<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body style="overflow-wrap: break-word; -webkit-nbsp-mode: space; line-break: after-white-space;"><div>Hi colleagues, </div><div><br></div>It’s worth mentioning that PRACK (and 200 OK for PRACK) often participates in SDP offer/answer negotiation (RFC 3262, RFC 6337). I’m wondering how this can be implemented solely on the SIP proxy side?<br><div>—</div><div>Alexey Vasilyev<br id="lineBreakAtBeginningOfMessage"><div><br><blockquote type="cite"><div>14 нояб. 2025 г., в 10:39, Johan De Clercq <Johan@democon.be> написал(а):</div><br class="Apple-interchange-newline"><div><div dir="ltr">pfff, indeed. <div>you save a tiny little bit of networking traffic, that's the only thing that I see. </div><div><br></div><div>okay, </div><div>so the module should contain </div><div>- 200 OK'ing prack. </div><div>- (be able to send prack (?, if there is a use case)). </div><div>- handle update (via rtpprxoy and rtpengine). </div><div><br></div></div><br><div class="gmail_quote gmail_quote_container"><div dir="ltr" class="gmail_attr">Op vr 14 nov 2025 om 10:33 schreef Giovanni Maruzzelli <<a href="mailto:gmaruzz@gmail.com">gmaruzz@gmail.com</a>>:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr"><div>> It really is a mess, to me it seems that IMS guys are scared of rtp</div><div>+1 it is an endpoint thing, trunk providers are wrong to ask for it (what do they get from it?)<br></div><div><br></div><div>when you (trunk provider) know that the phone is actually ringing, what do you gain? It has meaning when you control the whole chain, end-to-end (carriers, IMS) not at all for deskphone->itsp->trunk->whatever->carrier->endphone</div><div><br></div><div>But I know they (trunk providers) start to *REQUIRE* PRACK</div><div><br></div><div>So, probably a module, or an extension of an existing module, can be warranted and welcome</div><div><br></div><div>Possibly on 3.6.X (that's the last LTS of the 3.0.0 series)</div><div><br></div><div>Let's open a thread on what functionalities can be useful in it?</div><div><br></div><div>-giovanni</div><div><br></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Fri, Nov 14, 2025 at 10:21 AM Johan De Clercq <<a href="mailto:Johan@democon.be" target="_blank">Johan@democon.be</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div dir="ltr">+1. I totally agree with you. <br><div>It really is a mess, to me it seems that IMS guys are scared of rtp. </div></div><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">Op vr 14 nov 2025 om 10:03 schreef Walter Schober <<a href="mailto:walter.schober@neotel.at" target="_blank">walter.schober@neotel.at</a>>:<br></div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div>
<div lang="DE">
<div><p class="MsoNormal"><span style="font-size:11pt;font-family:Calibri,sans-serif">Hi!<u></u><u></u></span></p><p class="MsoNormal"><span style="font-size:11pt;font-family:Calibri,sans-serif"><u></u> <u></u></span></p><p class="MsoNormal"><span lang="EN-US" style="font-size:11pt;font-family:Calibri,sans-serif">I also want to point out that its not done with PRACK handling alone. Followup (multiple) UPDATE with codec changes must be handled,
too. Sometimes that lead into AMR(WB)/PCMA/G722/OPUS transcoding in early state. Including all the DTMF PT issues.<u></u><u></u></span></p><p class="MsoNormal"><span lang="EN-US" style="font-size:11pt;font-family:Calibri,sans-serif">It is definitely a endpoint / softswitch feature.
