asterisk users - Nov 2005 - IAX2 multiple audio frames per UDP packet?

Hi,

I am wondering if it is possible to tweak IAX2 protocol to packetize audio
data
more efficiently. I would like to try setups where multiple audio frames
(gsm)
are combined into single UDP packet. I know that it will incur delay in
audio
streams but I don't care. Primary concern is to lower bandwidth so that
communication
can go over slow dialup link (33.6kbps).
Also, it looks to me that trunkfreq parameter might be of interest to try.
Am I
on good track? Any  advice/help is appreciated.
Regards,
Branko S.

On Friday 11 November 2005 13:00, Branko Samardzic
wrote:
> I am wondering if it is possible to tweak IAX2 protocol to packetize audio
> data
> more efficiently. I would like to try setups where multiple audio frames
> (gsm)
> are combined into single UDP packet. I know that it will incur delay in
> audio
> streams but I don't care. Primary concern is to lower bandwidth so that
> communication
> can go over slow dialup link (33.6kbps).
Take a look at IAX2 trunking, this is *exactly* what it's for.
> Also, it looks to me that trunkfreq parameter might be of interest to try.
> Am I
> on good track? Any  advice/help is appreciated.
Trunking frequency won't do a thing for you.  Take a look at the IAX2 spec
and
poke through the code a little if you like.  Please note that IAX2 trunking 
in the 1.0.x series is ... iffy.  CVS HEAD and 1.2.x trunking should be much, 
much better.

-A.

Hi Andrew,

thanks for your prompt response. However, I am not sure whether IAX trunking
can be of any benefit on 33.6kbps link. It shows significant bandwith
reduction
on 2 and more simultaneous calls. My question relates to single call over
such
link.
Current measurement say that gsm call consumes approx 32kbps in each
direction.
So, there is no question that single call is only possibility for such link.

I was able to tweak some old H323 implementations to consume far less
bandwith
by grouping 2 or more audio frames into single UDP packet (at the cost of
additional
delay and bigger jitter buffer). My question is related to this matter.
Is it possible to force Asterisk to package multiple audio frames in single
UDP
packet even in case of single IAX call. If that is the case then some
overhead
can be prevented thus enabling conversations even over such a slow link.
Regards,
Branko S.

How about you stop pulling your hair out and let me send you one of the  
56k modems I have sitting on my desk.  heh

On Fri, 11 Nov 2005 13:00:15 -0500, Branko Samardzic  
<branko_samardzic@rogers.com> wrote:
> Hi,
>
> I am wondering if it is possible to tweak IAX2 protocol to packetize  
> audio
> data
> more efficiently. I would like to try setups where multiple audio frames
> (gsm)
> are combined into single UDP packet. I know that it will incur delay in
> audio
> streams but I don't care. Primary concern is to lower bandwidth so that
> communication
> can go over slow dialup link (33.6kbps).
> Also, it looks to me that trunkfreq parameter might be of interest to  
> try.
> Am I
> on good track? Any  advice/help is appreciated.
> Regards,
> Branko S.
>
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