[Asterisk-Users] Maximum tollerable lag/jitter for IAX2 w/oji tterbuffer enabled?

[Kris Boutilier]

Collecting debug today - got 8mb so far. Just turned up IAX2 debug so
expecting it to balloon.

There is no NAT involved, nor stateful firewalling etc. - this is a flat
10.0.0.0/24 subnet with one 10base-t hub and two 10base-t cable modems
(operating peer to peer) in between the endpoints. Bitrate is proven out at
not less than 512kbps using Iperf (http://dast.nlanr.net/Projects/Iperf/).
Jitter buffer, trunking and now native bridging (notransfer) code has been
intentionally disabled to reduce possible culprits. Hosts are running a load
average of between 0.00 and 0.02.

The call drop issue has been very sporadic and effectively unreproducable
from a testing perspective. At the moment I'm leaning in the direction of an
IAX2 ACK packet being dropped off the network - I've noticed about 0.5%
collisions on the wire (this being a half-duplex network) which seems to be
contributing to audible pops and clicks with the jitter buffer disabled. 

I've also been getting occasional reports of far end echo on long distance
calls, but I suspect the ongoing thread about 'Question on echo's for
Canadian Asterisk users...' will get to the bottom of that one.

Does anyone know how robust/agressive the UDP retry code is in Asterisk?

> -----Original Message-----
> From: steve at daviesfam.org [mailto:steve at daviesfam.org]
> Sent: September 8, 2004 3:02 AM
> To: Asterisk Users Mailing List - Non-Commercial Discussion
> Cc: 'Chris Shaw'
> Subject: RE: [Asterisk-Users] Maximum tollerable lag/jitter for IAX2
> w/oji tterbuffer enabled?
> 
> On Tue, 7 Sep 2004, Kris Boutilier wrote:
> 
{clip}
> 
> 
> Run Asterisk with debugging turned on - see my various posts here 
> explaining how to capture it all in /var/log/asterisk/debug.  
> That will reveal all.
> 
> But I suspect you got some NAT between the end points, and 
> that NAT is messing up and breaking the communications?
> 
> Steve
>