[asterisk-users] ignore 183 session progress in parallel call scenarios

[Ishfaq Malik]

On 15 July 2013 15:14, Hristo Trendev <dist.lists at gmail.com> wrote:

> Hi,
> I am using asterisk 1.8.22 and have a problem when calling in parallel
> several SIP endpoints and I am not sure how to resolve it. In this case
> Asterisk will not bridge any audio to the caller before the 200 OK. Which
> means any progress announcements, including remotely generated ringback,
> are not passed back to the caller.
>
> This behavior is completely correct, because there is no way to know which
> early media audio stream to pass back to the caller in a parallel call
> scenario (as in this case several endpoint may indicate session progress
> all at the same time).
>
> The question is why is asterisk still sending 183 session progress back to
> the caller if no audio is to be bridged before the 200 OK anyway? If 183
> are not passed back to the caller, then at least a 180 Ringing that may
> come from another endpoint will cause the calling endpoint to generate
> local ringback. This won't happen if the caller has received a 183 already.
>
> So it's a bit of a race condition as well - if the first endpoint to reply
> sends a "183 session progress" this means the caller will not hear any
> ringback even if some of the other endpoints are sending back 180 Ringing.
>
> The question is can I somehow block 183 messages from being passed back to
> the calling endpoint when dialing several destinations in parallel? I don't
> see a point (please correct me if I'm wrong) to pass only the 183 SIP
> message back to the caller without the corresponding RTP stream, so it may
> be much better to actually ignore it when dealing with parallel call
> scenarios (bug?).
>
> BR,
> Hristo
>
> --
> _____________________________________________________________________
>

I think you need to look into early media and also this application

https://wiki.asterisk.org/wiki/display/AST/Application_Progress



-- 

Ishfaq Malik
Department: VOIP Support
Company: Packnet Limited
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