[Asterisk-Users] IAX crackilng

[Rich Adamson]

> I have a cisco VPN from router to router over a Data T-1. The ping times 
> are consistently 32ms with random ping responses of 295ms -408ms about 
> every 30 secs to a minute, I have jitter buffer enabled. The connection 
> goes like this… Mitel SIP phone to Asterisk A, IAX trunked to Asterisk B 
> and then T-1 to a PBX, the calls are internal so they are terminating on 
> Toshiba digital phones. Loud crackling even happens from time to time 
> when a Mitel SIP phone is connected to Asterisk B at that location over 
> thye LAN with no layer three routing, but it is consistent on the IAX 
> trunk. There is a lot of Data traffic, but thus should work regardless, 
> I don’t think the ping times are the issue.

If I had to troubleshoot the issue, I'd start with using Ethereal to 
"see" what type of traffic was happening every 30 seconds or so (causing 
the erratic ping times).

Then I'd also be looking at 'iax2 show netstats' to see what the jitter, 
delay, and lost packets look like.

If the ethereal packet trace indicates unusual traffic or broadcast 
storms, see if those can be corrected.  Might even try 'fair weighted 
queuing' in the Cisco box to see what impact it may have (attempts to 
provide equal amounts of bandwidth to each session crossing the vpn).