I'm in a bit of a jam. I've got a carrier that only supports sending either rfc2833 or plain g711u inband. I've been told from the uccx TAC that the only dtmf methods supported on uccx are a subscribe/notify model like RFC6665 ('dtmf-relay sip-notify' in a cube or other cisco mg) or KPML Events (like RFC4730, 'dtmf-relay sip-kpml' in a cube/mg).
As far as I know, our SBC (an acme netnet 3820) can only translate rfc2833 events to SIP INFO events. I've got a support case open with them just to confirm, but my expectations are low.
It looks like my only option is to use an MTP on that carrier's trunk in cucm.. But that's not very appealing from a survivability standpoint.
Does anyone here have any experience running into this? Do you have any other workaround suggestions that don't involve me buying a cube or switching carriers ?
Turns out Acme added an option called "kpml-interworking" in scx 6.4.x (we happen to be running a version behind). Looks like I can upgrade and enable kpml-interworking on the sip-interface for callmanager.. then we should be okay.
The session-agent(s) and sip-interface that were associated with cucm were changed to kpml-interworking enabled. kpml-interworking was set to disabled on the SA/SI sides facing our carrier, and rfc2833-mode on that SA was set to preferred.
I also turned on translate-non-rfc2833-events in the media-manager just for good measure, but toggling it doesn't seem to make any difiference.. so I might end up turning that back off.
Either way, I'm working now without an MTP, using rfc2833->KPML events
That is awesome information. Thank you for taking the time to research and post the results.
EDIT: I just realized this would solve the UCCE Mobile Agent (OOB DTMF) -> SIP PSTN (RFC2833) MTP requirement as well. Double thanks! (I will be testing and validating of course )
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