Signal SIP server to trigger SIP INFO DTMF

[farmorg]

Hi

As the subject says, I'd like a way to instruct a SIP server (OpenSIPS/Kamailio) to generate SIP INFO messages when RFC2833/4733 events are received. I know INFO is not an accepted method but I am working on a project that requires it. As it stands I will need to put in an Asterisk server to translate between RFC2833 and INFO. This feature would remove that requirement completly.

Is this something that could be done?

Many thanks for reading.

[rfuchs]

This is a bit more complicated than it might seem. Triggering an event when an RFC DTMF packet is received is not a big problem, but converting that into a SIP INFO would also require 1) an asynchronous callback mechanism to the SIP proxy, which is something we currently don't have at all, and 2) the SIP proxy then generating a SIP request, which is also not something that it normally does and would require tying this into an UAC module or some such. I'm afraid that for now this is out of scope for us.

[farmorg]

Thanks for your reply.

Is there a way to record the request for review at a more appropriate time?

[digipigeon]

I think that it would be enormously useful to have SIP INFO <->RFC2833/4733, but I understand that this would be on a longer roadmap, especially as a there would need to be a new method of pushing an event back up to OpenSIPs / Kamailio.

To break into this, what would the feasibility be of initially just generating a RFC2833/4733 packet from an OpenSIPs / Kamailio command sent to RTPEngine.

[rfuchs]

That would be relatively easy as it would only require injecting a generated packet into the outgoing RTP stream, plus possibly blocking a few that would cause seq/TS collisions. It would probably require renumbering all future outgoing RTP sequence numbers.

[mirackle-spb]

any movement with this feature?