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?