a bit of delay
before sending REFER packet, and everything is working fine now :-)

>
> Regards,
> Bogdan
>>
>> Any help/suggestions much appreciated.
>>
>> Regards,
>>
>> Chris
>>


Best regards,

Chris