[SR-Users] Peculiar Kamailio Asterisk behavior on outbound calls

Wilkins, Steve swwilkins at mitre.org
Fri Jun 8 15:08:41 CEST 2018

Yes, for example a WebRTC Client (VP8) calls a Soft-Phone (H264).  What is strange is that if it is the other way around and the Soft-Phone calls the WebRTC client, it works.

Thank you

From: sr-users [mailto:sr-users-bounces at lists.kamailio.org] On Behalf Of Pan Christensen
Sent: Friday, June 8, 2018 9:00 AM
To: Kamailio (SER) - Users Mailing List <sr-users at lists.kamailio.org>
Subject: Re: [SR-Users] Peculiar Kamailio Asterisk behavior on outbound calls

Hello Steve.

Does Asterisk negotiate different codecs with each client? If so, it needs to transcode, which I believe is currently not supported for video. What does Asterisk send back to device A?

With kind regards
Pan B. Christensen
Phonect AS

From: sr-users <sr-users-bounces at lists.kamailio.org<mailto:sr-users-bounces at lists.kamailio.org>> On Behalf Of Wilkins, Steve
Sent: fredag 8. juni 2018 14:03
To: Kamailio (SER) - Users Mailing List <sr-users at lists.kamailio.org<mailto:sr-users at lists.kamailio.org>>
Subject: [SR-Users] Peculiar Kamailio Asterisk behavior on outbound calls

Hi All,

Issue: when a Call is made through Kamailio and Asterisk.  Asterisk uses incorrect Video RTP Payload Type when sending Video packets.

I have a situation where I make a call from Device A to Device B and Device A is Registered in Kamailio.  When Device A Calls Device B, Kamailio sends an 'INVITE' to Asterisk, Asterisk then  'INVITES' Device B.  I get two-way Audio, the call stays connected, however, when Video packets are sent to Device B, the RTP Payload Type is incorrect.  The port is correct, but just not the Payload Type.

Here is where I think Kamailio is involved. In the first Invite from Kamailio to Asterisk, one of the offered Video codecs is '100 H264'; interesting enough, Device B wants to use '115 H264' and when Asterisk sends out Video packets, it is using '100' instead of '115', and of course I have no Video.  I don't know if this is just a coincidence but it sure seems like that is where the issue may lie.

Has anyone ever seen this behavior?  The Asterisk teams does not think it's an Asterisk issue.

Thank you,
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.kamailio.org/pipermail/sr-users/attachments/20180608/6e37943c/attachment.html>

More information about the sr-users mailing list