[OpenSIPS-Users] PRACK response to 183 without SDP

[Ovidiu Sas]

That's exactly what I suggest! If you remove 100rel from INVITE, the
SIP provider should send a regular 183, not a 183 with 100rel. Then
you can safely drop the 183 without SDP.

-ovidiu

On Mon, Jan 18, 2021 at 5:08 PM solarmon <solarmon at one-n.co.uk> wrote:
>
> The call flow is that we (our system) are the caller - we send the first INVITE. The SIP provider is responding back with 183s because they want to initiate early media.
>
> Are you suggesting that we remove 100rel from our INVITE that we send out to the SIP provider?
>
> On Mon, 18 Jan 2021 at 21:54, Ovidiu Sas <osas at voipembedded.com> wrote:
>>
>> 100rel in the initial INVITE means that the caller has support for it, if requested by the caller. If not present in INVITE, the caller should not send provisional replies with 100rel.
>>
>> -ovidiu
>>
>> On Mon, Jan 18, 2021 at 15:13 solarmon <solarmon at one-n.co.uk> wrote:
>>>
>>> H Ovidiu
>>>
>>> We do not want our system to change to a 'ringing' state, which would happen if it receives 180. We would like to drop the first 183 (without SDP) but reply back with an PRACK (since 100rel was sent) and let the subsequent 183 (with SDP) through. This is just a quirk in our system that we are looking to find a workaround for.
>>>
>>> I don't think removing 100rel from the INVITE would work? The sender of the INVITE has put in 100rel and is expecting a PRACK, so us removing it does not change this expectation?
>>>
>>> Thank you.
>>>
>>> On Mon, 18 Jan 2021 at 19:03, Ovidiu Sas <osas at voipembedded.com> wrote:
>>>>
>>>> You can change the 183 into an 180 and let the prack take its course.
>>>>
>>>> Alternatively, you can remove 100rel from the initial INVITE and drop the 183 without SDP.
>>>>
>>>> -ovidiu
>>>>
>>>> On Mon, Jan 18, 2021 at 11:05 solarmon <solarmon at one-n.co.uk> wrote:
>>>>>
>>>>> Hi,,
>>>>>
>>>>> I have a requirement to stop 183 without SDP packets from being passed, as well as having to reply back with a PRACK.
>>>>>
>>>>> I can stop the 183 without SDP from being passed on with the following in onreply_route[]
>>>>>
>>>>>  if ($rs == "183" && !has_body_part("application/sdp")) {
>>>>>                 drop();
>>>>>                 exit;
>>>>>         }
>>>>>
>>>>> However, how do I reply back with a PRACK?
>>>>>
>>>>> Thank you.
>>>>> _______________________________________________
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>>>>> Users at lists.opensips.org
>>>>> http://lists.opensips.org/cgi-bin/mailman/listinfo/users
>>>>
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>>
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