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DTMF is working but"show voip rtp session named-event" shows no output

ilyas.safarov
Level 1
Level 1

Hi All,

 

I've faced with a situation when I call our number from PSTN DTMF is working but "show voip rtp session named-event" shows no output.

 

INVITE SDP received from telco:

 

v=0
o=- 3838370 8411136 IN IP4 x.x.x.x
s=-
c=IN IP4 x.x.x.x
b=AS:0
t=0 0
m=audio 11538 RTP/AVP 8 0 96
b=RR:0
b=RS:0
a=rtpmap:8 PCMA/8000
a=rtpmap:0 PCMU/8000
a=rtpmap:96 telephone-event/8000
a=fmtp:96 0-15
a=ptime:20
a=sendrecv

 

 

Can anyone clarify this for me. Thanks in advance.

1 Accepted Solution

Accepted Solutions

Valeriy Kuznetsov
Cisco Employee
Cisco Employee

There were some architecture changes between ISR G2 and G3, so in G3 (4k) the command "debug voip rtp session named-event" would not generate any output even though everything works fine. 

There's enhancement request for same to be implemented - https://bst.cloudapps.cisco.com/bugsearch/bug/CSCtz60693 

 

To troubleshoot rfc2833/nte dtmf issues the only way to use packet captures.

 

BR,

Valeriy

View solution in original post

3 Replies 3

Check with your service provider regarding which RTP payload code they want for rtp-nte. When I have seen rtp-nte used, the code is generally 101 and not 96.

Maren

Valeriy Kuznetsov
Cisco Employee
Cisco Employee

There were some architecture changes between ISR G2 and G3, so in G3 (4k) the command "debug voip rtp session named-event" would not generate any output even though everything works fine. 

There's enhancement request for same to be implemented - https://bst.cloudapps.cisco.com/bugsearch/bug/CSCtz60693 

 

To troubleshoot rfc2833/nte dtmf issues the only way to use packet captures.

 

BR,

Valeriy

Thank you very much for clarification Valeriy. Very appreciate it.

 

Regards,

Ilyas