[asterisk-dev] 13.24.1 / PJSIP: early media via 180 Ringing containing SDP is ignored

Joshua C. Colp jcolp at digium.com
Thu Jan 24 05:08:35 CST 2019

On Thu, Jan 24, 2019, at 7:00 AM, Michael Maier wrote:
> Hello!
> Given is an outbound call to a callee via asterisk to the ISP. After 
> INVITE, the ISP sends 100 Trying and some time later 180 Ringing *w/* 
> SDP and the header
> "P-Early-Media: sendonly" (no 183 or any other thing until callee 
> responds). SDP in 180 contains media attribute *sendrecv* 
> (contradicting to the P-Early-Media header).
> Asterisk 13.24.1 sends PRACK to the ISP (w/o SDP) and the 180 to the 
> caller - but SDP is dropped and therefor no early media is possible!
> Is this behavior a bug or a feature?

It would be a bug. That's not a scenario that I think anyone has really tested or fully scoped out. Is media actually received while in the 180 with Ringing stage?

Joshua C. Colp
Digium - A Sangoma Company | Senior Software Developer
445 Jan Davis Drive NW - Huntsville, AL 35806 - US
Check us out at: www.digium.com & www.asterisk.org

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