<u></u><u></u></span></p><p class="MsoNormal"><span lang="EN-US" style="font-size:11pt;font-family:Calibri,sans-serif"><u></u> <u></u></span></p><p class="MsoNormal"><span lang="EN-US" style="font-size:11pt;font-family:Calibri,sans-serif">I know those ignorant IMS guys pushing out their internal mess to plain RFC3261 interconnects and forcing tasks previously done by an
MSC to the rest of the world.<u></u><u></u></span></p><p class="MsoNormal"><span lang="EN-US" style="font-size:11pt;font-family:Calibri,sans-serif"><u></u> <u></u></span></p><p class="MsoNormal"><span lang="EN-US" style="font-size:11pt;font-family:Calibri,sans-serif">Br<u></u><u></u></span></p><p class="MsoNormal"><span lang="EN-US" style="font-size:11pt;font-family:Calibri,sans-serif">Walter <u></u><u></u></span></p><p class="MsoNormal"><span lang="EN-US" style="font-size:11pt;font-family:Calibri,sans-serif"><u></u> <u></u></span></p>
<div style="border-right:none;border-bottom:none;border-left:none;border-top:1pt solid rgb(225,225,225);padding:3pt 0cm 0cm"><p class="MsoNormal"><b><span style="font-size:11pt;font-family:Calibri,sans-serif">Von:</span></b><span style="font-size:11pt;font-family:Calibri,sans-serif"> Users <<a href="mailto:users-bounces@lists.opensips.org" target="_blank">users-bounces@lists.opensips.org</a>>
<b>Im Auftrag von </b>Johan De Clercq<br>
<b>Gesendet:</b> Donnerstag, 13. November 2025 16:29<br>
<b>An:</b> <a href="mailto:gmaruzz@opentelecom.it" target="_blank">gmaruzz@opentelecom.it</a>; OpenSIPS users mailling list <<a href="mailto:users@lists.opensips.org" target="_blank">users@lists.opensips.org</a>><br>
<b>Betreff:</b> Re: [OpenSIPS-Users] 100rel / PRACK Interworking<u></u><u></u></span></p>
</div><p class="MsoNormal"><u></u> <u></u></p>
<div><p class="MsoNormal">Giovanni on a side note, what to do with update ? do you handle it locally or do you forward it to your endpoint ? <u></u><u></u></p>
<div><p class="MsoNormal"><u></u> <u></u></p>
</div>
<div><p class="MsoNormal">BR, Johan. <u></u><u></u></p>
</div>
</div><p class="MsoNormal"><u></u> <u></u></p>
<div>
<div><p class="MsoNormal">Op do 13 nov 2025 om 15:54 schreef Giovanni Maruzzelli <<a href="mailto:gmaruzz@gmail.com" target="_blank">gmaruzz@gmail.com</a>>:<u></u><u></u></p>
</div>
<blockquote style="border-top:none;border-right:none;border-bottom:none;border-left:1pt solid rgb(204,204,204);padding:0cm 0cm 0cm 6pt;margin-left:4.8pt;margin-right:0cm">
<div><p class="MsoNormal">Antonio, you may want to update this feature request from Johan: <a href="https://github.com/OpenSIPS/opensips/issues/2076" target="_blank">https://github.com/OpenSIPS/opensips/issues/2076</a><u></u><u></u></p>
</div><p class="MsoNormal"><u></u> <u></u></p>
<div>
<div><p class="MsoNormal">On Thu, Nov 13, 2025 at 3:48<span style="font-family:Arial,sans-serif"> </span>PM Antonios Psaras <<a href="mailto:apsaras@microbase.gr" target="_blank">apsaras@microbase.gr</a>> wrote:<u></u><u></u></p>
</div>
<blockquote style="border-top:none;border-right:none;border-bottom:none;border-left:1pt solid rgb(204,204,204);padding:0cm 0cm 0cm 6pt;margin-left:4.8pt;margin-right:0cm">
<div>
<div>
<div><p class="MsoNormal"><span lang="EN-US">Hello Giovanni<u></u><u></u></span></p><p class="MsoNormal"><span lang="EN-US"> <u></u><u></u></span></p><p class="MsoNormal"><span lang="EN-US">I totally agree with you. PRACK is an endpoint feature. But as you know, working with IMS, and having all kind or end point implementations of sip stack you need
