[asterisk-bugs] [JIRA] (ASTERISK-28661) chan_iax jitterbuffer growing when time sources not in sync

[Kevin Harwell (JIRA)]

    [ https://issues.asterisk.org/jira/browse/ASTERISK-28661?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=249234#comment-249234 ] 

Kevin Harwell commented on ASTERISK-28661:
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[~ktyerman] We're going to open this issue, but want to set some expectations.

I believe this issue could be interpreted as an improvement. I think it falls more under the "Bad timestamps" category where the sender is sending bad data. That said according to the wiki [1] we could be a bit more robust in handling these types of situations. So really this issue kind of spans the border of bug and improvement.

Not sure of a good workaround at this time. Perhaps lowering the _maxjitterbuffer_ size a bit?

Just a note too, but in my testing if I slewed the clock more than a few seconds the buffer would automatically resync and the problem did not occur. So the window for this isn't large.

[1] https://wiki.asterisk.org/wiki/display/AST/IAX2+Jitterbuffer

> chan_iax jitterbuffer growing when time sources not in sync
> -----------------------------------------------------------
>
>                 Key: ASTERISK-28661
>                 URL: https://issues.asterisk.org/jira/browse/ASTERISK-28661
>             Project: Asterisk
>          Issue Type: Bug
>      Security Level: None
>          Components: Channels/chan_iax2
>    Affects Versions: 16.4.0
>            Reporter: Kirsty Tyerman
>            Assignee: Unassigned
>         Attachments: adjust_clock.sh, debug_log_28661, iax2_show_channels.txt, iax.conf
>
>
> I have two asterisk servers, Server A and Server B. These two servers are peered via IAX. When I make a call between Server A and Server B I am experiencing poor audio quality and the jitter buffer on one end is continuously growing. 
> Server A's time is approximatley 10 minutes behind Server B.
> I have a PJSIP client registered to Server B call a PJSIP client registered to Server A. The call is established via IAX between Server A and Server B.
> I have the IAX jitter buffers enabled on both Server A and Server B with trunktimestamps=yes.
> When I establish the call, the "iax2 show channels" on Server A (date is behind) shows the "JitBuf" constantly growing. The max jitter buffer is 4000ms. It seems as though the jitter buffer is not handling the system clock being wrong when it should rely on the trunk timestamps that is relative to iax and disregard any system clocks.



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