IOS XE debug for RFC2833 DTMF not working

[gevander1]

Hello, 

I just replaced some older ISR with a new 4331 running following IOS-XE image: isr4300-universalk9.03.16.04b.S.155-3.S4b-ext.SPA.bin. 

I see in the debug ccsip messages that RFC2833 is correctly negotiated for DTMF between my device & the SIP-trunk provider, but when I try to see this via "debug voip rtp sess named" I don't see anything when pressing DTMF digits. 

Negotiated SDP: 

 m=audio 8084 RTP/AVP 8 101
 c=IN IP4 19.165.102.161
 a=rtpmap:8 PCMA/8000
 a=rtpmap:101 telephone-event/8000
 a=fmtp:101 0-15
 a=ptime:20

Is there something else to do on IOS-XE to see the PT 101 / DTMF digits in the debug output - if not has somebody else experienced this ?
Thx,
GP

[Mohammed al Baqari]

Hi,

During active call, get the output of the following "show call act voice |
i Dtmf". This will confirm the method used.

Also, make sure that your term monitor is enabled and your monitor logging
is set to debug

[gevander1]

Thanks Mohammed for your feedback. The show call active voice shows indeed it's using RFC2833/RTP-NTE (+5) also, so that looks OK and I suppose it's working fine.

I have indeed term mon / show logging activated and all looks fine with any other debugs I'm capturing, only this one doesn't want to come through. Still find it weird ... 

Gert

[Emmanuel Akum]

Hi Mohammed,

Which command is to be used on an IOS-XE platform to see the actual events, when the caller is hitting the keys/ choosing a menu option? debug voip rtp session named-event doesn't seem to work on the IOS-XE platforms? 

[rchaseling]

Ever find out if debugging this on IOS-XE is possible without packet capture?

[tattospick]

Me while negotiating RFC2833 for DTMF with my SIP trunk provider seems successful according to "debug ccsip messages," I'm encountering a peculiar challenge when attempting to debug VoIP RTP sessions. Despite the negotiated SDP showing support for DTMF events (PT 101), the expected information isn't appearing in the debug output. I've tried various debug commands, including "debug voip rtp sess named" and "debug voip rtp sess named detail," yet I'm not seeing the details of DTMF events when pressing digits.

[rchaseling]

Yeah I'm not sure how to get the debugs for it now. I've resorted to taking packet captures to check RFC2833