to do the dirty job in the middle for interoperability reasons. Commercial SBC have that feature called 100rel Interworking which can be enabled per Trunk. Hence, if a carrier requires 100rel/PRACK enforcement and the end point does not supporting it, the
function is engaged and handles the PRACK locally.<u></u><u></u></span></p><p class="MsoNormal"><span lang="EN-US"> <u></u><u></u></span></p><p class="MsoNormal"><span lang="EN-US">I will check Bogdan suggestion but in the first read looks like a tmp work around which I am not sure if that can be scaled to few hundreds of CPS that we work
with.<u></u><u></u></span></p><p class="MsoNormal"><span lang="EN-US"> <u></u><u></u></span></p><p class="MsoNormal"><span lang="EN-US">As this is a feature that will be needed for VoLTE/5G/IMS networks my suggestion is to create a module for that.<u></u><u></u></span></p><p class="MsoNormal"><span lang="EN-US"> <u></u><u></u></span></p><p class="MsoNormal"><span lang="EN-US">Regards
<u></u><u></u></span></p><p class="MsoNormal"><span lang="EN-US"> <u></u><u></u></span></p><p class="MsoNormal"><span lang="EN-US"> <u></u><u></u></span></p><p class="MsoNormal"><b><span lang="EN-US">From:</span></b><span lang="EN-US"> Giovanni Maruzzelli <<a href="mailto:gmaruzz@gmail.com" target="_blank">gmaruzz@gmail.com</a>>
<br>
<b>Sent:</b> Πέμπτη, 13 Νοεμβρίου 2025 16:37<br>
<b>To:</b> <a href="mailto:apsaras@microbase.gr" target="_blank">apsaras@microbase.gr</a>; OpenSIPS users mailling list <<a href="mailto:users@lists.opensips.org" target="_blank">users@lists.opensips.org</a>><br>
<b>Subject:</b> Re: [OpenSIPS-Users] 100rel / PRACK Interworking<u></u><u></u></span></p><p class="MsoNormal"><span lang="EN-US"> <u></u><u></u></span></p>
<div>
<pre style="margin-bottom:12pt"><span lang="EN-US"><u></u> <u></u></span></pre>
<pre><span lang="EN-US" style=""> </span><span lang="EN-US"><u></u><u></u></span></pre>
<pre><span lang="EN-US" style="">El 26/02/2024 a las 7:43 a. m., Bogdan-Andrei Iancu escribió:</span><span lang="EN-US"><u></u><u></u></span></pre>
<pre><span lang="EN-US" style="">><i> yes, you can use the b2b_logic (together with b2b_entities) for that, </i></span><span lang="EN-US"><u></u><u></u></span></pre>
<pre><span lang="EN-US" style="">><i> but it may be a too heavy tool for the purpose. Maybe you can try to </i></span><span lang="EN-US"><u></u><u></u></span></pre>
<pre><span lang="EN-US" style="">><i> generate the PRACK from OpenSIPS level by using the t_uac_dlg MI </i></span><span lang="EN-US"><u></u><u></u></span></pre>
<pre><span lang="EN-US" style="">><i> function [1] via the mi_script module [2] - basically to trigger that </i></span><span lang="EN-US"><u></u><u></u></span></pre>
<pre><span lang="EN-US" style="">><i> MI cmd from the onreply_route, when receiving the 180 reply.</i></span><span lang="EN-US"><u></u><u></u></span></pre>
<pre><span lang="EN-US" style="">><i> </i></span><span lang="EN-US"><u></u><u></u></span></pre>
<pre><span lang="EN-US" style="">><i> [1] <a href="https://opensips.org/html/docs/modules/3.4.x/tm.html#mi_t_uac_dlg" target="_blank">https://opensips.org/html/docs/modules/3.4.x/tm.html#mi_t_uac_dlg</a></i></span><span lang="EN-US"><u></u><u></u></span></pre>
<pre><span lang="EN-US" style="">><i> [2] <a href="https://opensips.org/html/docs/modules/3.4.x/mi_script.html#afunc_mi" target="_blank">https://opensips.org/html/docs/modules/3.4.x/mi_script.html#afunc_mi</a> </i></span><span lang="EN-US"><u></u><u></u></span></pre>
