[asterisk-users] Asterisk 11- Answer with [m=image 0 udptl t38] and Call Drop

[Matthew Jordan]

On 01/18/2013 05:37 AM, Salman Zafar wrote:

> No luck so far, should I consider it a bug in Asterisk 11 as I have
> tried different version of Asterisk 11 as well. Carrier sends BYE with
> service not implemented where as asterisk advertise udptl in  SDP for
> Answer. I do not want it to be advertised by Asterisk 11 in Answer() as
> I am not using it(udptl, fax etc) in any case.
>
>

It is not a bug in Asterisk. Asterisk is following what the RFC says it
MUST do. It is, however, a bug with your carrier. I would do the following:

1) Contact your carrier and ask why they are rejecting the 200 OK.

2) Assuming they won't change their behaviour, find out what they want
in a response that declines an image media format. Without knowing what
your carrier thinks the SDP should look like, any modifications you make
to Asterisk will be guesses.

3) When you find out what they want, modify chan_sip so that it answers
back with whatever they told you they want. This will occur in
chan_sip's add_sdp method - in particular, look for the portion where
add_sdp adds *either* the m_modem/a_modem strings to the SDP *or* the
pre-formatted decline_m_line.

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