[asterisk-users] Asterisk uses 3 seconds to send ACK after OK

[Matthew Jordan]

On 03/15/2013 09:21 AM, Pan B. Christensen wrote:
> Hello!
>  
> We recently upgraded one of our customers from 1.4.44 to 1.8.15-cert1.
> We have several other customers running both versions.
> The customer in question does not use us as their provider as they’re
> located in a different country.
>  
> When they make outgoing calls, there is a 3 second delay between
> answering the call and the call being established. When debugging this,
> I found that Asterisk waits 3 seconds after receiving 200 OK before
> returning the ACK. See attached image. There’s no verbose output in the
> CLI during this time. I turned on full debugging. This seems to produce
> around a hundred lines of debug per second until suddenly I see a full 3
> seconds stop just before sending the ACK.
>  
<snip>
>  
> Could it be a parsing issue because the Record-Route header doesn’t
> include a port?
>  
> With kind regards,
> Pan
>  

Taking a look at the DEBUG statements that are associated with the
thread processing the SIP response:

[Mar 15 13:16:05] DEBUG[27947] netsock2.c: Splitting 'FQDNz:5060' into...
[Mar 15 13:16:05] DEBUG[27947] netsock2.c: ...host 'FQDNz' and port '5060'.
[Mar 15 13:16:08] DEBUG[27947] netsock2.c: Splitting 'yyy.yyy.yyy.yyy'
 into...
[Mar 15 13:16:08] DEBUG[27947] netsock2.c: ...host 'yyy.yyy.yyy.yyy' and
 port ''.
[Mar 15 13:16:08] VERBOSE[27947] chan_sip.c: [Mar 15 13:16:08]
 Transmitting (no NAT) to yyy.yyy.yyy.yyy:5060:
 ACK sip:004741888800 at FQDNz:5060 SIP/2.0

If I had to guess, the DNS resolution of 'FQDNz' probably took 3
seconds. You may want to consider a local DNS cache to help speed up
results.

Matt

-- 
Matthew Jordan
Digium, Inc. | Engineering Manager
445 Jan Davis Drive NW - Huntsville, AL 35806 - USA
Check us out at: http://digium.com & http://asterisk.org