[Spce-user] Weird situation with End2End ACKs from a carrier

Raúl Alexis Betancor Santana rabs at dimension-virtual.com
Tue Mar 10 08:54:31 EDT 2020

I'll try and report back.

I was puzzled that it only happens with one carrier and on that random way.

Also, if the uac functions are not used on the kamailio script ... why to define their params ?

----- Original Message -----
From: "Andrew Pogrebennyk" <apogrebennyk at sipwise.com>
To: "Raúl Alexis Betancor Santana" <rabs at dimension-virtual.com>, "spce-user" <spce-user at lists.sipwise.com>
Sent: Tuesday, March 10, 2020 8:38:53 AM
Subject: Re: [Spce-user] Weird situation with End2End ACKs from a carrier

On 3/9/20 11:13 AM, Raúl Alexis Betancor Santana wrote:
> As you could see, the From on the second ACK get weird, also non RFC
> compliant and then sems refuse it and at the end, the call gets dropped.
> I've been trying to figure out what part of the proxy routing script
> it's responsible of this, but didn't find any uac_replace call or
> anything related
> This only happens on a 10:2 basis on the incoming calls ... but get
> people annoyed ... because the hear the the other end and begins their
> conversation and suddendly the call gets dropped.
> Any clue about what could be happening? ... it only happers with this
> USA based carrier, everything else works perfect.
> Its a SPCE mr7.5.3 with the latest patches ... but this happens since we
> upgraded from 5.5.1 to 7.5.3

as a rough guess what if you try to create a customtt for the file
/etc/ngcp-config/templates/etc/kamailio/proxy/kamailio.cfg.tt2 and
change only one parameter, uac restore_mode from auto:
modparam("uac", "restore_mode", "auto")
to none:
modparam("uac", "restore_mode", "none")
Does it help to solve the problem? If this doesn't help we'll need a
full PCAP to analyze.


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