Hi Mikko, AFAIK, RFC 2833/4733 is supported by lot of SIP devices and works well for End-to-End SIP scenario. Even though RFC 4730 exists, I heard that only few implementation supports KPML SUB/NOT mechanism.
As you expect, INFO will not be accepted in IETF but 3GPP IMS spec supports it (overlap signaling). In case your device support 3GPP spec, you may go in INFO way. As your B2BUA device has transcoding facilities, making DTMF interop is little bit simple :-) Regards Partha -----Original Message----- From: sip-implementors-boun...@lists.cs.columbia.edu [mailto:sip-implementors-boun...@lists.cs.columbia.edu] On Behalf Of Mikko Lehto Sent: Monday, January 31, 2011 5:35 AM To: sip-implementors@lists.cs.columbia.edu Subject: [Sip-implementors] Telephony DTMF adaptation Hi I wish things would turnout to be more simple for INFO based events, but it looks like DTMF Info-Package proposal¹ is not² going³ to fly. With INFO mess, few NOTIFY event mechanisms, RFC 2833/4733 and RFC 4730 in mind, what do you think is the best practice for maximun interoperability? I have started to lean towards optional transcoding with B2BUA (invoked by proxy layer when incompatible DTMF capability is known between caller and callee). In PSTN gateway service or PSTN emulating service I think just RFC 2833/4733 can be considered natural choice (due to stable recommendation and implementations + typically there is always managed media device on the path). But what about full end-to-end SIP scenarios where nobody wants to have excess hops in media path? [1] http://www.ietf.org/id/draft-kaplan-dispatch-info-dtmf-package http://www.ietf.org/proceedings/79/slides/dispatch-2.ppt [2] http://www.ietf.org/mail-archive/web/dispatch/current/msg02494.html [3] http://www.ietf.org/proceedings/79/minutes/dispatch.html -- Mikko Lehto _______________________________________________ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors _______________________________________________ Sip-implementors mailing list Sip-implementors@lists.cs.columbia.edu https://lists.cs.columbia.edu/cucslists/listinfo/sip-implementors
