[Asterisk-Dev] Purpose of trunkfreq in iax.conf?

[steve at daviesfam.org]

On Fri, 10 Sep 2004, Kris Boutilier wrote:

> I'm having a call quality problem with iax trunking. Specifically, when
> 'notrunking=no' between hosts I get very choppy/stuttery audio - the
> interference has a regular interval and occurs once or twice a second.
> Others on the list have reported similar problems with CVS code checked out
> since early August but I'm still disinclined to suspect a bug otherwise
> there would have been a flood of reports by now...

You can't currently use trunking and the jitter buffer at the same time.

The current trunking code mangles timestamps in a way that breaks the 
jitter buffer.

> What caught my eye was the setting in /etc/asterisk/iax.conf:
> 
>  trunkfreq=20                   ; How frequently to send trunk msgs (in ms)


trunking basically collects up frames from all the calls going to a 
particular peer, then sends the whole lot off at once in one ip packet 
every "trunkfreq" millisecs.

In principle you can make trunkfreq more (probably best if its a multiple 
of 20msec).  This will make trunking a bit more efficient, in return for 
more call latency.

But - to fix your problem you need to either turn of trunking or turn off 
the jitter buffer.

I'm working to fix this incompatibility at the moment.

Steve