[SR-Users] Ideas to reject a call due to RTPEngine failure when handling the 200Ok

Alex Balashov abalashov at evaristesys.com
Thu Jan 23 23:16:10 CET 2020

If the RTPEngine fails to answer the offer or answer command, the SDP
will be left unmodified. 

But of course, that will not result in a proper media path.

On Fri, Jan 24, 2020 at 09:01:25AM +1100, Patrick Wakano wrote:

> Hello list,
> Hope you all doing well!
> I have a setup of Kamailio + RTPEngine (so no B2BUA), and I've come to a
> situation which I can't really figure out the best decision.....
> The case is a late SDP negotiation that the 200Ok with the SDP offer fails
> to engage the RTPEngine (for example no RTPEngine available). Also, the
> same problem can happen with a normal SDP negotiation, in case the INVITE
> goes through normally but then when engaging the SDP answer for the 200Ok,
> the RTPengine answer request fails for any reason...
> In these cases, I can't generate a proper SDP for the 200OOk so the call
> will connect normally, but the media path will be broken...
> So for such cases, I am thinking it is reasonable to fail the call.
> However, failing a call during the 200Ok stage is tricky, at this point we
> can't convert the 200Ok to a 50X. I tried and Kamailio doesn't allow and
> also RFC wise this is a no no for a SIP proxy....
> I could completely remove the SDP body and forward the 200Ok. This will
> force a failed SDP negotiation and leave it for the endpoints the task to
> terminate the call. Is that acceptable? Has anyone faced such situation?
> Any idea is much appreciated!
> Kind regards,
> Patrick Wakano

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Alex Balashov | Principal | Evariste Systems LLC

Tel: +1-706-510-6800 / +1-800-250-5920 (toll-free) 
Web: http://www.evaristesys.com/, http://www.csrpswitch.com/

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