<pre><span lang="EN-US" style=""> </span><span lang="EN-US"><u></u><u></u></span></pre>
<pre><span lang="EN-US" style=""> </span><span lang="EN-US"><u></u><u></u></span></pre>
</div><p class="MsoNormal"><span lang="EN-US"> <u></u><u></u></span></p>
<div>
<div><p class="MsoNormal"><span lang="EN-US">On Thu, Nov 13, 2025 at 3:34</span><span lang="EN-US" style="font-family:Arial,sans-serif"> </span><span lang="EN-US">PM Giovanni Maruzzelli <<a href="mailto:gmaruzz@gmail.com" target="_blank">gmaruzz@gmail.com</a>>
wrote:<u></u><u></u></span></p>
</div>
<blockquote style="border-top:none;border-right:none;border-bottom:none;border-left:1pt solid rgb(204,204,204);padding:0cm 0cm 0cm 6pt;margin:5pt 0cm 5pt 4.8pt">
<div>
<div><p class="MsoNormal"><span lang="EN-US"> <u></u><u></u></span></p>
</div>
<div><p class="MsoNormal"><span lang="EN-US"> <u></u><u></u></span></p>
</div><p class="MsoNormal"><span lang="EN-US">eg: <a href="https://lists.opensips.org/pipermail/users/2024-March/047880.html" target="_blank">https://lists.opensips.org/pipermail/users/2024-March/047880.html</a><u></u><u></u></span></p>
<div><p class="MsoNormal"><span lang="EN-US"> <u></u><u></u></span></p>
</div>
<div><p class="MsoNormal"><span lang="EN-US"> <u></u><u></u></span></p>
</div>
</div><p class="MsoNormal"><span lang="EN-US"> <u></u><u></u></span></p>
<div>
<div><p class="MsoNormal"><span lang="EN-US">On Thu, Nov 13, 2025 at 3:27</span><span lang="EN-US" style="font-family:Arial,sans-serif"> </span><span lang="EN-US">PM Giovanni Maruzzelli <<a href="mailto:gmaruzz@gmail.com" target="_blank">gmaruzz@gmail.com</a>>
wrote:<u></u><u></u></span></p>
</div>
<blockquote style="border-top:none;border-right:none;border-bottom:none;border-left:1pt solid rgb(204,204,204);padding:0cm 0cm 0cm 6pt;margin:5pt 0cm 5pt 4.8pt">
<div><p class="MsoNormal"><span lang="EN-US">Hello Antonio,<u></u><u></u></span></p>
<div><p class="MsoNormal"><span lang="EN-US"> <u></u><u></u></span></p>
</div>
<div><p class="MsoNormal"><span lang="EN-US">PRACK is actually an endpoint feature, at the proxy level you can only fake it...<u></u><u></u></span></p>
</div>
<div><p class="MsoNormal"><span lang="EN-US"> <u></u><u></u></span></p>
</div>
<div><p class="MsoNormal"><span lang="EN-US">-giovanni<u></u><u></u></span></p>
</div>
</div><p class="MsoNormal"><span lang="EN-US"> <u></u><u></u></span></p>
<div>
<div><p class="MsoNormal"><span lang="EN-US">On Thu, Nov 13, 2025 at 3:14</span><span lang="EN-US" style="font-family:Arial,sans-serif"> </span><span lang="EN-US">PM Antonios Psaras <<a href="mailto:apsaras@microbase.gr" target="_blank">apsaras@microbase.gr</a>>
wrote:<u></u><u></u></span></p>
</div>
<blockquote style="border-top:none;border-right:none;border-bottom:none;border-left:1pt solid rgb(204,204,204);padding:0cm 0cm 0cm 6pt;margin:5pt 0cm 5pt 4.8pt">
<div>
<div>
<div><p class="MsoNormal"><span lang="EN-US">Dear Team<u></u><u></u></span></p><p class="MsoNormal"><span lang="EN-US"> <u></u><u></u></span></p><p class="MsoNormal"><span lang="EN-US">As many carriers requires 100rel for interoperability reason with IMS, the need for 100rel interworking is mandatory. Is there any solution available to implement
