[asterisk-users] Movistar sip Mexico

Andreas Sikkema h323 at ramdyne.nl
Sat Nov 23 05:15:13 CST 2013

On 20/11/13 20:32 , Damian Gonzalez wrote:
> I have a problem with movistar in Mexico with a sip calls. Movistar send
> to me T38 and G729 in the INVITE and they say that I have to ignore T38
> and use G729 in the voice call.

I have had the same problem with a carrier, where some calls we receive
from them have an image and an audio stream in the initial INVITE, even
though the call is intended to use the audio stream. Responding back
accepting T.38 will fail and *all* other options trying to reject the
T.38 using known SIP supported methods will also fail. The *only* option
is to just ignore the image stream, which is not allowed by the current
set of SIP RFCs...

Asterisk used to ignore the image stream, but since the 1.8(?) timeframe
its behaviour has changed more towards standards compliance in this
area. And now we're between a rock and a hard place.

The only way out that I could find is to put something in front of
Asterisk that just removes the image stream from initial INVITEs when
received from the carrier. (OpenSIPS has this nice method called
remove_stream() since a couple of versions)

Complaining about this didn't help, "Asterisk is not certified because
Open Source", was basically their answer.

Andreas Sikkema

More information about the asterisk-users mailing list