[OpenSIPS-Users] double sdp.

Johan De Clercq Johan at democon.be
Tue Oct 19 06:38:42 EST 2021

Jeff, I think that I should call only once rtpengine_offer (then the sdp is
But I forgot to mention that the port that the A side sees should not
change meaning that whatever I respond on the received 183 should remain
the same on the 200 OK.
Therefore I wonder, if the fix wouldn't be to call only rtpengine_answer a
second time upon receiving the 200 OK from C.

Anyway, I will test that tomorrow morning and come back on this.


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*Van:* Users <users-bounces at lists.opensips.org> namens Jeff Pyle <
jeff at ugnd.org>
*Verzonden:* Monday, October 18, 2021 11:50:22 PM
*Aan:* OpenSIPS users mailling list <users at lists.opensips.org>
*Onderwerp:* Re: [OpenSIPS-Users] double sdp.


To avoid problems like this, I call rtpengine_offer() in branch_route on
initial invites, and make sure to call rtpengine_delete() in any failure
route to remove any session from a failed offer that was never used.
Perhaps these will help in your situation as well.

- Jeff

On Mon, Oct 18, 2021 at 11:37 AM Johan De Clercq <Johan at democon.be> wrote:


A and B are on the same proxy.

A calls B,
    (as I need transcoding I need to call rtpengine_offer here)
B returns 183 with SDP.
     (this implies calling rtpengine_answer in onreply_route)
 B lets the call time out
On the proxy I intercept the 480 returned by B
and I change the INVITE so that it point to SEMS
      (this ismplies calling rtpengine_offer again)

Issue: when you call 2x rtpengine_offer, you end up with a double sdp body.

how can I instruct opensips to overwrite the body instead of appending one

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