02-09-2018 01:00 PM - edited 03-17-2019 12:09 PM
Hi,
We are troubleshooting some DTMF relay issues. The provider does RFC2833 (inband). The dial-peers on the VG facing CUCM and the provider are set to use rtp-nte and the SIP trunk in CUCM is set to use RFC2833. The Cisco traces and CUBE debugs all show negotiation of rtp-nte and inband but sometimes it works and DTMF digits are recognized by the remote party and sometimes they are not. Since RFC2833 is inband and I don’t see any discrepancies in the logs and traces, why is it not always working? Any assistance would be greatly appreciated.
The call flow is the following – IP phone --> CUCM SIP trunk --> CUBE --> ASA --> SIP provider
We have disabled SIP inspection on the firewall and modified the SIP headers on the CUBE to present the NAT address of the CUBE to the provider and the private IP of the CUBE to CUCM. The attached are excerpts from the CUCM traces and CUBE debugs that I have extracted and highlighted the pertinent information for you that show the proper DTMF negotiation between all points. In this particular case, the DTMF was finally recognized after placing a number of calls when it wasn’t and the debugs before this call all showed the same results. The only difference with this call was that the caller didn’t have it on speaker phone. When it was on speaker though the DTMF digits were not recognized. The outputs are the same for all calls made but sometimes it works and sometimes it doesn’t.
02-09-2018 01:14 PM
02-10-2018 09:06 AM
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