DTMF-Relay Info-Packagedraft-kaplan-dispatch-info-dtmf-package-00
Hadriel Kaplan
Terminology/Definitions
• DTMF: Dual-Tone Multi-Frequency (tones)• KPML: Key-Press Markup Language (RFC 4730)• Hadriel: the messenger (don’t shoot)
The Problem
• DTMF is just like other media:– It has to work
• And like media, there is no one global “codec”– 2833/4733, INFO, KPML, Notify-1, Notify-2
• The DTMF world isn’t what we hoped it would be – it has not converged on one solution– It has to be “negotiated”
Why isn’t the World perfect?
• DTMF needs to go the signaling path sometimes– SIP applications (calling card, IVR, etc.)– SIP to H.323/BICC/ISUP/etc.
• Didn’t we solve this with KPML?– YES!!!– It’s the greatest solution ever devised! We’re
geniuses!– But some pesky, horrible people seem to ignore us
What’s wrong with KPML?
• Nothing. It’s just not that popular• Why?– Some systems prefer not to create two
subscriptions for every call just in case someone presses a button someday
– What they have “works” right now, so why fix it?– This is just a button press – why make it more
complicated than that?– Lowest-common-denominator usually wins
What else is there?
• INFO– At least 2 flavors: “dtmf-relay” is the big one– 3GPP has something too (but not really for this)
• NOTIFY– At least 3 flavors, but not as popular– One flavor actually sends 2833 packets as its
payload! (yes, each 2833 packet… so many, many Notify’s)
The Proposed Solution
• Let the Wookie win: “standardize” the popular INFO one– It’s really, really simple (and it works)
• Three ways to do that:1. Publish an A-D sponsored RFC2. Publish an individual RFC (non-IETF)3. Publish an Info-Package• That was why we actually did Info-Packages, after all
• Current draft picks #3
Will this succeed?
• If we do an Info-Package for dtmf-relay would vendors go do that, vs. just legacy INFO?– I Dunno
• Most of our issues/concerns with INFO never really applied to dtmf-relay
• The Mime type was unique• The purpose of the INFO was unambiguous• The “negotiation” could be done with Accept headerNo problem to solve here, move along…
Options
• I am not advocating a new mini-WG for this– Though I do have an acronym:
Common Info Dtmf-Event-Relay (CIDER)• We could just ignore the whole topic– That hasn’t made it go away
Any Opinions?