[asterisk-users] Diagnosing dropped calls...

[Carlos Chavez]

	My customer has a 10mpbs fiber connection to the Internet so we have
always assumed that the connection is not really a problem.  We will
look into it.  Thank you.

On Thu, 2008-07-10 at 17:49 -0500, John Faubion wrote:
> > -----Original Message-----
> > Subject: [asterisk-users] Diagnosing dropped calls...
> > 
> > 	I have a system that is driving me nuts.  My customer 
> > is running Asterisk 1.4.20.1 on a CentOS 5.2 server.  It is a 
> > purely SIP and IAX2 service with no cards installed and it 
> > uses ztdummy from Zaptel 1.4.11.
> > They use Teliax for calls to the USA and Protel for calls in Mexico.
> > 
> > 	The problem is that users complain that their calls get dropped.
> > Sometimes every few minutes and sometimes after a very long 
> > call over two hours so there is no clear pattern.  There is a 
> 
> I just went through this same scenario. The customer originally using Teliax
> over AT&T DSL. Incoming calls would sometimes have a delay of 1-2 seconds
> before connecting and some would just drop at random intervals. We would
> generally see in the logs that our connection to Teliax would often show
> lagged or unresponsive around the time of the drops. Testing with AT&T
> revealed that the customer was 18,034 feet from the CO so we decided to move
> them to a cable modem from Charter. This was done as it was the only other
> internet provider short of a dedicated T1. Things improved but did not
> completely subside. The delay on answering was becoming the major complaint.
> We decided to try a different provider so an account with Junction Networks
> was added. This eliminated the delay immediately but did not eliminate the
> dropped calls. One of the techs at Teliax told us that the delay was an
> issue caused by Asterisk 1.4 trying to talk with Asterisk 1.4 server. We
> tried their work around but it did not eliminate the delay issue though it
> did reduce the issue. We also had Charter monitor the service for nearly two
> weeks in which time they replaced the modem 4 times and claimed to have
> repaired connectors, replaced repeater nodes and changed other connections
> to no avail. The customer lives and dies by their telephone so we moved them
> to Cbeyond SIP Connect. All of the issues are now gone. The is no delay,
> they some times spend hours at a time on training calls with no issues. I
> also did a bit of testing with the Junction Network account after moving to
> Cbeyond. This was done since we still had money in the account anyway. Again
> no more issues with dropped calls. The key is in an Internet connection that
> is either very clean or supports QoS. The Cbeyond connection seems to have
> both. Obviously we don't have QoS back to Junction but with the cleaner
> connection it doesn't seem to matter. Also if you trying to use a cable
> modem, make sure your using a business class service and not a residential
> service. 
> 
> Also use mtr (mytraceroute) to look at the latency between your server and
> the proxy. Under Charter and AT&T, both of which were business class
> services, the mtr would sometimes show up to 20% packet loss at various
> systems between us and the proxy. Also try different proxies. For us the
> best one was typically either Atlanta or Denver. Keep in mind that I'm not
> bashing Teliax or Junction. I use both Teliax at home and Junction in our
> office, over a cable modem provided by Time Warner and the only issue I have
> is the occasional delay on answer with Teliax. However that one is the home
> line and the delay seems to work great for telemarketers. 
> 
> John
> 
> 
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Director de Tecnología
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