[asterisk-bugs] [JIRA] (ASTERISK-28828) NOTIFY sequence upsets MS Teams SIP trunk

[lvl (JIRA)]

    [ https://issues.asterisk.org/jira/browse/ASTERISK-28828?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=250322#comment-250322 ] 

lvl commented on ASTERISK-28828:
--------------------------------

Well, I can see the difference between the two. In the "normal" version, Asterisk immediately sends three NOTIFYs:

* 180 Ringing
* 100 Trying
* 200 OK

In the "reverted" version, only two:

* 180 Ringing
* 100 Trying

That makes somewhat sense, since the patch from ASTERISK-28766 fixes {{refer_progress_framehook}} to allow generating a 200 OK after a previous 100/180. 

The 200 is sent very early though, if the logging's order is correct before the call is even answered/bridged. Seems like it's triggered too early, perhaps by {{if (f->frametype == AST_FRAME_VOICE}} or {{} else if (f->subclass.integer == AST_CONTROL_ANSWER) {}}. You'd have to add some debug statements here and then somebody smarter than me could investigate why :)

Why the trunk gets upset about 3 out-of-sequence NOTIFYs but not about 2, I don't know. You could try if the dialplan "Proceeding()" (in combination with the "regular" version) would fix the issue for you for now.

> NOTIFY sequence upsets MS Teams SIP trunk
> -----------------------------------------
>
>                 Key: ASTERISK-28828
>                 URL: https://issues.asterisk.org/jira/browse/ASTERISK-28828
>             Project: Asterisk
>          Issue Type: Bug
>      Security Level: None
>          Components: Resources/res_pjsip_refer
>    Affects Versions: 17.3.0
>         Environment: Ubuntu 18.04 install from sources
>            Reporter: Carlos Mendioroz
>            Assignee: lvl
>            Severity: Minor
>
> Resuming an on hold call from MS Teams side often results in the call going to limbo. Trace shows out of order NOTIFYs and 500 response to a Trying event.
> On Joshua's advise, rolled back https://gerrit.asterisk.org/c/asterisk/+/13852 and even though the out of order Trying subsists, it does not gerenate a 500 and the call resumes correctly.
> Discussion here:
> https://community.asterisk.org/t/sip-xfers-via-reinvite-refer-and-order-of-notifys/83572



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