[asterisk-dev] IAX Voice Framing

[Jared Smith]

On Sat, 2010-02-06 at 23:47 +0200, Stephen Davies wrote:
> Iax can already do this.  Just enable trunking and increase trunkfreq
> to 40 or 60 msec or more.

I'm not sure that's quite true.  I remember back in the good ol' days
when I came up with IAX2 trunking, that John Todd did some testing on it
with the ILBC codec, which defaults to 30ms between packets, and he
couldn't get the actual bandwidth to match his calculations.  I did a
bit of digging myself, and With IAX2 trunking turned on and trunkfreq
set to 20ms, we found that you'd see one packet sent in the trunk, and
then the next packet sent outside the trunk, and then the next packet
sent as part of the trunk again, etc.

I'm guessing the same might happen if you had incoming audio packets
arriving at 20ms and trunkfreq set to 40ms... that every other audio
packet would be put in the trunk, and that the other ones might be sent
outside the trunk.  You'd have to lab this up to make sure, though.

--
Jared Smith
Digium, Inc.