[Asterisk-Users] Dead air on 7960 sip at start of call.

[Sam Tilders]

Hi,

Despite much searching, I can't find anything quite like the problem
we seem to be experiencing with our recently activated asterisk pbx.

Of four people answering several calls per five minutes, I
have reports of the occasional call starting with dead air.

The user picks up the call from the queue, and they can hear that the line
is too quiet. If they start talking, the caller either doesn't
hear them, or only hears the end of the first sentence.

Reports are that this silence at the start of the call lasts
from 4-5 seconds, sometimes over 10 seconds and more rarely over
20 seconds.

After the period of silence the call proceeds with no further problems.

I have taken packet dumps of extended periods, there is nothing consistently
different about the calls with silent start compared to those without the
problem. The SIP INVITE is sent to the phone, the phone rings, and OK's the
call. The RTP stream begins straight away.

I'm using cvs-head as of 2004-06-10, CVS-D2004.06.09.14.00.00, recently
updated from v1-0_stable dated a few weeks before. This problem
existed with both versions.

The phones are Cisco 7960's with SIP image 6.3, the calls are incoming
on an E1 connected to a TE410P. Calls are queued and the phones
statically defined as agents in the queue which has a ringall
strategy. There is no queue announcement played to the answering user.

Asterisk in vvv verbose doesn't log anything different when this occurs.

So, has anyone else heard of something like this? Or have a suggestion
for further investigation?

Cheers.
-- 
-- 
Sam Tilders
sam at jovianprojects.com.au
(Move to Jupiter)