that on OpenSIPs Proxy level?<u></u><u></u></span></p><p class="MsoNormal"><span lang="EN-US"> <u></u><u></u></span></p><p class="MsoNormal"><span lang="EN-US">Regards<u></u><u></u></span></p><p class="MsoNormal"><span lang="EN-US"> <u></u><u></u></span></p><p class="MsoNormal"><span lang="EN-US">Antonis Psaras<u></u><u></u></span></p><p class="MsoNormal"><span lang="EN-US"> <u></u><u></u></span></p><p class="MsoNormal"><span lang="EN-US"> <u></u><u></u></span></p>
</div>
</div><p class="MsoNormal"><span lang="EN-US">_______________________________________________<br>
Users mailing list<br>
<a href="mailto:Users@lists.opensips.org" target="_blank">Users@lists.opensips.org</a><br>
<a href="http://lists.opensips.org/cgi-bin/mailman/listinfo/users" target="_blank">http://lists.opensips.org/cgi-bin/mailman/listinfo/users</a><u></u><u></u></span></p>
</div>
</blockquote>
</div>
<div><p class="MsoNormal"><span lang="EN-US"><br clear="all">
<u></u><u></u></span></p>
</div>
<div><p class="MsoNormal"><span lang="EN-US"> <u></u><u></u></span></p>
</div><p class="MsoNormal"><span lang="EN-US">--
<u></u><u></u></span></p>
<div><p class="MsoNormal" style="margin-bottom:12pt"><span lang="EN-US">Sincerely,<br>
<br>
Giovanni Maruzzelli<br>
OpenTelecom.IT<br>
cell: +39 347 266 56 18<u></u><u></u></span></p>
</div>
</blockquote>
</div>
<div><p class="MsoNormal"><span lang="EN-US"><br clear="all">
<u></u><u></u></span></p>
</div>
<div><p class="MsoNormal"><span lang="EN-US"> <u></u><u></u></span></p>
</div><p class="MsoNormal"><span lang="EN-US">--
<u></u><u></u></span></p>
<div><p class="MsoNormal" style="margin-bottom:12pt"><span lang="EN-US">Sincerely,<br>
<br>
Giovanni Maruzzelli<br>
OpenTelecom.IT<br>
cell: +39 347 266 56 18<u></u><u></u></span></p>
</div>
</blockquote>
</div>
<div><p class="MsoNormal"><span lang="EN-US"><br clear="all">
<u></u><u></u></span></p>
</div>
<div><p class="MsoNormal"><span lang="EN-US"> <u></u><u></u></span></p>
</div><p class="MsoNormal"><span lang="EN-US">--
<u></u><u></u></span></p>
<div><p class="MsoNormal" style="margin-bottom:12pt"><span lang="EN-US">Sincerely,<br>
<br>
Giovanni Maruzzelli<br>
OpenTelecom.IT<br>
cell: +39 347 266 56 18<u></u><u></u></span></p>
</div>
</div>
</div>
</div>
</blockquote>
</div>
<div><p class="MsoNormal"><br clear="all">
<u></u><u></u></p>
</div>
<div><p class="MsoNormal"><u></u> <u></u></p>
</div><p class="MsoNormal"><span>-- </span><u></u><u></u></p>
<div><p class="MsoNormal" style="margin-bottom:12pt">Sincerely,<br>
<br>
Giovanni Maruzzelli<br>
OpenTelecom.IT<br>
cell: +39 347 266 56 18<u></u><u></u></p>
</div><p class="MsoNormal">_______________________________________________<br>
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<a href="http://lists.opensips.org/cgi-bin/mailman/listinfo/users" target="_blank">http://lists.opensips.org/cgi-bin/mailman/listinfo/users</a><u></u><u></u></p>
</blockquote>
</div>
</div>
</div>
_______________________________________________<br>
Users mailing list<br>
<a href="mailto:Users@lists.opensips.org" target="_blank">Users@lists.opensips.org</a><br>
<a href="http://lists.opensips.org/cgi-bin/mailman/listinfo/users" rel="noreferrer" target="_blank">http://lists.opensips.org/cgi-bin/mailman/listinfo/users</a><br>
</div></blockquote></div>
_______________________________________________<br>
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</blockquote></div><div><br clear="all"></div><div><br></div><span class="gmail_signature_prefix">-- </span><br><div dir="ltr" class="gmail_signature">Sincerely,<br><br>Giovanni Maruzzelli<br>OpenTelecom.IT<br>cell: +39 347 266 56 18<br><br></div></div>
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