[OpenSIPS-Users] SIP message relay order

[Nick Altmann]

The easies way we use in such cases is:
if (is_method("INVITE")) usleep("500");
for in-dialog INVITEs (inside loose_route() / match_dialog() section).

It will delay slightly all reINVITES, but also will guarantee correct order
of packets.

2017-02-06 22:46 GMT+03:00 Stas Kobzar <stas.kobzar at modulis.ca>:

> Hello Bogdan,
>
> In my case, ACK for previous INVITE has already been received by OpenSIPS,
> but not sent yet.
> In this case, will the variable $DLG_status still equals 3 ?
>
> Thanks
>
> On Sun, Feb 5, 2017 at 11:15 AM, Bogdan-Andrei Iancu <bogdan at opensips.org>
> wrote:
>
>> Hi Stas,
>>
>> Such races may happen at application level or even at network level (when
>> using UDP) - so if you have 2 packets very close as time, they may swap.
>> That is SIP :)
>>
>> The full guilt is in the UAC device, IMHO - it should let some time gap
>> between the ACK and re-INVITE, to eliminate any possible races.
>>
>> Now, what you can do is to use the dialog module and to check the dialog
>> state when receiving the re-invite. If $DLG_status is *3* (Confirmed by
>> a final reply but no ACK received yet), drop with no reply the re-INVITEs
>> (to force a later retransmission) :
>>     http://www.opensips.org/html/docs/modules/2.2.x/dialog.html#id297400
>>
>> Regards,
>>
>> Bogdan-Andrei Iancu
>> OpenSIPS Founder and Developerhttp://www.opensips-solutions.com
>>
>> On 02/02/2017 10:31 PM, Stas Kobzar wrote:
>>
>> Hello List,
>>
>> My call flow has initial INVITE and re-INVITE to update RTP IP/port.
>> Usually everything works well, but sometimes OpenSIPS come up with
>> following example:
>>
>> UA                 OpenSIPS          PSTN GW
>> -------------------------------------------
>> INV(CSeq: 100) -----> | ---> INV(CSeq: 100)
>> <---- 200 OK          | <--- 200 OK
>>
>> (UA sends ACK then new INVITE)
>>
>> ACK(CSeq: 100) -----> |
>> reINV(Cseq: 101) ---> |
>>
>> (OpenSIPS relays first INVITE then ACK)
>>                       | ---> reINV(CSeq: 101)
>>                       | --->   ACK(CSeq: 100)
>>
>> When PSTN gateway receives re-INVITE before ACK for previous INVITE
>> it responds 500 with Retry-After header.
>> This is correct behaviour which conforms to the RFC 3261 section 14.2
>>
>> My question is:
>> Is it possible to assure order of received and relayed messages within
>> the same SIP session? Is there any configuration parameter?
>>
>> Thank you,
>> --
>>
>> Stas Kobzar
>>
>> Developeur VoIP / VoIP Developer
>>
>>
>> Modulis­.ca Inc.
>>
>> # Bureau / Office: 514-284-2020 x 246 <(514)%20284-2020>
>>
>> Email: s <http://firstname.lastname>tas.kobzar at modulis.ca
>>
>> https://www.modulis.com
>>
>>
>> _______________________________________________
>> Users mailing listUsers at lists.opensips.orghttp://lists.opensips.org/cgi-bin/mailman/listinfo/users
>>
>>
>>
>
>
> --
>
> Stas Kobzar
>
> Developeur VoIP / VoIP Developer
>
>
> Modulis­.ca Inc.
>
> # Bureau / Office: 514-284-2020 x 246
>
> Email: s <http://firstname.lastname>tas.kobzar at modulis.ca
>
> https://www.modulis.com
>
> _______________________________________________
> Users mailing list
> Users at lists.opensips.org
> http://lists.opensips.org/cgi-bin/mailman/listinfo/users
>
>
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